Polarizability study of nematic liquid crystal 4-cyano-4′-pentylbiphenyl (5CB) and its nitrogen derivatives

•Studied optical properties of nematic liquid crystal 4-cyno-4′-pentylbiphenyl (5CB) and its nitrogen derivatives.•Obtained variation of polarizability and HOMO-LUMO gap with electric field using density functional theory (DFT).•Comparison of B3LYP and M062X has been done.

The effect of electric field on the molecular polarizability and HOMO-LUMO gap for 4-cyano-4′-pentylbiphenyl (1) and its nitrogen derivatives 2-cyano-5-(4-pentylphenyl)pyridine (2), 2-(4-cyanophenyl)-5-pentylpyrimidine (3) and 5-cyano-2-(4-pentylphenyl)pyrimidine (4) has been studied using density functional theory (DFT). The effect on polarizability and HOMO-LUMO gap due to presence of substituent in the molecules is also investigated by comparing results obtained from two different DFT approaches B3LYP and M062X. It was observed that variation of polarizability with change in electric field for all molecules show a common feature that is stabilization of polarizability between two values of electric field (or for a range of electric field). 4-cyano-4′-pentylbiphenyl (1) polarizes more in comparison to all other derivatives and has widest stability region among all.

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