research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 72| Part 5| May 2016| Pages 741-746

Crystal structures of tetra­methyl­ammonium (2,2′-bi­pyridine)­tetra­cyanidoferrate(III) trihydrate and poly[[(2,2′-bi­pyridine-κ2N,N′)di-μ2-cyanido-dicyanido(μ-ethyl­enedi­amine)(ethyl­enedi­amine-κ2N,N′)­cadmium(II)iron(II)] monohydrate]

CROSSMARK_Color_square_no_text.svg

aDepartment of Chemistry, Faculty of Science and Research Center for Academic Excellence in Petroleum, Petrochemical and Advanced Materials, Naresuan University, Muang, Phitsanulok, 65000, Thailand, bNational Nanotechnology Center, National Science and Technology Development Agency, Khlong Luang, Pathum Thani, 12120, Thailand, and cDepartment of Physics, Faculty of Science and Technology, Thammasat University, Khlong Luang, Pathum Thani, 12120, Thailand
*Correspondence e-mail: kc@tu.ac.th

Edited by R. F. Baggio, Comisión Nacional de Energía Atómica, Argentina (Received 11 April 2016; accepted 22 April 2016; online 29 April 2016)

The crystal structures of the building block tetra­methyl­ammonium (2,2′-bi­pyridine-κ2N,N′)tetra­cyanidoferrate(III) trihydrate, [N(CH3)4][Fe(CN)4(C10H8N2)]·3H2O, (I), and a new two-dimensional cyanide-bridged bimetallic coordination polymer, poly[[(2,2′-bi­pyridine-κ2N,N′)di-μ2-cyanido-dicyanido(μ-ethyl­enedi­amine-κ2N:N′)(ethyl­enedi­amine-κ2N,N′)cadmium(II)iron(II)] monohydrate], [CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O, (II), are reported. In the crystal of (I), pairs of [Fe(2,2′-bipy)(CN)4] units (2,2′-bipy is 2,2′-bi­pyri­dine) are linked together through ππ stacking between the pyridyl rings of the 2,2′-bipy ligands to form a graphite-like structure parallel to the ab plane. The three independent water mol­ecules are hydrogen-bonded alternately with each other, forming a ladder chain structure with R44(8) and R66(12) graph-set ring motifs, while the disordered [N(CH3)4]+ cations lie above and below the water chains, and the packing is stabilized by weak C—H⋯O hydrogen bonds. The water chains are further linked with adjacent sheets into a three-dimensional network via O—H⋯O hydrogen bonds involving the lattice water mol­ecules and the N atoms of terminal cyanide groups of the [Fe(2,2′-bipy)(CN)4] building blocks, forming an R44(12) ring motif. Compound (II) features a two-dimensional {[Fe(2,2′-bipy)(CN)4Cd(en)2]}n layer structure (en is ethyl­enedi­amine) extending parallel to (010) and constructed from {[Fe(2,2′-bipy)(CN)4Cd(en)]}n chains inter­linked by bridging en ligands at the Cd atoms. Classical O—H⋯N and N—H⋯O hydrogen bonds involving the lattice water mol­ecule and N atoms of terminal cyanide groups and the N—H groups of the en ligands are observed within the layers. The layers are further connected via ππ stacking inter­actions between adjacent pyridine rings of the 2,2′-bipy ligands, completing a three-dimensional supra­molecular structure.

1. Chemical context

Over the past several decades, hexa­cyanido­metallate anions, [M(CN)6]n (n = 2–4), have been used extensively as building blocks for the design and construction of a large number of high-dimensional cyanide-bridged bimetallic coordination polymers because of their ability to act as multidentate ligands to link numerous metal atoms through all six cyanide groups (Ohba & Ōkawa, 2000[Ohba, M. & Ōkawa, H. (2000). Coord. Chem. Rev. 198, 313-328.]; Smith et al., 2000[Smith, J. A., Galán-Mascarós, J.-R., Clérac, R. & Dunbar, K. R. (2000). Chem. Commun. pp. 1077-1078.]; Berlinguette et al., 2005[Berlinguette, C. P., Dragulescu-Andrasi, A., Sieber, A., Güdel, H.-U., Achim, C. & Dunbar, K. R. (2005). J. Am. Chem. Soc. 127, 6766-6779.]). The highly insoluble three-dimensional Prussian blue and its more soluble Prussian blue analogues are perhaps the best known examples of this class of compounds, which are obtained by reacting the building block [M(CN)6]3– with octa­hedrally coordinated transition metal ions (Buser et al., 1977[Buser, H. J., Schwarzenbach, D., Petter, W. & Ludi, A. (1977). Inorg. Chem. 16, 2704-2710.]). The inclusion of a bidentate chelating ligand (L) such as 2,2′-bi­pyridine (2,2′-bipy) or 1,10-phenanthroline (1,10-phen) in cyanide-containing building blocks of general formula [M(L)(CN)4]n (n = 2, 3) instead of [M(CN)6]n has been a recent development in the field of low-dimensionality cyanide-bridged bimetallic coordination compounds (Lescouëzec et al., 2001[Lescouëzec, R., Lloret, F., Julve, M., Vaissermann, J., Verdaguer, M., Llusar, R. & Uriel, S. (2001). Inorg. Chem. 40, 2065-2072.]; Laza­rides et al., 2007[Lazarides, T., Easun, T. L., Veyne-Marti, C., Alsindi, W. Z., George, M. W., Deppermann, N., Hunter, C. A., Adams, H. & Ward, M. D. (2007). J. Am. Chem. Soc. 129, 4014-4027.]). The aromatic ligand L does not just block two coordination sites of the central atom, to yield one- and two-dimensional polymeric compounds, but also helps to stabilize the assembly as well as stabilizing the dimensionality of the three-dimensional supra­molecular structures through aromatic ππ stacking inter­actions (Lescouëzec et al., 2002[Lescouëzec, R., Lloret, F., Julve, M., Vaissermann, J. & Verdaguer, M. (2002). Inorg. Chem. 41, 818-826.]; Toma et al., 2004[Toma, L. M., Delgado, F. S., Ruiz-Pérez, C., Carrasco, R., Cano, J., Lloret, F. & Julve, M. (2004). Dalton Trans. pp. 2836-2846.]). It is also known that the non-coordinating nitro­gen atoms of the cyanide groups can act as hydrogen-bond acceptors to self-assemble into various supra­molecular architectures (Xiang et al., 2009[Xiang, H., Wang, S.-J., Jiang, L., Feng, X.-L. & Lu, T.-B. (2009). Eur. J. Inorg. Chem. pp. 2074-2082.]).

[Scheme 1]
[Scheme 2]

As part of our search for novel cyanide-bridged bimetallic coordination polymers, we herein describe the synthesis and crystal structure of [N(CH3)4][Fe(CN)4(C10H8N2)]·3H2O (I)[link] building block and a new two-dimensional cyanide-bridged cadmium–iron(II) bimetallic coordination polymer, [CdFe(CN4)(C10H8N2)(C2H8N2)2]·H2O (II)[link], in which ethylenedi­amine (en) adopts both bridging and chelating coordination modes.

2. Structural commentary

The asymmetric unit of (I) consists of one [Fe(2,2′-bipy)(CN)4] anion, one disordered tetra­methyl­ammonium cation, [N(CH3)4]+ and three water mol­ecules, as displayed in Fig. 1[link]. The FeIII ion is coordinated by two nitro­gen atoms from one 2,2′-bipy ligand and four cyanide carbon atoms in a distorted octa­hedral geometry. This distortion around the metal atom is defined by the sum of the octa­hedral angular deviations from 90° (Σ), in which the trigonal distortion angle = 0 for a perfect octa­hedron (Marchivie et al., 2005[Marchivie, M., Guionneau, P., Létard, J.-F. & Chasseau, D. (2005). Acta Cryst. B61, 25-28.]). In (I)[link], Σ for twelve bond angles, viz, 5C—Fe—C, 6C—Fe—N and 1N—Fe—N, is 41.03°, confirming a distorted octa­hedral geometry around the central FeIII ion. Another factor accounting for the distortion form ideal octa­hedral geometry of the FeIII atom is the acute angle subtended by the chelating 2,2′-bipy ligand, viz. N5—Fe1—N6 = 81.14 (11)°. The three trans angles [viz. C1—Fe1—N5 = 175.01 (15), C2—Fe1—N6 = 175.52 (14) and C3—Fe1—C4 = 178.06 (15)°] are bent slightly from the ideal value of 180°. The iron atom and terminal cyanido groups, viz. [Fe1—C3 N3 = 178.7 (3) and Fe1—C4 N4 = 179.8 (4)°] are almost linear compared to the iron atom and the corresponding equatorial cyano groups [viz. Fe1—C1—N1 = 175.8 (4) and Fe1—C2—N2 = 176.6 (4)°]. This difference is probably caused by hydrogen bonding (see below). The Fe—C bond lengths range from 1.917 (4) to 1.969 (4) Å, whereas the Fe—N bond lengths are 1.981 (3) and 1.985 (3) Å. The whole mol­ecule of 2,2′-bipy ligand is planar with an r.m.s. deviation of 0.016 Å; the dihedral angle between the two pyridyl rings is 1.57 (18)°. Bond lengths and angles within the [Fe(2,2′-bipy)(CN)4] anion in (I)[link] are in agreement with those reported for other cyanido and 2,2′-bipy-containing mononuclear iron(III) complexes such as K[Fe(2,2′-bipy)(CN)4]·H2O (Toma et al., 2002[Toma, L. M., Lescouëzec, R., Toma, L. D., Lloret, F., Julve, M., Vaissermann, J. & Andruh, M. (2002). J. Chem. Soc. Dalton Trans. pp. 3171-3176.]), PPh4[Fe(2,2′-bipy)(CN)4]·H2O (Lescouëzec et al., 2002[Lescouëzec, R., Lloret, F., Julve, M., Vaissermann, J. & Verdaguer, M. (2002). Inorg. Chem. 41, 818-826.]) and AsPPh4[Fe(2,2′-bipy)(CN)4]·CH3CN (Toma et al., 2007[Toma, L. M., Lescouëzec, R., Uriel, S., Llusar, R., Ruiz-Pérez, C., Vaissermann, J., Lloret, F. & Julve, M. (2007). Dalton Trans. pp. 3690-3698.]).

[Figure 1]
Figure 1
The asymmetric unit of (I)[link], showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 35% probability level. Dashed lines indicate O—H⋯O hydrogen bonds. Covalent bonds in the major and minor parts of the disordered are shaded differently and H atoms have been omitted for clarity. The labelling scheme A and B applied to the aromatic rings is used to identify the rings in the subsequent discussion.

