NIR and MWIR transparent liquid crystals

A fully deuterated liquid crystal with low absorption in mid-wave infrared (MWIR) is developed. This liquid crystal serves as an important nematic material for future development of low-loss infrared IR liquid crystals and devices. New synthetic approach of perdeuterated 4'-pentylbiphenyl-4-carbonitrile, known as PCB or 5CB, one of the most widely known nematic liquid crystal, has been developed. Title compound has been synthesized in cross-coupling reaction of deuterated 4-cyanophenylboronic acid with perdeuterated 4-pentylchlorobenzene. Presented synthetic path can be easily applied to the synthesis of other homologues of alkylcyanobiphenyl (nCB) series as well as for partially deuterated nCBs.