A comparison of smectic phase induction in a series of isostructural two‐ring esters by tail fluorination and tail elongation

Abstract

The effectiveness of smectic phase induction in a series of isostructural two‐ring nematic esters 1 by chain extension (2) or partial fluorination (3) of the pentyloxy group was investigated. Results show that the introduction of five fluorine atoms to 1 is more effective than the chain length doubling in suppressing nematic phases in favour of smectic phases in bicyclo[2.2.2]octane (1B), cyclohexane (1C) and benzene (1D) derivatives. Surprisingly, these structural transformations were ineffective in induction of smectic behaviour in the carborane ester 1A. Both chain modifications, i.e. tail fluorination and chain length doubling, increased the clearing point only for the benzene derivative 1D.

Keywords:

• smectic phase induction
• two‐ring esters
• tail fluorination
• tail elongation

Acknowledgement

Financial support for this work was received from the National Science Foundation (DMR‐0606317).