Compound (II)[link] is a new cyanido-bridged Fe–Cd bimetallic coordination polymer synthesized using the precursor complex (I)[link] as building block in which the FeIII precursor was reduced to FeII under the crystallization conditions. The asymmetric unit contains half each of an [Fe(2,2′-bipy)(CN)4] anion and a [Cd(en)2]2+ cation, with the mol­ecules lying across twofold rotation axes, Fig. 2[link]. The coordination polyhedron of FeII ion is a distorted octa­hedron with a Σ of 28.90°. The Fe—C—N angles for both bridging [Fe1—C1—N1 = 178.15 (14)°] and terminal [Fe1—C2—N2 = 176.85 (16)°] cyanide groups deviate slightly from strict linearity. The Fe—Ccyanide bond lengths at 1.8950 (16) and 1.9363 (17) Å are slightly shorter than the Fe—N2,2′-bipy bond length, 1.9976 (14) Å. The CdII ion is six-coordinated by two N atoms from two cyanide groups, two N atoms from a chelating en ligand and two N atoms from two different bridging en ligands in a highly distorted octa­hedral geometry with a Σ of 108.08°. The Cd—N bond lengths and the N—Cd—N bond angles in (II)[link] are in the range 2.3980 (15)–2.5046 (14) Å and 73.24 (5)–157.20 (5)°, respectively. These values are comparable to those observed in compounds (Et4N)[{Fe(CN)6}3{Cd(en)}4] (Maľarová et al., 2003[Maľarová, M., Kuchár, J., Černák, J. & Massa, W. (2003). Acta Cryst. C59, m280-m282.]), [Fe(CN)6Cd(en)2] (Fu & Wang, 2005[Fu, A.-Y. & Wang, D.-Q. (2005). Z. Kristallogr. New Cryst. Struct. 220, 501-502.]) and [{Fe(CN)6}2{Cd(en)}3]·4H2O (Maľarová et al., 2006[Maľarová, M., Černák, J. & Massa, W. (2006). Acta Cryst. C62, m119-m121.]). Each [Fe(2,2′-bipy)(CN)4]2– anion uses two cyanide groups to link [Cd(en)]2+cations, forming a chain of [Fe(2,2′-bipy)(CN)4Cd(en)] units running parallel to the a axis. Along the b axis, adjacent chains are then inter­connected through the N atoms of the bridging en ligands at the Cd atoms into a two-dimensional layer of [Fe(2,2′-bipy)(CN)4Cd(en)2], as shown in Fig. 3[link]. The layer contains hexa­nuclear cyclic [{Fe(CN)2}2{Cd(en)}2] units with an Fe⋯Cd distance through the cyanide bridge and a Cd⋯Cd distance through the en bridge of 5.1292 (7) and 7.6692 (12) Å, respectively. The MM distances across the cyclic windows vary from 5.5614 (10) to 14.0061 (10) Å.

[Figure 2]
Figure 2
The structures of the molecular entities in (II)[link], showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 35% probability level. The pyridine ring labelled C is discussed in the text. [Symmetry codes: (i) 1 − x, y, [{1\over 2}] − z; (ii) −x, y, [{1\over 2}] − z.]
[Figure 3]
Figure 3
A view of the layer structure of (II)[link] along the b axis. 2,2′-Bipy mol­ecules and H atoms bonded to C and N atoms of the en ligands have been omitted for clarity.

3. Supra­molecular features

The three-dimensional supra­molecular structure in (I)[link] is the result of combinations of inter­molecular inter­actions including aromatic ππ stacking and hydrogen bonds. As can be seen in Fig. 4[link], pairs of [Fe(2,2′-bipy)(CN)4] mol­ecules are linked together through the parallel pyridyl rings of the 2,2′-bipy ligands to generate a graphite-like layers parallel to the ab plane. Within the sheets, the neighbouring pyridyl moieties related by an inversion centre are in a head-to-head arrangement with centroid (Cg) to centroid distances of 4.005 (3) Å [inter­planar angle = 0.0 (4)°] and 3.903 (3) Å [inter­planar angle = 0.0 (3)°] for rings AAi and BBii [symmetry codes: (i) −x, 2 − y, 1 − z; (ii) 1 − x, 1 − y, 1 − z], respectively. The FeIII⋯FeIII separations along the ππ stacking of parallel rings AAi and rings BBii are 8.2821 (12) and 8.4572 (13) Å, respectively. The adjacent pyridyl rings A and Biii [symmetry code: (iii) x − 1, y, z] related by translation parallel to the a axis are arranged alternately in a head-to-tail manner with a CgCg distance of 3.865 (2) Å [inter­planar angle = 1.51 (12)°] and an FeIII⋯FeIII separation of 6.8690 (9) Å.

[Figure 4]
Figure 4
A view of the two-dimensional anionic [Fe(2,2′-bipy)(CN)4] graphite-like sheet structure in (I)[link], parallel to the ab plane, with ππ inter­actions shown as dashed lines. H atoms have been omitted for clarity.

A notable feature of (I)[link] is the self-assembly of the tetra­meric (H2O)4 and hexa­meric (H2O)6 subunits into (H2O)10 units [the dihedral angle between the best plane of the (H2O)4 and (H2O)6 subunits is 55.2 (2)°]; neighbouring units are further joined together, giving rise to ladder-like water chains running parallel to the a axis. As can be seen from Fig. 5[link], the water mol­ecules at O1, O1i, O2, and O2i (for symmetry code see Table 1[link]) form centrosymmetric cyclic tetra­meric units through classical O—H⋯O hydrogen bonds with an R44(8) ring motif according to graph-set notation. In this unit, each water monomer acts as a single donor and a single acceptor of hydrogen bonds, and the four water mol­ecules are perfectly coplanar (mean deviation of all non-hydrogen atoms = 0.00 Å). The average O⋯O distance in (I)[link] is 2.805 Å. This value is comparable to the average distances for the gas-phase water tetra­mer (D2O)4 (2.78 Å; Liu et al., 1996[Liu, K., Cruzan, J. D. & Saykally, R. J. (1996). Science, 271, 929-933.]), liquid water (2.85 Å; Belch & Rice, 1987[Belch, A. C. & Rice, S. A. (1987). J. Chem. Phys. 86, 5676-5682.]) and other tetra­meric water units in the solid state (2.81 Å; Tao et al., 2004[Tao, J., Ma, Z.-J., Huang, R.-B. & Zheng, L.-S. (2004). Inorg. Chem. 43, 6133-6135.], and 2.83 Å; Long et al., 2004[Long, L. S., Wu, Y. R., Huang, G. B. & Zheng, L. S. (2004). Inorg. Chem. 43, 3798-3800.]). The average O⋯O⋯O angle is 90°, which is similar to those of the cyclic water tetra­mer found in liquid water and in the crystal host of metal–organic frameworks, [Cu(adipate)(4,4-bipy)]·2H2O (Long et al., 2004[Long, L. S., Wu, Y. R., Huang, G. B. & Zheng, L. S. (2004). Inorg. Chem. 43, 3798-3800.]) and [Cd3(pbtz)3(DMF)4(H2O)2]·4DMF·4H2O (Tao et al., 2004[Tao, J., Ma, Z.-J., Huang, R.-B. & Zheng, L.-S. (2004). Inorg. Chem. 43, 6133-6135.]).

Table 1
Hydrogen-bond geometry (Å, °) for (I)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
C17A—H17C⋯O2i 0.96 2.50 3.112 (11) 122
O3—H3A⋯N4 0.84 (1) 2.00 (1) 2.841 (5) 178 (5)
O1—H1A⋯N1 0.84 (1) 2.03 (1) 2.859 (5) 176 (7)
O3—H3B⋯O1ii 0.85 (1) 1.89 (1) 2.736 (6) 174 (7)
O2—H2A⋯O3 0.84 (1) 1.87 (2) 2.709 (6) 172 (7)
O2—H2B⋯O1 0.84 (1) 1.98 (1) 2.818 (7) 177 (14)
O1—H1B⋯O2iii 0.84 (1) 2.02 (6) 2.792 (8) 152 (11)
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) x+1, y, z; (iii) -x+1, -y+1, -z.
[Figure 5]
Figure 5
Self-assembly of the water tetra­mer (H2O)4 and hexa­mer (H2O)6 by O—H⋯O hydrogen bonds into the ladder-like chain, and representation of O—H⋯N hydrogen bonds between the water chain and anionic [Fe(2,2′-bipy)(CN)4] units. See Table 1[link] for symmetry codes.

The hexa­meric water unit has crystallographically imposed inversion symmetry. The six water mol­ecules O1i, O1ii, O2, O2iii, O3, and O3iii (for symmetry codes, see Table 1[link]) are almost coplanar with a mean deviation of 0.025 Å. Similar to the situation in the tetra­meric water unit, each water mol­ecule acts as both a single hydrogen-bond donor and acceptor, and is simultaneously involved in classical O—H⋯O inter­actions, leading to a cyclic R66(12) hydrogen-bonding motif with an average O⋯O distance of 2.786 Å. This value is slightly shorter than the average distance for the tetra­meric unit and liquid water; however, it is comparable with the distance in ice Ih (2.74 Å; Eisenberg & Kauzmann, 1969[Eisenberg, D. & Kauzmann, W. (1969). In The Structure and Properties of Water. Oxford University Press.]) and water trapped in a metal–organic framework (2.78 Å; Ghosh & Bharadwaj, 2003[Ghosh, S. K. & Bharadwaj, P. K. (2003). Inorg. Chem. 42, 8250-8254.]). The average O⋯O⋯O angle in the planar hexa­meric unit is 120°, deviating considerably from the corresponding value of 109.3° in hexa­gonal ice (Fletcher, 1970[Fletcher, N. H. (1970). In The Chemical Physics of Ice. Cambridge University Press.]). Another remarkable feature in (I)[link] is that the ladder-like water chains are incorporated with the aromatic ππ stacking graphite-like layers through classical O—H⋯N hydrogen bonds involving the lattice water mol­ecules (O1 and O3) and the N atoms of the cyanido groups (N1 and N4), forming an R44(12) ring motif. In addition, the [N(CH3)]+ cations lie above and below the water chains and take part in the formation of weak C—H⋯O hydrogen bonds with the water mol­ecule.

For (II)[link], classical O—H⋯N and N—H⋯O hydrogen bonds involving the lattice water mol­ecules and N atoms of terminal cyanide groups and the N—H group of the en ligands are observed within a layer, Table 2[link]. The layers are further linked together into a three-dimensional network via ππ stacking between adjacent pyridyl rings with CgCg distances of 4.2925 (18) [inter­planar angle = 1.55 (18)°] and 4.0642 (18) Å [inter­planar angle = 0.0 (3)°] for rings CCiv and CCv [symmetry codes: (iv) 2 − x, y, [{1\over 2}] − z; (v) [{3\over 2}] − x, [{3\over 2}] − y, 1 − z], respectively, Fig. 6[link].

Table 2
Hydrogen-bond geometry (Å, °) for (II)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N5—H5A⋯O1i 0.89 2.20 3.0726 (18) 167
O1—H1⋯N2 0.87 (1) 1.99 (1) 2.8045 (19) 156 (2)
Symmetry code: (i) -x+1, -y+1, -z+1.
[Figure 6]
Figure 6
A portion of the crystal packing in (II)[link] viewed in the bc plane showing ππ stacking inter­actions (dashed lines).

4. Synthesis and crystallization

The building block N(CH3)4[Fe(2,2′-bipy)(CN)4]·3H2O (I)[link] was prepared following the procedure described for PPh4[Fe(2,2′-bipy)(CN)4]·H2O (Lescouëzec et al., 2002[Lescouëzec, R., Lloret, F., Julve, M., Vaissermann, J. & Verdaguer, M. (2002). Inorg. Chem. 41, 818-826.]), except that tetra­methyl­ammonium chloride was used instead of tetra­phenyl­phospho­nium chloride. Dark-red single crystals of (I)[link] suitable for structure determination were obtained by recrystallization from water and methanol (1:1, v/v). Analysis calculated for C18H26FeN7O: C, 48.66; H, 5.90; N, 22.07%. Found: C, 48.66; H, 5.90; N, 22.07%.

