Matrix studies of the thermal and photolytic reactions of Zn, Cd and Hg (M) atoms with H2O: formation and characterisation of the adduct M⋯OH2 and photoproduct HMOH

Abstract

IR spectra have been used to chart the thermal and photolytic reactions occurring during or after the codeposition of Zn, Cd or Hg (M) vapour with an excess of H₂O-doped Ar. Following the formation of the contact pair M⋯OH₂, detected after deposition of a matrix including thermally evaporated metal atoms, UV irradiation (200 ≤ λ/nm ≤ 400) causes M⋯OH₂ to rearrange with insertion of the metal atom into an O–H bond in forming the M(II) hydride HMOH. Characterisation of the molecules has been underpinned by reference (i) to the effects of isotopic change (^1,2H) and (ii) to the results of density functional theory (DFT) calculations. The properties of the molecules are compared with those of related species, and the mechanism of the photochemical change is discussed.