Poly[(μ2-4,4′-bipyridine-κ2 N:N′)(μ2-2,2-dimethylcyclopentane-1,3-dicarboxylato-κ4 O 1,O 1′:O 3,O 3′)cadmium]

In the title polymeric compound, [Cd(C9H12O4)(C10H8N2)]n, the CdII atom is located on a twofold rotation axis and is coordinated by two 4,4′-bipyridine ligands and two 2,2-dimethylcyclopentane-1,3-dicarboxylate ions. The carboxylate ion and the N-heterocycle both function as bridges to link adjacent CdII atoms to result in the formation of a layer structure parallel to (010). The mid-point of the central C—C bond of the 4,4′-bipyridine ligand is located on an inversion center. In the crystal, the carboxylate ion is disordered over a twofold rotation axis in respect of its methyl group and the cyclopentane ring.

In the title polymeric compound, [Cd(C 9 H 12 O 4 )(C 10 H 8 N 2 )] n , the Cd II atom is located on a twofold rotation axis and is coordinated by two 4,4 0 -bipyridine ligands and two 2,2dimethylcyclopentane-1,3-dicarboxylate ions. The carboxylate ion and the N-heterocycle both function as bridges to link adjacent Cd II atoms to result in the formation of a layer structure parallel to (010). The mid-point of the central C-C bond of the 4,4 0 -bipyridine ligand is located on an inversion center. In the crystal, the carboxylate ion is disordered over a twofold rotation axis in respect of its methyl group and the cyclopentane ring.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.93-0.96 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2-1.5U(C).
The 2,2-dimethylcyclopentadicarboxylate dianion is disordered over a twofold rotation axis in respect of the methyl groups and the cyclopentane ring; the carboxyl -CO 2 unit is ordered. In the disordered part, all carbon-carbon distances were restrained to 1.50 ± 0.01 Å; the anisotropic temperature factors were restrained to be nearly isotropic.
The final difference Fourier map had a peak in the vicinity of H4a and a hole in the vicinity of Cd1.
The temperature factors of the two oxygen atoms are large, but are not significantly larger than that of the carbon atom to which they are connected. The temperature factors of the carbon atoms of the pyridine ring are also somewhat large; splitting the ring as two overlapping rings in a disorder model did not improve the refinement much.