Alamro Fowzia S, Ahmed Hoda A, Gomha Sobhi M, Shaban Mohamed
Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
Department of Chemistry, Faculty of Science, Cairo University, Cairo, Egypt.
Front Chem. 2021 Sep 3;9:686788. doi: 10.3389/fchem.2021.686788. eCollection 2021.
New asymmetrical Schiff base series based on lateral methoxy group in a central core, (E)-3-methoxy-4-(((4-methoxyphenyl)imino)methyl)phenyl 4-alkoxybenzoate (), were synthesized and their optical and mesomorphic characteristics were investigated. The lateral OCHgroup was inserted in the central ring in ortho position with respect to the azomethine linkage. FT-IR, and NMR spectroscopy as well as elemental analyses were used to elucidate their molecular structures. Their mesomorphic behaviors were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). These examinations indicated that all the designed series were monomorphic and possessed nematic (N) mesophase enantiotropically, except derivative which exhibited monotropic N phase. A comparative study was made between the present investigated series () and their corresponding isomers (). The results revealed that the kind and stability of the mesophase as well as its temperature range are affected by the location and special orientation of the lateral methoxy group electric-resistance, conductance, energy-gap, and Urbach-energy were also reported for the present investigated series. These results revealed that all electrodes exhibit Ohmic properties and electric-resistances in the GΩ range, whereas the electric resistance was decreased from 221.04 to 44.83 GΩ by lengthening the terminal alkoxy-chain to = 12. The band gap of the series was reduced from 3.43 to 2.89 eV by increasing the terminal chain length from = 6 to = 12 carbons. Therefore, controlling the length of the terminal chain can be used to improve the series' electric conductivity and optical absorption, making it suitable for solar energy applications.
基于中心核中侧向甲氧基的新型不对称席夫碱系列，即（E）-3-甲氧基-4-（（（4-甲氧基苯基）亚氨基）甲基）苯基4-烷氧基苯甲酸酯（），已被合成，并对其光学和介晶特性进行了研究。侧向OCH基团相对于偶氮甲碱键处于邻位插入中心环中。利用傅里叶变换红外光谱、核磁共振光谱以及元素分析来阐明它们的分子结构。它们的介晶行为通过偏光显微镜（POM）和差示扫描量热法（DSC）进行表征。这些研究表明，除了表现出单变向向列相（N）的衍生物外，所有设计的系列都是单态的，并且具有对映性的向列相（N）中间相。对本研究系列（）与其相应的异构体（）进行了比较研究。结果表明，中间相的种类和稳定性及其温度范围受到侧向甲氧基的位置和特殊取向的影响。还报道了本研究系列的电阻、电导率、能隙和乌尔巴赫能量。这些结果表明，所有电极均表现出欧姆特性，电阻在GΩ范围内，而通过将末端烷氧基链延长至 = 12，电阻从221.04 GΩ降至44.83 GΩ。通过将末端链长度从 = 6增加到 = 12个碳，系列的带隙从3.43 eV降低到2.89 eV。因此，控制末端链的长度可用于提高系列的电导率和光吸收，使其适用于太阳能应用。
