Based on the chemical incompatibility between the aromatic mesogenic cores and the flexible end aliphatic (methylene units) chains, which can lead to the formation of polarization modulated layered undulated phases, four-ring bent-core compounds have been designed and synthesized. The designed compounds are thermally and hydrolytically stable due to intramolecular hydrogen bonding, highly fluorescent and exhibit 2D-polarization modulated layer undulated (PMLU) smectic phases. The phase transition temperatures have been confirmed by differential scanning calorimetry and the phases are confirmed by polarizing optical microscopy and X-ray diffraction studies. For compounds 1-10-11 and 1-15-11 the peaks are indexed to tilted columnar lattice (Colob), while for 2-12-11 the peaks are indexed to the rectangular lattice belonging to the PMLU family The influence of the direction of ester linking group played an important role in the mesophase as well as the evaluated parameters of the dipole moment, the bending angle and the asymmetry parameter by spin-restricted DFT calculations using the B3LYP exchange-correlation functional and the 6-311G(d,p) basis set.
芳香族中生核与柔性末端脂肪族(亚甲基单元)链之间的
化学不相容性可导致形成偏振调制层状起伏相,基于这种
化学不相容性,我们设计并合成了四环弯曲核化合物。由于分子内氢键的作用,所设计的化合物具有热稳定性和
水解稳定性,具有高荧光性,并表现出二维偏振调制层状起伏(PMLU)胶凝相。相变温度已通过差示扫描量热法得到证实,相位也通过偏振光学显微镜和 X 射线衍射研究得到证实。对于化合物 1-10-11 和 1-15-11,峰值被划分为倾斜柱状晶格(Colob),而对于 2-12-11,峰值被划分为属于 PMLU 家族的矩形晶格、通过使用 B3LYP 交换相关函数和 6-311G(d,p) 基集进行自旋限制的 DFT 计算,评估了偶极矩、弯曲角和不对称参数。