For the synthesis of (II)[link], Cd(NO3)2·4H2O (0.062 g, 0.2 mmol) and ethyl­enedi­amine (stock solution, 0.01 ml, 0.2 mmol) were dissolved in distilled H2O (4 ml), and this was pipetted into one side of an H-tube. N(CH3)4[Fe(2,2′-bipy)(CN)4]·3H2O (0.089 g, 0.2 mmol) was dissolved in distilled H2O (4 ml), and this was pipetted into the other side arm of the H-tube. The H-tube (15 ml capacity) was then carefully filled with distilled H2O. Slow diffusion in the dark for three weeks yielded dark-yellow plate-shaped crystals of (II)[link] suitable for X-ray crystallographic analysis. Analysis calculated for C18H26CdFeN10O: C, 38.15; H, 4.62; N, 24.72%. Found: C, 38.18; H, 4.60; N, 24.68%.

5. Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 3[link]. H atoms bonded to C and N atoms were placed at calculated positions and refined using a riding-model approximation, with C—H = 0.93 (aromatic), 0.96 (meth­yl) or 0.97 (methyl­ene) Å and N—H = 0.89 Å, and with Uiso(H) = 1.5Ueq(C) for methyl groups and 1.2Ueq(C, N) otherwise. For (I)[link], the water-H atoms were located in a difference Fourier map and refined with distance restraints: O—H = 0.84 (1) Å and H⋯H = 1.39 (2) Å with Uiso(H) = 1.5Ueq(O). For (II)[link], the water-H atoms were refined with restraints of O—H = 0.82 (1) Å with Uiso(H) = 1.5Ueq(O). The tetra­metyl­ammonium cation in (I)[link] exhibits rotational positional disorder in three of the methyl groups, and was refined with occupancy factors of 0.440 (6) for C16A, C17A and C18A, and 0.560 (6) for atoms C16B, C17B, and C18B. Anisotropic displacement parameters of all atoms were restrained using enhanced rigid-bond restraints (RIGU command, s.u.'s 0.001 Å2; Thorn et al., 2012[Thorn, A., Dittrich, B. & Sheldrick, G. M. (2012). Acta Cryst. A68, 448-451.]). The restraint SADI was also used for the disordered tetra­metyl­ammonium cation.

Table 3
Experimental details

  (I) (II)
Crystal data
Chemical formula (C4H12N)[Fe(CN)4(C10H8N2)]·3H2O [CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O
Mr 444.31 566.74
Crystal system, space group Triclinic, P[\overline{1}] Monoclinic, C2/c
Temperature (K) 296 296
a, b, c (Å) 6.8690 (9), 11.9405 (16), 14.2731 (17) 7.4184 (14), 28.534 (5), 11.094 (2)
α, β, γ (°) 104.107 (4), 99.695 (4), 92.235 (4) 90, 109.143 (6), 90
V3) 1115.2 (2) 2218.3 (7)
Z 2 4
Radiation type Mo Kα Mo Kα
μ (mm−1) 0.71 1.65
Crystal size (mm) 0.22 × 0.16 × 0.08 0.30 × 0.26 × 0.14
 
Data collection
Diffractometer Bruker APEXII D8 QUEST CMOS Bruker APEXII D8 QUEST CMOS
Absorption correction Multi-scan (SADABS; Bruker, 2014[Bruker (2014). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]) Multi-scan (SADABS; Bruker, 2014[Bruker (2014). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.691, 0.745 0.633, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 20120, 3982, 3015 51158, 2757, 2478
Rint 0.072 0.038
(sin θ/λ)max−1) 0.599 0.667
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.142, 1.04 0.020, 0.046, 1.07
No. of reflections 3982 2757
No. of parameters 321 146
No. of restraints 87 2
H-atom treatment H atoms treated by a mixture of independent and constrained refinement H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.72, −0.59 0.47, −0.47
Computer programs: APEX2 and SAINT (Bruker, 2014[Bruker (2014). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2014 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]), publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]) and enCIFer (Allen et al., 2004[Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335-338.]).

Supporting information


Chemical context top

Over the past several decades, hexa­cyano­metallate anions, [M(CN)6]n- (n = 2–4), have been used extensively as building blocks for the design and construction of a large number of high-dimensional cyanide-bridged bimetallic coordination polymers because of their ability to act as multidentate ligands to link numerous metal centers through all six cyanide groups (Ohba & Ōkawa, 2000; Smith et al., 2000; Berlinguette et al., 2005). The highly insoluble three-dimensional Prussian blue and its more soluble Prussian blue analogues are perhaps the best known examples of this class of compounds, which are obtained by reacting the building block [M(CN)6]3– with o­cta­hedral transition metal ions (Buser et al., 1977). The inclusion of a bidentate chelating ligand (L) such as 2,2'-bi­pyridine (2,2'-bipy) or 1,10-phenanthroline (1,10-phen) in cyanide-containing building blocks of general formula [M(L)(CN)4]n- (n = 2, 3) instead of [M(CN)6]n- has been a recent development in the field of low-dimensionality cyanide-bridged bimetallic coordination compounds (Lescouëzec et al., 2001; Laza­rides et al., 2007). The aromatic ligand L does not just block two coordination sites of the central atom, to yield one- and two-dimensional polymeric compounds, but also helps to stabilize the assembly as well as increasing the dimensionality of the three-dimensional supra­molecular structures through aromatic ππ stacking inter­actions (Lescouëzec et al., 2002; Toma et al., 2004). It is also known that the non-coordinating nitro­gen atoms of the cyanide groups can act as hydrogen-bond acceptors to self-assemble into various supra­molecular architectures (Xiang et al., 2009). As part of our search for novel cyanide-bridged bimetallic coordination polymers, we herein describe the synthesis and crystal structure of N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (I) building block and a new two-dimensional cyanide-bridged iron(II)-cadmium(II) bimetallic coordination polymer, [Fe(2,2'-bipy)(CN4){Cd(en)2}]·H2O (II), in which enthylenedi­amine (en) adopts both bridging and chelating coordination modes.

Structural commentary top

The single crystal X-ray diffraction study reveals that (I) crystallizes in the triclinic space group P1 with the asymmetric unit consisting of one [Fe(2,2'-bipy)(CN)4]- anion, one disordered tetra­methyl­ammonium cation, [N(CH3)4]+ and three water molecules, as displayed in Fig. 1. All atoms are in general positions. The FeIII ion is coordinated by two nitro­gen atoms from one 2,2'-bipy ligand and four cyanide carbon atoms in a distorted o­cta­hedral geometry. This distortion around the metal atom is defined by the sum of the o­cta­hedral angular deviations from 90° (Σ), in which the trigonal distortion angle = 0 for a perfect o­cta­hedron (Marchivie et al., 2005). In (I), Σ for twelve bond angles, viz 5C—Fe—C, 6C—Fe—N and 1N—Fe—N, is 41.03°, confirming a distorted o­cta­hedral geometry around the central FeIII ion. Another factor accounting for the distortion form ideal o­cta­hedral geometry of the FeIII atom is the acute angle subtended by the chelated 2,2'-bipy ligand viz N5—Fe1—N6 = 81.14 (11)°. The three trans angles [viz C1—Fe1—N5 = 175.01 (15), C2—Fe1—N6 = 175.52 (14) and C3—Fe1—C4 = 178.06 (15)°] are bent slightly from the ideal value of 180°. The iron atom and terminal cyanide ligands viz [Fe1—C3N3 = 178.7 (3) and Fe1—C4N4 = 179.8 (4)°] are almost linear compared to the iron atom and the corresponding equatorial cyano groups [viz Fe1—C1—N1 = 175.8 (4) and Fe1—C2—N2 = 176.6 (4)°]. This difference is probably caused by hydrogen bonding (see below). The Fe—C bond lengths range from 1.917 (4) to 1.969 (4) Å, whereas the Fe—N bond lengths are 1.981 (3) and 1.985 (3) Å. The whole molecule of 2,2'-bipy ligand is planar with an r.m.s. deviation of 0.016 Å; the dihedral angle between the two pyridyl rings is 1.57 (18)°. Bond lengths and angles within the [Fe(2,2'-bipy)(CN)4]- anion in (I) are in agreement with those reported for other cyano and 2,2'-bipy-containing mononuclear iron(III) complexes such as K[Fe(2,2'-bipy)(CN)4]·H2O (Toma et al., 2002), PPh4[Fe(2,2'-bipy)(CN)4]·H2O (Lescouëzec et al., 2002) and AsPPh4[Fe(2,2'-bipy)(CN)4]·CH3CN (Toma et al., 2007).

Compound (II) is a new cyanide-bridged Fe–Cd bimetallic coordination polymer synthesized using the precursor complex (I) as building block in which the FeIII precursor was reduced to FeII under the crystallization conditions. The asymmetric unit contains half each of an [Fe(2,2'-bipy)(CN)4]- anion and a [Cd(en)2]2+ cation, with the molecules lying across twofold rotation axes, Fig. 2. The coordination polyhedron of FeII ion is a distorted o­cta­hedron with a Σ of 28.90°. The Fe—C—N angles for both bridging [Fe1—C1—N1 = 178.15 (14)°] and terminal [Fe1—C2—N2 = 176.85 (16)°] cyanide groups deviate slightly from strict linearity. The Fe—Ccyanide bond lengths at 1.8950 (16) and 1.9363 (17) Å are slightly shorter than the Fe—N2,2'-bipy bond length, 1.9976 (14) Å. The CdII ion is six-coordinated by two N atoms from two cyanide groups, two N atoms from a chelating en ligand and two N atoms from two different bridging en ligands in a highly distorted o­cta­hedral geometry with a Σ of 108.08°. The Cd—N bond lengths and the N—Cd—N bond angles in (II) are in the range 2.3980 (15)–2.5046 (14) Å and 73.24 (5)–157.20 (5)°, respectively. These values are comparable to those observed in compounds (Et4N)[{Fe(CN)6}3{Cd(en)}4] (Mal'arová et al., 2003), [Fe(CN)6Cd(en)2] (Fu & Wang, 2005) and [{Fe(CN)6}2{Cd(en)}3]·4H2O (Mal'arová et al., 2006). Each [Fe(2,2'-bipy)(CN)4]2– anion uses two cyanide groups to link [Cd(en)]2+cations, forming a one-dimensional chain of [Fe(2,2'-bipy)(CN)4Cd(en)] units running parallel to the a axis. Along the b axis, adjacent chains are then inter­connected through the N atoms of the bridging en ligands at the Cd atoms into a two-dimensional layer of [Fe(2,2'-bipy)(CN)4Cd(en)2], as shown in Fig. 3. The layer contains hexanuclear cyclic [{Fe(CN)2}2{Cd(en)}2] units with an Fe···Cd distance through the cyanide bridge and a Cd···Cd distance through the en bridge of 5.1292 (7) and 7.6692 (12) Å, respectively. The M···M distances across the cyclic windows vary from 5.5614 (10) to 14.0061 (10) Å.

