Some Novel Binuclear Group 13 Metal Tin Hydrides Formed in Ar Matrices Following the Codeposition of the Metal Vapor with SnH 4

IR measurements show that co‐condensation of Al or Ga atoms (M) with SnH 4 in a solid Ar matrix at about 12 K results mainly in the spontaneous insertion of the metal into an SnH bond to form the M II hydride HMSnH 3 . Simultaneously the Ga 2 dimer also reacts with SnH 4 , possibly to form a nido ‐type cluster Ga 2 (μ‐H) 4 Sn, with a metal‐deficient cubane‐like structure. All of these products are photolabile. Irradiation with visible light causes HMSnH 3 to tautomerize to the novel dihydrido‐bridged species H 2 M(μ‐H) 2 Sn, which decomposes in turn under broad‐band UV‐visible light ( λ =200–800 nm); some H 2 Al(μ‐H) 2 Sn is formed even on deposition. The data collected from experiments with SnH 4 and SnD 4 and different reagent concentrations, together with the results of quantum chemical calculations, are used to interpret the results and elucidate the structures and bonding of the new species.