Poly[[{μ3-dihydrogen [(pyridin-4-yl­methyl­imino)­bis­(methyl­ene)]diphos­phon­ato-κ5 O:O′,N,O′′:N′}copper(II)] dihydrate]

Shi-Yong Zhang; Zhong-Gao Zhou; Ke-Jun Wang

doi:10.1107/S1600536811052512

. 2011 Dec 10;68(Pt 1):m38–m39. doi: 10.1107/S1600536811052512

Poly[[{μ₃-dihydrogen [(pyridin-4-ylmethylimino)bis(methylene)]diphosphonato-κ⁵ O:O′,N,O′′:N′}copper(II)] dihydrate]

Shi-Yong Zhang ^a, Zhong-Gao Zhou ^a,^*, Ke-Jun Wang ^a

PMCID: PMC3254309 PMID: 22259339

Abstract

In the title polymer, {[Cu(C₈H₁₂N₂O₆P₂)]·2H₂O}_n, the geometry of the five-coordinate Cu^II ion can best be described as slightly distorted square-pyramidal formed by one N and two O atoms of an N(CH₂PO₃H)₂ group and one N atom from a pyridine ring. The elongated apex of the pyramid is occupied by one O atom from a third diphosphonate ligand. The interconnection of Cu²⁺ ions by the diphosphonate ligands results in the formation of a double-chain array along the b axis, in which the two sub-chains are interlocked by pairs of PO₃ groups. The outside of each sub-chain is decorated by other PO₃ groups. These double chains are further assembled into a three-dimensional supramolecular architecture via a large number of O—H⋯O hydrogen bonds between the phosphonate groups and lattice water molecules.

Related literature

For background to metal phosphonate chemistry, see: Maeda (2004 ▶); Mao (2007 ▶); Shimizu et al. (2009 ▶). For the synthetic strategy of attaching functional groups to a phosphonic acid ligand, see: Drumel et al. (1995 ▶); Mao et al. (2002 ▶); Liang & Shimizu (2007 ▶); Du et al. (2006 ▶, 2010b ▶). For a structurally related complex, see: Song & Mao (2005 ▶). For the zwitterionic behavior of aminophosphonic acid, see: Yang et al. (2008 ▶); Du et al. (2009 ▶, 2010a ▶).

Experimental

Crystal data

[Cu(C₈H₁₂N₂O₆P₂)]·2H₂O
M _r = 393.71
Triclinic,
a = 8.9250 (3) Å
b = 9.0000 (3) Å
c = 10.5066 (3) Å
α = 75.648 (2)°
β = 67.124 (2)°
γ = 67.126 (2)°
V = 711.75 (4) Å³
Z = 2
Mo Kα radiation
μ = 1.80 mm⁻¹
T = 296 K
0.40 × 0.03 × 0.02 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.605, T _max = 0.746
7659 measured reflections
3267 independent reflections
2309 reflections with I > 2σ(I)
R _int = 0.043

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.118
S = 1.03
3267 reflections
202 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.60 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and DIAMOND (Brandenburg, 2010 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811052512/fj2483sup1.cif

e-68-00m38-sup1.cif^{(17.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811052512/fj2483Isup2.hkl

e-68-00m38-Isup2.hkl^{(160.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1B⋯O1W	0.82	1.68	2.494 (4)	169
O6—H6C⋯O2W	0.82	1.75	2.567 (5)	172
O1W—H1WA⋯O5ⁱ	0.83 (2)	1.92 (2)	2.746 (4)	177 (5)
O1W—H1WB⋯O5ⁱⁱ	0.84 (2)	1.93 (2)	2.747 (4)	167 (5)
O2W—H2WA⋯O1ⁱⁱⁱ	0.85 (2)	2.09 (3)	2.882 (4)	155 (5)
O2W—H2WB⋯O3^iv	0.85 (2)	1.96 (3)	2.776 (4)	161 (6)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

