First Examples of Electrophilic Addition to a Fe2Q Face of [Fe3(μ3-Q)(CO)9]2− (Q=Se, Te)—Synthesis and Characterisation of [MFe3(μ4-Q)(CO)9Cp*] and [IrFe2(μ3-Q)(CO)7Cp*] (M=Rh, Ir; Cp*=η5-C5(CH3)5)

The reaction of [Et4N]2[Fe3(μ3-Q)(CO)9] (Q=Se ([Et4N]2[1b]), Te ([Et4N]2[1c])) with [Cp*M(CH3CN)3][CF3SO3]2 (M=Rh, Ir) leads to the addition of a Cp*M2+ unit to a Fe2Q face of the initial cluster. In this way four new heteronuclear clusters [MFe3(μ4-Q)(CO)9Cp*] (M=Rh (2b, c); M=Ir (3b, c)) were obtained possessing a butterfly-shaped cluster core bridged by a μ4-Q unit. Furthermore, reaction with the Ir starting complex leads to the metal-substituted derivatives [IrFe2(μ3-Q)(CO)7Cp*] (4b, c) in lower yields, whose structures consist of a triangular metal core capped by a μ3-Q ligand. The products were comprehensively characterised by spectroscopic methods and the molecular structures of 2b, 3c, and 4c were established by single crystal X-ray diffraction measurements.