Abstract
Reaction of in situ generated (Me4Al)(3)Tm with 2,3,4,5-tetramethylpyrrole afforded Tm(Me)-{mu-CH2AlMe2(eta(5)-NC4Me4)](2)} (1),containing a terminally bonded CH3 group. The two pyrrolide rings confer the bent-metallocenic motif to the lanthanide by adopting a fairly symmetrical pi-bonding mode. Each of the N atoms of the pyrrolide rings is bonded to one AlMe2 residue, which, in turn bridges the lanthanide through a CH2 unit of an Al-2(mu-CH2)Tm moiety. The reactivity of the terminal Me group of I was examined with both H-2 and PhSiH3. Reaction with H, under high pressure and room temperature caused loss of the terminal methyl group and major redistribution of the pyrrolyl moieties, yielding Tm[AlMe2(eta(5)-NC4Me4)(2)][(mu-Me)(AlMe2)][(mu(3)-CH2)(AlMe3)] (2) with a stable ansa-metallocene type of structure and intacting Al-2(mu-CH2)Tm unit. Reaction of 1 with PhSiH3 under mild conditions afforded an even more complex transformation accompanied by evolution of CH4 and formation of toluene. The resulting Tm[AlMe2(eta(5)-NC4Me4)(2)](AlMe3)-(mu(3)-CH2)(mu(3)-SiH3)(AlMe2)[Al Me-2(NC4Me4)] (3) complex provides a rare example of SiH3 unit trapping.