Supra­molecular features top

The three-dimensional supra­molecular structure in (I) is the result of combinations of inter­molecular inter­actions including aromatic ππ stacking and hydrogen bonds. As can be seen in Fig. 4, pairs of [Fe(2,2'-bipy)(CN)4]- molecules are linked together through the parallel pyridyl rings of the 2,2'-bipy ligands to generate a two-dimensional graphitic-like sheet structure parallel to the ab plane. Within the sheets, the neighbouring pyridyl moieties related by an inversion centre are in a head-to-head arrangement with centroid (Cg) to centroid distances of 4.005 (3) Å [inter­planar angle = 0.0 (4)°] and 3.903 (3) Å [inter­planar angle = 0.0 (3)°] for rings A···Ai [symmetry code: (i) -x, 2 - y, 1 - z] and rings B···Bii [symmetry code: (ii) 1 - x, 1 - y, 1 - z], respectively. The FeIII···FeIII separations along the ππ stacking of parallel rings A···Ai and rings B···Bii are 8.2821 (12) and 8.4572 (13) Å, respectively. The adjacent pyridyl rings A and Biii [symmetry code: (iii) x - 1, y, z] related by translation parallel to the a axis are arranged alternately in a head-to-tail manner with a Cg···Cg distance of 3.865 (2) Å [inter­planar angle = 1.51 (12)°] and an FeIII···FeIII separation of 6.8690 (9) Å.

A notable feature of (I) is the self-assembly of the tetra­meric (H2O)4 and hexameric (H2O)6 subunits into (H2O)10 clusters [the dihedral angle between the best plane of the (H2O)4 and (H2O)6 subunits is 55.2 (2)°]; neighbouring clusters are further joined together, giving rise to one-dimensional ladder-like water chains running parallel to the a axis. As can be seen from Fig. 5, the water molecules at O1, O1i, O2, and O2i (for symmetry code see Table 1) form centrosymmetric cyclic tetra­meric cluster through classical O—H···O hydrogen bonds with an R44(8) ring motif according to graph-set notation. In this cluster, each water monomer acts as a single donor and a single acceptor of hydrogen bonds, and the four water molecules are perfectly coplanar ( mean deviation of all non-hydrogen atoms = 0.00 Å). The average O···O distance in (I) is 2.805 Å. This value is comparable to the average distances for the gas-phase water tetra­mer (D2O)4 (2.78 Å; Liu et al., 1996), liquid water (2.85 Å; Belch & Rice, 1987) and other tetra­meric water clusters in the solid state (2.81 Å; Tao et al., 2004, and 2.83 Å; Long et al., 2004). The average O···O···O angle is 90°, which is similar to those of the cyclic water tetra­mer found in liquid water and in the crystal host of metal–organic frameworks, [Cu(adipate)(4,4-bipy)]·2H2O (Long et al., 2004) and [Cd3(pbtz)3(DMF)4(H2O)2]·4DMF·4H2O (Tao et al., 2004).

The hexameric water cluster has crystallographically imposed inversion symmetry. The six water molecules O1i, O1ii, O2, O2iii, O3, and O3iii (for symmetry codes see Table 1) are almost coplanar with a mean deviation of 0.025 Å. Similar to the situation in the tetra­meric water cluster, each water molecule acts as both a single hydrogen-bond donor and acceptor, and is simultaneously involved in classical O—H···O inter­actions, leading to a cyclic R66(12) hydrogen-bonding motif with an average O···O distance of 2.786 Å. This value is slightly shorter than the average distance for the tetra­meric cluster and liquid water; however, it is comparable with the distance in ice Ih (2.74 Å; Eisenberg & Kauzmann, 1969) and water trapped in a metal–organic framework (2.78 Å; Ghosh & Bharadwaj, 2003). The average O···O···O angle in the planar hexameric cluster is 120°, deviating considerably from the corresponding value of 109.3° in hexagonal ice (Fletcher, 1970). Another remarkable feature in (I) is that the one-dimensional ladder-like water chains are incorporated with the two-dimensional aromatic ππ stacking graphitic-like sheets through classical O—H···N hydrogen bonds involving the lattice water molecules (O1 and O3) and the N atoms of the cyano groups (N1 and N4), forming an R44(12) ring motif. In addition, the [N(CH3)]+ cations lie above and below the water chains and take part in the formation of weak C—H···O hydrogen bonds with the water molecule.

For (II), classical O—H···N and N—H···O hydrogen bonds involving the lattice water molecules and N atoms of terminal cyanide groups and the N—H group of the en ligands are observed within a two-dimensional layer, Table 2. The layers are further linked together into a three-dimensional network via ππ stacking between adjacent pyridyl rings with Cg···Cg distances of 4.2925 (18) [inter­planar angle = 1.55 (18)°] and 4.0642 (18) Å [inter­planar angle = 0.0 (3)°] for rings C···Civ and rings C···Cv [symmetry codes: (iv) 2 - x, y, 1/2 - z; (v) 3/2 - x, 3/2 - y, 1 - z], respectively, Fig. 6.

Synthesis and crystallization top

The building block N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (I) was prepared following the procedure described for PPh4[Fe(2,2'-bipy)(CN)4]·H2O (Lescouëzec et al., 2002), except that tetra­methyl­ammonium chloride was used instead of tetra­phenyl­phospho­nium chloride. Dark-red single crystals of (I) suitable for structure determination were obtained by recrystallization from water and methanol (1:1, v/v). Analysis calculated for C18H26CdFeN10O: C, 48.66; H, 5.90; N, 22.07%. Found: C, 48.66; H, 5.90; N, 22.07%.

For the synthesis of (II), Cd(NO3)2·4H2O (0.062 g, 0.2 mmol) and ethyl­enedi­amine (stock solution, 0.01 ml, 0.2 mmol) were dissolved in distilled H2O (4 ml), and this was pipetted into one side of an H-tube. N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (0.089 g, 0.2 mmol) was dissolved in distilled H2O (4 ml), and this was pipetted into the other side arm of the H-tube. The H-tube (15 ml capacity) was then carefully filled with distilled H2O. Slow diffusion in the dark for three weeks yielded dark-yellow plate-shaped crystals of (II) suitable for X-ray crystallographic analysis. Analysis calculated for C18H26CdFeN10O: C, 38.15; H, 4.62; N, 24.72%. Found: C, 38.18; H, 4.60; N, 24.68%.

Refinement top

Crystal data, data collection, and structure refinement details are summarized in Table 3. H atoms bonded to C and N atoms were placed at calculated positions and refined using a riding-model approximation, with C—H = 0.93 (aromatic), 0.96 (methyl) or 0.97 (methyl­ene) Å and N—H = 0.89 Å, and with Uiso(H) = 1.5Ueq(C) for methyl groups and 1.2Ueq(C, N) otherwise. For (I), the water-H atoms were located in a difference Fourier map and refined with a distance restraints: O—H = 0.84 (1) Å and H···H = 1.39 (2) Å with Uiso(H) = 1.5Ueq(O). For (II), the water-H atoms were refined with restraints of O—H = 0.82 (1) Å with Uiso(H) = 1.5Ueq(O). The tetra­metyl­ammonium cation in (I) exhibits rotational positional disorder in three of the methyl groups, and was refined with occupancy factors of 0.440 (6) for C16A, C17A and C18A, and 0.560 (6) for atoms C16B, C17B, and C18B. Anisotropic displacement parameters of all atoms were restrained using enhanced rigid-bond restraints (RIGU command, s.u.'s 0.001 Å2; Thorn et al., 2012). The restraint SADI was also used for the disordered tetra­metyl­ammonium cation.

Structure description top

Over the past several decades, hexa­cyano­metallate anions, [M(CN)6]n- (n = 2–4), have been used extensively as building blocks for the design and construction of a large number of high-dimensional cyanide-bridged bimetallic coordination polymers because of their ability to act as multidentate ligands to link numerous metal centers through all six cyanide groups (Ohba & Ōkawa, 2000; Smith et al., 2000; Berlinguette et al., 2005). The highly insoluble three-dimensional Prussian blue and its more soluble Prussian blue analogues are perhaps the best known examples of this class of compounds, which are obtained by reacting the building block [M(CN)6]3– with o­cta­hedral transition metal ions (Buser et al., 1977). The inclusion of a bidentate chelating ligand (L) such as 2,2'-bi­pyridine (2,2'-bipy) or 1,10-phenanthroline (1,10-phen) in cyanide-containing building blocks of general formula [M(L)(CN)4]n- (n = 2, 3) instead of [M(CN)6]n- has been a recent development in the field of low-dimensionality cyanide-bridged bimetallic coordination compounds (Lescouëzec et al., 2001; Laza­rides et al., 2007). The aromatic ligand L does not just block two coordination sites of the central atom, to yield one- and two-dimensional polymeric compounds, but also helps to stabilize the assembly as well as increasing the dimensionality of the three-dimensional supra­molecular structures through aromatic ππ stacking inter­actions (Lescouëzec et al., 2002; Toma et al., 2004). It is also known that the non-coordinating nitro­gen atoms of the cyanide groups can act as hydrogen-bond acceptors to self-assemble into various supra­molecular architectures (Xiang et al., 2009). As part of our search for novel cyanide-bridged bimetallic coordination polymers, we herein describe the synthesis and crystal structure of N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (I) building block and a new two-dimensional cyanide-bridged iron(II)-cadmium(II) bimetallic coordination polymer, [Fe(2,2'-bipy)(CN4){Cd(en)2}]·H2O (II), in which enthylenedi­amine (en) adopts both bridging and chelating coordination modes.

The single crystal X-ray diffraction study reveals that (I) crystallizes in the triclinic space group P1 with the asymmetric unit consisting of one [Fe(2,2'-bipy)(CN)4]- anion, one disordered tetra­methyl­ammonium cation, [N(CH3)4]+ and three water molecules, as displayed in Fig. 1. All atoms are in general positions. The FeIII ion is coordinated by two nitro­gen atoms from one 2,2'-bipy ligand and four cyanide carbon atoms in a distorted o­cta­hedral geometry. This distortion around the metal atom is defined by the sum of the o­cta­hedral angular deviations from 90° (Σ), in which the trigonal distortion angle = 0 for a perfect o­cta­hedron (Marchivie et al., 2005). In (I), Σ for twelve bond angles, viz 5C—Fe—C, 6C—Fe—N and 1N—Fe—N, is 41.03°, confirming a distorted o­cta­hedral geometry around the central FeIII ion. Another factor accounting for the distortion form ideal o­cta­hedral geometry of the FeIII atom is the acute angle subtended by the chelated 2,2'-bipy ligand viz N5—Fe1—N6 = 81.14 (11)°. The three trans angles [viz C1—Fe1—N5 = 175.01 (15), C2—Fe1—N6 = 175.52 (14) and C3—Fe1—C4 = 178.06 (15)°] are bent slightly from the ideal value of 180°. The iron atom and terminal cyanide ligands viz [Fe1—C3N3 = 178.7 (3) and Fe1—C4N4 = 179.8 (4)°] are almost linear compared to the iron atom and the corresponding equatorial cyano groups [viz Fe1—C1—N1 = 175.8 (4) and Fe1—C2—N2 = 176.6 (4)°]. This difference is probably caused by hydrogen bonding (see below). The Fe—C bond lengths range from 1.917 (4) to 1.969 (4) Å, whereas the Fe—N bond lengths are 1.981 (3) and 1.985 (3) Å. The whole molecule of 2,2'-bipy ligand is planar with an r.m.s. deviation of 0.016 Å; the dihedral angle between the two pyridyl rings is 1.57 (18)°. Bond lengths and angles within the [Fe(2,2'-bipy)(CN)4]- anion in (I) are in agreement with those reported for other cyano and 2,2'-bipy-containing mononuclear iron(III) complexes such as K[Fe(2,2'-bipy)(CN)4]·H2O (Toma et al., 2002), PPh4[Fe(2,2'-bipy)(CN)4]·H2O (Lescouëzec et al., 2002) and AsPPh4[Fe(2,2'-bipy)(CN)4]·CH3CN (Toma et al., 2007).

