Experimental determination of octanol-water partition coefficient (K) of 39 liquid crystal monomers (LCMs) by use of the shake-flask method.

Liquid crystal monomers (LCMs) were recently proposed as persistent, bioaccumulative, and toxic substances; however, there is a dearth of information regarding their experimental octanol-water partition coefficients (K). In the present study, we determined the experimental K values of these 39 LCMs by use of a classic shake-flask method. We observed that experimental K values of LCMs largely varied depending on their specific structures, and the Log transformed K generally fall in the range of 4.94-7.62. The experimental K values were further compared with those predicted by Estimation Programs Interface (EPI) Suite software. Interestingly, we observed that experimental and estimated Log K values were generally comparable for LCMs containing two benzene or cyclohexane rings; however, the estimated values gradually deviated from the experimental ones as the number of benzene or cyclohexane rings of LCM structures increased. Based on the experimental Log K values of 39 LCMs, we established a quantitative structure activity relationship (QSAR) model for predicting Log K values of other LCMs, for which authentic standards are not available. Adjusted square of determination coefficient (R) of the developed model is 0.810, indicating its goodness-of-fit for estimation of Log K values of other substances with similar backbone structures. Overall, our present study provides the first insight on experimental Log K values of LCMs, and suggests that LCMs are inclined to accumulative in the fatty tissue of organisms in the aqueous environments.