Reactivity of Copper(III)–Oxo Complexes in the Gas Phase

Abstract

An efficient way to generate [(L)CuO] complexes with a number of monodentate and bidentate ligands (L) from their [(L)Cu(ClO )] precursors by electrospray ionization was herein explored. Further, we studied [(L)CuO] with L=9,10-phenanthraquinone, 1,10-phenanthroline, and acetonitrile in detail. The signature of these terminal copper-oxo complexes was found to be elimination of the oxygen atom upon collisional activation. We investigated and compared their reactions with water, ethane, ethylene, and 1,4-cyclohexadiene. The [(MeCN)CuO] complex oxidized water and performed C-H activation and hydroxylation of ethane. The complexes with bidentate ligands did not react with water and oxidized only larger hydrocarbons. All the investigated complexes showed comparable reactivities in the oxygen-transfer reaction with ethylene.

Experimentally Calibrated Analysis of the Electronic Structure of CuO+: Implications for Reactivity

“…[17] We also attempted to investigate bare [CuO] + , which can be generated upon collisional activation of [(CH 3 CN)CuO] + in the collision cell. [17] We also attempted to investigate bare [CuO] + , which can be generated upon collisional activation of [(CH 3 CN)CuO] + in the collision cell.…”

M−O Bonding Beyond the Oxo Wall: Spectroscopy and Reactivity of Cobalt(III)‐Oxyl and Cobalt(III)‐Oxo Complexes

“…[39,40] We have thus probed this approach for [(N4Py)Co II (ClO 3 )](ClO 3 ). [39,40] We have thus probed this approach for [(N4Py)Co II (ClO 3 )](ClO 3 ).…”

“…High-valent gaseous metal-oxo complexes can be prepared from metal-chlorate or nitrate precursors because these precursors eliminate ClO 2 C or NO 2 C radicals in collisional activation during the transfer to the gas phase. [39,40] We have thus probed this approach for [(N4Py)Co II (ClO 3 )](ClO 3 ). [41] Electrospray ionization of an acetonitrile solution of [(N4Py)Co II (ClO 3 )](ClO 3 )a fforded the desired cobalt complexes [(N4Py)Co II (ClO 3 )] + (m/z 509) and [(N4Py)Co III (O)] + (1; m/z 221;F igure S1 ai nt he Supporting Information).…”

“…[47] Consistently,w e found that 2 is also capable of hydrogen-atom abstraction from an on-activated alkane,i nt his case cyclohexane (Figure 3c,d,C ÀHb ond dissociation energy:9 9.5 kcal mol À1 [48] ). [49][50][51] Even high-valent nonheme iron(IV)-oxo and iron(V)-oxo complexes,r eadily reactive towards these CÀHbonds in solution, are unreactive in the gas phase.W eh ave also probed the activation of ap rimary C À Hb ond in ethane,w hich was not observed (k rel (ethane/cyclohexane) < 0.02), and the reaction with water, [40] which did not occur either.Inconclusion, complex 2 is astrong hydrogen-atom abstractor capable to react with nonactivated secondary CÀHb onds. [49][50][51] Even high-valent nonheme iron(IV)-oxo and iron(V)-oxo complexes,r eadily reactive towards these CÀHbonds in solution, are unreactive in the gas phase.W eh ave also probed the activation of ap rimary C À Hb ond in ethane,w hich was not observed (k rel (ethane/cyclohexane) < 0.02), and the reaction with water, [40] which did not occur either.Inconclusion, complex 2 is astrong hydrogen-atom abstractor capable to react with nonactivated secondary CÀHb onds.…”

“…Activation of strong secondary CÀHb onds in as ingle collision experiment in the gas phase has only been reported for bare metal or metal-oxo ions,o rf or coordinatively unsaturated, highly reactive species such as [(phen)Cu(O)] + so far,because the reaction must be barrierless with respect to the separated reactants to occur. [49][50][51] Even high-valent nonheme iron(IV)-oxo and iron(V)-oxo complexes,r eadily reactive towards these CÀHbonds in solution, are unreactive in the gas phase.W eh ave also probed the activation of ap rimary C À Hb ond in ethane,w hich was not observed (k rel (ethane/cyclohexane) < 0.02), and the reaction with water, [40] which did not occur either.Inconclusion, complex 2 is astrong hydrogen-atom abstractor capable to react with nonactivated secondary CÀHb onds.…”