Stepwise substitution of N,N-di-isopropylcarbamato groups of Ti(O2CNiPr2)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(O2CNiPr2)4, 1, by triphenylsilanol led to the bis(silanolato)bis(carbamato) complex Ti(O2CNiPr2)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.