Structural Diversity of Metallosupramolecular Assemblies from Cu(phen) 2+ (phen = 1,10‐Phenanthroline) Building Blocks and 4,4′‐Bipyridine

Attempts to crystal engineer metallosupramolecularcomplexes from Cu(phen) 2+ building blocks and the prototypical,rod‐like, exo ‐bidentate ligand 4,4′‐bipyridine (4,4′‐bipy) by layering techniques are described. Reactions of Cu(phen) 2+ (phen = 1,10‐phenanthroline) with 4,4′‐bipy in the presence of NO 3 – counterions yielded two distinct, discrete, dinuclear, C i symmetric, dumbbell‐typecomplexes, [{Cu(NO 3 ) 2 (phen)} 2 (4,4′‐bipy)] ( 1 ) and [{Cu(NO 3 )(phen)(H 2 O)} 2 (4,4′‐bipy)](NO 3 ) 2 ( 2 ), depending upon the mixture of solvents used for crystallization. In compound 1 , a mono‐ and a bidentate nitrato group coordinate to Cu 2+ , whereas in 2 the monodentate nitrato groups are replaced by aqua ligands, which introduce additional hydrogen‐bond donor functionality to the molecule. The crystal structure of 1 was determined by single‐crystal X‐ray analysis at 296 and 110 K. Upon cooling, a disorder‐order transition occurs, with retention of the space group symmetry. The crystal structure of 2 at room temperature was reported previously [Z.‐X. Du, J.‐X. Li, Acta Cryst . 2007 , E63 , m2282]. We have redetermined the crystal structure of 2 at 100 K. A phase transition is not observed for 2 , but the low temperature single‐crystal structure determination is of significantly higher precision than the room temperature study. Both 1 and 2 are obtained phase‐pure, as proven by powder X‐ray diffraction of the bulk materials. Crystals of [Cu(phen)(CF 3 SO 3 ) 2 (4,4′‐bipy) · 0.5H 2 O] n ( 3 ), a one‐dimensional coordination polymer, were obtained from [Cu(CF 3 SO 3 ) 2 (phen)(H 2 O) 2 ] and 4,4′‐bipy. In 3 , Cu(phen) 2+ corner units are joined by 4,4′‐bipy via the two vacant cis sites to form polymeric zig‐zag chains, which are tightly packed in the crystal. Compounds 1 – 3 were further studied by infrared spectroscopy.