Vadivelu Manivannan

Electron transfer. 143. Reductions of benzopyrazine derivatives with indium(I)

Abstract Solutions of In(I)(aq) in 0.03–0.20 M H + reduce quinoxaline (Q), phenazine (P), and the N -methylphenazonium cation (MP + ) in kinetically separable steps, yielding first a colored radical, then a colorless dihydro compound. The initial stage of these reductions yields 2 equiv. of the radical, and the much slower second stage likewise entails loss of nearly 2 mol of radical per mol of In(I). Individual kinetic profiles exhibit no irregularities attributable to the intervention of In(II). Reactions of phenazine and its N -methylated cation are exceptionally photosensitive. Reductions of phenazine and quinoxaline to their radicals are favored by N -protonation, but reduction of the N -methyl cation is independent of [H + ], as are the further reductions of both phenazonium radicals. Reduction of the quinoxalinium radical utilizes paths at two protonation levels (QH and QH 2 + ). Although oxidants and reductant alike have access to 2 e − paths, observations in all three systems are consistent with reactions via successive 1 e − steps.

Iron(III) Chloride mediated reduction of Bis(1-isoquinolylcarbonyl)amide to an Amide†

AbstractIn methanol, FeCl3 reacted readily with L1H (L1H = bis(1-isoquinolylcarbonyl)amide) and afforded a complex having the formula [Fe(L2)Cl2] (1) {L2− = N-((1-isoquinolyl)(methoxy)methyl)isoquinoline-1-carboxamide ion}. This reaction involves reduction of one of the two carbonyl groups present in L1H to (methoxy)methyl group. A plausible mechanism for the conversion of L1H to L2− has been proposed. Determination of molecular structure of 1 confirmed this conversion. Fe(III) ion is surrounded by three nitrogen atoms of the ligand and two chloride ions, imparting a rare distorted trigonal bipyramidal N3Cl2 coordination environment. Graphical AbstractIn methanol, FeCl3 reacted with bis(1-isoquinolylcarbonyl)amide affording N-((1-isoquinolyl)(methoxy)methyl)isoquinoline-1-carboxamide bound iron(III) complex. This reaction involves reduction of one of the two carbonyl groups to (methoxy)methyl group.