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)₂·4CH₃NO₂ (3), [AgL]NO₃·0.5CH₃OH (4), [AgL]BF₄ (5) and [Cu₄L₂(OCH₃)₂(OH)₂(NO₃)₂](NO₃)₂·0.32H₂O (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.