Synthesis and structures of the first titanium(IV) complexes with cyclic tetrasiloxide ligands: Incomplete and complete cage titanosiloxanes

The first titanium(IV) complexes with cyclic tetrasiloxide ligands, [Ti((LH)-H-1)(OSiMe3)](2)(H2O) (1) and (CpTiCl)(4)(L-2)(2) (2), were synthesized using the all-cis isomer of cyclotetrasiloxane-tetraols R-4(SiO)(4)(OH)(4) ((LH4)-H-1 : R = Ph, (LH4)-H-2: R = Pr-i) as ligand precursors. X-ray analysis revealed that I is a dinuclear complex with bridging siloxy and aqua ligands while 2 has a tetranuclear cage structure capped by two L 2 ligands.