Synthesis and characterization of liquid crystals containing a non-activated 1',3',3'-trimethylspiro\[2H-1-benzopyran-2,2-indoline] group

Abstract

Abstract Two series of mesogens derived from the non-activated spiropyran dyes 6-hydroxy-1,3,3-trimethylspiro\[2H -1-benzopyran-2,2-indoline] (series trimethylspiro\[2 H -1-benzopyran-2,2-indoline] (series 2) have been synthesized. Analysis by differential scanning calorimetry, polarizing microscopy and X-ray diffraction showed compounds in series 1 form monotropic nematic and SmA phases, while compounds in series 2 form only a monotropic nematic phase.