title: Halochromism, ionochromism, solvatochromism and density functional study of a synthesized copper(II) complex containing hemilabile amide derivative ligand.
abstract: This study investigates chromotropism of newly synthesized 3,3'-(ethane-1,2-diylbis(benzylazanediyl))dipropanamide copper(II) perchlorate complex. The compound was structurally characterized by physico-chemical and spectroscopic methods. X-ray crystallography of the complex showed that the copper atom achieved a distorted square pyramidal environment through coordination of two amine N atoms and two O atoms of the amide moieties. The pH effect on the visible absorption spectrum of the complex was studied which functions as pH-induced "off-on-off" switches through protonation and deprotonation of amide moieties along with the CuO to CuN bond rearrangement at room temperature. The complex was also observed to show solvatochromism and ionochromism. The distinct solution color changes mainly associated with hemilability of the amide groups. The solvatochromism of the complex was investigated with different solvent parameter models using stepwise multiple linear regression method. The results suggested that the basicity power of the solvent has a dominant contribution to the shift of the d-d absorption band of the complex. Density functional theory, DFT calculations were performed in order to study the electronic structure of the complex, the relative stabilities of the CuN/CuO isomers, and to understand the nature of the halochromism processes taking place. DFT computational results buttressed the experimental observations indicating that in the natural pH (5.8) the CuO isomer is more stable than its linkage isomer and conversely in alkaline aqueous solution.
authors.affiliation: Department of Chemistry, University of Mazandaran, Babol-sar 47416-95447, Iran; Department of Chemistry, Mohammad Reza Hariri Science Foundation, Babol 47146-38474, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Golchoubian
authors.affiliation: Department of Chemistry, University of Mazandaran, Babol-sar 47416-95447, Iran.
authors.forename: Golasa
authors.initials: G
authors.lastname: Moayyedi
authors.affiliation: Department of Chemistry, University of Mazandaran, Babol-sar 47416-95447, Iran.
authors.forename: Neda
authors.initials: N
authors.lastname: Reisi
mesh_terms: D000577:Amides / Q000737:chemistry*; D003116:Color; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004560:Electricity; D004583:Electrons; D006219:Halogens / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics; D014732:Vibration
chemical_list: D000577:Amides; D056831:Coordination Complexes; D006219:Halogens; D007477:Ions; D008024:Ligands; D012996:Solutions; D012997:Solvents; D003300:Copper
keywords: Amide derivative ligand; Chromotropism; Copper(II) complex; DFT; Hemilabile ligand