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The structure of poly[caesium(I) [([mu]4-ethyl­enediphosphon­ato)­cobalt(II)]], {Cs[Co(C2H5O6P2)]}n, reveals a three-dimensional polymeric open framework consisting of tetra­hedral CoII atoms coordinated by four different ethyl­ene­diphosphonate O atoms and inter­molecular O-H...O hydrogen bonds. The largest open window is made of corner-sharing CoO4 and PO3C tetra­hedra, giving 16-membered rings of dimensions 9.677 (5) × 4.684 (4) Å2. There are two independent ethylenediphosphonate ligands, each lying about an inversion centre.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107029113/sq3080sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107029113/sq3080Isup2.hkl
Contains datablock I

CCDC reference: 659115

Comment top

Metal phosphonates are currently the subject of intense interest in open-framework materials because of their distinct catalytic, magnetic and electric properties. Multifunctional diphosphonate ligands such as simple ethylenediphosphonate have been used to produce inorganic–organic hybrid materials with a wide range of dimensions and structures. Examples from our laboratory include [Ga2(VO)3K2(OH2)3(C2H4P2O6)4(H2O)13] (Cheng et al., 2003), containing a three-dimensional open framework with multidimensional channels, and a redox Cu(I/II)-based coordination polymer, [Cu(C12H8N2)(HO3P—C2H4—PO3H)(OH2)2] (Lin et al., 2004), which exhibits supramolecular device behavior. In contrast to CoII phosphate systems, relatively few examples of tetrahedral geometry in CoII phosphonate systems have been reported. This paper reports what is, to our knowledge, the first structural characterization of a tetrahedrally coordinated cobalt(II) ethylenediphosphonate with open-framework structure.

[CsCo(C2H5P2O6)]n adopts a three-dimensional framework with two-dimensional channels. The Co atom has a distorted tetrahedral geometry (Fig. 1) composed of four O atoms (O1, O4B, O3A and O6) from different ethylenediphosphonate anions. The Co—O bond lengths [1.934 (3)–1.965 (2) Å] and O—Co—O angles [103.99 (11)–113.09 (11)°] are comparable to those found in other cobalt(II) phosphonates (Gemmill et al., 2005; LaDuca et al., 1996; Turner et al., 2003; Distler et al., 1999; Rabu et al., 1999; Gustschke et al., 1999; Lohse & Sevov, 1997) containing cobalt in a tetrahedral environment. Moreover, the bond-valence calculation gives a value of 2.00 for the cobalt ions (Brown & Altermatt, 1985). Owing to the CsI:CoII:ethylenediphosphonate ratio of 1:1:1 in the asymmetric unit, the diphosphonate anions should be monoprotonated. Analyses of tetrahedral coordination of cobalt ions in related systems (Pothiraja et al., 2004; Gemmill et al., 2005) shows that the P—O bonds associated with metal ions [ranging from 1.517 (3) to 1.525 (3) Å in our case] are somewhat shorter than those of noncoordinated P—OH or PO bonds [1.531 (3) and 1.536 (3) Å]. These noncoordinated O atoms also participate in a short O—H···O hydrogen bond (Table 1), which plays a key role in constructing the robust open framework.

The architecture of this material is shown in Fig. 2. The structural building unit may be described as a bicyclic ring (dots and bold lines) that is constructed via corner-sharing tetrahedra of [CoO4] and [PO3C] to be polymeric open-windows [(–CoII—PO3C—CoII–)]n comprising 12 Co atoms. The bicyclic rings are stacking upon each other in such a way as to generate two infinite channel systems that run through the entire structure. One has square-like windows that run in the c direction, while the largest channels are clearly revealed while viewed along the a axis (Fig. 3). The open window is made of eight corner-sharing tetrahedra of [CoO4] and [PO3C] to give 16-membered rings (Fig. 4) in which the effective dimensions are ca 9.677 (5) Å (O4A···O4B) × 4.684 (4) Å (O1A···O1B). Two symmetry-related Cs+ cations occupy these channels. Each caesium ion is coordinated by eight O atoms from the surrounding six phosphonate anions. The Cs—O bond lengths range from 3.030 (3) to 3.573 (3) Å. In conclusion, this three-dimensional open framework can be described as a new type of zeolite-like analog structure in which the framework is composed of tetrahedrally coordinated cobalt phosphonate.

