Solid crystalline polymorphism in M-24

Abstract

Infrared absorption, differential scanning calorimetric, microscopic and x-ray diffraction studies of 4-cyano-4'-octyloxy biphenyl (M-24) has brought out clearly the solid crystalline polymorphism in this compound. There are at least three solid crystalline forms SCI, SCII & SCIII. The appearance and the preponderance of these solid crystalline forms depend critically on the manner in which liquid crystalline melt solidifies. Each of the phases has its characteristic I.R. absorption in the C-N stretching band. Solid crystalline phase SCII shows a doublet in the C-N stretching region and this seems to arise out of Devydov or correlation splitting.