Crystal structure of catena-poly[N,N,N′,N′-tetra­methyl­guanidinium [(chlorido­cadmate)-di-μ-chlorido]]

Ndiaye, M.; Samb, A.; Diop, L.; Maris, T.

doi:10.1107/S2056989015020836

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Volume 72| Part 1| January 2016| Pages 1-3

doi:10.1107/S2056989015020836

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Crystal structure of catena-poly[N,N,N′,N′-tetramethylguanidinium [(chloridocadmate)-di-μ-chlorido]]

Mamadou Ndiaye,^a Abdoulaye Samb,^a Libasse Diop ^b ^* and Thierry Maris ^c ^*

^aLaboratoire des Produits Naturels, Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, ^bLaboratoire de Chimie Minérale et Analytique, Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, and ^cDépartement de Chimie, Université de Montréal, 2900 Boulevard Édouard-Montpetit, Montréal, Québec, H3C 3J7, Canada
^*Correspondence e-mail: dlibasse@gmail.com, thierry.maris@umontreal.ca

Edited by M. Weil, Vienna University of Technology, Austria (Received 20 August 2015; accepted 3 November 2015; online 1 January 2016)

In the structure of the title salt, {(C₅H₁₄N₃)[CdCl₃]}_n, the Cd^II atom of the complex anion is five-coordinated by one terminal and four bridging Cl atoms. The corresponding coordination polyhedron is a distorted trigonal bipyramid, with Cd—Cl distances in the range 2.4829 (4)–2.6402 (4) Å. The bipyramids are condensed into a polyanionic zigzag chain extending parallel to [101]. The tetramethylguanidinium cations are situated between the polyanionic chains and are linked to them through N—H⋯Cl hydrogen bonds, forming a layered network parallel to (010).

Keywords: crystal structure; five-coordinated cadmium; N—H⋯Cl hydrogen bonds; polyanionic chain.

CCDC reference: 1434977

1. Chemical context

Tetramethylguanidine is known to crystallize in its neutral form, as a Lewis base or as a singly protonated cation. Several cationic complexes of Pd, Ga and Pt have been reported with tetramethylguanidine acting as a ligand (Li et al., 2005 ; Cowley et al., 2005 ; Eliseev et al., 2013 ), and halogenidometalates have been reported with tetramethylguanidinium as a counter-cation (Bujak et al., 1999 ; Bujak & Zaleski, 2007 ). Since none of these complexes has cadmium as a component, we decided to study the interactions between tetramethylguanidine and [CdCl₂]·H₂O, which has yielded the title salt, (C₅H₁₄N₃)⁺[CdCl₃]⁻, (I).

2. Structural commentary

The asymmetric unit of (I) (Fig. 1) consists of a Cd^II cation surrounded by four Cl atoms and one N,N,N′,N′-tetramethylguanidinium cation. The coordination polyhedron around Cd^II can be described best as a distorted trigonal bipyramid where atoms Cl1, Cl2 and Cl4 define the equatorial plane while atoms Cl3 and Cl4ⁱ [symmetry code: (i) $[{3\over 2}]$ − x, $[{1\over 2}]$ − y, 1 − z] are in axial positions with a Cl3—Cd1—Cl4ⁱ angle of 166.347 (10)°. The equatorial Cd—Cl bond lengths range from 2.4829 (4) Å to 2.5829 (4) Å while the axial bond lengths Cd1—Cl3 and Cd1—Cl4ⁱ are 2.5854 (4) Å and 2.6403 (4) Å, respectively. The CdCl₄ moieties of the asymmetric unit are related by an inversion center, generating an extended zigzag chain of edge-sharing trigonal bipyramids running parallel to [101]. These ¹_∞[CdCl_4/2Cl_1/1]⁻ chains are formed by the bridging atoms Cl2, Cl3, Cl4 and Cl4ⁱ with a Cd—Cd—Cd angle of 137.893 (6)°. The corrugation of the chains results in rather short Cd⋯Cd distances of 3.8720 (3) and 3.8026 (3) Å. The same kind of zigzag chain is found, for example, in the [CdCl₃]⁻ salt obtained with benzyltriethylammonium as counter-cation (Sun & Jin, 2013 ) but with a less pronounced corrugation. Accordingly, the angle between two successive rectangular [Cd₂Cl₂] units is 57.928 (3)° in the structure of the benzyltriethylammonium compound compared with 129.859 (2)° for the present structure. The tetramethylguanidinium cation has the central atom C1 in an almost trigonal–planar configuration. The three N—C—N angles range from 119.26 (14) to 121.14 (14)° and the r.m.s deviation from the least-squares plane calculated with atoms C1, N1, N2 and N3 is only 0.005 Å. The corresponding C—N bond lengths of 1.330 (2), 1.3360 (19), and 1.3441 (19) Å indicate a partial double-bond character. Hence the positive charge may be considered as delocalized in the CN₃ plane (Tiritiris, 2012 ). The two pairs of dimethylammonium groups are twisted by 24.67 (8) and 27.31 (9)° with respect to this plane.