Related literature top

For related literature, see: Brown & Altermatt (1985); Cheng et al. (2003); Distler et al. (1999); Gemmill et al. (2005); Gustschke et al. (1999); LaDuca, Rose, DeBord, Haushalter, O'Connor & Zubieta (1996); Lin et al. (2004); Lohse & Sevov (1997); Pothiraja et al. (2004); Rabu et al. (1999); Turner et al. (2003).

Experimental top

A reaction mixture of CoCl2.6H2O (0.1189 g, 0.5 mmol), ethylenediphosphonic acid (0.1421 g, 0.75 mmol), 1,10-phenanthroline monohydrate (0.0991 g, 0.5 mmol), CsOH (99%, 50 wt% solution in water, 0.3 ml) and ethanol (8 ml) was placed in a 23 ml Teflon-lined stainless autoclave, which was sealed and heated at 373 K for 2 h, then heated at 473 K for 96 h, then cooled to 344 K at 9 K h-1, and finally allowed to cool to room temperature (final pH < 7). The resulting deep-blue crystals were collected by filtration and washed with ethanol.

Refinement top

H were placed in calculated positions and included as riding atoms with C—H = 0.97 Å and O—H = 0.82 Å. The displacement parameters were set at 1.2 (CH2) or 1.5 (OH) times Ueq of the parent C or O atoms. Given the nearly identical P—O distances involving O2 and O5, it was not obvious which O atom should carry the acidic H atom so it was assigned to O2 arbitrarily. We cannot rule out a symmetrical arrangement, which would be consistent with the equivalent P—O bond lengths.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SMART or SAINT?; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The Co atom is coordinated by four phosphonate anions in a slightly distorted tetrahedral environment. [Symmetry codes: (A) -x + 1, y + 1/2, -z + 1/2; (B) x, -y + 1/2, z + 1/2.]
[Figure 2] Fig. 2. A schematic presentation of structural building units of bicyclic rings. [CoO4] tetrahedra, phosphonate ligands [PO3C] and ethylene groups [–CH2—CH2–] are denoted as dots, bold lines and narrow lines, respectively.
[Figure 3] Fig. 3. The crystal packing as viewed along the a axis. Channels containing the Cs+ cations are clearly visible.
[Figure 4] Fig. 4. A detailed view of the 16-membered ring that forms the boundary of the channel running along the a axis. The dimensions are 9.677 (5) Å (O4A···O4B) × 4.684 (4) Å (O1A···O1B). [Symmetry codes: (A) -x + 1, y + 1/2, -z + 1/2; (B) x, -y + 1/2, z + 1/2; (C) -x + 1, -y + 1, -z + 1.]
poly[caesium(I) [(µ4-ethylenediphosphonato)cobalt(II)]], top
Crystal data top
Cs[Co(C2H5O6P2)]Z = 4
Mr = 378.84F(000) = 708
Monoclinic, P21/cDx = 2.994 Mg m3
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 8.2580 (6) Åθ = 2.7–27.5°
b = 9.6225 (7) ŵ = 6.68 mm1
c = 10.7899 (7) ÅT = 293 K
β = 101.382 (1)°Hexagonal, blue
V = 840.53 (10) Å30.28 × 0.23 × 0.20 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1913 independent reflections
Radiation source: fine-focus sealed tube1801 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
ϕ and ω scansθmax = 27.5°, θmin = 2.5°
Absorption correction: empirical (using intensity measurements)
(SADABS; Bruker, 2000)
h = 1010
Tmin = 0.172, Tmax = 0.263k = 1112
5135 measured reflectionsl = 814
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.080H-atom parameters constrained
S = 1.19 w = 1/[σ2(Fo2) + (0.0482P)2 + 0.857P]
where P = (Fo2 + 2Fc2)/3
1913 reflections(Δ/σ)max = 0.001
109 parametersΔρmax = 0.67 e Å3
0 restraintsΔρmin = 2.45 e Å3
Crystal data top
Cs[Co(C2H5O6P2)]V = 840.53 (10) Å3
Mr = 378.84Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.2580 (6) ŵ = 6.68 mm1
b = 9.6225 (7) ÅT = 293 K
c = 10.7899 (7) Å0.28 × 0.23 × 0.20 mm
β = 101.382 (1)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
1913 independent reflections
Absorption correction: empirical (using intensity measurements)
(SADABS; Bruker, 2000)
1801 reflections with I > 2σ(I)
Tmin = 0.172, Tmax = 0.263Rint = 0.025
5135 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.080H-atom parameters constrained
S = 1.19Δρmax = 0.67 e Å3
1913 reflectionsΔρmin = 2.45 e Å3
109 parameters
Special details top

