Two novel copper(II) salamo-based complexes: Syntheses, X-ray crystal structures, spectroscopic properties and Hirshfeld surfaces analyses

Abstract

Two novel Cu(II) complexes, [{Cu(L1)}2(CH3OH)]·CH3OH (1) and [Cu(L2)2] (2) derived from a half-salamo-based N2O-donor ligand (HL: 2-[O-(1-ethyloxyamide)]oxime-4-nitrophenol) were synthesized and characterized by elemental analyses, infrared spectroscopy, ultraviolet–visible absorption spectroscopy, X-ray single crystal diffraction and Hirshfeld surfaces analyses. Here, ligands H2L1 (4,4′-Dinitro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) and HL2 ((E)-2-Hydroxy-5-nitrobenzaldehyde O-(2-((propan-2-ylideneamino)oxy)ethyl) oxime) are obtained by rearrangement reaction due to the catalysis of Cu(II) ion during the formation of the complexes 1 and 2. The complex 1 consists of two Cu(II) ions, two fully deprotonated ligand (L1)− units, one coordinated methanol and one crystallized methanol molecules, forming an novel unsymmetric dinuclear structure previously unreported, and possesses an infinite 3D supramolecular structure. The Cu(II) ions are penta-coordinated and with distorted tetragonal pyramidal geometric configuration. The complex 2 is an novel symmetric mononuclear structure, consists of one Cu(II) ion, two fully deprotonated ligand (L2)− units, forming a four-coordinated planar quadrilateral geometric configuration with a Cu(II) ion occupying the center of symmetry, and possesses an infinite 2D supramolecular structure. Simultaneously, the fluorescence properties and Hirshfeld surfaces analyses of the Cu(II) complexes 1 and 2 were also investigated.