Stepwise substitution of N,N-di-iso-propylcarbamato groups of Ti(O2CN-i-Pr2)4 by triphenylsilanol leading from eight- to six- and four-co-ordinated titanium(IV)

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