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.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cs10.75557 (3)0.07151 (2)0.08576 (2)0.02497 (11)
Co10.25602 (5)0.22162 (5)0.17153 (4)0.01255 (13)
P10.45649 (10)0.04347 (9)0.29323 (8)0.01226 (18)
P20.03015 (10)0.30607 (9)0.10652 (8)0.01212 (18)
O10.4026 (3)0.0592 (3)0.1853 (2)0.0176 (5)
O30.6181 (3)0.1112 (3)0.2781 (3)0.0203 (5)
O20.3215 (3)0.1511 (3)0.3012 (2)0.0223 (5)
H20.30340.19770.23630.034*
O40.0786 (3)0.2999 (3)0.2354 (2)0.0196 (5)
O60.1494 (4)0.2258 (3)0.0071 (2)0.0263 (6)
O50.1472 (3)0.2543 (3)0.1161 (3)0.0277 (6)
C10.4901 (4)0.0479 (4)0.4417 (3)0.0162 (6)
H1A0.58860.10450.44850.019*
H1B0.39760.10990.44210.019*
C20.0284 (5)0.4871 (4)0.0615 (3)0.0192 (7)
H2A0.13890.52440.05440.023*
H2B0.04360.53770.12830.023*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cs10.03459 (17)0.02100 (16)0.02082 (16)0.00329 (8)0.00914 (11)0.00354 (8)
Co10.0131 (2)0.0118 (2)0.0130 (2)0.00018 (15)0.00303 (16)0.00018 (15)
P10.0127 (4)0.0124 (4)0.0118 (4)0.0013 (3)0.0026 (3)0.0004 (3)
P20.0126 (4)0.0128 (4)0.0109 (4)0.0000 (3)0.0022 (3)0.0011 (3)
O10.0214 (12)0.0163 (12)0.0153 (12)0.0066 (9)0.0042 (10)0.0025 (9)
O30.0184 (12)0.0171 (12)0.0277 (13)0.0086 (10)0.0100 (10)0.0044 (10)
O20.0252 (13)0.0237 (14)0.0171 (12)0.0105 (10)0.0017 (10)0.0026 (10)
O40.0182 (12)0.0266 (14)0.0151 (11)0.0024 (10)0.0063 (9)0.0008 (10)
O60.0364 (16)0.0250 (15)0.0145 (12)0.0125 (11)0.0025 (11)0.0007 (10)
O50.0217 (14)0.0421 (17)0.0213 (13)0.0180 (12)0.0090 (10)0.0105 (12)
C10.0188 (16)0.0149 (15)0.0144 (16)0.0013 (12)0.0022 (13)0.0017 (13)
C20.0275 (18)0.0130 (16)0.0200 (17)0.0030 (13)0.0113 (14)0.0014 (13)
Geometric parameters (Å, º) top
Co1—O3i1.934 (3)P2—C21.810 (4)
Co1—O4ii1.944 (3)O3—Co1iii1.934 (3)
Co1—O61.955 (3)O2—H20.8200
Co1—O11.965 (2)O4—Co1iv1.944 (3)
P1—O31.523 (2)C1—C1v1.542 (7)
P1—O11.525 (3)C1—H1A0.9700
P1—O21.536 (3)C1—H1B0.9700
P1—C11.800 (4)C2—C2vi1.512 (7)
P2—O61.517 (3)C2—H2A0.9700
P2—O41.522 (3)C2—H2B0.9700
P2—O51.531 (3)
O3i—Co1—O4ii111.18 (11)P1—O1—Co1130.97 (16)
O3i—Co1—O6111.88 (12)P1—O3—Co1iii139.41 (17)
O4ii—Co1—O6105.84 (12)P1—O2—H2109.5
