Protonation of eta(5)-Indenyl ruthenium hydride complexes (eta(5)-C9H7)Ru(L-2)H and eta(5)-eta(6) haptotropic rearrangement. X-ray crystal structures of (eta(5)-C9H7)Ru(dppm)H and [(eta(6)-C9H8)Ru(dppp)H]

摘要

Protonation of indenyl complexes (eta(5)-C9H7)Ru(dppm)H and (eta(5)-C9H7)Ru(PPh3)(2)H with CF3-SO3H or HBF4. Et2O at -60 degrees C gives the eta(2)-dihydrogen complex [(eta(5)-C9H7)Ru(dppm)(H-2)](+) and the dihydride [(eta(5)-C9H7)Ru(PPh3)(2)H-2](+), respectively. Upon warming to room temperature, proton shift from the eta(2)-H-2 ligand of the former to the indenyl ligand and subsequent migration of the metal fragment from the five-membered ring to the six-membered ring of the indene Ligand results in the formation of the eta(6)-indene complex [(eta(6)-C9H8)Ru(dppm)H](+). The PPh3 analogue[(eta(6)-C9H8)Ru(PPh3)(2)H](+) is formed in a similar fashion, but in this case, the proton shift is from Ru-H to the indenyl ligand. Low-temperature acidification of (eta(5)-C9H7)Ru(dppe)H and (eta(5)-C9H7)Ru(dppp)H yield mixtures of eta(2)-dihydrogen complex and dihydride in both cases. Similar to the dppm and PPh3 analogues, eta(6)-indene complexes [(eta(6)-C9H8)Ru(dppe)H](+) and [(eta(6)-C9H8)Ru(dppp)H](+) are generated upon warming solutions of the eta(2)-dihydrogen complex/dihydride mixtures to room temperature. In the dppp system, the eta(5) --> eta(6) haptotropic rearrangement only occurs after the eta(2)-dihydrogen complex --> dihydride tautomerization is nearly completed, whereas in the dppe system the two processes seem to occur simultaneously. The parent hydride complexes (eta(5)-C9H7)Ru(L-2)H can be regenerated upon deprotonation of the eta(6)-indene complexes with Et3N. Crystal structures of (eta(5)-C9H7)-Ru(dppm)H and [(eta(6)-C9H8)Ru(dppp)H](+) have been determined by X-ray crystallography; both complexes have three-legged piano-stool structures. [References: 44]