Synthesis and characterisation of the benzene butterfly cluster [(η6-C6H6)Ru(R1C2R2)Os3(CO)9](R1= R2= Me, Et or Ph; R1= Me, R2= H, Et or Ph); X-ray crystal structure of [(η6-C6H6)Ru(MeC2Me)Os3(CO)9]

Abstract
Reduction of the triosmium cluster [Os3(CO)10(R1C2R2)](R1= R2= Me 1a, Et 1b or Ph 1c; R1= Me, R2= H 1d, Et 1e or Ph 1f) with K–Ph2CO has yielded the dianionic cluster [Os3(CO)9(R1C2R2)]2–2a–2f. When this dianion is treated with HBF4·Et2O or [Au(PPh3)Cl] the compounds [Os3(CO)9-(R1C2R2)X(Y)](X = Y = H 3a–3f; X = Y = AuPPh34a–4f; X = H, Y = AuPPh35a–5f) are formed. The dianion 2 also reacts with the dication [Ru(C6H6)(MeCN)3]2+ to give the mixed-metal cluster [(η6-C6H6)Ru(R1C2R2)Os3(CO)9]6a–6f. Compound 6a(R1= R2= Me) has been characterised by single-crystal X-ray diffraction analysis and shown to contain a butterfly metal geometry spanned by the Me2C2 grouping with a η6-C6H6 bonded to the ‘wingtip’ ruthenium atom.