O3i—Co1—O1110.57 (11)P2—O4—Co1iv146.82 (16)
O4ii—Co1—O1113.09 (11)P2—O6—Co1144.19 (18)
O6—Co1—O1103.99 (11)C1v—C1—P1114.0 (3)
O3—P1—O1108.95 (15)C1v—C1—H1A108.7
O3—P1—O2112.26 (16)P1—C1—H1A108.7
O1—P1—O2111.95 (15)C1v—C1—H1B108.7
O3—P1—C1108.68 (16)P1—C1—H1B108.7
O1—P1—C1109.48 (15)H1A—C1—H1B107.6
O2—P1—C1105.40 (15)C2vi—C2—P2114.4 (3)
O6—P2—O4112.04 (15)C2vi—C2—H2A108.7
O6—P2—O5111.16 (18)P2—C2—H2A108.7
O4—P2—O5110.26 (15)C2vi—C2—H2B108.7
O6—P2—C2109.82 (17)P2—C2—H2B108.7
O4—P2—C2107.47 (15)H2A—C2—H2B107.6
O5—P2—C2105.84 (18)
O3—P1—O1—Co1157.4 (2)O4—P2—O6—Co1145.5 (3)
O2—P1—O1—Co177.8 (2)O5—P2—O6—Co190.6 (4)
C1—P1—O1—Co138.7 (3)C2—P2—O6—Co126.2 (4)
O3i—Co1—O1—P192.8 (2)O3i—Co1—O6—P257.8 (4)
O4ii—Co1—O1—P132.7 (2)O4ii—Co1—O6—P263.4 (4)
O6—Co1—O1—P1147.0 (2)O1—Co1—O6—P2177.2 (3)
O1—P1—O3—Co1iii157.0 (2)O3—P1—C1—C1v73.0 (4)
O2—P1—O3—Co1iii32.4 (3)O1—P1—C1—C1v168.1 (3)
C1—P1—O3—Co1iii83.8 (3)O2—P1—C1—C1v47.5 (4)
O6—P2—O4—Co1iv26.7 (4)O6—P2—C2—C2vi61.6 (4)
O5—P2—O4—Co1iv151.0 (3)O4—P2—C2—C2vi176.3 (3)
C2—P2—O4—Co1iv94.1 (3)O5—P2—C2—C2vi58.5 (4)
Symmetry codes: (i) x+1, y+1/2, z+1/2; (ii) x, y+1/2, z+1/2; (iii) x+1, y1/2, z+1/2; (iv) x, y+1/2, z1/2; (v) x+1, y, z+1; (vi) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O5vii0.821.732.432 (3)143
Symmetry code: (vii) x, y, z.

Experimental details

Crystal data
Chemical formulaCs[Co(C2H5O6P2)]
Mr378.84
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.2580 (6), 9.6225 (7), 10.7899 (7)
β (°) 101.382 (1)
V3)840.53 (10)
Z4
Radiation typeMo Kα
µ (mm1)6.68
Crystal size (mm)0.28 × 0.23 × 0.20
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(SADABS; Bruker, 2000)
Tmin, Tmax0.172, 0.263
No. of measured, independent and
observed [I > 2σ(I)] reflections
5135, 1913, 1801
Rint0.025
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.080, 1.19
No. of reflections1913
No. of parameters109
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.67, 2.45

Computer programs: SMART (Bruker, 1999), SMART or SAINT?, SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O5i0.821.732.432 (3)142.9
Symmetry code: (i) x, y, z.
 

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