Alkoxo-Bridged Dinuclear and Tetranuclear Copper(II) Complexes with Schiff-Bases Derived from Benzoylacetone and 1,n-Diamino-n′-hydroxyalkanes (n, n′ = 3, 2; 4, 2; and 5, 3)

Abstract

Abstract Alkoxo-bridged copper(II) complexes with N,N′-bis(1-methyl-3-hydroxy-3-phenyl-2-propen-1-ylidene)-1,3-diamino-2-propanol (H3bzacpro), N,N′-bis(1-methyl-3-hydroxy-3-phenyl-2-propen-1-ylidene)-1,4-diamino-2-butanol (H3bzacbu), and N,N′-bis(1-methyl-3-hydroxy-3-phenyl-2-propen-1-ylidene)-1,5-diamino-3-pentanol (H3bzacpen), [Cu2(bzacpro)(CH3CO2)] (1), [Cu4(bzacpro)2(C2H5O)2] (2), [Cu2(bzacbu)(CH3CO2)] (3), [Cu4(bzacbu)2(CH3O)2] (4), [Cu4(bzacpen)2(CH3CO2)2] (5), and [Cu4(bzacpen)2O]·H2O (6) have been synthesized and characterized by measurements of the infrared and electronic spectra, and the magnetic susceptibilities. Single-crystal X-ray analyses revealed that 1 and 3 are dinuclear copper(II) complexes having a dinuclear core bridged by an alkoxo-oxygen atom of bzacpro or bzacbu and acetato-oxygen atoms, whereas 2, 4, 5, and 6 are tetranuclear copper(II) complexes composed of μ-alkoxo(bzacpro)-μ-ethoxo-, μ-alkoxo(bzacbu)-μ-methoxo-, μ-alkoxo(bzacpen)-μ-acetato-, and μ-alkoxo(bzacpen)-μ-oxo-bridged units, respectively. Magnetic-susceptibility data show that an antiferromagnetic interaction is operative within the dinuclear or tetranuclear core in 1–3, 5 and 6, whereas a ferromagnetic coupling is operative in 4. The crystal structures of the three Schiff-base ligands have also been elucidated.