THE REACTIONS OF PROTIC ACIDS WITH ORGANOMETAL CLUSTERS - STRUCTURE-SENSITIVE, ACID-PROMOTED REDUCTIVE CLEAVAGE OF ORGANIC-LIGANDS IN (MU-H)(MU-3-ETA-3-RCCR CR)RU3(CO)9

The reactions of the organometal clusters (mu-H) (mu-3-eta-3-RCCR'CR'')Ru3(CO)9 with CF3COOH are reported. In the case of the symmetrical complex (mu-H)[mu-3-eta-3-CH3CC(H)CCH3]Ru3(CO)9, 1, the organic ligand is cleaved to give 2-pentyl trifluoroacetate as identified by H-1 and C-13 NMR and MS. The isomeric (mu-H)[mu-3-eta-3-CH3CC(CH3)CH]Ru3(CO)9, 3, undergoes an initial rearrangement to a mu-3-eta-2-vinylidene complex in CF3COOH which then decomposes. Protonation of (mu-H)[mu-3-eta-3-CH3CC(H)CCH3]Ru3(CO)8P(C6H5)3, 1a, gives only monoprotonation at the metal core in CF3COOH. The C6 analogue of 1, (mu-H)[mu-3-eta-3-CH3CH2CC(H)CCH3]Ru3(CO)9, 2, also decomposes in trifluoroacetic acid, while its allenic isomer (mu-H)[mu-3-eta-3-CH3CH2CCC(H)CH3]Ru3(CO)9, 4, gives a stable monoprotonated dihydride in CF3COOH. The structures of the monocations are discussed and reasons for the observed differences in the behaviour of this family of complexes in CF3COOH are suggested.