Reactions of dioxygen complexes of nickel and palladium

A Monomeric Nickel−Dioxygen Adduct Derived from a Nickel(I) Complex and O2

“…The electrophilic character of 2 is reminiscent of reactivity observed for a Ni(II)-peroxo adduct. 22 In summary, spectroscopic analysis of the thermally sensitive brown intermediate, 2, produced from dioxygen supports the structural assignment of a side-on dioxygen adduct best described as a Ni(II)-superoxo complex in which the superoxide radical is antiferromagnetically coupled to the high-spin Ni(II) center to yield an S ) 1 / 2 EPR spectrum characteristic of a d z 2 ground state electronic configuration. Electronic structure calculations provide strong support for the side-on coordination mode as the calculated EPR g values and metric parameters agree well with those determined experimentally.…”

Activation and transfer of O2 to organic electrophiles by [RuH(dcpe)2]+

“…the deÐnition by Collman and Otsuka (that is, the formal oxidation state of the metal does not change in the net oxygentransfer reaction) 23. In the present case, the overall oxygen-transfer reaction from 4 to the substrate regenerates the species 1 without oxidation of the metal.…”

The Quenching of Singlet Oxygen (1Δg) by Transition Metal Chelates

“…However, both the charge transfer process [IS] and the energy transfer reaction 16 might well operate for different transition metal chelates. Another attractive source of '0, quenching by some of the metal chelates involves the formation of a loose complex, possibly analogous to those formed between 302 and many Co, Ni, and Fe complexes (30,31). Although the high stability of many cobaltoxygen complexes would preclude efficient '0, quenching, a transient association could lead to efficient quenching.…”