Synthesis, structures and some reactions of Ru(CΞCCΞCFc)(PP)Cp (PP = dppm, dppe) and related compounds

Abstract

The compounds Ru(C≡CC≡CFc)(PP)Cp [PP=dppe (1), dppm (2)], have been obtained from reactions between RuCl(PP)Cp and FcC≡CC≡CSiMe3 in the presence of KF (1) or HC≡CC≡CFc and K[PF6] (2), both with added dbu. The dppe complex reacts with Co2(CO)6 (L2)[L2=(CO)2, dppm] to give 3, 4 in which the Co2(CO)4 (L2) group is attached to the outer C≡C triple bond. The PPh 3 analogue of 3 (5) has also been characterised. In contrast, tetracyanoethene reacts to give two isomeric complexes 6 and 7, in which the cyano-olefin has added to either C≡C triple bond. The reaction of RuCl(dppe)Cp with HC≡CC≡CFc, carried out in a thf/NEt3 mixture in the presence of Na[BPh4], gave [Ru{C≡CC(NEt3)- CHFc}(dppe)Cp]BPh4 (8), probably formed by addition of the amine to an (unobserved) intermediate butatrienylidene [Ru(-C-C-C-CHFc)(dppe)Cp]+. The reaction of I2 with 8 proceeds via an unusual migration of the alkynyl group to the Cp ring to give [RuI(dppe) {η-C5H4 C≡CC(NEt3)-CHFc}]I3 (9). Single-crystal X-ray structural determinations of 1, 2 and 4-9 are reported. © Published by Elsevier B.V.