Formation of Titanosilicate N,N‐dialkyl Carbamates by CO₂ Insertion into the [(^tBuO)₃SiO]₃TiNR₂ Scaffold

Abstract

Molecular titanosilicates {(tBuO3)3SiO}2Ti(NR2)2 (1, R= Et; 2, R= Me) and {(tBuO3)3SiO}3TiNR2 (TSA1, R= Et; 3, R= Me) were obtained from the reaction between silanol (tBuO3)3SiOH (S1) and titanium amides Ti(NR2)4 (R= Et, R= Me). Additionally, the reaction of 3 and TSA1 with CO2 led to the exclusive formation of carbamates {(tBuO)3SiO}3Ti(O2NCR2) (4, R= Et; 5, R= Me). The molecular structure of 5 confirmed the proposed connectivity and presence of SiO4 and Ti(O2NCR2) units. In compound 5, titanium is coordinated to five oxygen atoms belonging to one bidentate carbamate group and three silicate ligands in a distorted square‐base pyramidal geometry. Also, we have performed DFT calculations and QTAIM analysis to study the distribution of the electron density in the carbamatecarbamate {(tBuO)3SiO}3Ti(O2CNEt2) (4) and salt {(tBuO)3SiO}3TiO(H2NMe2) 6 which was obtained by the hydrolysis of compound 5.