Complexos cofaciais de dirutênio contendo haletos em ponte e fosfinas como ligantes: estudos espectrais, eletroquímicos e de reatividade
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2001
Autores
Araujo, Márcio Peres de [UNESP]
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Universidade Estadual Paulista (Unesp)
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O complexo mer-[RuCl3(dppb)H2O] foi utilizado como precursor para a síntese de uma série de complexos binucleares de valência mista, estes apresentam fórmula geral [Ru2Cl5(dppb)(P)2] e [Ru2Cl5(dppb)(P-P)] e forma estudados por técnicas eletroquímicas e espectroscópicas. A maior característica destas espécies é que apresentam acoplamento metal-metal, ou seja transferência de elétrons entre seus centros metálicos em função dessa caracterísitica apresentam absorção na região do infravermelho-próximo do espectro eletrônico, além de dois processos eletroquímicos com separação (ΔE1/2) ~0,60 V, indicativo de forte interação entre os centros metálicos. Complexos com fórmula [Ru2Cl4CO(dppb)(P)2] e [Ru2Cl4(N-het.)(dppb)2] foram sintetizados e caracterizados. Alguns dos complexos obtidos foram testados em reações de hidrogenação de iminas, sendo que alguns mostraram grande atividade. Complexos do tipo [RuCl2(dppb)(N-N)] e [RuCl2(dppb)(N)2] foram utilizados para a redução da acetofenona usando transferência de hidrogênio, as conversões alcançadas foram satisfatórias em função das condições não terem sido optimizadas. Além disso o aqua complexo mer-[RuCl3(dppb)H2O] também foi eficiente para gerar in situ espécies catalíticamente ativas. A reatividade do complexo [Ru2Cl4(dppb)3] com CuCl2.2H2O e [NBu4][AuCl4] foi testada e o produto destas reações foi identificado como [Ru2Cl5(dppb)2]. Estas reações ocorrem via oxidação do complexo de rutênio e posterior fomação do complexo de valência mista contendo três cloretos em ponte. O complexo [RuCl2(PPh3)3] também foi oxidado com excesso de CuCl2.2H2O levando a formação de [CuCl(PPh3)3] (caracterizado por RMN 31P{1H}) e do complexo solvato [RuCl3(PPh3)2MeOH]MeOH (caracterizado por RPE), além destas espécies uma solução amarela é obtida e com a adição de dppm a esta solução o complexo...
The compound mer-[RuCl3(dppb)H2O] was used as precursor for the synthesis of a wide range of mixed valence complexes and present the general formula [Ru2Cl5(dppb)(P)2] and [Ru2Cl5(dppb)(PP)]. These complexes were studied by electrochemical and spectroscopic techniques. The main characteristic of these species is that they present metal-metal coupling or metal-metal electron transfer due to this electron transfer absorptions in the near infrared region can be observed. Cyclic voltammetry studies reveals that these complexes show two reversible electrochemical processes with separation (ΔE1/2) ~0,60 V, which is indicative of strong interaction between metallic centers. Complex with formula [Ru2Cl4(CO)(dppb)(P)2] and [Ru2Cl4(N-het.)(dppb)2] were synthesized and characterized. Some of the compounds synthesized were tested in reactions of imines hydrogenation, and some showed great activity. Complexes of the type [RuCl2(dppb)(N-N)] and [RuCl2(dppb)(N)2] were used for the acetophenone reduction using hydrogen-transfer reactions, conversions were satisfactory due to the conditions has not been optimized. Besides the aqua complex mer-[RuCl3(dppb)H2O] was also efficient to in situ generates active species. The reactivity of the compound [Ru2Cl4(dppb)3] with CuCl2.2H2O and [NBu4][AuCl4] was tested and the product of these reactions was identified as [Ru2Cl5(dppb)2]. These reactions occurs through oxidation and dimerization of the ruthenium complexes to form the mixed valence complex. The compound [RuCl2(PPh3)3] was reacted with excess of CuCl2.2H2O leading to the formation of [CuCl(PPh3)3] (characterized by RMN 31P{1H}) and the compound [RuCl3(PPh3)2MeOH]MeOH (characterized by RPE), besides these species a yellow solution was obtained and with addition of dppm to this solution the compound [Ru2Cl5(dppm)2] is obtained. X-ray structures for the compounds [Ru2Cl5(dppb)2], [Ru2Cl5(dppm)2],...(Complete abstract click electronic access below)
The compound mer-[RuCl3(dppb)H2O] was used as precursor for the synthesis of a wide range of mixed valence complexes and present the general formula [Ru2Cl5(dppb)(P)2] and [Ru2Cl5(dppb)(PP)]. These complexes were studied by electrochemical and spectroscopic techniques. The main characteristic of these species is that they present metal-metal coupling or metal-metal electron transfer due to this electron transfer absorptions in the near infrared region can be observed. Cyclic voltammetry studies reveals that these complexes show two reversible electrochemical processes with separation (ΔE1/2) ~0,60 V, which is indicative of strong interaction between metallic centers. Complex with formula [Ru2Cl4(CO)(dppb)(P)2] and [Ru2Cl4(N-het.)(dppb)2] were synthesized and characterized. Some of the compounds synthesized were tested in reactions of imines hydrogenation, and some showed great activity. Complexes of the type [RuCl2(dppb)(N-N)] and [RuCl2(dppb)(N)2] were used for the acetophenone reduction using hydrogen-transfer reactions, conversions were satisfactory due to the conditions has not been optimized. Besides the aqua complex mer-[RuCl3(dppb)H2O] was also efficient to in situ generates active species. The reactivity of the compound [Ru2Cl4(dppb)3] with CuCl2.2H2O and [NBu4][AuCl4] was tested and the product of these reactions was identified as [Ru2Cl5(dppb)2]. These reactions occurs through oxidation and dimerization of the ruthenium complexes to form the mixed valence complex. The compound [RuCl2(PPh3)3] was reacted with excess of CuCl2.2H2O leading to the formation of [CuCl(PPh3)3] (characterized by RMN 31P{1H}) and the compound [RuCl3(PPh3)2MeOH]MeOH (characterized by RPE), besides these species a yellow solution was obtained and with addition of dppm to this solution the compound [Ru2Cl5(dppm)2] is obtained. X-ray structures for the compounds [Ru2Cl5(dppb)2], [Ru2Cl5(dppm)2],...(Complete abstract click electronic access below)
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Sintese inorganica, Summary inorganic
Como citar
ARAUJO, Márcio Peres de. Complexos cofaciais de dirutênio contendo haletos em ponte e fosfinas como ligantes: estudos espectrais, eletroquímicos e de reatividade. 2001. 123 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Química, 2001.