Figure 1
The asymmetric unit of compound (I)

, with displacement ellipsoids drawn at the 50% probability level. The N—H⋯Cl hydrogen bond is indicated by a dashed line.

3. Supramolecular features

The ¹_∞[CdCl_4/2Cl_1/1]⁻ chains are interconnected through N—H⋯·Cl hydrogen bonds by pairs of tetramethylguanidinium cations linked to symmetry-related Cl1 atoms (Table 1). These interactions define layers extending parallel to (010) (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯Cl1	0.83 (2)	2.51 (2)	3.2871 (15)	157 (2)
N2—H2B⋯Cl1ⁱ	0.83 (2)	2.46 (2)	3.2710 (15)	164 (2)
Symmetry code: (i) $[-x+1, y, -z+{\script{3\over 2}}]$ .

Figure 2
Partial packing diagram of (I)

, viewed along [010], showing one layer made up of alternating ¹_∞[CdCl_4/2Cl_1/1]⁻ chains and intermediate tetramethylguanidinium cations. N—H⋯Cl hydrogen bonds are shown as black dotted lines.

4. Database survey

The trichloridocadmate anion, [CdCl₃]⁻, may have various discrete or chain structures with tetrahedral, octahedral and trigonal–bipyramidal environments around the central Cd^II cation. A search in the Cambridge Structural Database (CSD Version 5.36 with three updates; Groom & Allen, 2014 ) returned only five entries with the chains having a trigonal–bipyramidal environment for Cd^II. The corresponding structures contain different cations such as sulfonium ylide (Sabounchei et al., 2013 ), tetraethylammonium (Lakshmi et al., 2004 ), hexadecyl sulfonium (Sokka et al., 2008 ), benzyltriethylammonium (Sun & Jin, 2013) or trimethylammoniumphenyl-4-thiol (Tang & Lang, 2011 ).

5. Synthesis and crystallization

Crystals suitable for a single-crystal X-ray diffraction study were obtained by mixing stoichiometric amounts of tetramethylguanidine with CdCl₂·H₂O in ethanol and allowing the solvent to evaporate slowly at room temperature.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The H-atom positions of all methyl groups were placed geometrically and refined with U_iso(H) = 1.5U_eq(C). H atoms bonded to the N atoms were located from a Fourier difference map and were refined freely.

