Syntheses, crystal structures and properties of silver(I) and copper(II) complexes with an oxazoline-containing tetradentate ligand

Six new coordination complexes, [AgL]CF3SO3 (1 and 2), [Ag2L2](NO3)(2)center dot 4CH(3)NO(2) (3), [AgL]NO3 center dot 0.5CH(3)OH (4), [AgL]BF4 (5) and [Cu4L2(OCH3)(2)(OH)(2)(NO3)(2)](NO3)(2)center dot 0.32H(2)O (6), were obtained by reactions of the corresponding metal salts with ligand N,N'-bis[4-(4,5-dihydrooxazol-2-yl)-benzyl]ethane-1,2-diamine (L). The results of X-ray crystallographic analysis indicate that complexes 1 and 2 are supramolecular isomers with a wavelike cationic two-dimensional network structure of 1 and a double-stranded helical chain of 2. Complexes 4 and 5 also have helical chain structures with P and M forms. Differing from polymeric structure of 1, 2, 4 and 5, complexes 3 and 6 are a M2L2 molecular rectangle and a M4L2 cage, respectively. The results show that the flexible ligand L can have different conformation and coordination modes leading to complexes with varying structures. Magnetic data show that there are antiferromagnetic interactions in the dimeric unit of complex 6.