Imido transfer from bis(imido)ruthenium(VI) porphyrins to hydrocarbons: Effect of imido substituents, C-H bond dissociation energies, and RUVIN reduction potentials

[Ru-VI(TMP)(NSO2R)(2)] (SO2R = Ms, Ts, Bs, Cs, Ns; R = p-C6H4OMe, P-C6H4Me, C6H5, p-C6H4Cl, p-C6H4NO2, respectively) and [Ru-VI(Por)(NTs)(2)] (Por = 2,6-Cl2TPP, F-20-TPP) were prepared by the reactions of [Ru-II(Por)(CO)] with Phl=NSO2R in CH2Cl2. These complexes exhibit reversible Ru-VI/V couple with E-1/2 = -0.41 to -0.12 V vs CP2Fe+/O and undergo imido transfer reactions with styrenes, norbornene, cis-cyclooctene, indene, ethylbenzenes, cumene, 9,10-dihydroanthracene, xanthene, cyclohexene, toluene, and tetrahydrofuran to afford aziridines or amides in up to 85% yields. The second-order rate constants (k(2)) of the aziridination/amidation reactions at 298 K were determined to be (2.6 +/- 0.1) x 10(-5) to 14.4 +/- 0.6 dm(3) Mol(-1) s(-1), which generally increase with increasing Ru-VI/V reduction potential of the imido complexes and decreasing C-H bond dissociation energy (BIDE) of the hydrocarbons. A linear correlation was observed between log k' (k' is the k(2) value divided by the number of reactive hydrogens) and BIDE and between log k2 and E-1/2(Ru-VI/V); the linearity in the former case supports a H-atom abstraction mechanism. The amidation by [Ru-VI(TMP)(NNS)(2)] reverses the thermodynamic reactivity order cumene > ethylbenzene/toluene, with k'(3 degrees C-H)/k'(2 degrees C-H) = 0.2 and k'(3 degrees C-H)/k'(1 degrees C-H) = 0.8.