Stepwise substitution of N,N-di-isopropylcarbamato groups of Ti((O2CNPr2)-Pr-i)(4) by triphenylsilanol leading from eight- to six- and four-co-ordinated titanium(IV)

Carbamato displacement from the hydrocarbon soluble N,N-diisopropylcarbamat o derivative Ti((O2CNPr2)-Pr-i)(4), 1, by triphenylsilanol led to the bis(s ilanolato)bis(carbamato) complex Ti((O2CNPr2)-Pr-i)(2)(OSiPh3)(2), 2. X-Ray diffraction showed the mononuclear compound 1 to contain eight-co-ordinate d titanium with slightly asymmetric bidentate carbamato groups in a distort ed dodecahedral geometry. Titanium is six-co-ordinated in 2 to six oxygen a toms belonging to two bidentate carbamato groups and to two cis-arranged si lanolato ligands in a distorted octahedral geometry. Exhaustive carbamato d isplacement from titanium, carried out with a silanol:titanium molar ratio >4:1, afforded the mononuclear tetrasilanolato complex Ti(OSiPh3)(4), 3, co ntaining a tetrahedral titanium centre.