catena-Poly[[bis(N,N′-dimethylformamide)cadmium(II)]-μ2-oxalato]

The title compound, [Cd(C2O4)(C3H7NO)2]n, is isostructural with its MnII analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the CdII atoms located on twofold rotation axes. The coordination geometry around CdII is distorted octahedral and the intrachain Cd⋯Cd distance is 5.842 (1) Å. C—H⋯O hydrogen bonds exist between the parallel polymeric chains.

The title compound, [Cd(C 2 O 4 )(C 3 H 7 NO) 2 ] n , is isostructural with its Mn II analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the Cd II atoms located on twofold rotation axes. The coordination geometry around Cd II is distorted octahedral and the intrachain CdÁ Á ÁCd distance is 5.842 (1) Å . C-HÁ Á ÁO hydrogen bonds exist between the parallel polymeric chains.
We are grateful to Professor Lars Ö hrströ m for his interest in this work and to Chalmers University of Technology for financial support.  [[bis(N,N'-dimethylformamide)

Comment
Crystal engineering of coordination polymers, based on pre-defined interactions of metal ions with organic spacers, is an area of research that has received substantial interest (Zaworotko, 2007). In this field, employing N-and/or O-donor ligands as bridging organic modules has been intensively implemented (Ockwig et al., 2005). Oxalate anions are known as chelating bis-bidentate ligands and many infinite two-dimensional and three-dimensional coordination polymers with a [MM'(ox) n ] n' formula have been reported comprising two different and/or similar metal centres (Borel et al., 2006: Imaz et al., 2005: Xia et al., 2004: Decurtins et al., 1994. However, solvent ligation to the metal centres may result in structures with lower dimensionality (Prasad et al., 2002). Here we present a coordination chain based on bis-oxalato cadmium(II) with coordinated DMF solvent molecules.
A perspective drawing of the title compound with the atomic numbering scheme is shown in Figure 1 was dried in a desiccator (Zavalij et al., 2003). A solution of 3.9 g Li[B(ox) 2 ] in 50 ml DMF was prepared and heated to 343 K. A precipitate formed, probably a sign of the disintegration of the bis(oxalate)borate ion, and the solution was filtered.
One eighth of this filtrate was then mixed with a solution of 0.2 g C d(NO 3 ) 2 .4H 2 O and the resulting solution was set aside for 1-2 weeks, after which colourless prismatic crystals suitable for x-ray diffraction were collected and dried.