Comparative Analysis of Fluorine-Containing Mesogenic Derivatives of Carborane, Bicyclo[2.2.2]octane, Cyclohexane, and Benzene using the Maier-Meier Theory

Two series of related three-ring nematoges with Delta epsilon > 0 and containing 12-vetex carborane (A), 10-vertex carborane (B), bicyclo[2.2.2]octane (C), cyclohexane (D) and benzene (E) were prepared and investigated as additives to 6-CHBT nematic host and in the pure form (series 2). Dielectric results were analyzed with the Maier-Meier relationship to gain an understanding of behavior of additives in nematic solutions. Molecular parameters for each nematogen were obtained at the B3LYP/6-31G(d,p) level of theory in the host's dielectric medium, and dielectric data was used as the only experimental parameter to calculate apparent order parameter S-app and the Kirkwood factor g. The results demonstrated that compounds in series I stabilize the nematic phase (high S-app) of the host more than additives in series 2 (low S-app), and carbocycles C and D are more effective (higher S-app) than carborane analogues A and B (lower S-app). The method provides insight into behavior of additives in nematic solutions and is useful for comparative analysis of a series of compounds or a series of hosts.