Kinetics evidence for a complex between peroxynitrous acid and titanium(IV).
The reaction between TiO(2+) and ONOOH in 0.9 M H(2)SO(4) provides evidence for direct formation, previously unobserved, of a HOONO-metal complex. The reaction proceeds via formation of an end-on complex (k = 3.0 x 10(2) M(-1) s(-1)) that rearranges to form a side-on complex (k approximately equal to 20 s(-1)). With ONOOH in excess, this rearrangement proceeds more slowly (k approximately equal to 0.1 s(-1)), probably because multiple hydrogen oxoperoxonitrate molecules form end-on complexes with oxotitanium(IV) and hinder rearrangement to the side-on complex. The absorption spectrum of the final product is that of TiO(2)(2+). Presumably, during the rearrangement or later, NO+ is lost.
Laboratorium für Anorganische Chemie, Departement Chemie und Angewandte Biowissenschaften, ETH Hönggerberg, HCI H211, CH-8093 Zürich, Switzerland.
Patrick K
PK
Wick
Reinhard
R
Kissner
Willem H
WH
Koppenol