title: A comprehensive electronic structure description of a biscyanotetraazacobalt(III) macrocyclic complex.
abstract: Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(meso)(CN)(2)](+) (meso = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics (MM+), ZINDO/S and PM3) quantum-mechanics calculations. The energy and the composition of the molecular orbitals of the complex were calculated and a quantitative diagram was constructed. The simulated UV-vis spectrum exhibited a reasonably good accordance with the experimental one and fully assignments of seven bands were made. An optimized configuration of the complex showed a strong cobalt-cyanide axial bond in agreement with the major contribution of the cyanide to the composition of the molecular orbitals in contrast to a discrete participation of the macrocyclic meso to the ground state of the complex.
authors.affiliation: Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, C.P. 19081, 81531-990 Curitiba, PR, Brazil.
authors.forename: Fabiana Hitomi Ono
authors.initials: FH
authors.lastname: Ishiruji
authors.forename: Fábio Souza
authors.initials: FS
authors.lastname: Nunes
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D003035:Cobalt / Q000032:analysis / Q000737:chemistry*; D004566:Electrodes; D004581:Electronics; D004583:Electrons; D008024:Ligands; D046911:Macromolecular Substances / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014466:Ultraviolet Rays
chemical_list: D001372:Aza Compounds; D008024:Ligands; D046911:Macromolecular Substances; D009942:Organometallic Compounds; C524454:biscyanotetraazacobalt; D003035:Cobalt