This work was supported by the NSF of Jiangxi Provincial Education Department (grant No. GJJ10714).

supplementary crystallographic information

Comment

During the past few decades, the syntheses of metal phosphonates with various structures has attracted much attention, owing to their potential applications in areas such as catalysis, ion exchange, intercalation chemistry, and material chemistry (Maeda, 2004; Mao, 2007; Shimizu et al., 2009). The strategy of attaching functional groups such as amine, hydroxyl, carboxylate, sulfonate, and sulfone groups to the phosphonic acid has proven to be an effective method for the isolation of a variety of metal phosphonates with new structures (Drumel et al., 1995; Mao et al., 2002; Liang & Shimizu, 2007; Du et al. 2006, 2010b). Recently, we are interested in the combination of multiple functional groups to phosphonic acid as a more complex ligand. Herein, we report a copper(II) phosphonate based on an amino-bis(methyl-phosphonic acid) ligand, which contains pyridyl group as an additional functional group. As far as we are aware, only one layered cobalt(II) phosphonate has been reported based on the same ligand (Song & Mao, 2005).

The title compound (I) features a one-dimensional double-chain structure. The formula of it contains one Cu²⁺ ion, one H₂L^2- anion and two lattice water molecules. Cu(1) ion is five-coordinate and its coordination geometry can be described as a slightly distorted square-pyramid (Fig. 1): the square plane is formed by one N and two O atoms of a N(CH₂PO₃H)₂ group as well as one N atom of a pyridyl group from two H₂L^2- ligand, and the prolonged apex of the pyramid is occupied by one O atom from a third H₂L^2- ligand. The H₂L^2- ligand in compound (I) acts as a pentadentate chelating and bridging ligand. It chelates one Cu²⁺ ion by its N(CH₂PO₃H)₂ group in a tridentate fashion (2O and 1 N), and also bridges with other two Cu²⁺ ions via its pyridyl group and a third O atom (Scheme 1). The two phosphonate groups of the H₂L^2- ligand both are 1H-protonated as the requirement for charge balance and also as indicated by two much longer P—O bonds. It is worthy of note that the strongly basic N atom in the H₂L^2- ligand is not protonated but bonded to a Cu²⁺ ion, which is rarely observed for phosphonic acid ligands containing a tertiary amine group (Yang et al., 2008; Du et al., 2009, 2010a).

The interconnection of the Cu²⁺ ions by the HL^2- anions results in the formation of a one-dimensional double-chain array along the b-axis, in which the two sub-chains are inter-locked by pairs of P(1)O₃ groups and the outside of each sub-chain is decorated by P(2)O₃ groups. It is worthy of note that such two sub-chains are related by inversion centers, and the shortest Cd···Cd distance between them is 5.170 (4) Å while that in each sub-chain is 9.000 (1) Å. These double-chains are further assembled into a three-dimensional supramolecular architecture via a large number of hydrogen bonds between the phosphonate groups and lattice water molecules (Fig. 3 and Table 1).

Experimental

4-Pyridyl-CH₂N(CH₂PO₃H₂)₂ (0.2 mmol) was dissolved in 4 ml H₂O and poured into a test tube, then CuCl₂.2H₂O (0.15 mmol) dissolved in 8 ml EtOH was carefully layered onto it and left to stand at room temperature. Blue column-shaped crystals of (I) were obtained after about two weeks later. IR data for (I) (KBr, cm^-1): 3477(s), 3228(s), 3141(m), 3079(m), 2975(m), 2913(m), 2376(m), 1846(m), 1624(s), 1502(m), 1448(m), 1433(m), 1350(m), 1266(s), 1221(m), 1173(s), 1140(versus), 1065(s), 1051(s), 1032(s), 945(s), 929(m), 906(m), 866(m), 844(m), 795(m), 742(m), 648(m), 588(s), 524(m), 482(m), 453(m).