Substituent and solvent effects on UV-visible absorption spectra of liquid crystalline disubstituted biphenylcyclohexane derivatives - a computational approach

A computational approach has been carried out on liquid crystalline disubstituted biphenylcyclohexanes (BCHs) of general formula R-C6H10-C6H4-C6H4-X with R: C3H7; X: H (BCH30) and R: C5H11; X: CN (BCH5CN) using the CNDO/S + CI and INDO/S + CI methods. These methods have been employed to calculate and analyze the spectral shifts, and absorbance measurements in UV-visible range of the systems. The electronic transitions, absorption wavelength, HOMO (Highest Occupied Molecular Orbital), and LUMO (Lowest Unoccupied Molecular Orbital) energies have been calculated. Further, ultraviolet (UV) stability of the molecules has been discussed in the light of absorption wavelength and electronic transition oscillator strength (f). The effect of different solvent media and substituents on transition energies, oscillator strength, and other absorption parameters has also been reported. The present article provides valuable information regarding enhancing the UV stability of molecules by marinating their conductivity. Further, these absorption spectra will provide valuable data base for future computational studies, and the other experimental investigations. (c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)