Unsubstituted (1) and 3,7,10-trimethyl substituted (2) 1-(4′-tolyl)-silatranes were synthesized. 1H, 13C, 15N and 29Si NMR spectra were recorded and assigned. The conformation of the 2 stereoisomers in solution were characterized by the NMR spectra. 1 is monoclinic, P21/c, with a = 13.454(2), b = 13.888(2), c = 14.345(2) Å, β = 99.10(2)°. The major stereoisomer fraction of 2 is orthorhombic, Pbca, with a = 12.168(2), b = 13.754(4), c = 20.260(3) Å. The structures were solved by direct methods and were refined by least squares to R values of 0.039 and 0.066 for 3523 and 2158 reflexions. The N→Si distances are 1: 2.169(2) (mean) and 2: 2.236(3) Å. The solid state conformation of the 2 major stereoisomer fraction is different from that in solution and this is the first example of a silatrane crystal structure where the silatrane moiety lacks C3 symmetry.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry