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

Citation

Zavras, A and Ghari, H and Ariafard, A and Canty, AJ and O'Hair, RAJ, Gas-phase ion-molecule reactions of copper hydride anions [CuH2]- and [Cu2H3]-, Inorganic Chemistry, 56, (5) pp. 2387-2399. ISSN 0020-1669 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 American Chemical Society

DOI: doi:10.1021/acs.inorgchem.6b02145

Abstract

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 ∗ 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(2-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.

Item Details

Item Type:Refereed Article
Keywords:gas-phase ion−molecule reactions, copper, density functional theory (DFT)
Research Division:Chemical Sciences
Research Group:Inorganic Chemistry
Research Field:Transition Metal Chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Ariafard, A (Associate Professor Alireza Ariafard)
Author:Canty, AJ (Professor Allan Canty)
ID Code:115333
Year Published:2017
Deposited By:Chemistry
Deposited On:2017-03-17
Last Modified:2017-05-18
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