Phosphine and isonitrile complexes of eta(5)-tetramethylcyclopentadienylrhodium chlorides; crystal structures of (eta(5)-C5Me4H)RhCl2(PPh2R) (R = Ph or C6F5)

The reaction between [(eta(5)-C5Me4H)RhCl(mu-Cl)](2) and the phosphines PPh 2R (R = Ph or C6F5) or cyclohexylisonitrile yields the complexes (eta(5)-C5 Me4H)RhCl2L (1, L = PPh3; 2, L = PPh2(C6F3); 3, L = CNC6H11). The structure s of complexes 1 and 2 have been determined by single-crystal X-ray diffrac tion. Both exhibit three-legged piano stool geometry about the rhodium atom . Unlike the structures of (eta(5)-C5Me5)RhCl2L complexes, the rhodium atom s of 1 and 2 do not lie on axes normal to the C-5 centroids, but are displa ced towards the CII carbon atoms. Treatment of 1 with cyclohexylisonitrile or 3 with PPh2(C6F5) in the presence of NaBF4, yield the chiral-at-metal sa lts [(eta(5)-C5Me5)RhCl(PPh2R)(CNC6H11)](+). BF4- as racemic mixtures. The bis(isonitrile) complex, [(eta(5)-C5Me4H)RhCl(CNC6H11)(2)](+). BF4-, is for med similarly from 3. Treatment of [(eta(5)-C5Me4H)RhCl(mu-Cl)](2) with dpp e in the presence of NaBF4 yields [(eta(5)-C5Me4H)RhCl(dppe)]+. BF4-. (C) 1 999 Elsevier Science S.A. All rights reserved.