138735-97-4Relevant academic research and scientific papers
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
Heterotrinuclear Oxo-Bridged FeIIIORuIVOFeIII Complexes of Ruthenium Porphyrin and Borylated Low-Spin Iron Dioximes
Vernik, Isak,Stynes, Dennis V.
, p. 10 - 17 (2008/10/08)
The synthesis, structure, spectra, and reactivity of diamagnetic linear chain heterotrinuclear oxo-bridged complexes L-FeIII N4-O-RuIV(TPP′)-O-FeIIIN4-L are described where TPP′ is tetrakis(4-methoxyphenylporphyrinate). N4 is one of the borylated bis(dioximate) macrocycles, N4 = ((DMG)BF2)2 in 1, ((DMG)BPh2)2 in 2, and ((DPG)-BF2)2 in 3, and L is a monodentate terminal ligand, L = BuNH2, CH3CN, Py, 1-MeIm, (BuO)3P, etc. Crystal data for 3-(BuNH2)2 = [(BuNH2)Fe((DPG)BF2)2-O] 2Ru(TPP′) monoclinic space group P21ln, a = 16.845 A, b = 27.184 A, c = 24.593 A, β= 90.41°, Fe-O = 1.79(1) A, Ru-O = 1.80(1) A, Fe-O-Ru = 175°. Large porphyrin and phenyl ring current shifts permit ready characterization of the materials by 1H NMR. A red-shifted Soret band at 433 nm and two charge transfer transitions in the 650-850 nm region are observed in the visible spectra. Clean reduction of 1, 2, and 3-(CH3CN)2 with 4-tert-butylcatechol is observed giving Fe(II) and Ru(II) products. The kinetics of reduction parallel those of low-spin (μ-oxo)diiron FeN4 systems showing a 1/[CH3CN] dependence, but the rates are 103-105 times slower. The RuIV is proposed to stabilize the μ-oxo-Fe bonds toward reductive cleavage via dclocalization of the oxo π electrons onto the ruthenium. Electrochemical data for the heterotrinuclear Fe-O-Ru-O-Fe systems are compared with those for the binuclear Fe-O-Fe systems. The HOMO is stabilized by 120 mV over the corresponding Fe-O-Fe system.
Synthesis and Magnetic Exchange Properties of Linear Trinuclear Oxo- Bridged M(III)ORu(IV)OM(III) Complexes (M = Fe, Cr, Mn) Formed by Two-Electron Redox Reactions
Berry, Kevin J.,Moubaraki, Boujemaa,Murray, Keith S.,Nichols, Peter J.,Schulz, Lewis D.,West, Bruce O.
, p. 4123 - 4133 (2008/10/08)
The two-electron reductions of various porphyrin complexes Ru(VI)(O)2(P) by Fe(II), Cr(II), and Mn(II) compounds of porphyrins and salicylaldimines result in the formation of heterotrimetallic oxo-bridged complexes (L)M(III)ORu(IV)(P)OM(III)(L) (M = Fe(III), Cr(III), Mn(III); P is the dianion of 5,10,15,20-tetraarylporphyrins, such as tetraphenylporphyrin (TPP), tetrakis(p-methoxyphenyl)porphyrin (TMP), or 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP); L is TPP, TMP, or OEP or the dianions of N,N'-(4-methyl-4-azaheptane-1,7-diyl)bis(salicylaldimine) (salmah) or N,N'-ethane-1,2-diylbis(salicylaldimine) (salen). A detailed study of the temperature- and field-dependent magnetic properties of this rather novel series of (L)M(III)ORu(IV)(P)OM(III)(L) compounds has been made. The spin-states of the constituent metal centers are as follows: Ru(IV), SRu = 1 (d(4)); Fe(III), SFe = 5/2 (d(5)); Cr(III), SCr = 3/2 (d(3)); Mn(III), SMn= 4/2 (d(4)). The spin-state and coordination geometry of the (L)Fe(III) groups were confirmed by Moessbauer spectral measurements. Trinuclear combinations of the present kind give rise to unusual coupled spin-stateenergy levels which, in the case of (L)Fe(III)ORu(IV)(P)OFe(III)(L) compounds, result in "ferromagnetic-like" plots of magnetic moment versus temperature, particularly at low temperatures. The following best-fit values of parameters were deduced from the magnetic moment data, obtained in 1 T fields over the temperature range 4.2-300 K. (salmah)FeORu(TPP)OFe(salmah): g = 1.97, J12 = -19.7 cm**-1, J13 = +6.5 cm**-1, α = J13/J12 = -0.33, ground-state S = 4; (TMP)FeORu(TPP)OFe(TMP): g = 1.95, J12= -23.4 cm**-1, J13 = 5.4 cm**- 1, α = -0.23, ground-state S = 4.(TPP)FeORu(TPP)OFe(TPP): g = 2.0, J12 = -35.7 cm**-1, J13 = 11.2 cm**-1, α = -0.31, ground-state S = 4, [(TPP)Fe]2O impurity = 13%, zero-field splitting of the S = 4 state (D ~ 5 cm**-1). (TMP)MnORu(TPP)OMn(TMP): g = 1.93, J12 = -17.4 cm**-1, J13 = 9.6 cm**-1, α = -0.55, ground-state S = 3. (TPP)CrORu(TPP)OCr(TPP): g = 1.98, J12 = -25.3 cm**-1, J13 = -11.1 cm**-1, α = 0.44, ground-state S = 1. Possiblereasons for the small sizes of the J12 values, in comparison to those of related M(III)OM(III) and Ru(IV)ORu(IV) compounds, are discussed.
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.
