A [[TiCl2(isodiCp)]2(mu-O)] dimer and a twinned cyclic [TiCl(isodiCp)(mu-O)]4 tetramer.

The mu-oxo dimer mu-oxo-bis[dichloro[(1,2,3,3a,7a-eta)- 4,5,6,7-tetrahydro-4,7-methano-1H-indenyl]titanium], [Ti2Cl4(mu-O)(C10H11)2], and the mu-oxo cyclic tetramer, cyclo-tetra-mu-oxo-tetrakis[chloro[(1,2,3,3a,7a-eta)-4,5,6,7-tetrahydro- 4,7-methano-1H-indenyl]titanium], [Ti4Cl4(mu-O)4(C10H11)4], have been synthesized by electrophilic attack of TiCl4 on the exo-trimethylsilyl derivative of isodiCp (isodiCp is the isodicyclopentadienide anion or 4,5,6,7-tetrahydro-4,7-methano-1H-indene) in the presence of trace amounts of moisture. Both structures are endo isomers, with each Ti atom bonded in a eta 5 manner to the Cp ring of the isodiCp ligand. Both display a slight bending of the isodiCp group about the bond common to the Cp ring and the norbornane fragment, such that the norbornane group is displaced in the direction away from the Ti atom. The dihedral angles which describe this bending are 9.0 (3) and 10.2 (3) degrees for the dimer, and 9.2 (2) degrees for the tetramer. The dimer contains a bent Ti-O-Ti angle of 159.5 (2) degrees. The tetramer forms tetragonal crystals, which are twinned by merohedry on the (110) plane. The tetramer molecule contains a crystallographic 4 axis, with the Ti atoms linked by the O atoms in a mu-oxo manner to form an eight-membered ring.