Binuclear metal complexes of a doubly bridged cyclopentadienyl ligand

Binuclear metal complexes derived from the doubly bridged cyclopentadiene system 2,2,8,8-tetramethyl-2,8-di~ilatricyclo[7.3.O.O3~7]dodeca-3,5,9,ll-tetraene (LH,) are examined. This compound is deprotonated with 2 equiv of l-butyllithium to form the dilithio salt LLi2 (2). Reaction of 2 with trimethyltin chloride yields (Me&L space group P1; a = 8.7443 (13), A, b = 18.561 (3) A, c = 20.576 (4) A; CY = 89.340 (13)O, B = 89.160 (13)O, y = 78.300 (12)O; 2 = 4). The structure investigations on the cis isomer of 6 also show a nonplanar ligand L (crystal system monoclinic; space group P2,/n; a = 10.496 (2) A, 6 = 13.380 (2) A, c = 14.537 (6) A; 0 = 92.96 (3)O; 2 = 4). The flexibility of L is estimated, and the potential of its binuclear complexes for catalytic processes is discussed.