Poly[[hexa­aqua­bis­(μ3-pyrimidine-4,6-dicarboxyl­ato)dicalcium] dihydrate]

Starosta, W.; Leciejewicz, J.

doi:10.1107/S160053681204617X

Volume 68
Part 12
Pages m1478-m1479
December 2012

Received 7 November 2012
Accepted 8 November 2012
Online 14 November 2012

Key indicators
Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.003 Å
R = 0.033
wR = 0.107
Data-to-parameter ratio = 16.5
Details

Poly[[hexaaquabis(₃-pyrimidine-4,6-dicarboxylato)dicalcium] dihydrate]

Wojciech Starosta ^a and Janusz Leciejewicz ^a ^*

^aInstitute of Nuclear Chemistry and Technology, ul.Dorodna 16, 03-195 Warszawa, Poland
Correspondence e-mail: j.leciejewicz@ichtj.waw.pl

The polymeric structure of the title compound, {[Ca₂(C₆H₂N₂O₄)₂(H₂O)₆]·2H₂O}_n, is built up of molecular layers composed of Ca^II ions bridged by both ligand N and O atoms with one of the O atoms being bis-monodentate. Two adjacent Ca^II ions are bridged by these O atoms, forming a centrosymmetric dimer which is the building unit of the structure. The dimers are nodes of a cross-linked molecular layer parallel to (101). The Ca^II ion is coordinated by two bidentate ligands, one monodentate ligand and three water molecules in the form of a distorted polyhedron with a coordination number of eight. Solvate water molecules located between adjacent layers participate as donors and acceptors in a system of hydrogen bonds in which coordinating water molecules also act as donors and non-coordinating carboxylate O atoms act as acceptors.

Related literature

For the crystal structures of Ca^II complexes with pyrazine-2,6-dicarboxylate and water ligands, see: Starosta et al. (2003, 2004). The crystal structure of pyrimidine-4,6-dicarboxylic acid dihydrate was reported by Beobide et al. (2007).

Experimental

Crystal data

[Ca₂(C₆H₂N₂O₄)₂(H₂O)₆]·2H₂O
M_r = 278.24
Monoclinic, P 2₁ /n
a = 7.7053 (15) Å
b = 11.432 (2) Å
c = 11.916 (2) Å
= 92.16 (3)°
V = 1048.9 (4) Å³
Z = 4
Mo K radiation
= 0.64 mm^-1
T = 293 K
0.10 × 0.04 × 0.03 mm

Data collection

Kuma KM-4 four-circle diffractometer
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]$ ) T_min = 0.968, T_max = 0.982
3274 measured reflections
3065 independent reflections
1709 reflections with I > 2(I)
R_int = 0.049
3 standard reflections every 200 reflections intensity decay: 2.9%

Refinement

R[F² > 2(F²)] = 0.033
wR(F²) = 0.107
S = 1.01
3065 reflections
186 parameters
H atoms treated by a mixture of independent and constrained refinement
_max = 0.44 e Å^-3
_min = -0.59 e Å^-3

Table 1
Selected bond lengths (Å)

Ca1-O5	2.398 (2)
Ca1-O7	2.420 (2)
Ca1-O3ⁱ	2.4361 (17)
Ca1-O1ⁱⁱ	2.4823 (16)
Ca1-O6	2.502 (2)
Ca1-O1	2.5061 (17)
Ca1-N1	2.563 (2)
Ca1-N3ⁱ	2.6133 (19)
Symmetry codes: (i) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) -x, -y, -z+1.

Table 2
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
O7-H72O2ⁱⁱⁱ	0.80 (6)	2.34 (6)	3.048 (3)	149 (6)
O6-H61O2ⁱⁱ	0.85 (5)	1.88 (5)	2.698 (3)	163 (5)
O8-H81O3^iv	0.76 (4)	2.04 (4)	2.793 (3)	170 (4)
O8-H82O6^v	0.77 (5)	2.09 (5)	2.818 (3)	157 (5)
O5-H52O8^vi	0.87 (4)	1.94 (4)	2.798 (3)	169 (4)
O6-H62O4ⁱⁱⁱ	0.77 (4)	1.96 (4)	2.719 (2)	167 (4)
O7-H71O4^vii	0.79 (4)	2.16 (4)	2.902 (3)	158 (3)
O5-H51O8^iv	0.78 (4)	2.04 (4)	2.816 (3)	176 (4)
Symmetry codes: (ii) -x, -y, -z+1; (iii) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (iv) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (v) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (vi) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (vii) -x, -y+1, -z+1.

Data collection: KM-4 Software (Kuma, 1996 $[Kuma (1996). KM-4 Software. Kuma Diffraction Ltd, Wroclaw, Poland.]$ ); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001 $[Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wroclaw, Poland.]$ ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: QM2088 ).

References

Beobide, G., Castillo, O., Luque, A., Garcia-Couceiro, U., Garcia-Teran, J. P. & Roman, P. (2007). Dalton Trans. pp. 2668-2680.
Kuma (1996). KM-4 Software. Kuma Diffraction Ltd, Wroclaw, Poland.
Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wroclaw, Poland.
Oxford Diffraction (2008). CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Starosta, W., Ptasiewicz-Bak, H. & Leciejewicz, J. (2003). J. Coord. Chem. 56, 677-682.
Starosta, W., Ptasiewicz-Bak, H. & Leciejewicz, J. (2004). J. Coord. Chem. 57, 167-173.

metal-organic compounds

Poly[[hexaaquabis(3-pyrimidine-4,6-dicarboxylato)dicalcium] dihydrate]