Chlorido-bridged polymeric and dinuclear copper(II) complexes with tridentate Schiff base: Synthesis, crystal structure and magnetic properties

Two copper(II) complexes, [Cu(qsal)Cl](DMF) (1) and [Cu2(qsalBr)2Cl2](DMF) (2), with tridentate Schiff base ligands, 8-(salicylideneamino)quinoline (Hqsal) and 8-(5-bromo-salicylideneamino)quinoline (HqsalBr), respectively, were synthesised and structurally characterized. Each copper(II) ion in the two complexes is in a distorted square pyramidal N2OCl2 environment. Complex 1 exists as a polymeric species via equatorial–apical chloride bridges, whereas 2 is a di-chlorido-bridged dinuclear complex, where each bridging chloride simultaneously occupies an in-plane coordination site on one copper(II) ion and an apical site on the other copper(II) ion. Variable-temperature magnetical susceptibility measurements on the two complexes in the temperature range 2–300 K indicate the occurrence of intrachain ferromagnetic (J = +6.58 cm−1) and intramolecular antiferromagnetical (J = −6.91 cm−1) interactions.

By using a tridentate Schiff base, 8-(salicylideneamino)quinoline (Hqsal) or its derivatives, 8-(5-bromo-salicylideneamino)quinoline (HqsalBr) and the same synthesis procedure, two copper(II) complexes with different structure type were isolated. Complex 1 presents a chain structure via equatorial–apical chloride bridges, while 2 is a di-chlorido-bridged dinuclear complex. Quite different magnetic interactions (from ferromagnetic to antiferromagnetic) were found to exist in the two complexes.Figure optionsDownload as PowerPoint slide