91042-27-2Relevant academic research and scientific papers
Critical factors in determining the heterolytic versus homolytic bond cleavage of terminal oxidants by Iron(III) porphyrin complexes
Yokota, Sawako,Fujii, Hiroshi
, p. 5127 - 5137 (2018/04/24)
Heterolytic versus homolytic cleavage of the metal-bound terminal oxidant is the key for determining the nature of reactive intermediates in metalloenzymes and metal catalyzed oxygenation reactions. Here, we study the bond cleavage process of hypochlorite
Preparation of catalysts based on iron(III) porphyrins heterogenized on silica obtained by the sol-gel process for hydroxylation and epoxidation reactions
Castro, Kelly A. D. F.,Halma, Matilte,Machado, Guilherme S.,Ricci, Gustavo P.,Ucoski, Geani M.,Ciuffi, Katia J.,Nakagaki, Shirley
experimental part, p. 1329 - 1340 (2010/11/04)
Solid catalysts have been prepared by chemical interaction of iron(III) porphyrins with the surface of the pores of a silica matrix obtained by the sol-gel method. The presence of the complexes in the silica matrix and the morphology of the obtained parti
Characterization and catalytic activity of iron(III) mono(4-N-methyl pyridyl)-tris(halophenyl)porphyrins in homogeneous and heterogeneous systems
Prado-Manso, Cynthia M.C.,Vidoto, Ednalva A.,Vinhado, Fabio S.,Sacco, Herica C.,Ciuffi, Katia J.,Martins, Patricia R.,Ferreira, Antonio G.,Lindsay-Smith, John R.,Nascimento, Otaciro R.,Iamamoto, Yassuko
, p. 251 - 266 (2008/10/09)
The synthesis, characterization and catalytic activity of the cationic iron porphyrins Fe[M(4-N-MePy)TDCPP]Cl2 and Fe[M(4-N-MePy)TFPP]Cl2 in the epoxidation of (Z)-cyclooctene by PhIO in homogeneous solution and supported on silica gel (SG), imidazole propyl gel (IPG) or SG modified with 2-(4- sulfonatophenyl)ethyl groups (SiSO3) have been accomplished. When supported on IPG, both cationic FeP bind to the support via Fe-imidazole coordination. Fe[M(4-N-MePy)TDCPP]IPG contains a mixture of low-spin bis-coordinated Fe(III)P and high-spin mono-coordinated Fe(III)P species, whereas Fe[M(4-N- MePy)TFPP]IPG only contains high-spin mono-coordinated Fe(III)P. These FePIPG catalysts also contain Fe(II)P species, whose presence was confirmed by EPR spectroscopy using NO as a paramagnetic probe. Both cationic FePs coordinate to SG through Fe-O ligation and they are present as high-spin Fe(III)P species. The cationic FePs supported on SiSO-/3 are also high-spin Fe(III) P species and they bind to the support via electrostatic interaction between the 4-N-methyl-pyridyl groups and the SO-/3 groups present on the matrix. In homogeneous solution, both Fe[M(4-N-MePy)TDCPP]Cl2 and Fe[M(4-N- MePy)TFPP]Cl2 have similar catalytic activity to Fe(TDCPP)Cl and Fe(TFPP)Cl, leading to cis-epoxycyclooctane yields of 92%. When supported on inorganic matrices, both FePs lead to epoxide yields comparable to their homogeneous analogues and their anchoring enables catalyst recovery and re-use. Recycling of Fe[M(4-N-MePy)TDCPP]SiSO-/3 shows that this FeP maintains its activity in a second reaction.
Factors which affect the catalytic activity of iron(III) meso tetrakis(2,6-dichlorophenyl) porphyrin chloride in homogeneous system
Iamamoto, Yassuko,Assis, Marilda D.,Ciuffi, Katia J.,Sacco, Herica C.,Iwamoto, Lidia,Melo, Andrea J.B.,Nascimento, Otaciro R.,Prado, Cynthia M.C.
, p. 189 - 200 (2008/10/09)
An optimization study of the reaction conditions of Fe(TDCPP)Cl when it is used as catalyst in the hydroxylation of cyclohexane by iodosylbenzene (PhIO) has been carried out. It was found that Fe(TD CPP)Cl follows the classical PhIO mechanism described for Fe(TPP)Cl, which involves the monomeric active species Fe(IV)(O)P+ (I). In the optimized condition ([Fe(TDCPP) = 3.0 x 10-4 mol-1 in 1,2-dichloroethane (DCE); ultrasound stirring at 0°C; PhIO/FeP molar ratio = 100), this PeP led to a yield of cyclohexanol (C-ol) of 96% and a turnover number of 96. Therefore, Fe(TDCPP)Cl may be considered a good biomimetic model and a very stable, resistant and selective catalyst, which yields C-ol as the sole product. DCE showed to be a better solvent than dichloromethane (DCM), I DCE:I MeOH mixture or acetonitrile (ACN). Since the Fe(IV)(O)P+ is capable of abstracting hydrogen atom from (DCM), MeOH or ACN, the solvent competes with the substrate. Presence of O2 lowers the yield of C-ol, as it can further oxidize this alcohol to carboxylic acid in the presence of radicals. Presence of H2O also causes a decrease in the yield, since it converts the active species I into Fe(IV)(OH)P, which cannot oxidize cyclohexane. Addition of excess imidazole or OH to the system results in a decrease in the yield of C-ol, due to the formation of the hexacoordinated complexes Fe(TDCPP)Im2/+ (low-spin, β2= 2.5 x 108 mol-2 l2) and Fe(TDCPP)(OH) 2/- (high-spin, β2 = 6.3 x 107 mol-2 l2). The formation of both Fe(TDCPP)lm+ and Fe(TDCPP)(OH)2/- complexes were confirmed by EPR studies. The catalytic activities of Fe(TDCPP)Cl and Fe(TFPP)Cl were compared. The unusually high yields of C-ol with Fe(TFPP)Cl obtained when ultrasound, DCM and 02 atmosphere were used, suggest that a parallel mechanism involving the μ-oxo dimer form, O2 and radicals may also be occurring with this FeP, besides the Phi() mechanism.