Compound (II) is a new cyanide-bridged Fe–Cd bimetallic coordination polymer synthesized using the precursor complex (I) as building block in which the FeIII precursor was reduced to FeII under the crystallization conditions. The asymmetric unit contains half each of an [Fe(2,2'-bipy)(CN)4]- anion and a [Cd(en)2]2+ cation, with the molecules lying across twofold rotation axes, Fig. 2. The coordination polyhedron of FeII ion is a distorted o­cta­hedron with a Σ of 28.90°. The Fe—C—N angles for both bridging [Fe1—C1—N1 = 178.15 (14)°] and terminal [Fe1—C2—N2 = 176.85 (16)°] cyanide groups deviate slightly from strict linearity. The Fe—Ccyanide bond lengths at 1.8950 (16) and 1.9363 (17) Å are slightly shorter than the Fe—N2,2'-bipy bond length, 1.9976 (14) Å. The CdII ion is six-coordinated by two N atoms from two cyanide groups, two N atoms from a chelating en ligand and two N atoms from two different bridging en ligands in a highly distorted o­cta­hedral geometry with a Σ of 108.08°. The Cd—N bond lengths and the N—Cd—N bond angles in (II) are in the range 2.3980 (15)–2.5046 (14) Å and 73.24 (5)–157.20 (5)°, respectively. These values are comparable to those observed in compounds (Et4N)[{Fe(CN)6}3{Cd(en)}4] (Mal'arová et al., 2003), [Fe(CN)6Cd(en)2] (Fu & Wang, 2005) and [{Fe(CN)6}2{Cd(en)}3]·4H2O (Mal'arová et al., 2006). Each [Fe(2,2'-bipy)(CN)4]2– anion uses two cyanide groups to link [Cd(en)]2+cations, forming a one-dimensional chain of [Fe(2,2'-bipy)(CN)4Cd(en)] units running parallel to the a axis. Along the b axis, adjacent chains are then inter­connected through the N atoms of the bridging en ligands at the Cd atoms into a two-dimensional layer of [Fe(2,2'-bipy)(CN)4Cd(en)2], as shown in Fig. 3. The layer contains hexanuclear cyclic [{Fe(CN)2}2{Cd(en)}2] units with an Fe···Cd distance through the cyanide bridge and a Cd···Cd distance through the en bridge of 5.1292 (7) and 7.6692 (12) Å, respectively. The M···M distances across the cyclic windows vary from 5.5614 (10) to 14.0061 (10) Å.

The three-dimensional supra­molecular structure in (I) is the result of combinations of inter­molecular inter­actions including aromatic ππ stacking and hydrogen bonds. As can be seen in Fig. 4, pairs of [Fe(2,2'-bipy)(CN)4]- molecules are linked together through the parallel pyridyl rings of the 2,2'-bipy ligands to generate a two-dimensional graphitic-like sheet structure parallel to the ab plane. Within the sheets, the neighbouring pyridyl moieties related by an inversion centre are in a head-to-head arrangement with centroid (Cg) to centroid distances of 4.005 (3) Å [inter­planar angle = 0.0 (4)°] and 3.903 (3) Å [inter­planar angle = 0.0 (3)°] for rings A···Ai [symmetry code: (i) -x, 2 - y, 1 - z] and rings B···Bii [symmetry code: (ii) 1 - x, 1 - y, 1 - z], respectively. The FeIII···FeIII separations along the ππ stacking of parallel rings A···Ai and rings B···Bii are 8.2821 (12) and 8.4572 (13) Å, respectively. The adjacent pyridyl rings A and Biii [symmetry code: (iii) x - 1, y, z] related by translation parallel to the a axis are arranged alternately in a head-to-tail manner with a Cg···Cg distance of 3.865 (2) Å [inter­planar angle = 1.51 (12)°] and an FeIII···FeIII separation of 6.8690 (9) Å.

A notable feature of (I) is the self-assembly of the tetra­meric (H2O)4 and hexameric (H2O)6 subunits into (H2O)10 clusters [the dihedral angle between the best plane of the (H2O)4 and (H2O)6 subunits is 55.2 (2)°]; neighbouring clusters are further joined together, giving rise to one-dimensional ladder-like water chains running parallel to the a axis. As can be seen from Fig. 5, the water molecules at O1, O1i, O2, and O2i (for symmetry code see Table 1) form centrosymmetric cyclic tetra­meric cluster through classical O—H···O hydrogen bonds with an R44(8) ring motif according to graph-set notation. In this cluster, each water monomer acts as a single donor and a single acceptor of hydrogen bonds, and the four water molecules are perfectly coplanar ( mean deviation of all non-hydrogen atoms = 0.00 Å). The average O···O distance in (I) is 2.805 Å. This value is comparable to the average distances for the gas-phase water tetra­mer (D2O)4 (2.78 Å; Liu et al., 1996), liquid water (2.85 Å; Belch & Rice, 1987) and other tetra­meric water clusters in the solid state (2.81 Å; Tao et al., 2004, and 2.83 Å; Long et al., 2004). The average O···O···O angle is 90°, which is similar to those of the cyclic water tetra­mer found in liquid water and in the crystal host of metal–organic frameworks, [Cu(adipate)(4,4-bipy)]·2H2O (Long et al., 2004) and [Cd3(pbtz)3(DMF)4(H2O)2]·4DMF·4H2O (Tao et al., 2004).

The hexameric water cluster has crystallographically imposed inversion symmetry. The six water molecules O1i, O1ii, O2, O2iii, O3, and O3iii (for symmetry codes see Table 1) are almost coplanar with a mean deviation of 0.025 Å. Similar to the situation in the tetra­meric water cluster, each water molecule acts as both a single hydrogen-bond donor and acceptor, and is simultaneously involved in classical O—H···O inter­actions, leading to a cyclic R66(12) hydrogen-bonding motif with an average O···O distance of 2.786 Å. This value is slightly shorter than the average distance for the tetra­meric cluster and liquid water; however, it is comparable with the distance in ice Ih (2.74 Å; Eisenberg & Kauzmann, 1969) and water trapped in a metal–organic framework (2.78 Å; Ghosh & Bharadwaj, 2003). The average O···O···O angle in the planar hexameric cluster is 120°, deviating considerably from the corresponding value of 109.3° in hexagonal ice (Fletcher, 1970). Another remarkable feature in (I) is that the one-dimensional ladder-like water chains are incorporated with the two-dimensional aromatic ππ stacking graphitic-like sheets through classical O—H···N hydrogen bonds involving the lattice water molecules (O1 and O3) and the N atoms of the cyano groups (N1 and N4), forming an R44(12) ring motif. In addition, the [N(CH3)]+ cations lie above and below the water chains and take part in the formation of weak C—H···O hydrogen bonds with the water molecule.

For (II), classical O—H···N and N—H···O hydrogen bonds involving the lattice water molecules and N atoms of terminal cyanide groups and the N—H group of the en ligands are observed within a two-dimensional layer, Table 2. The layers are further linked together into a three-dimensional network via ππ stacking between adjacent pyridyl rings with Cg···Cg distances of 4.2925 (18) [inter­planar angle = 1.55 (18)°] and 4.0642 (18) Å [inter­planar angle = 0.0 (3)°] for rings C···Civ and rings C···Cv [symmetry codes: (iv) 2 - x, y, 1/2 - z; (v) 3/2 - x, 3/2 - y, 1 - z], respectively, Fig. 6.

Synthesis and crystallization top

The building block N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (I) was prepared following the procedure described for PPh4[Fe(2,2'-bipy)(CN)4]·H2O (Lescouëzec et al., 2002), except that tetra­methyl­ammonium chloride was used instead of tetra­phenyl­phospho­nium chloride. Dark-red single crystals of (I) suitable for structure determination were obtained by recrystallization from water and methanol (1:1, v/v). Analysis calculated for C18H26CdFeN10O: C, 48.66; H, 5.90; N, 22.07%. Found: C, 48.66; H, 5.90; N, 22.07%.

For the synthesis of (II), Cd(NO3)2·4H2O (0.062 g, 0.2 mmol) and ethyl­enedi­amine (stock solution, 0.01 ml, 0.2 mmol) were dissolved in distilled H2O (4 ml), and this was pipetted into one side of an H-tube. N(CH3)4[Fe(2,2'-bipy)(CN)4]·3H2O (0.089 g, 0.2 mmol) was dissolved in distilled H2O (4 ml), and this was pipetted into the other side arm of the H-tube. The H-tube (15 ml capacity) was then carefully filled with distilled H2O. Slow diffusion in the dark for three weeks yielded dark-yellow plate-shaped crystals of (II) suitable for X-ray crystallographic analysis. Analysis calculated for C18H26CdFeN10O: C, 38.15; H, 4.62; N, 24.72%. Found: C, 38.18; H, 4.60; N, 24.68%.

Refinement details top

Crystal data, data collection, and structure refinement details are summarized in Table 3. H atoms bonded to C and N atoms were placed at calculated positions and refined using a riding-model approximation, with C—H = 0.93 (aromatic), 0.96 (methyl) or 0.97 (methyl­ene) Å and N—H = 0.89 Å, and with Uiso(H) = 1.5Ueq(C) for methyl groups and 1.2Ueq(C, N) otherwise. For (I), the water-H atoms were located in a difference Fourier map and refined with a distance restraints: O—H = 0.84 (1) Å and H···H = 1.39 (2) Å with Uiso(H) = 1.5Ueq(O). For (II), the water-H atoms were refined with restraints of O—H = 0.82 (1) Å with Uiso(H) = 1.5Ueq(O). The tetra­metyl­ammonium cation in (I) exhibits rotational positional disorder in three of the methyl groups, and was refined with occupancy factors of 0.440 (6) for C16A, C17A and C18A, and 0.560 (6) for atoms C16B, C17B, and C18B. Anisotropic displacement parameters of all atoms were restrained using enhanced rigid-bond restraints (RIGU command, s.u.'s 0.001 Å2; Thorn et al., 2012). The restraint SADI was also used for the disordered tetra­metyl­ammonium cation.

