文摘
Monocationic bis(hydrocarbyl)yttrium complexes [YR2(THF)2][A] (R = CH2SiMe3, CH2C6H4-o-NMe2; A = weakly coordinating anion) underwent hydrogenolysis using dihydrogen or phenylsilane to give a mixture of polynuclear solvent-stabilized dihydride cations [YH2(THF)2]n[A]n. The mixture composition as well as the nuclearity n depended on the starting material, solvent, and reaction conditions. NMR spectroscopic data in solution and X-ray diffraction data suggested that the main product was tetranuclear, although conclusive structural data were not obtained. DFT calculations supported a closo-type tetrahedral [YH2(THF)2]44+ core. The hydridic character of these cations was revealed by their reaction with benzophenone to give the bis(diphenylmethoxy) cation [Y(OCHPh2)2(THF)4][AlR4]. The reaction of this cluster with the (NNNN)-type macrocycle Me4TACD under dihydrogen gave the dinuclear tetrahydride dication with quadruply bridging hydride ligands, [Y2(渭-H)4(Me4TACD)2][A]2, analogous to the previously characterized lutetium derivative. NH-acidic (Me3TACD)H gave the dinuclear dihydride dication [Y2(渭-H)2(Me3TACD)2(THF)2][A]2.
