Insight into fluorescent properties, DFT and Hirshfeld analyses of a newly synthesized and structurally novel trinuclear copper(II) Salamo-based complex invoving phenoxo-O bridged coordination

Abstract

A novel trinuclear Cu(II) (Cu2+:(L)3− = 3:2) complex derived from a newly designed pentadentate salamo-based ligand (H3L), namely [Cu3(L)2(CH3OH)2]·CH3COCH3, is synthesized. This structure is different from the structures of reported earlier salamo-based Cu(II) complexes. The structure of the Cu(II) complex is elucidated by X-ray crystallography. Each completely deprotonated ligand (L)3– unit actually participates in the coordination as a pentadentate ligand. The coordination of a 3-position phenoxo-O atom is a key factor in the formation of the tri\xadnuclear Cu(II) complex. The five-coordinated terminal Cu(II) atoms (Cu1 and Cu3) possess slightly distorted tetragonal pyramidal geometries. The six-coordinated central Cu(II) atom (Cu2) adopts a distorted octahedral geometry. The study of the molecular packing by the Hirshfeld surface analysis exhibits that the percentages of H—H/H—H, C—H/H—C, and O—H/H—O contacts are calculated to be 54.9 %, 22.5 %, and 19.6 %, respectively. DFT investigations indicate that the stability of the complex is much higher than that of H3L. The Cu(II) complex forms a three-dimensional supramolecular structure through intermolecular hydrogen bonding and C—H⋯π interactions.