Please use this identifier to cite or link to this item: http://www.repositorio.ufc.br/handle/riufc/16941
Title in Portuguese: Complexos Fosfínicos de Rutênio: Síntese, Caracterização, Imobilização e Atividade Catalítica
Title: Ruthenium Phosphinic Complex: Synthesis, Characterization, Immobilization and Catalytic Activity
Author: Francisco, Thiago dos Santos
Advisor(s): Diógenes, Izaura Cirino Nogueira
Keywords: Química inorgânica
Compostos de coordenação
Rutênio
Fosfinas
Ligantes não-inocentes
Catálise
Issue Date: 2015
Citation: FRANCISCO, T. S. (2015)
Abstract in Portuguese: Os resultados apresentados neste trabalho envolvem a síntese de compostos de coordenação contendo fosfinas e ligantes redox ativos (ligantes não-inocentes) na esfera de coordenação do rutênio. Este trabalho está inserido em uma linha de pesquisa do Grupo de Bioinorgânica que visa, como objetivo final, a aplicação dos compostos isolados na catálise de reações de hidrogenação. Durante o desenvolvimento das atividades de doutorado, período de março de 2010 a janeiro de 2015, foram sintetizados seis (06) compostos inéditos na literatura, um dos quais sendo classificado como complexo precursor, [RuIICl2(binap)(PPh3)], onde binap = 2,2′-bis(difenilfosfina)-1,1′-dinaftaleno. Todos estes compostos foram caracterizados por ressonância magnética nuclear de fósforo (RMN 31P{1H}), análise elementar e espectroscopias vibracional na região do infravermelho e eletrônica nas regiões do ultravioleta e visível. A despeito das diversas tentativas de formação de cristais dos complexos isolados, apenas o composto trans-[RuIICl2(dppb)(opda-Clcat)], onde dppb = 1,4-bis(difenilfosfina)butano e opda-Clcat = 4-cloro-1,2-fenilenodiamina, forneceu cristais passíveis de análise por difração de raios X. A partir dos resultados obtidos durante o período citado, dois trabalhos foram publicados em periódicos indexados (Polyhedron 2010, 29, 3349–3354 e Polyhedron 2012, 31, 104–109) e cinco trabalhos foram apresentados em congressos nacionais e internacionais. Os espectros de RMN 31P{1H} dos compostos sintetizados apresentaram um único sinal indicando que os átomos de fósforo ocupam posições equivalentes e trans aos átomos doadores dos ligantes não-inocentes. Apenas o composto trans-[RuIICl2(dppb)(opda-Clcat)] apresentou um dubleto de dubleto que foi atribuído à assimetria do ligante opda-Cl, sendo confirmado pelos dados de difração de raios X. Os dados de espectroscopia eletrônica indicaram o estado oxidado dos ligantes o-fenilênicos após coordenação ao centro metálico sendo possível, portanto, a observação de interações de retrodoação. Os ensaios de atividade catalítica foram monitorados por cromatografia gasosa acoplada à espectrometria de massa utilizando a reação padrão de hidrogenação da molécula de acetofenona ao álcool 1-feniletanol. Além dos complexos originalmente apresentados nesta tese, [RuIICl2(binap)(PPh3)](1), trans-[RuIICl2(binap)(opda-Clcat)](2), trans-[RuIICl2(binap)(fenantq)](3), trans-[RuIICl2(PPh3)2(opdaq)](5) e trans-[RuIICl2(PPh3)2(fenantq)](6), onde fenantq e opdaq são, respectivamente, 9,10-fenantrequinona e 1,2-fenilenodiamina, tais ensaios foram, também, realizados com compostos previamente sintetizados durante a dissertação de mestrado e por outros membros do Grupo de Bioinorgânica, resultando em um total de vinte (20) catalisadores estudados. Destes complexos, dois foram estudados em condições heterogêneas após imobilização sobre esferas híbridas de sílica/quitosana. Dentre os sistemas estudados, os complexos trans-[RuIICl2(dppb)(Quinone)](10), cis-[RuIICl2(dppb)(opda-Clq)](13), trans-[RuIICl2(dppb)(tabq,cat)](15) e cis-[RuIICl2(dppb)(tabq,cat)](16), onde tabq,cat = 3,3’,4,4’-tetraaminobifenil, apresentaram os mais altos valores de conversão (> 90%) em todas as condições analisadas. Os valores de conversão observados para os sistemas heterogêneos, ~ 60%, embora menores que aqueles calculados para os sistemas homogêneos em condições similares, não representam desvantagem, uma vez que implicam na redução da etapa de separação. Os compostos que apresentaram maiores valores de conversão em meio homogêneo apresentam, em comum, a presença de ligantes não-inocentes no estado oxidado. Essa observação indica a presença de efeitos sinérgicos que influenciam na afinidade do substrato, a citar: (i) aumento da acidez de Lewis do metal pela oxidação do ligante e (ii) função de reservatório de densidade eletrônica do ligante redox ativo que permitir o metal estocar (doar) densidade eletrônica no (para o) ligante durante as etapas elementares do ciclo catalítico, evitando a localização excessiva de carga sobre o metal.
