Nitric
Oxide Release from a Nickel Nitrosyl Complex Induced by One-Electron
Oxidation
Ashley M. Wright
Homaira T. Zaman
Guang Wu
Trevor W. Hayton
10.1021/ic302697v.s001
https://acs.figshare.com/articles/journal_contribution/Nitric_Oxide_Release_from_a_Nickel_Nitrosyl_Complex_Induced_by_One_Electron_Oxidation/2433391
Reaction of [Ni(NO)(bipy)][PF<sub>6</sub>] (<b>2</b>) with AgPF<sub>6</sub> or [NO][PF<sub>6</sub>] in MeCN results in formation of [Ni(bipy)<sub><i>x</i></sub>(MeCN)<sub><i>y</i></sub>]<sup>2+</sup> and release
of NO gas in moderate yields. In contrast, the addition of the inner
sphere oxidant Ph<sub>2</sub>S<sub>2</sub> to <b>2</b> does
not result in denitrosylation. Instead, the diphenyldisulfide adduct
[{(bipy)(NO)Ni}<sub>2</sub>(μ-S<sub>2</sub>Ph<sub>2</sub>)][PF<sub>6</sub>]<sub>2</sub> (<b>3</b>) is formed in good yield. However,
oxidation of <b>2</b> with 2,2,6,6-tetramethylpiperidine-1-oxyl
(TEMPO) does results in cleavage of the Ni–NO bond and generation
of NO. The metal-containing product, [(bipy)Ni(η<sup>2</sup>-TEMPO)][PF<sub>6</sub>] (<b>4</b>), can be isolated as an
orange-brown solid in excellent yields. In the solid state, complex <b>4</b> contains a side-on bound TEMPO<sup>–</sup> ligand,
which is characterized by a long N–O bond length [1.383(2)
Å]. The contrasting reactivity of Ph<sub>2</sub>S<sub>2</sub> and TEMPO likely relates to their different redox potentials, as
Ph<sub>2</sub>S<sub>2</sub> is a relatively weak oxidant. Finally,
the addition of pyridine-<i>N</i>-oxide to <b>2</b> results in the formation of the adduct, [(bipy)Ni(NO)(ONC<sub>5</sub>H<sub>5</sub>)][PF<sub>6</sub>] (<b>5</b>). No evidence of
NO release is observed in this reaction, probably because of the low
one-electron (1e<sup>–</sup>) reduction potential of pyridine-<i>N</i>-oxide.
2016-02-19 17:22:53
adduct
bipy
yield
bond
release
formation
Nitric Oxide Release
Nickel Nitrosyl Complex Induced
Ph 2S
sphere oxidant Ph 2S