The oxidative conversion of the N,S-bridged complexes [{RhLL'(μ-X)}₂] to [(RhLL')₃(μ-X)2]+ (X = mt or taz): a comparison with the oxidation of N,N-bridged analogues

The structures of [{RhLL'(mu-X)}2] [LL' = cod, (CO)2, (CO)(PPh3) or {P(OPh)3}2; X = mt or taz], prepared from [{RhLL'(mu-Cl)}2] and HX in the presence of NEt3, depend on the auxiliary ligands LL'. The head-to-tail arrangement of the two N,S-bridges is accompanied by a rhodium-eclipsed conformation for the majority but the most hindered complex, [{Rh[P(OPh)3]2(mu-taz)}2], uniquely adopts a sulfur-eclipsed structure. The least hindered complex, [{Rh(CO)2(mu-mt)}2], shows intermolecular stacking of mt rings in the solid state. The complexes [{RhLL'(mu-X)}2] are chemically oxidised to trinuclear cations, [(RhLL')3(mu-X)2]+, most probably via reaction of one molecule of the dimer, in the sulfur-eclipsed form, with the fragment [RhLL']+ formed by oxidative cleavage of a second.