Synthesis of pentanuclear clusters derived from [Ru3RhH2(CO)10(PPh3)(µ-COMe)]. Crystal structures of [Ru3Rh2H2(CO)12(PPh3)2] and [Ru3RhAuH(CO)10(PPh3)2-(µ3-COMe)]
Abstract
Reaction of [Ru3RhH2(CO)10(PPh3)(η-COMe)]2 with K[BHBus3] and then [Rh(CO)3(PPh3)2][PF6] afforded [Ru3Rh2H2(CO)12(PPh3)2]3 in 29% yield. A single-crystal X-ray diffraction characterisation of compound 3 was carried out: monoclinic, space group C2/c(no. 15), a= 19.409(4), b= 9.944(6), c= 26.153(4)Å, β= 103.35(2)°, Z= 4 and R= 0.033. A trigonal-bipyramidal cluster framework of C2 symmetry was established, with an equatorial Ru3 plane, and apical Rh(CO)(PPh3) units. The hydride ligands cap two triangular faces. Using [Au(PPh3)Cl] as an alternative electrophile, [Ru3RhAuH(CO)10(PPh3)2(µ3-COMe)]4 and [Ru3RhAuH2(CO)11(PPh3)2]5 were formed in 5 and 19% yields, respectively. Complex 4 was characterised by X-ray diffraction: triclinic, space group P(no. 2), a= 11.361(3), b= 13.745(4), c= 17.124(3)Å, α= 74.15(2), β= 74.59(2), γ= 73.02(2)°, Z= 2 and R= 0.037. This cluster also showed a trigonal-bipyramidal framework, with an equatorial Ru2Rh plane and capping AuPPh3 and Ru(CO)2 units. There are three bridging ligands: the COMe ligand bridges the Ru3 face, one CO bridges a Rh–Ru(apical) bond, and the hydride a Ru2Rh face. Both these clusters are 72-electron species.