Oxygen-Carrying Iridium Complexes: Kinetics, Mechanism, and Thermodynamics

Abstract

The rates of oxygenation and deoxygenation of a series of iridium complexes increase and decrease, respectively, with increasing electron-releasing tendency of the anionic ligands (A) attached to the metal atom in the oxygencarrying compounds, [IrA(CO)(Ph(3)P)(2)]. Calculated heats of oxygenation (-DeltaH(2)(0)), related to Ir-O(2) bond energies, are proportional to the previously reported O-O bond lengths in the oxygen adducts, [O(2)IrA(CO)(Ph(3)P)(2)].

A Kinetic Study of the Oxidative Addition of Substituted Benzenethiols Towards trans-Halocarbonylbis(triphenylphosphine)iridium(I)

“…were too fast to be reliably monitored with the available instrumentation. This order of reactivity parallels that observed for the reactions of H, and 0, with these iridium(1) complexes (4,6,7). The rates of reaction also varied with the nature of the para-substituent on the benzenethiol; the trend is towards an increase in rate as the acidity of the substituted benzenethiol increases (14).…”

“…The rates of reaction also varied with the nature of the para-substituent on the benzenethiol; the trend is towards an increase in rate as the acidity of the substituted benzenethiol increases (14). For a given substrate the rates of reaction increase as the electron with- Hz react with these iridium(1) substrates (4,(6)(7)(8). The rate of reaction of S-deuterated benzenethiol with trans-[IrCl(CO)(Ph,P),] was also measured and these kinetic data are included in Table 3.…”

“…Several kinetic studies have been carried out in order to ascertain the mechanism of the oxidative addition towards these particular substrates (4)(5)(6)(7)(8). Previous work from this laboratory as well as others has shown that substituted benzenethiols will oxidatively add to trans-[IrCl(CO)(Ph,P),] to form [IrHCl(SAr)(CO)-(Ph,P),] where -SAr is a substituted benzenethiolato ligand (9)(10)(11).…”

Ligand‐Controlled Formation of a Low‐Valent Pincer Rhodium(I)–Dioxygen Adduct Bearing a Very Short OO Bond

“…In addition, most of them are early transition metals in high oxidation states, unable to donate high electron densities into the antibonding orbitals of O 2 [38]. OÀO Bond distances of similar length with respect to 2a have been found in the following late-transition-metal complexes: [20] [46], Br [47]). In these compounds, the OÀO distances were in the range of 1.30 to 1.37 Å.…”

Probing metal-mediated O2 activation in chemical and biological systems

“…In an effort to illuminate the more subtle factors which influence 18 bis(diphenylphosphino)ethane, CN t Bu = tert-n-butylisocyanide) [20][21][22][23][24]. We have applied Bigeleisen's formalism [14] considering the ν O-O , the symmetric ν M-O and the asymmetric ν M-O vibrational modes (Fig.…”