Fluorination of [Os3(CO)12] and [Ir4(CO)12]

Fluorination of [Os3CO12] in HF/SbF5 affords [Os(CO)4(FSbF5)2]. According to its crystal structure (orthorhombic, Pna21, a = 1590.3 (3), b = 1036.6(1), c = 878.2(2) pm, Z = 4), the two SbF6 units occupy cis positions in the octahedral environment around the Os atom. Fluorination of [Ir4(CO)12] in HF/SbF5 produced three different compounds: (1) [Ir4(CO)8((mu)-F)2(Sb2F11)2] (tetragonal, P4n2, a = 1285.2(2), c = 952.9(1) pm, Z = 2). Here, two of the six edges of the Ir4 tetrahedron in [Ir4CO12] are replaced by bridging fluorine atoms. (2) [fac-Ir(CO)3(FSbF5)2HF]SbF6·HF (orthorhombic, Pnma, a = 1250.6(1), b = 1340.7(2), c = 1092.6(2) ppm, Z = 4). The Ir4 tetrahedron in Ir4(CO)12 is completely broken down, but the facial Ir(CO)3 configuration is retained. (3) [mer-Ir(CO)3F(FSbF5)2] (triclinic, P1, a = 834.9(1), b = 86 4.9(1), c = 1060.0(1) pm, (alpha)= 69.173(4)°, (beta)= 77.139(4) °, (gamma)= 88.856(4) °, Z = 2).