Table 2
Experimental details

Crystal data
Chemical formula	(C₅H₁₄N₃)[CdCl₃]
M_r	334.94
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	100
a, b, c (Å)	15.1305 (7), 14.2921 (6), 11.6939 (5)
β (°)	117.370 (2)
V (Å³)	2245.69 (17)
Z	8
Radiation type	Ga Kα, λ = 1.34139 Å
μ (mm⁻¹)	14.50
Crystal size (mm)	0.19 × 0.10 × 0.10

Data collection
Diffractometer	Bruker Venture Metaljet
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.400, 0.752
No. of measured, independent and observed [I > 2σ(I)] reflections	24837, 2593, 2575
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.016, 0.040, 1.13
No. of reflections	2593
No. of parameters	122
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.63, −0.40
Computer programs: APEX2 and SAINT (Bruker, 2014 ), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), OLEX2 (Dolomanov et al., 2009 ), Mercury (Macrae et al., 2008 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1434977

Crystal structure: contains datablock I. DOI: 10.1107/S2056989015020836/wm5207sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015020836/wm5207Isup2.hkl

checkCIF report

Computing details top

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) and Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).

catena-Poly[N,N,N',N'-tetramethylguanidinium [(chloridocadmate)-di-µ-chlorido]] top

Crystal data top

(C₅H₁₄N₃)[CdCl₃]	F(000) = 1312
M_r = 334.94	D_x = 1.981 Mg m⁻³
Monoclinic, C2/c	Ga Kα radiation, λ = 1.34139 Å
a = 15.1305 (7) Å	Cell parameters from 9941 reflections
b = 14.2921 (6) Å	θ = 3.9–60.7°
c = 11.6939 (5) Å	µ = 14.50 mm⁻¹
β = 117.370 (2)°	T = 100 K
V = 2245.69 (17) Å³	Block, clear light colourless
Z = 8	0.19 × 0.10 × 0.10 mm

Data collection top

Bruker Venture Metaljet diffractometer	2593 independent reflections
Radiation source: Metal Jet, Gallium Liquid Metal Jet Source	2575 reflections with I > 2σ(I)
Helios MX Mirror Optics monochromator	R_int = 0.043
Detector resolution: 10.24 pixels mm^-1	θ_max = 60.7°, θ_min = 3.9°
ω and φ scans	h = −19→19
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	k = −18→18
T_min = 0.400, T_max = 0.752	l = −15→15
24837 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.016	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.040	w = 1/[σ²(F_o²) + (0.0144P)² + 2.6083P] where P = (F_o² + 2F_c²)/3
S = 1.13	(Δ/σ)_max = 0.001
2593 reflections	Δρ_max = 0.63 e Å⁻³
122 parameters	Δρ_min = −0.40 e Å⁻³
0 restraints

Special details top

Experimental. X-ray crystallographic data for I were collected from a single-crystal sample, which was mounted on a loop fiber. Data were collected using a Bruker Venture diffractometer equipped with a Photon 100 CMOS Detector, a Helios MX optics and a Kappa goniometer. The crystal-to-detector distance was 4.0 cm, and the data collection was carried out in 1024 x 1024 pixel mode.