Computing details top

For both compounds, data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: publCIF (Westrip, 2010) and enCIFer (Allen et al., 2004).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 35% probability level. Dashed lines indicate O—H···O hydrogen bonds. Covalent bonds in the major and minor parts of the disordered are shaded differently and H atoms have been omitted for clarity. The labelling scheme A and B applied to the aromatic rings is used to identify the rings in the subsequent discussion.
[Figure 2] Fig. 2. The asymmetric unit of (II), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 35% probability level. The pyridine ring labelled C is discussed in the text. [Symmetry codes: (i) 1 - x, y, 1/2 - z; (ii) -x, y, 1/2 - z.]
[Figure 3] Fig. 3. A view of the two-dimensional layer structure of (II) along the b axis. 2,2'-Bipy molecules and H atoms bonded to C and N atoms of the en ligands have been omitted for clarity.
[Figure 4] Fig. 4. A view of the two-dimensional anionic [Fe(2,2'-bipy)(CN)4]- graphitic-like sheet structure in (I), parallel to the ab plane, with ππ interactions shown as dashed lines. H atoms have been omitted for clarity.
[Figure 5] Fig. 5. Self-assembly of the water tetramer (H2O)4 and hexamer (H2O)6 by O—H···O hydrogen bonds into the one-dimensional ladder-like chain, and representation of O—H···N hydrogen bonds between the water chain and anionic [Fe(2,2'-bipy)(CN)4]- units. See Table 1 for symmetry codes.
[Figure 6] Fig. 6. A portion of the crystal packing in (II) viewed in the bc plane showing ππ stacking interactions (dashed lines).
(I) Tetramethylammonium (2,2'-bipyridine-κ2N,N')tetracyanidoferrate(III) trihydrate top
Crystal data top
(C4H12N)[Fe(CN)4(C10H8N2)]·3H2OZ = 2
Mr = 444.31F(000) = 466
Triclinic, P1Dx = 1.323 Mg m3
a = 6.8690 (9) ÅMo Kα radiation, λ = 0.71073 Å
b = 11.9405 (16) ÅCell parameters from 9941 reflections
c = 14.2731 (17) Åθ = 3.0–36.4°
α = 104.107 (4)°µ = 0.71 mm1
β = 99.695 (4)°T = 296 K
γ = 92.235 (4)°Block, orange
V = 1115.2 (2) Å30.22 × 0.16 × 0.08 mm
Data collection top
Bruker APEXII D8 QUEST CMOS
diffractometer
3982 independent reflections
Radiation source: microfocus sealed x-ray tube, Incoatec Iµus3015 reflections with I > 2σ(I)
GraphiteDouble Bounce Multilayer Mirror monochromatorRint = 0.072
Detector resolution: 10.5 pixels mm-1θmax = 25.2°, θmin = 3.0°
ω and φ scansh = 88
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
k = 1414
Tmin = 0.691, Tmax = 0.745l = 1617
20120 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.053H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.142 w = 1/[σ2(Fo2) + (0.0712P)2 + 0.9213P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
3982 reflectionsΔρmax = 0.72 e Å3
321 parametersΔρmin = 0.59 e Å3
87 restraints
Crystal data top
(C4H12N)[Fe(CN)4(C10H8N2)]·3H2Oγ = 92.235 (4)°
Mr = 444.31V = 1115.2 (2) Å3
Triclinic, P1Z = 2
a = 6.8690 (9) ÅMo Kα radiation
b = 11.9405 (16) ŵ = 0.71 mm1
c = 14.2731 (17) ÅT = 296 K
α = 104.107 (4)°0.22 × 0.16 × 0.08 mm
β = 99.695 (4)°
Data collection top
Bruker APEXII D8 QUEST CMOS
diffractometer
3982 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
3015 reflections with I > 2σ(I)
Tmin = 0.691, Tmax = 0.745Rint = 0.072
20120 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.05387 restraints
wR(F2) = 0.142H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.72 e Å3
3982 reflectionsΔρmin = 0.59 e Å3
321 parameters
Special details top

