title: Manganese chlorins immobilized on silica as oxidation reaction catalysts.
abstract: Synthetic strategies that comply with the principles of green chemistry represent a challenge: they will enable chemists to conduct reactions that maximize the yield of products with commercial interest while minimizing by-products formation. The search for catalysts that promote the selective oxidation of organic compounds under mild and environmentally friendly conditions constitutes one of the most important quests of organic chemistry. In this context, metalloporphyrins and analogues are excellent catalysts for oxidative transformations under mild conditions. In fact, their reduced derivatives chlorins are also able to catalyze organic compounds oxidation effectively, although they have been still little explored. In this study, we synthesized two chlorins through porphyrin cycloaddition reactions with 1.3-dipoles and prepared the corresponding manganese chlorins (MnCHL) using adequate manganese(II) salts. These MnCHL were posteriorly immobilized on silica by following the sol-gel process and the resulting solids were characterized by powder X-ray diffraction (PXRD), UVVIS spectroscopy, FTIR, XPS, and EDS. The catalytic activity of the immobilized MnCHL was investigated in the oxidation of cyclooctene, cyclohexene and cyclohexane and the results were compared with the ones obtained under homogeneous conditions.
authors.affiliation: Laboratório de Bioinorgânica e Catálise, Universidade Federal do Paraná (UFPR), CP 19032, CEP 81531980 Curitiba, Paraná, Brazil; Department of Chemistry and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Kelly A D F
authors.initials: KADF
authors.lastname: Castro
authors.affiliation: Department of Chemistry and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Sónia M G
authors.initials: SMG
authors.lastname: Pires
authors.affiliation: Laboratório de Bioinorgânica e Catálise, Universidade Federal do Paraná (UFPR), CP 19032, CEP 81531980 Curitiba, Paraná, Brazil.
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Ribeiro
authors.affiliation: Department of Chemistry and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Mário M Q
authors.initials: MMQ
authors.lastname: Simões
authors.affiliation: Department of Chemistry and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: M Graça P M S
authors.initials: MGPMS
authors.lastname: Neves
authors.affiliation: Laboratório de Bioinorgânica e Catálise, Universidade Federal do Paraná (UFPR), CP 19032, CEP 81531980 Curitiba, Paraná, Brazil.
authors.forename: Wido H
authors.initials: WH
authors.lastname: Schreiner
authors.affiliation: Laboratório de Bioinorgânica e Catálise, Universidade Federal do Paraná (UFPR), CP 19032, CEP 81531980 Curitiba, Paraná, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Wypych
authors.affiliation: Department of Chemistry and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: jcavaleiro@ua.pt.
authors.forename: José A S
authors.initials: JAS
authors.lastname: Cavaleiro
authors.affiliation: Laboratório de Bioinorgânica e Catálise, Universidade Federal do Paraná (UFPR), CP 19032, CEP 81531980 Curitiba, Paraná, Brazil. Electronic address: shirleyn@ufpr.br.
authors.forename: Shirley
authors.initials: S
authors.lastname: Nakagaki
keywords: Chlorins; Heterogeneous catalysis; Immobilization; Oxidation; Porphyrins; Sol–gel