title: Preparation, crystallography and spectroscopic properties of the polymeric {(1-(E)-2-pyridinylmethylidene)semicarbazone)(aqua)copper(II)} sulphate dihydrate complex: evidence of dynamic Jahn-Teller effect.
abstract: Pyridine-2-carbaldehyde semicarbazone ligand (HL) reacts with copper(II) sulphate in water solution to yield the coordination polymer [{Cu(II)(HL)(H(2)O)(SO(4))}(n)] (1). The crystals are triclinic with space group P(-1) and the metal ion is occupying a distorted octahedral geometry. EPR results show that a dynamic Jahn-Teller (J-T) effect is operative in water solutions and also support the stability of the polymeric chains as they continue to show a characteristic half-field Δm(S)=±2 transitions. UV-visible spectrum analysis allowed access to the J-T stabilization energy of 5995 cm(-1) in water. Thermogravimetric/differential thermal analysis curves showed a step-by-step decomposition of complex 1 with loss of water, release of SO(3) and oxidation of the semicarbazone ligand in the 30-422°C range.
authors.affiliation: Departamento de Química, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Ellery R
authors.initials: ER
authors.lastname: Garbelini
authors.forename: Ronny Rocha
authors.initials: RR
authors.lastname: Ribeiro
authors.forename: Manfredo
authors.initials: M
authors.lastname: Hörner
authors.forename: Aline
authors.initials: A
authors.lastname: Locatelli
authors.forename: Fábio S
authors.initials: FS
authors.lastname: Nunes
mesh_terms: D003198:Computer Simulation; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D008024:Ligands; D008956:Models, Chemical; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D011208:Powders; D011522:Protons; D011725:Pyridines / Q000737:chemistry; D012664:Semicarbazones / Q000138:chemical synthesis* / Q000737:chemistry*; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013818:Thermogravimetry
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D011108:Polymers; D011208:Powders; D011522:Protons; D011725:Pyridines; D012664:Semicarbazones; D012996:Solutions; C432864:pyridine-2-carbaldehyde