catena-Poly[[(1,10-phenanthroline)copper(II)]-μ-oxalato]

In the title coordination polymer, [Cu(C2O4)(C12H8N2)]n, the CuII atom is six-coordinated by four O atoms from two oxalate ligands and two N atoms from one 1,10-phenanthroline (phen) ligand in a distorted octahedral coordination geometry. The oxalate anions act as bis-bidentate ligands, bridging the Cu–phen units in zigzag chains extending parallel to [100]. Interchain C—H⋯O hydrogen bonding and π–π stacking interactions [centroid–centroid distance = 3.7439 (17) Å] assemble neighboring chains, forming a three-dimensional supramolecular network.

In the title coordination polymer, [Cu(C 2 O 4 )(C 12 H 8 N 2 )] n , the Cu II atom is six-coordinated by four O atoms from two oxalate ligands and two N atoms from one 1,10-phenanthroline (phen) ligand in a distorted octahedral coordination geometry. The oxalate anions act as bis-bidentate ligands, bridging the Cuphen units in zigzag chains extending parallel to [100]. Interchain C-HÁ Á ÁO hydrogen bonding andstacking interactions [centroid-centroid distance = 3.7439 (17) Å ] assemble neighboring chains, forming a three-dimensional supramolecular network.

Comment
The design and construction of metal coordination polymers based on metal ions and multifunctional bridging ligands is of great interest due to their intriguing topologies and potential applications as functional materials (Benneli & Gatteschi, 2002;Qiu et al., 2007). Copper, with its variable coordination numbers and flexible coordination geometry, provides unique opportunities for the discovery of unusual networks in this interesting and challenging field (Qin et al., 2005). We chose oxalate ligands as organic spacers since this rigid molecule has proven to be able to establish a bridge between metal centers.
Herein, we present the structure of the title compound, [Cu(C 2 O 4 )(C 12 H 8 N 2 )] n .

Experimental
A sample of cupric acetate (0.0399 g, 0.20 mmol), oxalic acid (0.1015 g, 0.50 mmol), 1,10-phenanthroline (0.2523 g, 0.50 mmol), were added to water (10 ml). The resultant mixture was sealed in a 25 ml stainless steel reactor with a Teflon liner and kept under autogenous pressure at 413 K for 78 h, and then cooled to room temperature at a rate of 0.5 K/min. Colorless blocky crystals of the title compound suitable for single-crystal X-ray diffraction analyses formed in a yield of approximately 65%.

Refinement
All H atoms were placed at calculated positions and were treated as riding on the parent C atoms with C-H = 0.93 Å, and with U iso (H) = 1.2 (C).