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.18403 (9)	0.36639 (9)	0.56127 (12)	0.0134 (2)
N2	0.35116 (10)	0.36153 (11)	0.61584 (14)	0.0191 (3)
N3	0.24068 (10)	0.42244 (9)	0.41914 (13)	0.0150 (3)
C1	0.25851 (11)	0.38434 (10)	0.53204 (15)	0.0132 (3)
C2	0.09488 (11)	0.42502 (11)	0.51613 (15)	0.0153 (3)
H2C	0.1042	0.4816	0.4756	0.023*
H2D	0.0835	0.4425	0.5894	0.023*
H2E	0.0373	0.3901	0.4532	0.023*
C3	0.19647 (12)	0.29906 (11)	0.66197 (15)	0.0152 (3)
H3A	0.2479	0.2535	0.6719	0.023*
H3B	0.1334	0.2664	0.6379	0.023*
H3C	0.2164	0.3322	0.7435	0.023*
C4	0.14557 (12)	0.41074 (12)	0.30272 (15)	0.0200 (3)
H4A	0.1074	0.3604	0.3163	0.030*
H4B	0.1581	0.3948	0.2300	0.030*
H4C	0.1076	0.4692	0.2842	0.030*
C5	0.32011 (13)	0.46786 (12)	0.40087 (17)	0.0212 (3)
H5A	0.3718	0.4902	0.4841	0.032*
H5B	0.2926	0.5210	0.3420	0.032*
H5C	0.3491	0.4228	0.3643	0.032*
Cd1	0.60861 (2)	0.27596 (2)	0.41882 (2)	0.01199 (5)
Cl1	0.54707 (3)	0.30385 (3)	0.57950 (3)	0.01619 (8)
Cl2	0.5000	0.15363 (3)	0.2500	0.01344 (10)
Cl3	0.5000	0.39855 (4)	0.2500	0.01852 (11)
Cl4	0.76617 (3)	0.35865 (2)	0.45006 (4)	0.01607 (8)
H2A	0.3944 (15)	0.3603 (16)	0.591 (2)	0.021 (5)*
H2B	0.3677 (16)	0.3540 (16)	0.694 (2)	0.026 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0108 (6)	0.0151 (6)	0.0146 (6)	0.0020 (5)	0.0061 (5)	0.0016 (5)
N2	0.0120 (6)	0.0333 (8)	0.0139 (7)	0.0037 (5)	0.0076 (5)	0.0038 (6)
N3	0.0148 (6)	0.0161 (6)	0.0152 (6)	0.0008 (5)	0.0079 (5)	0.0010 (5)
C1	0.0143 (7)	0.0120 (7)	0.0141 (7)	0.0012 (5)	0.0072 (6)	−0.0027 (5)
C2	0.0118 (7)	0.0156 (7)	0.0196 (7)	0.0026 (5)	0.0083 (6)	−0.0001 (6)
C3	0.0140 (7)	0.0174 (7)	0.0151 (7)	0.0016 (6)	0.0073 (6)	0.0020 (6)
C4	0.0200 (8)	0.0249 (8)	0.0124 (7)	0.0067 (6)	0.0052 (6)	0.0027 (6)
C5	0.0232 (8)	0.0210 (8)	0.0254 (8)	0.0017 (6)	0.0163 (7)	0.0050 (7)
Cd1	0.00895 (7)	0.01692 (7)	0.01027 (7)	−0.00065 (3)	0.00457 (5)	−0.00147 (3)
Cl1	0.01164 (16)	0.02608 (19)	0.01180 (16)	0.00064 (14)	0.00620 (13)	−0.00316 (14)
Cl2	0.0121 (2)	0.0156 (2)	0.0115 (2)	0.000	0.00446 (18)	0.000
Cl3	0.0168 (2)	0.0176 (2)	0.0151 (2)	0.000	0.00209 (19)	0.000
Cl4	0.01132 (16)	0.01586 (16)	0.02072 (18)	−0.00045 (12)	0.00710 (14)	0.00232 (13)

Geometric parameters (Å, º) top

N1—C1	1.3441 (19)	C4—H4A	0.9800
N1—C2	1.4649 (19)	C4—H4B	0.9800
N1—C3	1.4643 (19)	C4—H4C	0.9800
N2—C1	1.330 (2)	C5—H5A	0.9800
N2—H2A	0.83 (2)	C5—H5B	0.9800
N2—H2B	0.83 (2)	C5—H5C	0.9800
N3—C1	1.3360 (19)	Cd1—Cl1	2.4829 (4)
N3—C4	1.467 (2)	Cd1—Cl2	2.5829 (4)
N3—C5	1.465 (2)	Cd1—Cl3	2.5854 (4)
C2—H2C	0.9800	Cd1—Cl4	2.5323 (4)
C2—H2D	0.9800	Cd1—Cl4ⁱ	2.6403 (4)
C2—H2E	0.9800	Cl2—Cd1ⁱⁱ	2.5830 (4)
C3—H3A	0.9800	Cl3—Cd1ⁱⁱ	2.5854 (4)
C3—H3B	0.9800	Cl4—Cd1ⁱ	2.6402 (4)
C3—H3C	0.9800