Abstract: The results presented in this thesis involve the synthesis of coordination compounds containing phosphine ligands and redox active (non-innocent ligands) in the ruthenium coordination sphere. This work is part of a research line of Bioinorganic Group research aimed, as the ultimate goal, the application of the isolated compounds in catalysis of hydrogenation reactions. During the development of PhD activities, from March 2010 to January 2015, six compounds (06) unpublished in the literature were synthesized; one of which being classified as a precursor complex, [RuIICl2(binap)(PPh3)], where binap = 2,2′-bis(diphenylphosphine)-1,1′-dinaphthalene. All of these complexes were characterized by means of phosphorous nuclear resonance magnetic (RMN 31P{1H}), elemental analysis, infrared spectroscopy and electronic spectroscopy in the ultraviolet and visible regions. Despite several attempts to produce crystals of the synthesized compounds, only the trans-[RuIICl2(dppb)(opda-Clcat)] complex, where dppb = 1,4-bis(diphenylphosphine)butane and opda-Clcat = 4-cloro-1,2-phenylenediamine, yielded suitable crystals for determination of X-ray structure. From the results obtained during the cited time, two papers were published in indexed journals ((Polyhedron 2010, 29, 3349–3354 and Polyhedron 2012, 31, 104–109) and five works were shown in national and international meetings. The RMN 31P{1H} spectra of the isolated compounds presented only one signal indicating that the phosphorous atoms lie in equivalent positions and trans in relation to the donor atoms of the non-innocent ligands. For the trans-[RuIICl2(dppb)(opda-Clcat)] complex, however, a dublet of dublet was observed and was assigned to the assimetry of the opda-Cl moiety, which was confirmed by X ray diffraction. The electronic spectroscopic data indicated the oxidized state of the o-phenylene ligands upon coordination to the metal atom thus making possible the back-bonding interaction. The catalytic activity assays were monitored by gas chromatography coupled to mass spectrometry using the standard hydrogenation reaction of the alcohol molecule acetophenone to 1-phenyl ethanol. In addition to the complex originally presented in this thesis, [RuIICl2(binap)(PPh3)](1), trans-[RuIICl2(binap)(opda-Clcat)](2), trans-[RuIICl2(binap)(fenantq)](3), trans-[RuIICl2(PPh3)2(opdaq)](5) and trans-[RuIICl2(PPh3)2(fenantq)](6), where fenantq and opdaq are, respectively, 9,10-phenanthraquinone and 1,2-phenylenediamine, such assays were also carried out for compounds which were previously synthesized during the master course and by other researchers of the Bioinorganic Group resulting resulting in a total of twenty (20) studied catalysts. Among these complexes, two were studied in heterogeneous condition upon immobilization on hybrid spheres of silica chitosan. By accounting for all the studied conditions, the highest values of conversion (> 90%) were observed for trans-[RuIICl2(dppb)(Quinone)](10), cis-[RuIICl2(dppb)(opda-Clq)](13), trans-[RuIICl2(dppb)(tabq,cat)](15) and cis-[RuIICl2(dppb)(tabq,cat)](16), where tabq,cat = 3,3’,4,4’-tetraaminobiphenyls. The values of conversion observed for the heterogeneous systems, c.a. 60%, although lower than those calculated for the homogeneous systems under similar conditions, do not constitute a disadvantage, since separation step is no longer needed. The compounds that showed the higher conversion values in homogeneous medium feature in common the presence of non-innocent ligands in the oxidized state. This observation indicates, very probably, two synergistic effects which influence the affinity of the substrate: (i) the increase of the Lewis acidity of the metal by the oxidation of the ligand and (ii) the function of electron density reservoir of the redox active ligand that allows the metal to store (donate) electron density from (to) the ligand during the elementary steps of the catalytic cycle by preventing excessive charge density on the metal.
