The reactivity of diazabutadienes toward low oxidation state Group 13 iodides and the synthesis of a new gallium(i) carbene analogue

The reactions of two diazabutadiene ligands, Ar-DAB [(ArNCH)2 , Ar = 2,6-Pri2C6H3] and But-DAB [(ButNCH)2] with either GaI or an AlI3/Al mixture have afforded the paramagnetic compounds, [{IGaII(But-DAB)}2], [I2GaIII(But-DAB)] and [I2AlIII(Ar-DAB)] which have been characterised by X-ray crystallography and EPR spectroscopy. In addition, the diamagnetic, ionic complex, [I2AlIII(Ar-DAB)]I, has been prepared and structurally characterised. The reduction of [I2GaIII(Ar-DAB)] with potassium metal in the presence of various Lewis bases has led to three structurally characterised compounds, [{(Et2O)KGaI(Ar-DAB)}2], [{(TMEDA)KGaI(Ar-DAB)}2] and [:GaI(Ar-DAB)]2[{K(18-crown-6)}2(μ-18-crown-6)], which contain the second example of an anionic gallium(I) carbene analogue. In addition, the former two compounds display Ga⋯Ga interactions in the solid state which are unprecedented for this complex type.