Electronic, EPR and IR spectral evidence are given for the formation of the following active species: (1) ruthenium(VIII) in ruthenium(III)-PIA system, (2) ruthenium(V) oxo species in ruthenium(III)-N- oxide system, and (3) ruthenium(II)-phosphine oxide complex in ruthenium(II) N-oxide system. Cyclic voltammetric studies also suggest the formation of Ru(V) in ruthenium(III)-N-oxide system. © 1986.

K. Vijayasri

Jayaraman Rajaram

Joseph C. Kuriacose

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

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IIT Madras

Spectral evidence for the formation of active intermediates from RuCl3 and RuCl2(PPh3)3 with N-methylmorpholine N-oxide (NMO) and phenyliodosoacetate (PIA) as mild oxidants

Inorganica Chimica Acta

Ruthenium(II) perchlorate complexes, [Ru(dppm)3(ClO4)]ClO4 1, [Ru(dppe)3(ClO4)]ClO4 2, and [Ru(dpae)3(ClO4)]ClO4 3, catalyse the selective homogeneous oxidation of alkenes with TBHP and H2O2 as oxidizing agents. Oxidation of cyclohexene with TBHP gave 2-cyclohexene-1-ol, 2- cyclohexenone and 1-(tert-butylperoxy)-2-cyclohexene. The homogeneous liquid phase oxidation of cyclohexene with TBHP shows appreciable solvent effect. Styrene on oxidation with TBHP gave benzaldehyde as the major product and styrene oxide as the minor product. Oxidation with H2O2 is radical- initiated and gives low conversion to products. TBHP and H2O2 are compared for their oxidizing ability and TBHP is more effective than H2O2 as an oxidizing agent. Linear and long chain alkenes are not efficiently oxidized. Cyclooctene and trans-stilbene are oxidized to the corresponding epoxides.

Journal of Molecular Catalysis A: Chemical

Selective oxidation of alkenes catalysed by Ruthenium(II) complexes containing coordinated perchlorate

The induction period observed in the cis‐RuCl2(DMSO)4 catalyzed oxidation of thioethers (S) to sulfoxides by N‐methylmorpholine N‐oxide (NMO) is attributed to the rate of formation of the active species viz. RuCl2(DMSO)3S. Cyclic voltammetric studies indicate formation of the RuIV = 0 species. Based on the variable orders in NMO and first order in each of the other reactants, a mechanism is proposed where the active species generated in situ reacts with NMO in a slow step to form RuIV oxo complex which then decomposes to give the product. Copyright © 1990 John Wiley &amp; Sons, Inc.

International Journal of Chemical Kinetics

cis‐RuCl2(DMSO)4‐catalyzed oxidation of sulfides by N‐methylmorpholine N‐oxide (NMO)

N-methylmorpholine N-oxide (NMO) in conjunction with catalytic amounts of RuCl3 oxidizes unsaturated alcohols and primary alcohols selectively to the corresponding aldehydes. Kinetic studies indicate that the order with respect to NMO and catalyst is one. The order with respect to the substrate is variable, being zero at high concentrations and fractional at low concentrations. The proposed mechanism involves the rate-determining formation of an adduct between the alcohol and Ru(V). The activation parameters, determined under zero-order conditions with respect to the substrate, pertain to the formation of RuVO species from RuCl3 and NMO. © 1990.

Journal of Molecular Catalysis

Selective oxidation of unsaturated alcohols and primary alcohols by RuCl3/lv-methylmorpholine n-oxide (NMO) system: a kinetic study

A catalytic amount of RuCl3 in the presence of excess of N-methyl-morpholine N-oxide (NMO) in DMF oxidizes secondary alcohols to ketones. Spectral studies reveal the formation of a Ru(V)-oxo species which is formed in situ on adding N-oxide. The formation of Ru(V) has been established by cyclic voltammetric studies. The mechanism involves the formation of Ru(V)-oxo species in steady state concentrations from Ru(III) and NMO, and this in turn reacts with the substrate in the rate-determining step. © 1987.

Journal	Inorganica Chimica Acta
ISSN	00201693
Open Access	No