C1—N1—C2	122.68 (13)	N3—C4—H4B	109.5
C1—N1—C3	121.14 (12)	N3—C4—H4C	109.5
C3—N1—C2	114.98 (12)	H4A—C4—H4B	109.5
C1—N2—H2A	118.6 (14)	H4A—C4—H4C	109.5
C1—N2—H2B	121.6 (15)	H4B—C4—H4C	109.5
H2A—N2—H2B	120 (2)	N3—C5—H5A	109.5
C1—N3—C4	122.47 (13)	N3—C5—H5B	109.5
C1—N3—C5	121.21 (14)	N3—C5—H5C	109.5
C5—N3—C4	115.83 (13)	H5A—C5—H5B	109.5
N2—C1—N1	119.26 (14)	H5A—C5—H5C	109.5
N2—C1—N3	119.57 (14)	H5B—C5—H5C	109.5
N3—C1—N1	121.14 (14)	Cl1—Cd1—Cl2	111.033 (10)
N1—C2—H2C	109.5	Cl1—Cd1—Cl3	98.115 (10)
N1—C2—H2D	109.5	Cl1—Cd1—Cl4ⁱ	95.516 (13)
N1—C2—H2E	109.5	Cl1—Cd1—Cl4	118.137 (13)
H2C—C2—H2D	109.5	Cl2—Cd1—Cl3	85.262 (13)
H2C—C2—H2E	109.5	Cl2—Cd1—Cl4ⁱ	89.152 (12)
H2D—C2—H2E	109.5	Cl3—Cd1—Cl4ⁱ	166.347 (10)
N1—C3—H3A	109.5	Cl4—Cd1—Cl2	130.701 (9)
N1—C3—H3B	109.5	Cl4—Cd1—Cl3	91.126 (11)
N1—C3—H3C	109.5	Cl4—Cd1—Cl4ⁱ	83.088 (12)
H3A—C3—H3B	109.5	Cd1—Cl2—Cd1ⁱⁱ	94.798 (17)
H3A—C3—H3C	109.5	Cd1ⁱⁱ—Cl3—Cd1	94.679 (18)
H3B—C3—H3C	109.5	Cd1—Cl4—Cd1ⁱ	96.910 (13)
N3—C4—H4A	109.5

C2—N1—C1—N2	148.47 (15)	C4—N3—C1—N1	−27.1 (2)
C2—N1—C1—N3	−33.2 (2)	C4—N3—C1—N2	151.23 (15)
C3—N1—C1—N2	−18.4 (2)	C5—N3—C1—N1	161.27 (14)
C3—N1—C1—N3	159.92 (14)	C5—N3—C1—N2	−20.4 (2)

Symmetry codes: (i) −x+3/2, −y+1/2, −z+1; (ii) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2C···Cl4ⁱⁱⁱ	0.98	2.87	3.6567 (16)	138
C3—H3B···Cl1^iv	0.98	2.92	3.7614 (16)	144
C4—H4B···Cl4ⁱⁱ	0.98	2.87	3.8347 (17)	169
N2—H2A···Cl1	0.83 (2)	2.51 (2)	3.2871 (15)	157 (2)
N2—H2B···Cl1^v	0.83 (2)	2.46 (2)	3.2710 (15)	164 (2)

Symmetry codes: (ii) −x+1, y, −z+1/2; (iii) −x+1, −y+1, −z+1; (iv) −x+1/2, −y+1/2, −z+1; (v) −x+1, y, −z+3/2.

Acknowledgements

The authors acknowledge the Cheikh Anta Diop University of Dakar (Sénégal), the Canada Foundation for Innovation and the Université de Montréal for financial support.

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