Multiple hydrogen bonded mesomorphic complexes between complementary 1,3,5-triazine and pyrimidine derivatives
作者:Alexandra Kohlmeier、Laura Vogel、Dietmar Janietz
DOI:10.1039/c3sm51554k
日期:——
A 2,4-diamino-6-phenyl-1,3,5-triazine grafted with two semiperfluorinated chains at the phenyl substituent has been investigated in binary mixtures with complementary orotic acid and barbituric acid derivatives carrying either a lipophilic alkyl or a semiperfluoroalkyl tail. Equimolar mixtures of the triazine with nucleobases form triple hydrogen-bonded heterodimers with an elongated central core. Mesomorphic properties are observed only if the pyrimidinone component provides an additional free NH function not involved in triple H-bonding with the triazine nucleus. In that case, additional H-bond interactions orthogonal to the rod-shaped core of the heterodimers initiate the formation of cyclotrimeric rosette-type associates with circular geometry of the polar core region. Rosettes of heterodimers involving an alkyl substituted nucleobase organize to hexagonal columnar mesophases. Replacing the alkyl tail of the pyrimidine with a semiperfluorinated fragment leads to the formation of a micellar cubic phase. The individual micelles are composed of segmented columns three-dimensionally surrounded by a continuum of the semiperfluorinated segments.
我们研究了在苯基取代基上接枝了两条半哌氟化链的 2,4-二氨基-6-苯基-1,3,5-三嗪与带有亲脂烷基或半哌氟烷基尾部的互补奥罗酸和巴比妥酸衍生物的二元混合物。三嗪与核碱基的等摩尔混合物会形成三重氢键异二聚体,并具有一个拉长的中心核。只有当嘧啶酮成分提供了额外的自由 NH 功能而不参与与三嗪核的三重氢键结合时,才会观察到介形特性。在这种情况下,与异源二聚体的杆状核心正交的额外 H 键相互作用会启动环状三聚体莲座型结合体的形成,其极性核心区域呈环状几何形状。有烷基取代的核碱基参与的杂二聚体的玫瑰花环组织成六角柱状介相。用半哌氟化片段取代嘧啶的烷基尾部可形成立方胶束相。单个胶束由三维分段柱组成,周围环绕着半哌氟化片段的连续体。