Selective lithiation and phosphane-functionalization of [(eta(7)-C7H7)Ti(eta(5)-C5H5)] (troticene) and its use for the preparation of early-late heterobimetallic complexes.

The cycloheptatrienyl-cyclopentadienyl sandwich complex [(eta(7)-C(7)H(7))Ti(eta(5)-C(5)H(5))] (troticene) can be dilithiated (once at each ring) or selectively monolithiated, either at the seven- or five-membered ring, depending on the reaction conditions. Treatment of the resulting lithiotroticenes with ClPPh(2) afforded the corresponding troticenyl-phosphanes [(eta(7)-C(7)H(6)PPh(2))Ti(eta(5)-C(5)H(4)PPh(2))] (1), [(eta(7)-C(7)H(6)PPh(2))Ti(eta(5)-C(5)H(5))] (2), or [(eta(7)-C(7)H(7))Ti(eta(5)-C(5)H(4)PPh(2))] (3). The use of nBuLi/N,N',N',N'',N"-pentamethyldiethylenetriamine (pmdta) allowed us to isolate the lithium complexes [(eta(7)-C(7)H(6)Li)Ti(eta(5)-C(5)H(4)Li)] x pmdta (4) and [(eta(7)-C(7)H(7))Ti(eta(5)-C(5)H(4)Li)] x pmdta (5), which were structurally characterized by X-ray diffraction analyses. Reaction of the monophosphane 3 with Mo(CO)(6) and [(tht)AuCl] (tht = tetrahydrothiophene) afforded the heterobimetallic complexes [(3)Mo(CO)(5)] (6) and [(3)AuCl] (7) and also the trimetallic species [(3)(2)AuCl] (8). The reaction of trans-[PtCl(2)(SEt(2))(2)] with the diphosphane 1 led to the formation of cis-[(1)PtCl(2)] (9), whereas the complexes trans-[(2)(2)PtCl(2)] (10) and trans-[(3)(2)PtCl(2)] (11) were isolated by reaction of two equivalents of the monophosphanes 2 and 3 with trans-[PtCl(2)(SEt(2))(2)]. The X-ray crystal structures of 6-11 are also reported.