Unprecedented Dinuclear CuII N,O-Donor Complex: Synthesis, Structural Characterization, Fluorescence Property, and Hirshfeld Analysis

Abstract

An unprecedented dinuclear Cu II complex, [Cu 2 (L 2 ) 2 ], derived from a salamo-like chelating ligand H 2 L 2 , was produced by the cleavage of a newly synthesized, half-salamo-like ligand HL 1 (2-[O-(1-ethyloxyamide)]oxime-3,5-dichloro-phenol). This was synthesized and characterized by elemental analyses, IR, UV-Vis and fluorescent spectra, single crystal X-ray diffraction analysis, and Hirshfeld surface analysis. X-ray crystallographic analysis indicated that the two Cu II (Cu1 and Cu2) ions bore different (N 2 O 3 and N 2 O 2 ) coordination environments, the penta-coordinated Cu1 ion possessed a slightly twisted tetragonal pyramid geometry with the τ value τ = 0.004, and the tetra-coordinated Cu2 ion showed a slightly twisted square planar geometry. Interestingly, one oxime oxygen atom participated in the coordination reported previously. Moreover, an infinite two-dimensional layered supramolecular network was formed. Compared with HL 1 , the Cu II complex possessed the characteristic of fluorescence quenching.Crystals 2019, 9, 607 2 of 15 complexes, the participation of oxime oxygen atoms of salamo-like ligands in coordination should be constantly emerging.In order to study the structures and properties of metal salamo-like complexes, we have designed and synthesized a new half-salamo-like ligand, HL 1 , and a Cu II complex [Cu 2 (L 2 ) 2 ]. The Cu II complex [Cu 2 (L 2 ) 2 ] was obtained by the reaction of the ligand HL 1 with Cu(OAc) 2 ·H 2 O and contained no acetate ion. This contrasts with the salamo-like complexes previously reported [52,53], in which an acetate ion often accompanied and coordinated with metal ions. The fluorescence property and Hirshfeld surface analysis of the Cu II complex were studied [54]. Experimental Materials and Instrumentation2-Hydroxy-3,5-dichlorobenzaldehyde of 99% purity was obtained from the Alfa Aesar. The other reagents and solvents used in the experiment were purchased from the Tianjin Chemical Reagent Factory at the analytical reagent level and used without further purification [55]. Elemental analyses of metal element (Cu) and non-metallic elements (C, H, and N) were measured by an atomic emission spectrometer (IRIS ER/S·WP-1 ICP) and automatic elemental detection analyzer (GmbH VariuoEL V3.00) from Berlin, Germany, respectively, melting points were measured by the use of a microscopic melting point apparatus made by the Beijing Taike Instrument Limited Company (Beijing, China) and was uncorrected, 1H NMR (nuclear magnetic resonance) spectra were measured by German Bruker AVANCE DRX-400/600 spectroscopy (Bruker AVANCE, Billerica, MA, USA), single crystal X-ray structure data was collected by a CCD surface detecting diffractometer (Bruker, Germany), and Mo-Kα (λ = 0.71073 Å) ray radiation was monochromated with graphite, IR spectra were recorded on a VERTEX 70 spectrophotometer with samples prepared as KBr (500-4000 cm −1 ) from Bruker, Germany, UV-Vis spectra were measured on a UV-3900 spectrophotometer from Hitachi, Tokyo, Japan, fluorescence spectra were recorded ...

Influence of structural variation of salamo‐based ligand on supramolecular architectures, Hirshfeld analyses, and fluorescence properties of new tetranuclear NiII complexes

“…Salamo‐based compounds as derivatives of salen‐based ligands have received a lot of attention in recent years. [ 11,19,24–26 ] Unlike the salen‐based ligands, the oxygen atoms are introduced into the diamine units. [ 20,27,28 ] Compared with the classic salen‐based ligands, the salamo‐based ligands are less prone to hydrolysis and have better stabilities.…”

Investigation of mononuclear, dinuclear, and trinuclear transition metal (II) complexes derived from an asymmetric Salamo‐based ligand possessing three different coordination modes

“…The phenomenon of fluorescence quenching was due to LMCT caused by the coordination of the ligand H 2 L with the Cu (II), Co (II), and Ni (II) atoms. [ 61 ]…”

Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex

“…Both the salen-based ligands and their derivatives have shown strong development potential in the research of materials chemistry, coordination chemistry, and environmental monitoring for decades because of their good application prospects in organic catalytic synthesis, molecular magnetic properties, and luminescent properties [1][2][3][4][5], which, owing to their N 2 O 2 -donor structure, usually have excellent coordination ability to transition metal ions for various structural novel complexes (derivatives) [6][7][8][9][10][11].…”