Kinetics and mechanism of oxidation of aliphatic alcohols by oxo(salen) manganese(V) complexes

The oxidation of aliphatic alcohols by substituted oxo(salen)-manganese(V) (H(2)salen = N,N'-Bissalicylideneethylenediamine) complexes, in acetonitril e. leads to the formation of the corresponding carbonyl compounds. The reac tion is first order each in alcohol and Mn(V) complex. The oxidation of [1, 1-H-2(2)]ethanol and [2-H-2]propan-2-ol exhibits substantial kinetic isotop e effects. The rate of oxidation of twelve alcohols by four Mn(V) complexes have been determined. The oxidation is susceptible to both the polar and s teric effects of the substituent in the alcohol molecule. The reaction cons tants are negative. The rate of reduction of the substituted Mn(V) complexe s shows an excellent correlation in terms of Hammett equation with positive reaction constants. The reactivity-selectivity principle (RSP) is obeyed i n this reaction. The validity of RSP is verified by Exner's mathematical pr ocedure, suitable mechanisms have been discussed.