Synthesis, transition temperatures, and optical properties of various 2,6-disubstituted naphthalenes and related 1-benzothiophenes with butylsulfanyl and cyano or isothiocyanato terminal groups
作者:Alexander J. Seed、Kenneth J. Toyne、John W. Goodby、Michael Hird
DOI:10.1039/b003818k
日期:——
Fourteen compounds based on 2,6-disubstituted naphthalenes
or related 1-benzothiophene moieties with butylsulfanyl and cyano or isothiocyanato
terminal groups have been synthesised. The transition temperatures of the
compounds and their refractive indices have been determined and the derived
values for the optical anisotropies, polarisabilities and order parameters
have been calculated. With one exception (which also shows a smectic
A phase), all the compounds with naphthyl and phenyl groups are solely
nematogenic; for these compounds the naphthyl unit gives an average increase
in TN–I value and melting point of 72 and 20 °C
respectively compared to the values for the compounds with a phenyl in place
of the naphthyl unit. The incorporation of a 2,5-thiophene unit in place
of phenyl lowers TN–I and when it is part of a 1-benzothiophene
unit the depression is even greater. The naphthalene compounds increase the
values of optical anisotropy by approximately 0.04, compared to the phenyl
systems, mainly because they increase the refractive index of the e-ray (n∥
values); compound 12 has an
exceptionally high optical anisotropy (Δn value)
of 0.54.
基于2,6-二取代萘或相关1-苯并噻吩结构,带有丁硫基和氰基或异硫氰酸酯端基的14种化合物已被合成。这些化合物的转变温度和折射率已被测定,并计算了由此得出的光学各向异性、极化率和顺序参数。除了一个例外(也表现出向列-A相),所有带有萘基和苯基的化合物都是纯向列型的;对于这些化合物,萘基单元相比用苯基替代的化合物,平均提高了72度和20度的转变温度和熔点。将2,5-噻吩单元引入苯基位置会降低转变温度,当其作为1-苯并噻吩单元的一部分时,降低更为显著。与苯基系统相比,萘化合物大约增加了0.04的光学各向异性值,主要是因为它们增加了e光线的折射率(n∥值);化合物12具有异常高的光学各向异性(Δn值)为0.54。