SYNTHESIS AND REACTIVITIES OF THE INDENYL-RUTHENIUM CLUSTER [(ETA(5)-C9H7)RU(MU-SET)](3) - INDENYL EFFECT IN THE TRINUCLEAR RUTHENIUM CLUSTER

The triruthenium cluster with bridging ethanethiolato and indenyl liga nds [(eta(5)-C9H7)Ru(mu-SEt)](3) (2) was synthesized by heating the mo nonuclear indenyl complex [(eta(5)-C9H7)Ru(SEt)(PPh3)(2)] (la) in tolu ene. Cluster 2 reacted with Mel to afford the S-methylated cluster [(e ta(5)-C9H7)(3)Ru-3(mu-SEt)(2)(mu-SEtMe)]I . CH2Cl2 (4a) with high ster eoselectivity through the attack of Mel on the axial SEt group from th e equatorial side. The PF6- salt of the cationic cluster [(eta(5)-C9H7 )(3)Ru(mu-SEt)(2)(mu-SEtMe)][PF6] was further converted into the catio nic carbonyl complex [(eta(5)-C9H7)(2)Ru-2(mu-SEt)(CO)(4)][PF6] (5) by treatment with CO at 50 degrees C. The crystal structures of 4a and 5 were determined by X-ray diffraction study. When a THF solution of 2 was allowed to contact with atmospheric pressure of CO at room tempera ture, the trinuclear carbonyl cluster [(eta(5)-C9H7)(3)Ru-3(mu-SEt)(3) (mu-CO)(CO)] (6) and the dinuclear carbonyl complex [(eta(5)-C9H7)Ru(m u-SEt)(CO)](2) (7) were obtained. The structures of 6 and 7 were also crystallographically determined. Furthermore, cluster 2 was oxidized i n refluxing CHCl3 to give [(eta(5)-C9H7)Ru(SEt)Cl](n) (9). The Cp anal ogue of 2, [CpRu(mu-SEt)](3), failed to react with CO and CHCl3, and t he hapticity change of the indenyl ligand in 2 is considered to be cru cial for the initial interaction of 2 with CO and CHCl3. These reactio ns provide rare examples of the indenyl ligand effect in a multinuclea r complex. (C) 1998 Elsevier Science S.A. All rights reserved.