Derivatives of [Rh6(CO)13C]2-: Solution structure of [Rh6H(CO)13C]- from nuclear magnetic resonance measurements and the X-ray crystal structure of [Rh6(CO)11C(μ-Ph2PCH2CH 2PPh2)]2-

Multielement n.m.r. measurements (1H, 1H-{103Rh}, 13C, 13C-{103Rh}, and 103Rh) show that protonation of [Rh6(CO)13C]2- at low temperature gives [Rh6H(CO)13C]- which contains an edge-bridging hydride with the carbonyl distribution being very similar to that found in [Rh6(CO)13C]2- Warming this solution to < -20 °C results in complete CO- and H-migration over the Rh6 octahedron and at ≥ -20 °C there is formation of [Rh6H(CO)15C]- together with loss of hydrogen to give [Rh12(CO)24(C)2]2- which has been spectroscopically characterised. Multielement n.m.r. studies on products resulting from the reaction of [Rh6(CO)13C]2- (1 mol equiv.) with diphosphines Ph2P(CH2)nPPh2 [0.5 mol equiv.; n = 1,2 (dppe), 3, or 4] or Ph2AsCH2CH2AsPh2 suggest that they all have similar structures and an X-ray crystallographic analysis of the dppe derivative shows it to be [Rh6(CO)11C(μ-dppe)]2-.