Abstract in Spanish: The results presented in this thesis involve the synthesis of coordination compounds containing phosphine ligands and redox active (non-innocent ligands) in the ruthenium coordination sphere. This work is part of a research line of Bioinorganic Group research aimed, as the ultimate goal, the application of the isolated compounds in catalysis of hydrogenation reactions. During the development of PhD activities, from March 2010 to January 2015, six compounds (06) unpublished in the literature were synthesized; one of which being classified as a precursor complex, [RuIICl2(binap)(PPh3)], where binap = 2,2′-bis(diphenylphosphine)-1,1′-dinaphthalene. All of these complexes were characterized by means of phosphorous nuclear resonance magnetic (RMN 31P{1H}), elemental analysis, infrared spectroscopy and electronic spectroscopy in the ultraviolet and visible regions. Despite several attempts to produce crystals of the synthesized compounds, only the trans-[RuIICl2(dppb)(opda-Clcat)] complex, where dppb = 1,4-bis(diphenylphosphine)butane and opda-Clcat = 4-cloro-1,2-phenylenediamine, yielded suitable crystals for determination of X-ray structure. From the results obtained during the cited time, two papers were published in indexed journals ((Polyhedron 2010, 29, 3349–3354 and Polyhedron 2012, 31, 104–109) and five works were shown in national and international meetings. The RMN 31P{1H} spectra of the isolated compounds presented only one signal indicating that the phosphorous atoms lie in equivalent positions and trans in relation to the donor atoms of the non-innocent ligands. For the trans-[RuIICl2(dppb)(opda-Clcat)] complex, however, a dublet of dublet was observed and was assigned to the assimetry of the opda-Cl moiety, which was confirmed by X ray diffraction. The electronic spectroscopic data indicated the oxidized state of the o-phenylene ligands upon coordination to the metal atom thus making possible the back-bonding interaction. The catalytic activity assays were monitored by gas chromatography coupled to mass spectrometry using the standard hydrogenation reaction of the alcohol molecule acetophenone to 1-phenyl ethanol. In addition to the complex originally presented in this thesis, [RuIICl2(binap)(PPh3)](1), trans-[RuIICl2(binap)(opda-Clcat)](2), trans-[RuIICl2(binap)(fenantq)](3), trans-[RuIICl2(PPh3)2(opdaq)](5) and trans-[RuIICl2(PPh3)2(fenantq)](6), where fenantq and opdaq are, respectively, 9,10-phenanthraquinone and 1,2-phenylenediamine, such assays were also carried out for compounds which were previously synthesized during the master course and by other researchers of the Bioinorganic Group resulting resulting in a total of twenty (20) studied catalysts. Among these complexes, two were studied in heterogeneous condition upon immobilization on hybrid spheres of silica chitosan. By accounting for all the studied conditions, the highest values of conversion (> 90%) were observed for trans-[RuIICl2(dppb)(Quinone)](10), cis-[RuIICl2(dppb)(opda-Clq)](13), trans-[RuIICl2(dppb)(tabq,cat)](15) and cis-[RuIICl2(dppb)(tabq,cat)](16), where tabq,cat = 3,3’,4,4’-tetraaminobiphenyls. The values of conversion observed for the heterogeneous systems, c.a. 60%, although lower than those calculated for the homogeneous systems under similar conditions, do not constitute a disadvantage, since separation step is no longer needed. The compounds that showed the higher conversion values in homogeneous medium feature in common the presence of non-innocent ligands in the oxidized state. This observation indicates, very probably, two synergistic effects which influence the affinity of the substrate: (i) the increase of the Lewis acidity of the metal by the oxidation of the ligand and (ii) the function of electron density reservoir of the redox active ligand that allows the metal to store (donate) electron density from (to) the ligand during the elementary steps of the catalytic cycle by preventing excessive charge density on the metal.
Description: FRANCISCO, Thiago dos Santos. Complexos Fosfínicos de Rutênio: Síntese, Caracterização, Imobilização e Atividade Catalítica. 2015. 146 f. Tese (doutorado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2015.
URI: http://www.repositorio.ufc.br/handle/riufc/16941
metadata.dc.type: Dissertação
Appears in Collections:DQOI - Teses defendidas na UFC

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