Trinuclear and mononuclear copper(II) complexes incorporating tetradentate 2,2′-[1,1′-(ethylenedioxydinitrilo)diethylidyne]diphenol ligand: Syntheses, crystal structures, spectral and thermal behaviors

Mononuclear and trinuclear Cu(II) complexes with chemical formula [CuL]·CH3OH (1) and [{(Cu(μ-L))2(OAc)2}Cu] (2), where H2L = 2,2′-[1,1′-(ethylenedioxydinitrilo)diethylidyne]diphenol, have been synthesized and characterized by elemental analyses, 1H NMR, IR and UV–vis spectra et al. Crystallographic data of complex 1 reveal the formation of an asymmetric mononuclear structure and a slight distortion toward tetrahedral geometry from the square planar structure, in which the introduction of the non-coordinated methanol molecule lead to the assembly of the 1D chains by hydrogen bonding, Cu⋯π and π⋯π interactions. Complex 2 have the elongated square pyramidal geometries for the two terminal Cu(II) ions and an octahedral coordinated geometry for the central Cu(II) ion. In complex 2, two acetate ions coordinate to three Cu(II) ions adopting a familiar syn–syn (μM-O-C-O-M) coordinated fashion. The central Cu(II) ion sits in a crystallographic inversion centre. Therefore, the whole molecule of complex 2 is rigorously centrosymmetric, and forms a 3D supramolecular networks through intermolecular C–H⋯O and C–H⋯π interactions.