| Journal: | Journal of the Brazilian Chemical Society |
| Database: | PERIÓDICA |
| System number: | 000311291 |
| ISSN: | 0103-5053 |
| Authors: | Niedwieski, Antonio C1 Hitchcock, Peter B2 Motta-Neto, Joaquim D. da Wypych, Fernando Leigh, G. Jeffery Nunes, Fabio S |
| Institutions: | 1Universidade Federal do Parana, Centro Politecnico, Curitiba, Parana. Brasil 2University of Sussex, School of Chemistry, Physics and Environmental Science, Brighton, East Sussex. Reino Unido |
| Year: | 2003 |
| Season: | Sep |
| Volumen: | 14 |
| Number: | 5 |
| Pages: | 750-758 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, aplicado |
| English abstract | The synthesis, spectroscopic characterisation and reactivity of a series of vanadium(II) complexes, [VCl2(diamine)2] (diamine = dmeda: N,N'-dimethylethane-1,2-diamine, deeda: N,N'diethylethane-1,2-diamine, tmeda: N,N,N',N'-tetramethylethane-1,2-diamine, dieda: N,N'diisopropylethane-1,2-diamine, teeda: N,N,N',N'-tetraethylethane-1,2-diamine, dtbeda: N,N'-ditert-butylethane-1,2-diamine and dfeda: N,N'-diphenylethane-1,2-diamine) are reported. Some of these complexes can be converted into the trinuclear cation [V3(µCl)3(µ3Cl)2(diamine) 3]+ through the reaction with [V2(µ-Cl)3(thf)3]+ under mild conditions. The compounds were characterised by microanalysis, positive ion FAB mass spectrometry, UVvisible and infrared spectroscopies, thermogravimetric analysis and magnetic moment measurements in the solid state. We characterised fully by single-crystal X-ray diffraction analysis the complex [VCl2(deeda)2]. The stability of [VCl2(diamine)2] as they vary with the different diamines is correlated with crystal field and infrared parameters along with decomposition temperatures and the calculated molecular orbital energies. We also presented a new synthetic route to prepare [V3(µ-Cl)3(µ3-Cl)2(diamine) 3]+ which allows a better control of the reaction pathway, avoiding the formation of undesired redox reaction products |
| Portuguese abstract | A série de complexos de vanádio(II), [VCl2(diamina)2] (diamina = dmeda: N,N'dimetiletano-1,2-diamina, deeda: N,N'-dietiletano-1,2-diamina, tmeda: N,N,N',N'tetrametiletano1,2-diamina, dieda: N,N'-diisopropiletano-1,2-diamina, teeda: N,N,N',N'-tetraetiletano-1,2-diamina, dtbeda: N,N'-ditert-butiletano-1,2-diamina and dfeda: N,N'difeniletano-1,2-diamina) foi preparada e caracterizada por análise elementar, espectrometria de massas (FAB), espectroscopia de absorção no UV-visível e infravermelho, termogravimetria e magnetoquímica. O complexo [VCl2(deeda)2] foi caracterizado por difração de raios X de monocristal. Alguns destes compostos podem ser convertidos no cátion trinuclear [V3(µ-Cl)3(µ3-Cl)2(diamina) 3]+ por reação com [V2(µ-Cl)3(thf)3]+ em condições brandas. A estabilidade dos complexos [VCl2(diamina)2] varia com a natureza da diamina e correlaciona-se com parametros de campo cristalino, frequências de modos vibracionais, as temperaturas de decomposição e com as energias dos orbitais de fronteira. Uma nova rota de síntese de [V3(µCl)3(µ3-Cl)2(diamina) 3]+ é apresentada e permite um melhor controle do caminho da reação e evita a formação de subprodutos indesejáveis |
| Disciplines: | Química |
| Keyword: | Química analítica, Química organometálica, Complejos de vanadio (II)-diamina, Análisis de campo cristalino, Cristalografía de rayos X, Espectroscopía de infrarrojo, Termoquímica |
| Keyword: | Chemistry, Analytical chemistry, Organometallic chemistry, Vanadium (II) diamine complexes, Crystal field analysis, X-ray crystallography, Infrared spectroscopy, Thermochemistry |
| Full text: | Texto completo (Ver HTML) |
