An Unexpected Salamo-Type Copper(II) Complex: Synthesis, Crystal Structure, Thermal Behavior, and Spectroscopic Analysis

Abstract

A novel supramolecular Cu(ΙΙ) complex [Cu₂(L²)₂] (H₂L₂ = 4-bromosalicylaldehyde O-(2-hydroxyethyl)oxime) is synthesized through the complexation of Cu(OAc)₂·H₂O with an asymmetric salamo-type ligand 4-bromo-6′-hydroxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H₃L¹) and is structurally characterized by single crystal X-ray diffraction. The X-ray crystal structure of the Cu(ΙΙ) complex reveals it to crystallize in the triclinic system, space group \(P\overline1\), in which each Cu(II) atom is in a distorted square pyramidal geometry. The whole Cu(ΙΙ) complex consists of a series of [Cu₂(L²)₂] units, forming an infinite 1D chain supramolecular structure. Meanwhile, the Cu(II) complex exhibits emission with the maximum emission wavelength λ_max = 431 nm when excited at λ_ex = 367 nm.