Alkyl/alkenyloxy phenyl/biphenylpyrimidines: Dependence of the liquid crystal transition temperatures on the position of the nitrogen atoms and the position and configuration of carbon-carbon double bonds

Abstract

The influence on the transition temperatures of a carbon-carbon double bond in the terminal alkenyloxy (ether) chain of four series of three-ring phenylhiphenyl-pyrimidines has been systematically investigated. The position and configuration of the double bond has been varied systematically in order to determine the optimal configuration and conformation of the terminal chains for smectic C formation. Four positions of the two nitrogen atoms were chosen. This produced four isomeric series of pyrimidines and differences in the mesomorphic behaviour were observed. The dependence of the transition temperatures on chain length was studied for the same four isomeric pyrimidine series. Comparisons between the new three-ring phenyV biphenyl-pyrimidines and the corresponding two-ring phenylpyrimidines revealed almost identical tendencies. These results are consistent with a linearly-extended conformation of the chain. Several of the new ethers exhibit remarkably low viscosity values (i.e. short response times) and wide switching angles in an optically active base mixture used for evaluation and comparison purposes. Hence they can be used to widen the temperature range of mixtures designed for electro-optic display devices based on ferroelectric effects (FLCDs) without leading to longer response times.

Synthesis and Characterization of Bis(3-chloro-4-dodecyloxyphenyl) Malondialdehyde Complexes of Cu(II) and Ni(II)

“…Thus 3-chloro-4-hydroxyphenylacetic acid 1 was converted into its m ethyl ester 2 by standard procedures. Alkylation [10 Table I. C om pared to the non-halogenated 4-dodecyloxyphenyl m alondi aldehyde ligand, 6 ( n = l l , X=H), the halogenated ligand, 6 ( n = ll, X=C1) show s a sm all decrease in the m elting point.…”

The influence of the chiral terphenylate on the tilt angle in pyrimidine ferroelectric mixtures

“…SmC 83.4-87.3 SmA 91.1-92.8 N 98.8-102.1 Iso Melting point of mixture A is below 10 C. The synthesis of compounds 1-6 is given in [6][7][8] and chiral dopant B in [9]. Compounds 1-6 as well as mixture A were doped with chiral dopant B in the amount of 2, 5, and 10 wt.%.…”

Prediction of the Clearing Temperatures of a Series of Liquid Crystals from Molecular Structure

“…Data Set. The compounds and transition temperatures used in the development of the predictive models were taken from the literature. − As discussed in each of the original sources, all transition temperatures were determined by optical microscopy using a Leitz Ortholux II POL BK microscope in conjunction with a Mettler FP 82 heating stage and FP 80 control unit. The transition temperatures were confirmed using a Mettler DTA TA 2000.…”