Cocrystallising Rotamers of a Pentacoordinate Silicon Complex with a Chiral Aminodiol Ligand



Crystal structure analysis reveals the cocrystallysation of two turnstyle rotamers of a pentacoordinate silicon complex with a chiral backbone derived from 2-amino-1,1,2-triphenylethanol. The structures of the two epimers are well reproduced by DFT calculations. In addition, the coexistence of two rotamers, which readily interconvert in solution, is confirmed by their solid-state NMR spectroscopic data. Possible mechanisms of their interconversion are discussed, and preference is given to a turnstile-like rotation of three ligands at the silicon atom about 120°.