Left- and right-handed chiral nematic mesophase of (trityl)(alkyl)cellulose derivatives

Abstract

A series of novel specifically substituted 6-O-trityl-2,3-O-alkyl cellulose derivatives have been prepared by the reaction of triphenylmethyl (trityl) cellulose in DMSO with powdered sodium hydroxide and an alkyl iodide (iodohexane, iodopentane, and iodobutane). These derivatives form lyotropic chiral nematic mesophases that exhibit both left- and right-handed twists. The dilute solution circular dichroism due to the phenyl chromophores along the chain does not correlate with the twist sense of the tertiary structures. However, a striking difference in the optical activity of the phenyl chromophores was observed in mesophases with the opposite twist sense. This may reflect some molecular factor responsible for the change in the macroscopic twist sense, or it may be due to the chirality of the helicoidal tertiary structure of the mesophase. Keywords: cellulose, trityl, mesophase, cholesteric, chiroptical.