Radiation chemical study of the reaction of Ni+, Co+ and Cd+ with N2O. Evidence for the formation of a hyperoxidised state by oxygen atom transfer

Abstract

Reaction of the hyper-reduced metal ions Ni+, Cof and Cd+ with N 2 0 produces N2 and a hyperoxidised state M(III) of the metal ion by oxygen atom transfer. When formate is present a chain reaction occurs showing that CO; reduces M2+, and that M(II1) reacts with formate ion to produce CO,. Detailed studies of the chain reaction kinetics show that M(II1) exists in at least two forms, one probably being a hydrolysis product of the other. With nickel (and probably cadmium) M(III) is not stable and is either chemically similar to the hydroxyl radical or produces it on hydrolysis, e.g., H 2 0 MO+--tMO(OH) + H+ ' A. 0. Allen, C.

Reactivity of Hydrated Monovalent First Row Transition Metal Ions M+(H2O)n, M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn, toward Molecular Oxygen, Nitrous Oxide, and Carbon Dioxide

“…10,11 For nitrous oxide it is Co + > Zn + ≥ Ni + > Cd + . 105 The reactions of zinc and nickel are probably too slow to be detected in our experiments. Even in high pressure experiments with a nitrous oxide pressure of p ≈ 3.5 × 10 −7 mbar, no hints for reaction products were found.…”

“…Both products seem to appear together as primary products. Following this argument, the formation of the cobalt hydroxide clusters is the secondary reaction Buxton et al 105 studied the reactions of Co + , Zn + , Ni + , and Cd + with nitrous oxide using pulse radiolysis. They found a different reactivity sequence for reaction with nitrous oxide than the general one derived by Meyerstein and Mulac.…”

Pulse radiolytic study of nickel(1+) ion. Nickel-carbon bond formation

“…However, part of the OH radicals can undergo combination to form H202 20H -* HA (8) Since Ni+ and OH are formed in about equal amounts, not all of the Ni+ ions can be reoxidized by the OH radical. About 25% of Ni+ remain after the OH radicals have disappeared.…”

“…The rate constants of such processes were measured in pulse radiolytic experiments by recording the decay of the Ni+ absorption in solutions containing both Ni2+ and the reactant. [1][2][3][4][5][6][7][8] The products of these reactions have not yet been investigated, however. Irradiation of a solution containing a divalent metal ion often leads to the precipitation of the corresponding metal. 9 The yield is generally significant only if an organic OH scavenger is simultaneously present.…”

Metal ions in unusual valency states

“…A particularly useful way of studying this reaction has been to y-irradiate N20 saturated solutions containing the divalent metal ion and sodium formate (24). Under these conditions a chain reaction results, and from the dependences of the nitrogen yield on sotute concentrations, dose rate, etc., it has been possible to establish beyond doubt that OH radicals are not formed but rather that reaction occurs by an O-atom transfer.…”