Liquid crystalline radicals: discotic behavior of unsymmetrical derivatives of 1,3,5-triphenyl-6-oxoverdazyl
作者:Aleksandra Jankowiak、Damian Pociecha、Jacek Szczytko、Hirosato Monobe、Piotr Kaszyński
DOI:10.1039/c3tc31984a
日期:——
A series of six 6-oxoverdazyl (1[10]) substituted with a total of three 3,4,5-tri(decyloxy)phenyl and/or 3,4,5-tri(decylsulfanyl)phenyl groups was investigated by thermal, XRD, spectroscopic, magnetic and photovoltaic methods. The compounds exhibit columnar hexagonal (1[10]c, Colh), columnar hexagonal ordered (1[10]b, Colh(o)), columnar hexagonal 3D (1[10]a, 1[10]e and 1[10]f, Colh(3D)) or a sequence of two phases (1[10]b, Colh–Colh(3D)). The mesophase structure and stability and also thermochromism were investigated as a function of the number and distribution of decyloxy and decylsulfanyl substituents in the molecule. Thermal analysis demonstrated that the presence of the 3,4,5-tri(decyloxy)phenyl substituent in the C(3) position increases the phase stability. Spectroscopic analysis showed that only all-decyloxy derivative 1[10]b exhibits a hypsochromic shift upon Colh(o) formation, while all other compounds in the series show a modest bathochromic shift in the columnar phase relative to the isotropic phase. Magnetization investigation of 1[10]d demonstrated the paramagnetic behavior of isolated spins in isotropic and columnar phases. Negligible photocurrent was detected for 1[10]d in the columnar phase.
通过热学、X 射线衍射、光谱、磁学和光伏方法,研究了一系列共被三个 3,4,5-三(癸氧基)苯基和/或 3,4,5-三(癸基硫基)苯基取代的 6-oxoverdazyl (1[10])。化合物呈现柱状六方(1[10]c,Colh)、柱状六方有序(1[10]b,Colh(o))、柱状六方三维(1[10]a、1[10]e 和 1[10]f ,Colh(3D))或两相序列(1[10]b,Colh-Colh(3D))。根据分子中癸氧基和癸硫基取代基的数量和分布情况,研究了中间相的结构和稳定性以及热致变色性。热分析表明,C(3)位上的 3,4,5-三(癸氧基)苯基取代基增加了相的稳定性。光谱分析显示,只有全癸氧基衍生物 1[10]b 在形成 Colh(o) 时表现出低变色偏移,而该系列中的所有其他化合物在柱状相中相对于各向同性相都表现出适度的浴变色偏移。1[10]d 的磁化研究表明,各向同性相和柱相中的孤立自旋具有顺磁性。在柱状相中检测到的 1[10]d 光电流微不足道。