123051-66-1Relevant articles and documents
Kinetic studies of oxygen atom transfer reactions from trans- dioxoruthenium(VI) porphyrins to sulfides
Abebrese, Chris,Huang, Yan,Pan, Alice,Yuan, Zhibo,Zhang, Rui
experimental part, p. 1555 - 1561 (2012/05/19)
The kinetics of the reactions of three trans-dioxoruthenium(VI) porphyrin derivatives with organic sulfides were measured. The dioxo systems studied were 5,10,15,20-tetramesityl porphyrin-dioxoruthenium(VI) (2a), 5,10,15,20- tetraphenylporphyrin-dioxoruthenium(VI) (2b), and 5,10,15,20- tetrakis(pentafluorophenyl)porphyrin-dioxoruthenium(VI) (2c). Species 2 were competent oxidants and reacted rapidly with thioanisoles to generate the corresponding sulfoxides. Typical second-order rate constants determined from pseudo-first-order kinetic studies for sulfoxidation reactions are 8-60 M - 1 s- 1, which are 3 orders of magnitude larger in comparison with those of well studied alkene epoxidations and activated C-H bond oxidations by the same dioxo species. For a given sulfide substrate, the reactivity order for the dioxoruthenium(VI) species was 2a 2b 2c, which is in agreement with expectation on the basis of the electron-withdrawing and steric effects of the porphyrin macrocycles. Various para-substituted thioanisoles react in a narrow kinetic range with the same dioxo species. The kinetic results obtained in this study indicate a concerted oxygen atom transfer and/or electron transfer followed by oxygen transfer mechanism from oxidant to sulfide. Competition kinetic reactions with a catalytic amount of porphyrin ruthenium(II) species and a terminal oxidant give relative rate constants for sulfoxidations of competing substrates that are somewhat smaller than the ratios of absolute rate constants, implying a multiple oxidant model for sulfoxidation reactions.
Generation of trans-dioxoruthenium(VI) porphyrins: A photochemical approach
Zhang, Rui,Huang, Yan,Abebrese, Chris,Thompson, Helen,Vanover, Eric,Webb, Cathleen
, p. 152 - 157 (2011/11/06)
trans-Dioxoruthenium(VI) porphyrin complexes have been developed as one of the best-characterized model systems for heme-containing enzymes. Traditionally, this type of compounds can be prepared by oxidation of ruthenium(II) precursors with peroxyacids an
Structural determination of ruthenium-porphyrin complexes relevant to catalytic epoxidation of olefins
Gallo, Emma,Caselli, Alessandro,Ragaini, Fabio,Fantauzzi, Simone,Masciocchi, Norberto,Sironi, Angelo,Cenini, Sergio
, p. 2039 - 2049 (2008/10/09)
A reproducible synthesis of a competent epoxidation catalyst, [Ru VI(TPP)(O)2] (TPP = tetraphenylporphyrin dianion), starting from [RuII(TPP)(CO)L] (L = none or CH3OH), is described. The molecular structure of the complex
Kinetics of C-H Bond and Alkene Oxidation by trans-Dioxoruthenium(VI) Porphyrins
Ho, Clare,Leung, Wa-Hung,Che, Chi-Ming
, p. 2933 - 2940 (2007/10/02)
A series of VILO2> complexes (H2L = para-substituted tetraphenylporphyrins) have been synthesised and characterized, and the kinetics and mechanism of oxidation of the C-H bond and alkenes investigated.The complexes were selective towards tertiary C-H bonds in saturated alkanes but were almost inactive towards secondary C-H bonds.However, they were reactive towards aromatic hydrocarbons and the second-order rate constants (k2) for the oxidation of ethylbenzene and cumene by (tpp = 5,10,15,20-tetraphenylporphyrinate) were 2.21*10-4 and 3.16*10-4 dm3 mol-1 s-1 respectively.A kinetic isotope effect (kH/kD) of 11.7 was found for the allylic oxidation of cyclohexene by .The major organic products of the oxidation of alkenes in CH2Cl2-MeOH mixtures were epoxides and gave a monomeric product formulated as IV(tpp)O>*EtOH or IV(tpp)(OH)2>*EtOH.Similar reactions with VI(oep)O2> (oep = 2,3,7,8,12,13,17,18-octaethylporphyrinate) gave IV(oep)(OH)>2O> in non-co-ordinating solvents.The observed rate law for alkene oxidation was rate = k2VI>.There exists an almost linear free-energy relationship between log k2 and E1/2 (one-electron oxidation potentials of alkenes) with slope = -1.1 V-1 for the system.Activation parameters have been determined for the oxidation of styrene, norbornene and cyclooctene by VILO2>.Non-linear and U-shaped Hammett plots were observed for the oxidation of substituted styrenes.The mechanism of alkene oxidation is proposed to involve a continuum of transition states, the structures of which may change and be stabilized by different substituents.
High-Valent Ruthenium(IV) and -(VI) Oxo Complexes of Octaethylporphyrin. Synthesis, Spectroscopy, and Reactivities
Leung, Wa-Hung,Che, Chi-Ming
, p. 8812 - 8818 (2007/10/02)
Oxidation of by m-chloroperoxybenzoic acid in methanol gave , isolated as air-stable diamagnetic purple solid (μeff ca. 0 μB). shows one intense IR band at 821 cm-1 assignable to νas (O=Ru=O) stretch.In CH2Cl2, it reacts with olefins to give epoxides and 2O in quantitative yields.In alcohols (ROH), the epoxidation reactions give , which readily dimerizes to 2O in noncoordinating solvents. is paramagneticwith measured μeff of 3.1 μB.Its (1)H NMR spectrum shows three broad singlets, the paramagnetic isotropic shifts of which vary inversely with temperature.The E0 for the /- couple in CH2Cl2/py (py = pyridine) is -0.86 V vs Cp2Fe+/0.In CH2Cl2/py solution, reacts with olefins to give and epoxides.
