Ab initio study of sphere-like mesogen properties

Sphere-like compound C8H17Si(OPhC12H25)(3)N (1) forms mesophases. In order to investigate the relationship between molecular structure and liquid crys tal properties, structural studies are carried out on the model molecules o f compound 1 and its substituted derivatives using ab initio calculations. The results show that the cyano or chloro substituted tribenzosilatrane com pounds (RSi)-Si-1(OPhR2)(3)N (R-1,R-2 = CN or Cl) have much bigger dipole m oments or anisotropy of polarizability and more like sphere than the corres ponding alkyl substituted compounds. Cyano or chloro substituted tribenzosi latranes would be better candidates for sphere-like mesogens.