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Gas-phase ion-molecule reactions of copper hydride anions [CuH2]- and [Cu2H3]-

journal contribution
posted on 2023-05-19, 03:11 authored by Zavras, A, Ghari, H, Alireza AriafardAlireza Ariafard, Allan CantyAllan Canty, O'Hair, RAJ
Gas-phase reactivity of the copper hydride anions [CuH2] and [Cu2H3] toward a range of neutral reagents has been examined via multistage mass spectrometry experiments in a linear ion trap mass spectrometer in conjunction with isotope labeling studies and Density Functional Theory (DFT) calculations. [CuH2] is more reactive than [Cu2H3], consistent with DFT calculations, which show it has a higher energy HOMO. Experimentally, [CuH2] was found to react with CS2 via hydride transfer to give thioformate (HCS2) in competition with the formation of the organometallic [CuCS2] ion via liberation of hydrogen; CO2 via insertion to produce [HCuO2CH]; methyl iodide and allyl iodide to give I and [CuHI]; and 2,2,2-trifluoroethanol and 1-butanethiol via protonation to give hydrogen and the product anions [CuH(OCH2CF3)] and [CuH(SBu)]. In contrast, the weaker acid methanol was found to be unreactive. DFT calculations reveal that the differences in reactivity between CS2 and CO2 are due to the lower lying π* orbital of the former, which allows it to accept electron density from the Cu center to form the initial three-membered ring complex intermediate, [H2Cu(η2-CS2)]. In contrast, CO2 undergoes the barrierless side-on hydride transfer promoted by the high electronegativity of the oxygen atoms. Side-on SN2 mechanisms for reactions of [CuH2] with methyl iodide and allyl iodide are favored on the basis of DFT calculations. Finally, the DFT calculated barriers for protonation of [CuH2] by methanol, 2,2,2-trifluoroethanol, and 1-butanethiol correlate with their gas-phase acidities, suggesting that reactivity is mainly controlled by the acidity of the substrate.


Publication title

Inorganic Chemistry










School of Natural Sciences


Amer Chemical Soc

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1155 16Th St, Nw, Washington, USA, Dc, 20036

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Copyright 2017 American Chemical Society

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