Syntheses and structures of the heterometallic complexes [{MeIn(μ-PCy)}2(μ-PCy)]2(Li · Et2O)4, [Me2In(PhMes)2]−[Li(TMEDA)2]+ and [Me2(PHMes)2In]−[K(PMDETA)2]+ [Cy = cyclohexyl, Mes = 2,4,6-Me3C6H2, TMEDA = (Me2NCH2)2, PMDETA = (Me2NCH2CH2)2NMe]

The reaction of CyPHLi (Cy = cyclohexyl) with InMe 3 in Et 2 O gives the heterometallic cage [{MeIn(μ-PCy)} 2 (μ-PCy)] 2 (Li · Et 2 O) 4 ( 1 ), containing the heterometallic tetraanion [ { MeIn ( μ - PCy ) } 2 ( μ - PCy ) ] 2 4 - . In contrast, similar reactions of InMe 3 with MesPHM (M = Li, K) in the presence of the Lewis bases TMEDA and PMDETA give [Me 2 In(PhMes) 2 In] − [Li(TMEDA) 2 ] + ( 2 ) and [Me 2 (PHMes) 2 In] − [K(PMDETA) 2 ] + ( 3 ), respectively. The formation of [Me 2 (PHMes) 2 In] − anions in these complexes provides key evidence of the mechanism of formation of the metallocyclic tetraanion of 1 .