C–H⋯Cl relevant discrepancy on structure, magnetic and electronic conductivity of two mixed-valence CuICuII coordination polymers

Two mixed-valence CuICuII coordination polymers [CuICuII(qdiol)ClL]n (qdiol2−=2,3-dioxyquinoxalinate, L=2,2′-bipyridine, 1; L=1,10-phenanthroline, 2) were obtained in basic ethanolic solution of CuCl2, 1,4-dihydro-2,3-quinoxalinedione and L under the solvothermal condition. 1 and 2 are similar in composition, but differ remarkably in structure. The coordination modes of CuII, qdiol2− and L are identical in both complexes. But the CuI ions are two- and three-coordinated, and the Cl− ions are terminal and bridging, in 1 and 2, respectively, which are relevant to the significantly different C–H⋯Cl hydrogen bonding pattern of bpy and phen. The temperature variable magnetic susceptibilities show that 1 is paramagnetic and 2 is weakly antiferromagnetic. The complex impedance spectroscopic studies indicate that both 1 and 2 are semiconductors and 2 is more conducting.

Graphical AbstractSubtly different C–H⋯Cl bonding nature leads to diverse coordination modes and supramolecular networks, as well as physical properties of two CuICuII coordination polymers with similar compositions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Two new Cu(I)–Cu(II) mixed-valence coordination polymers are obtained. ► Environments of Cu(I) and Cl are different caused by C–H…Cl H-bonding. ► Supramolecular networks are hence diverse. ► Magnetic and semiconducting properties are influenced by the structures.