Experimental. Absorption correction: SADABS-2014/4 (Bruker,2014/4) was used for absorption correction. wR2(int) was 0.0760 before and 0.0587 after correction. The Ratio of minimum to maximum transmission is 0.9266. The λ/2 correction factor is 0.00150.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Fe10.66815 (7)0.18786 (4)0.33212 (4)0.03351 (19)
N10.3698 (6)0.2365 (4)0.1661 (3)0.0673 (11)
N20.8300 (7)0.0198 (4)0.1707 (3)0.0754 (12)
N30.4210 (6)0.0265 (3)0.3445 (3)0.0589 (9)
N40.9261 (6)0.3973 (3)0.3139 (3)0.0596 (10)
N50.8717 (4)0.1745 (2)0.4441 (2)0.0316 (6)
N60.5553 (4)0.2840 (2)0.4410 (2)0.0329 (6)
C10.4755 (6)0.2152 (3)0.2280 (3)0.0458 (9)
C20.7745 (6)0.0849 (4)0.2313 (3)0.0467 (10)
C30.5079 (5)0.0512 (3)0.3399 (2)0.0353 (8)
C40.8320 (6)0.3212 (4)0.3207 (3)0.0415 (9)
C51.0370 (5)0.1194 (3)0.4385 (3)0.0368 (8)
H51.06150.08230.37680.044*
C61.1713 (5)0.1153 (3)0.5197 (3)0.0420 (9)
H61.28490.07640.51320.050*
C71.1364 (6)0.1694 (3)0.6109 (3)0.0456 (9)
H71.22480.16680.66720.055*
C80.9667 (6)0.2285 (3)0.6182 (3)0.0449 (9)
H80.94040.26640.67930.054*
C90.8387 (5)0.2298 (3)0.5336 (3)0.0341 (8)
C100.6566 (5)0.2913 (3)0.5321 (3)0.0346 (8)
C110.5933 (6)0.3533 (3)0.6147 (3)0.0460 (9)
H110.66650.35830.67690.055*
C120.4214 (6)0.4078 (3)0.6046 (3)0.0495 (10)
H120.37670.44980.65970.059*
C130.3164 (6)0.3992 (3)0.5119 (3)0.0458 (10)
H130.19940.43530.50340.055*
C140.3861 (5)0.3368 (3)0.4321 (3)0.0388 (8)
H140.31390.33080.36960.047*
N70.7782 (5)0.1799 (3)0.9466 (2)0.0597 (8)
C150.7397 (8)0.0530 (4)0.9254 (4)0.0789 (12)
H15A0.76210.02960.98590.118*
H15B0.82720.01610.88380.118*
H15C0.60480.03070.89280.118*
C16A0.901 (2)0.1995 (11)0.8753 (9)0.078 (2)0.440 (6)
H16A0.83500.16080.80990.116*0.440 (6)
H16B1.02720.16930.88890.116*0.440 (6)
H16C0.92020.28110.88090.116*0.440 (6)
C16B0.7816 (19)0.2208 (9)0.8579 (6)0.081 (2)0.560 (6)
H16D0.64840.21990.82370.121*0.560 (6)
H16E0.85510.17090.81580.121*0.560 (6)
H16F0.84360.29840.87600.121*0.560 (6)
C17A0.5779 (14)0.2172 (11)0.9193 (10)0.085 (2)0.440 (6)
H17A0.48130.16900.93610.128*0.440 (6)
H17B0.54970.21050.84990.128*0.440 (6)
H17C0.57290.29640.95420.128*0.440 (6)
C17B0.6394 (16)0.2374 (9)1.0058 (8)0.091 (2)0.560 (6)
H17D0.64230.31771.00520.137*0.560 (6)
H17E0.67660.23121.07210.137*0.560 (6)
H17F0.50790.20110.97890.137*0.560 (6)
C18A0.846 (2)0.2542 (10)1.0479 (6)0.080 (2)0.440 (6)
H18A0.81360.33221.05000.120*0.440 (6)
H18B0.98630.25311.06640.120*0.440 (6)
H18C0.78030.22531.09270.120*0.440 (6)
C18B0.9780 (11)0.1987 (8)1.0119 (7)0.0764 (19)0.560 (6)
H18D1.02510.27901.02730.115*0.560 (6)
H18E1.06900.15220.97870.115*0.560 (6)
H18F0.96780.17701.07150.115*0.560 (6)
O31.0432 (6)0.5315 (3)0.1904 (3)0.0675 (9)
O10.3484 (7)0.4452 (4)0.1018 (4)0.0881 (12)
O20.6905 (8)0.5827 (5)0.1007 (4)0.1151 (16)
H3A1.007 (7)0.491 (3)0.226 (3)0.076 (16)*
H1A0.360 (10)0.384 (3)0.120 (4)0.12 (2)*
H3B1.134 (9)0.500 (6)0.162 (5)0.19 (4)*
H2A0.795 (6)0.561 (6)0.129 (5)0.15 (3)*
H2B0.588 (7)0.543 (9)0.103 (9)0.28 (7)*
H1B0.296 (16)0.432 (6)0.042 (2)0.23 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Fe10.0330 (3)0.0381 (3)0.0315 (3)0.0052 (2)0.0066 (2)0.0119 (2)
N10.064 (3)0.084 (3)0.055 (2)0.008 (2)0.008 (2)0.031 (2)
N20.082 (3)0.089 (3)0.053 (2)0.024 (2)0.025 (2)0.003 (2)
N30.055 (2)0.056 (2)0.066 (2)0.0004 (19)0.0092 (19)0.0178 (19)
N40.054 (2)0.060 (2)0.077 (3)0.0019 (19)0.019 (2)0.035 (2)
N50.0305 (15)0.0323 (15)0.0343 (15)0.0044 (12)0.0081 (13)0.0111 (13)
N60.0304 (15)0.0314 (16)0.0389 (16)0.0045 (12)0.0072 (13)0.0119 (13)
C10.047 (2)0.051 (2)0.041 (2)0.0047 (19)0.0058 (19)0.0161 (19)
C20.048 (2)0.053 (2)0.036 (2)0.0061 (19)0.0045 (19)0.0080 (19)
C30.0358 (19)0.039 (2)0.0297 (18)0.0055 (17)0.0033 (15)0.0075 (16)
C40.038 (2)0.052 (2)0.038 (2)0.0141 (18)0.0082 (17)0.0172 (18)
C50.0346 (19)0.037 (2)0.042 (2)0.0053 (15)0.0102 (16)0.0131 (16)
C60.0337 (19)0.041 (2)0.057 (2)0.0072 (16)0.0088 (18)0.0224 (19)
C70.041 (2)0.053 (2)0.046 (2)0.0026 (18)0.0016 (18)0.026 (2)
C80.045 (2)0.054 (2)0.037 (2)0.0031 (18)0.0056 (18)0.0144 (18)
C90.0322 (18)0.0364 (19)0.0345 (18)0.0009 (15)0.0042 (15)0.0121 (15)
C100.0330 (18)0.0348 (19)0.0382 (19)0.0023 (15)0.0096 (16)0.0116 (16)
C110.050 (2)0.050 (2)0.037 (2)0.0049 (19)0.0113 (18)0.0074 (18)
C120.048 (2)0.046 (2)0.054 (3)0.0067 (19)0.024 (2)0.0024 (19)
C130.037 (2)0.037 (2)0.067 (3)0.0083 (17)0.017 (2)0.0128 (19)
C140.0310 (18)0.039 (2)0.049 (2)0.0039 (16)0.0074 (17)0.0156 (17)
N70.0690 (19)0.0535 (17)0.0545 (17)0.0007 (15)0.0077 (15)0.0133 (14)
C150.089 (3)0.0683 (19)0.078 (3)0.0004 (17)0.014 (2)0.0188 (17)
C16A0.092 (4)0.069 (4)0.074 (4)0.003 (3)0.023 (3)0.018 (3)
C16B0.100 (5)0.076 (4)0.067 (3)0.001 (4)0.010 (3)0.024 (3)
C17A0.084 (3)0.085 (4)0.079 (4)0.012 (3)0.006 (2)0.012 (3)
C17B0.100 (4)0.097 (4)0.081 (4)0.024 (3)0.024 (3)0.023 (3)
C18A0.086 (5)0.081 (4)0.065 (2)0.006 (3)0.010 (2)0.008 (2)
C18B0.082 (3)0.068 (4)0.074 (3)0.002 (2)0.004 (2)0.015 (3)
O30.075 (2)0.068 (2)0.070 (2)0.0046 (18)0.0206 (19)0.0325 (18)
O10.083 (3)0.089 (3)0.116 (4)0.025 (2)0.035 (3)0.058 (3)
O20.078 (3)0.146 (4)0.142 (4)0.012 (3)0.006 (3)0.084 (4)
Geometric parameters (Å, º) top
Fe1—N51.981 (3)N7—C16B1.468 (6)
Fe1—N61.985 (3)N7—C17A1.482 (7)
Fe1—C11.917 (4)N7—C17B1.460 (7)
Fe1—C21.917 (4)N7—C18A1.486 (7)
Fe1—C31.969 (4)N7—C18B1.498 (6)
Fe1—C41.969 (4)C15—H15A0.9600
N1—C11.132 (5)C15—H15B0.9600
N2—C21.142 (5)C15—H15C0.9600
N3—C31.105 (5)C16A—H16A0.9600
N4—C41.127 (5)C16A—H16B0.9600
N5—C51.339 (4)C16A—H16C0.9600
N5—C91.349 (4)C16B—H16D0.9600
N6—C101.348 (4)C16B—H16E0.9600
N6—C141.346 (4)C16B—H16F0.9600
C5—H50.9300C17A—H17A0.9600
C5—C61.367 (5)C17A—H17B0.9600
C6—H60.9300C17A—H17C0.9600
C6—C71.370 (5)C17B—H17D0.9600
C7—H70.9300C17B—H17E0.9600
C7—C81.391 (5)C17B—H17F0.9600
C8—H80.9300C18A—H18A0.9600
C8—C91.372 (5)C18A—H18B0.9600
C9—C101.475 (5)C18A—H18C0.9600
C10—C111.379 (5)C18B—H18D0.9600
C11—H110.9300C18B—H18E0.9600
C11—C121.373 (6)C18B—H18F0.9600
C12—H120.9300O3—H3A0.840 (10)
C12—C131.374 (6)O3—H3B0.847 (10)
C13—H130.9300O1—H1A0.836 (10)
C13—C141.371 (5)O1—H1B0.838 (10)
C14—H140.9300O2—H2A0.842 (10)
N7—C151.475 (5)O2—H2B0.840 (10)
N7—C16A1.481 (7)
N5—Fe1—N681.14 (11)C15—N7—C17A102.4 (6)
C1—Fe1—N5175.01 (15)C15—N7—C18A122.6 (6)
C1—Fe1—N695.97 (14)C15—N7—C18B101.2 (5)
C1—Fe1—C286.42 (17)C16A—N7—C17A108.8 (8)
C1—Fe1—C392.47 (15)C16A—N7—C18A114.0 (8)
C1—Fe1—C487.33 (16)C16B—N7—C15112.9 (5)
C2—Fe1—N596.73 (14)C16B—N7—C18B111.8 (7)
C2—Fe1—N6175.52 (14)C17A—N7—C18A102.4 (8)
C2—Fe1—C386.72 (16)C17B—N7—C15110.2 (6)
C2—Fe1—C491.34 (17)C17B—N7—C16B112.9 (7)
C3—Fe1—N591.57 (13)C17B—N7—C18B107.1 (6)
C3—Fe1—N689.39 (13)N7—C15—H15A109.5
C4—Fe1—N588.73 (13)N7—C15—H15B109.5
C4—Fe1—N692.55 (13)N7—C15—H15C109.5
C4—Fe1—C3178.06 (15)H15A—C15—H15B109.5
C5—N5—Fe1126.4 (2)H15A—C15—H15C109.5
C5—N5—C9118.4 (3)H15B—C15—H15C109.5
C9—N5—Fe1115.1 (2)N7—C16A—H16A109.5
C10—N6—Fe1115.3 (2)N7—C16A—H16B109.5
C14—N6—Fe1126.3 (3)N7—C16A—H16C109.5
C14—N6—C10118.3 (3)H16A—C16A—H16B109.5
N1—C1—Fe1175.8 (4)H16A—C16A—H16C109.5
N2—C2—Fe1176.6 (4)H16B—C16A—H16C109.5
N3—C3—Fe1178.7 (3)N7—C16B—H16D109.5
N4—C4—Fe1179.8 (4)N7—C16B—H16E109.5
N5—C5—H5118.7N7—C16B—H16F109.5
N5—C5—C6122.7 (3)H16D—C16B—H16E109.5
C6—C5—H5118.7H16D—C16B—H16F109.5
C5—C6—H6120.5H16E—C16B—H16F109.5
C5—C6—C7119.1 (3)N7—C17A—H17A109.5
C7—C6—H6120.5N7—C17A—H17B109.5
C6—C7—H7120.5N7—C17A—H17C109.5
C6—C7—C8119.1 (4)H17A—C17A—H17B109.5
C8—C7—H7120.5H17A—C17A—H17C109.5
C7—C8—H8120.6H17B—C17A—H17C109.5
C9—C8—C7118.8 (4)N7—C17B—H17D109.5
C9—C8—H8120.6N7—C17B—H17E109.5
N5—C9—C8121.9 (3)N7—C17B—H17F109.5
N5—C9—C10114.4 (3)H17D—C17B—H17E109.5
C8—C9—C10123.7 (3)H17D—C17B—H17F109.5
N6—C10—C9114.0 (3)H17E—C17B—H17F109.5
N6—C10—C11121.6 (3)N7—C18A—H18A109.5
C11—C10—C9124.4 (3)N7—C18A—H18B109.5
C10—C11—H11120.2N7—C18A—H18C109.5
C12—C11—C10119.5 (4)H18A—C18A—H18B109.5
C12—C11—H11120.2H18A—C18A—H18C109.5
C11—C12—H12120.5H18B—C18A—H18C109.5
C11—C12—C13119.0 (4)N7—C18B—H18D109.5
C13—C12—H12120.5N7—C18B—H18E109.5
C12—C13—H13120.4N7—C18B—H18F109.5
C14—C13—C12119.2 (4)H18D—C18B—H18E109.5
C14—C13—H13120.4H18D—C18B—H18F109.5
N6—C14—C13122.4 (4)H18E—C18B—H18F109.5
N6—C14—H14118.8H3A—O3—H3B109 (3)
C13—C14—H14118.8H1A—O1—H1B112 (3)
C15—N7—C16A105.4 (6)H2A—O2—H2B112 (3)
Fe1—N5—C5—C6179.2 (3)C6—C7—C8—C90.5 (6)
Fe1—N5—C9—C8179.9 (3)C7—C8—C9—N50.8 (6)
Fe1—N5—C9—C100.3 (4)C7—C8—C9—C10178.8 (3)
Fe1—N6—C10—C92.4 (4)C8—C9—C10—N6178.2 (3)
Fe1—N6—C10—C11178.8 (3)C8—C9—C10—C110.5 (6)
Fe1—N6—C14—C13178.2 (3)C9—N5—C5—C61.2 (5)
N5—C5—C6—C70.1 (5)C9—C10—C11—C12179.7 (3)
N5—C9—C10—N61.4 (4)C10—N6—C14—C131.4 (5)
N5—C9—C10—C11179.8 (3)C10—C11—C12—C130.1 (6)
N6—C10—C11—C121.0 (6)C11—C12—C13—C140.1 (6)
C5—N5—C9—C81.7 (5)C12—C13—C14—N60.5 (6)
C5—N5—C9—C10178.0 (3)C14—N6—C10—C9179.6 (3)
C5—C6—C7—C81.0 (6)C14—N6—C10—C111.6 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C17A—H17C···O2i0.962.503.112 (11)122
O3—H3A···N40.84 (1)2.00 (1)2.841 (5)178 (5)
O1—H1A···N10.84 (1)2.03 (1)2.859 (5)176 (7)
O3—H3B···O1ii0.85 (1)1.89 (1)2.736 (6)174 (7)
O2—H2A···O30.84 (1)1.87 (2)2.709 (6)172 (7)
O2—H2B···O10.84 (1)1.98 (1)2.818 (7)177 (14)
O1—H1B···O2iii0.84 (1)2.02 (6)2.792 (8)152 (11)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x+1, y, z; (iii) x+1, y+1, z.
(II) Poly[[(2,2'-bipyridine-κ2N,N')di-µ2-cyanido-dicyanido(µ-ethylenediamine)(ethylenediamine-κ2N,N')cadmium(II)iron(II)] monohydrate] top
Crystal data top
[CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2OF(000) = 1144
Mr = 566.74Dx = 1.697 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 7.4184 (14) ÅCell parameters from 9748 reflections
b = 28.534 (5) Åθ = 3.0–30.3°
c = 11.094 (2) ŵ = 1.65 mm1
β = 109.143 (6)°T = 296 K
V = 2218.3 (7) Å3Block, dark red
Z = 40.3 × 0.26 × 0.14 mm
Data collection top
Bruker APEXII D8 QUEST CMOS
diffractometer
2757 independent reflections
Radiation source: microfocus sealed x-ray tube, Incoatec Iµus2478 reflections with I > 2σ(I)
GraphiteDouble Bounce Multilayer Mirror monochromatorRint = 0.038
Detector resolution: 10.5 pixels mm-1θmax = 28.3°, θmin = 3.0°
φ and ω scansh = 99
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
k = 3837
Tmin = 0.633, Tmax = 0.746l = 1414
51158 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.020H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.046 w = 1/[σ2(Fo2) + (0.0207P)2 + 2.0817P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.004
2757 reflectionsΔρmax = 0.47 e Å3
146 parametersΔρmin = 0.47 e Å3
2 restraints
Crystal data top
[CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2OV = 2218.3 (7) Å3
Mr = 566.74Z = 4
Monoclinic, C2/cMo Kα radiation
a = 7.4184 (14) ŵ = 1.65 mm1
b = 28.534 (5) ÅT = 296 K
c = 11.094 (2) Å0.3 × 0.26 × 0.14 mm
β = 109.143 (6)°
Data collection top
Bruker APEXII D8 QUEST CMOS
diffractometer
2757 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
2478 reflections with I > 2σ(I)
Tmin = 0.633, Tmax = 0.746Rint = 0.038
51158 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0202 restraints
wR(F2) = 0.046H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.47 e Å3
2757 reflectionsΔρmin = 0.47 e Å3
146 parameters
Special details top

