POLAR TOLANE LIQUID CRYSTALS

摘要

A new class of liquid crystal compounds is based on tolane and bis-tolane structures: (I), in which X is a polar group such as F (fluoro), CN (cyano), OCF3 (trifluoromethoxy), or NCS (isothiocyanate) at least one of the pairs of sites Y1 and Y2, Z1 and Z2, and for the bis-tolane derivatives, A1 and A2 are fluoro groups. T1 for the tolane derivatives is always a triple bond. For the bis-tolane derivatives, T1 and T2 are either both triple bonds or one of the two groups is a double bond with and the other remains a triple bond. Rn or Rm may be an alkyl group having the general formula CnH2n+1, an alkenyl group having the general formula CnH2n-1, an alkoxy group having the general formula OCnH2n+1, or an alkenoxy group having the general formula -OCnH2n-1. Additionally, for the tolane compounds, Rn may be a cyclohexyl substituent: (II), or a dioxane substituent: (III), in which Rx is an alkyl group having the general formula general formula CxH2x+1, an alkenyl group having the general formula CxH2x-1, an alkoxy group having the general formula OCxH2x+1, or an alkenoxy group having the general formula OCxH2x-1. These compounds exhibit useful nematic ranges and melting points. Also disclosed are eutectic mixtures including these compounds.