title: Spectroscopic and theoretical studies on axial coordination of bis(pyrrol-2-ylmethyleneamine)phenyl complexes.
abstract: Metal (M = Zn(II), Ni(II), Cu(II)) complexes with tetradentate Schiff base ligand, bis(pyrrol-2-ylmethyleneamine)phenyl, has been synthesized and characterized by elemental analyses, 1H NMR, mass spectra and UV-vis spectra. The standard association constants (Ktheta) and the thermodynamic parameters (Delta(r)Hmtheta,Delta(r)Smtheta,Delta(r)Gmtheta) for axial coordination of imidazole derivatives with these Shiff base complexes were measured with UV-vis spectrophotometric titration. The decrease of enthalpy is found to be the drive of the axial coordination. Our Schiff base complexes can incorporate two axial ligands, except 2-Et-4-MeIm with two big substituents of great steric bulk according to stoichiometry of 1:1. ZnL displays high selectively binding to imidazole due to the steric bulk effect. Supporting density functional theory (DFT) calculations have been undertaken on B3LYP/6-31G(d) level.
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, China.
authors.forename: Jia-Mei
authors.initials: JM
authors.lastname: Chen
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Ruan
authors.forename: Liang
authors.initials: L
authors.lastname: Meng
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Zhi-Ang
authors.initials: ZA
authors.lastname: Zhu
mesh_terms: D000588:Amines / Q000737:chemistry*; D004126:Dimethylformamide / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry*; D012984:Software; D013053:Spectrophotometry / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013816:Thermodynamics; D015032:Zinc / Q000737:chemistry
chemical_list: D000588:Amines; D008024:Ligands; D009942:Organometallic Compounds; D011758:Pyrroles; D012545:Schiff Bases; C533172:bis(pyrrol-2-ylmethyleneamine)phenyl complex; D004126:Dimethylformamide; D015032:Zinc