Experimental. SADABS-2014/5 (Bruker,2014/5) was used for absorption correction. wR2(int) was 0.0955 before and 0.0483 after correction. The Ratio of minimum to maximum transmission is 0.8480. The λ/2 correction factor is 0.00150.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cd11.00000.49884 (2)0.75000.02579 (6)
Fe10.50000.37467 (2)0.75000.02273 (7)
N40.75926 (17)0.48296 (5)0.56872 (12)0.0267 (3)
H4A0.79370.49170.50240.032*
H4B0.74000.45210.56320.032*
N30.3184 (2)0.32132 (5)0.68950 (13)0.0302 (3)
N10.8094 (2)0.44919 (5)0.85021 (13)0.0322 (3)
N50.9225 (2)0.56629 (5)0.85229 (14)0.0366 (3)
H5A0.79640.56990.82710.044*
H5B0.96390.56210.93650.044*
C80.5794 (2)0.50634 (5)0.56058 (14)0.0268 (3)
H8A0.59830.54000.56360.032*
H8B0.54250.49750.63360.032*
C10.6899 (2)0.42120 (5)0.81322 (14)0.0247 (3)
N20.5958 (3)0.37056 (6)0.49974 (16)0.0510 (4)
C20.5568 (2)0.37319 (5)0.59168 (15)0.0304 (3)
C70.3972 (3)0.27812 (6)0.71567 (17)0.0359 (4)
C30.1298 (3)0.32437 (7)0.62837 (18)0.0397 (4)
H30.07460.35390.61170.048*
C40.0142 (3)0.28557 (8)0.5892 (2)0.0524 (5)
H40.11580.28910.54660.063*
C91.0114 (3)0.60852 (6)0.82011 (18)0.0441 (4)
H9A1.14590.60920.87020.053*
H9B0.95170.63630.84060.053*
C60.2860 (3)0.23784 (7)0.6780 (2)0.0531 (5)
H60.34220.20840.69630.064*
C50.0941 (4)0.24163 (8)0.6142 (2)0.0593 (6)
H50.01930.21500.58830.071*
O10.50000.40519 (9)0.25000.0599 (6)
H10.510 (5)0.3877 (6)0.3156 (11)0.093 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.01948 (8)0.02751 (9)0.02482 (9)0.0000.00030 (6)0.000
Fe10.02656 (15)0.01792 (14)0.02166 (14)0.0000.00513 (11)0.000
N40.0199 (6)0.0310 (7)0.0259 (6)0.0007 (5)0.0030 (5)0.0003 (5)
N30.0388 (8)0.0243 (6)0.0276 (7)0.0063 (6)0.0111 (6)0.0029 (5)
N10.0300 (7)0.0325 (7)0.0321 (7)0.0047 (6)0.0074 (6)0.0002 (6)
N50.0442 (9)0.0326 (8)0.0365 (8)0.0031 (6)0.0178 (7)0.0032 (6)
C80.0190 (7)0.0330 (8)0.0239 (7)0.0019 (6)0.0009 (6)0.0024 (6)
C10.0270 (7)0.0246 (7)0.0214 (7)0.0042 (6)0.0066 (6)0.0024 (6)
N20.0791 (13)0.0434 (9)0.0369 (9)0.0018 (9)0.0277 (9)0.0007 (7)
C20.0373 (8)0.0218 (7)0.0292 (8)0.0003 (6)0.0072 (7)0.0009 (6)
C70.0507 (10)0.0233 (8)0.0370 (9)0.0040 (7)0.0188 (8)0.0015 (7)
C30.0390 (10)0.0344 (9)0.0411 (10)0.0077 (8)0.0069 (8)0.0013 (7)
C40.0465 (11)0.0498 (12)0.0560 (13)0.0194 (9)0.0100 (10)0.0085 (10)
C90.0634 (13)0.0291 (9)0.0427 (11)0.0014 (8)0.0213 (9)0.0030 (7)
C60.0699 (15)0.0250 (9)0.0675 (14)0.0094 (9)0.0265 (12)0.0060 (9)
C50.0670 (15)0.0395 (11)0.0710 (15)0.0264 (10)0.0222 (12)0.0154 (10)
O10.0733 (15)0.0704 (15)0.0342 (11)0.0000.0151 (11)0.000
Geometric parameters (Å, º) top
Cd1—N4i2.2546 (13)N5—H5B0.8900
Cd1—N42.2547 (13)N5—C91.473 (2)
Cd1—N1i2.5046 (14)C8—C8iii1.512 (3)
Cd1—N12.5045 (14)C8—H8A0.9700
Cd1—N5i2.3981 (15)C8—H8B0.9700
Cd1—N52.3980 (15)N2—C21.150 (2)
Fe1—N31.9976 (14)C7—C7ii1.465 (4)
Fe1—N3ii1.9976 (14)C7—C61.396 (3)
Fe1—C1ii1.8951 (16)C3—H30.9300
Fe1—C11.8950 (16)C3—C41.380 (3)
Fe1—C2ii1.9362 (17)C4—H40.9300
Fe1—C21.9363 (17)C4—C51.376 (3)
N4—H4A0.8900C9—C9i1.509 (4)
N4—H4B0.8900C9—H9A0.9700
N4—C81.4681 (19)C9—H9B0.9700
N3—C71.354 (2)C6—H60.9300
N3—C31.343 (2)C6—C51.370 (3)
N1—C11.163 (2)C5—H50.9300
N5—H5A0.8900O1—H10.865 (9)
N4i—Cd1—N4156.82 (7)C3—N3—C7118.18 (15)
N4i—Cd1—N1i83.39 (5)C1—N1—Cd1135.03 (12)
N4i—Cd1—N183.56 (5)Cd1—N5—H5A109.6
N4—Cd1—N183.39 (5)Cd1—N5—H5B109.6
N4—Cd1—N1i83.56 (5)H5A—N5—H5B108.1
N4i—Cd1—N588.96 (5)C9—N5—Cd1110.25 (11)
N4—Cd1—N5i88.96 (5)C9—N5—H5A109.6
N4—Cd1—N5109.92 (5)C9—N5—H5B109.6
N4i—Cd1—N5i109.91 (5)N4—C8—C8iii111.91 (16)
N1—Cd1—N1i111.12 (7)N4—C8—H8A109.2
N5—Cd1—N1i157.20 (5)N4—C8—H8B109.2
N5i—Cd1—N1i89.20 (5)C8iii—C8—H8A109.2
N5i—Cd1—N1157.20 (5)C8iii—C8—H8B109.2
N5—Cd1—N189.20 (5)H8A—C8—H8B107.9
N5—Cd1—N5i73.24 (7)N1—C1—Fe1178.15 (14)
N3—Fe1—N3ii80.69 (8)N2—C2—Fe1176.85 (16)
C1ii—Fe1—N394.13 (6)N3—C7—C7ii114.47 (10)
C1—Fe1—N3ii94.12 (6)N3—C7—C6120.93 (18)
C1ii—Fe1—N3ii174.82 (6)C6—C7—C7ii124.60 (13)
C1—Fe1—N3174.81 (6)N3—C3—H3118.5
C1—Fe1—C1ii91.06 (9)N3—C3—C4122.95 (19)
C1ii—Fe1—C292.07 (6)C4—C3—H3118.5
C1—Fe1—C289.69 (7)C3—C4—H4120.5
C1ii—Fe1—C2ii89.69 (7)C5—C4—C3119.0 (2)
C1—Fe1—C2ii92.07 (7)C5—C4—H4120.5
C2ii—Fe1—N3ii90.11 (6)N5—C9—C9i110.03 (14)
C2—Fe1—N3ii87.98 (6)N5—C9—H9A109.7
C2—Fe1—N390.11 (6)N5—C9—H9B109.7
C2ii—Fe1—N387.98 (6)C9i—C9—H9A109.7
C2ii—Fe1—C2177.49 (9)C9i—C9—H9B109.7
Cd1—N4—H4A108.8H9A—C9—H9B108.2
Cd1—N4—H4B108.8C7—C6—H6120.0
H4A—N4—H4B107.7C5—C6—C7120.1 (2)
C8—N4—Cd1113.68 (9)C5—C6—H6120.0
C8—N4—H4A108.8C4—C5—H5120.6
C8—N4—H4B108.8C6—C5—C4118.82 (19)
C7—N3—Fe1115.19 (12)C6—C5—H5120.6
C3—N3—Fe1126.62 (12)
Cd1—N4—C8—C8iii178.38 (14)C7—N3—C3—C41.2 (3)
Cd1—N5—C9—C9i43.1 (2)C7ii—C7—C6—C5179.9 (2)
Fe1—N3—C7—C7ii0.1 (2)C7—C6—C5—C40.5 (4)
Fe1—N3—C7—C6179.70 (15)C3—N3—C7—C7ii179.03 (18)
Fe1—N3—C3—C4179.74 (15)C3—N3—C7—C61.2 (3)
N3—C7—C6—C50.3 (3)C3—C4—C5—C60.4 (4)
N3—C3—C4—C50.4 (3)
Symmetry codes: (i) x+2, y, z+3/2; (ii) x+1, y, z+3/2; (iii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N5—H5A···O1iii0.892.203.0726 (18)167
O1—H1···N20.87 (1)1.99 (1)2.8045 (19)156 (2)
Symmetry code: (iii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
C17A—H17C···O2i0.962.503.112 (11)121.6
O3—H3A···N40.840 (10)2.001 (11)2.841 (5)178 (5)
O1—H1A···N10.836 (10)2.025 (13)2.859 (5)176 (7)
O3—H3B···O1ii0.847 (10)1.893 (13)2.736 (6)174 (7)
O2—H2A···O30.842 (10)1.872 (15)2.709 (6)172 (7)
O2—H2B···O10.840 (10)1.979 (14)2.818 (7)177 (14)
O1—H1B···O2iii0.838 (10)2.02 (6)2.792 (8)152 (11)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x+1, y, z; (iii) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
N5—H5A···O1i0.892.203.0726 (18)166.8
O1—H1···N20.865 (9)1.991 (10)2.8045 (19)156 (2)
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

(I)(II)
Crystal data
Chemical formula(C4H12N)[Fe(CN)4(C10H8N2)]·3H2O[CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O
Mr444.31566.74
Crystal system, space groupTriclinic, P1Monoclinic, C2/c
Temperature (K)296296
a, b, c (Å)6.8690 (9), 11.9405 (16), 14.2731 (17)7.4184 (14), 28.534 (5), 11.094 (2)
α, β, γ (°)104.107 (4), 99.695 (4), 92.235 (4)90, 109.143 (6), 90
V3)1115.2 (2)2218.3 (7)
Z24
Radiation typeMo KαMo Kα
µ (mm1)0.711.65
Crystal size (mm)0.22 × 0.16 × 0.080.3 × 0.26 × 0.14
Data collection
DiffractometerBruker APEXII D8 QUEST CMOSBruker APEXII D8 QUEST CMOS
Absorption correctionMulti-scan
(SADABS; Bruker, 2014)
Multi-scan
(SADABS; Bruker, 2014)
Tmin, Tmax0.691, 0.7450.633, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections
20120, 3982, 3015 51158, 2757, 2478
Rint0.0720.038
(sin θ/λ)max1)0.5990.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.142, 1.04 0.020, 0.046, 1.07
No. of reflections39822757
No. of parameters321146
No. of restraints872
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.72, 0.590.47, 0.47

Computer programs: APEX2 (Bruker, 2014), SAINT (Bruker, 2014), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b), OLEX2 (Dolomanov et al., 2009), publCIF (Westrip, 2010) and enCIFer (Allen et al., 2004).

 

Acknowledgements

This research was supported financially by a research career development grant (No. RSA5780056) from the Thailand Research Fund. SC acknowledges financial support from the Thailand Graduate Institute of Science and Technology (TGIST: TG-55–26-55–047M).

References

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Volume 72| Part 5| May 2016| Pages 741-746
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