Hetero-bimetallic alkali titanosilicates [MOTi{OSi(OtBu)3}3]2 (M = Li-Cs) with terminal Ti-O- groups.

The molecular titanosilicate [(tBuO3)3SiO]3TiNEt2 (1) was obtained from the reaction between silanol (tBuO3)3SiOH and titanium amide Ti(NEt2)4. The reaction of 1 with alkali metal hydroxides MOH (M = Li, Na, K, Rb, Cs) offers a straightforward route to the alkaline salts of titanosilicates [MOTi{OSi(OtBu)3}3]2 with a terminal Ti-O- moiety. All compounds were characterised by single-crystal X-ray diffraction studies. Hirshfeld atom refinement and QTAIM analysis of the electron density in 1 and in the Rb salt 5 revealed the D-A nature of the Ti-O and Ti-N bonds and the presence of agostic C-H⋯Rb interactions.