Synthesis, characterization and density functional theory study of low cost hydrazone sensitizers
作者:A. G. Al-Sehemi、A. Irfan、A. M. Asiri、Y. A. Ammar
DOI:10.4314/bcse.v29i1.13
日期:——
The 2-4-[2-benzylidenehydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 1), 2-4-[2-(1-naphthylmethylene)hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 2) and 2-4-[2-(9-anthrylmethylene)- hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 3) were synthesized by direct tricyanovinylation of hydrazones. The bathochromic shift in absorption spectra has been observed by increasing the solvent polarity. The FTIR spectra of these new dyes exhibited three important absorption bands. The first band centered near 3260 cm-1 in System 1 while 3208 cm-1 and 3211 cm-1 in System 2 and System 3 for the nNH absorption, respectively. The second band is a sharp absorption band in the region of 2212-2209 cm-1, which was attributed to the cyano group absorption. The third is an absorption band in the region of 1611-1603 cm-1 ascribed for the C=N. Density functional theory (DFT) calculation of relative energies, relative enthalpies and free energies shows that E isomers are the most stable except System 3 in which the most stable is Z isomers. The conformational energy profile shows two maxima near (-90 and 90o) while three local minima observed at (-180, 0 and 180) for N1-N2-C1-C2 torsional angle. The highest occupied molecular orbitals (HOMOs) are localized on the whole molecules while lowest unoccupied molecular orbitals (LUMOs) are distributed on the tricarbonitrile.
2-4-[2-亚苄基肼]苯基}乙烯-1,1,2-三腈(体系 1)、2-4-[2-(1-萘亚甲基)肼]苯基}乙烯-1,1、系统 2)和 2-4-[2-(9-蒽亚甲基)-肼基]苯基}乙烯-1,1,2-三腈(系统 3)是通过肼的直接三氰基化合成的。通过增加溶剂极性,观察到了吸收光谱的浴色偏移。这些新染料的傅立叶变换红外光谱显示出三个重要的吸收带。第一个吸收带在体系 1 中位于 3260 cm-1 附近,而在体系 2 和体系 3 中则分别位于 3208 cm-1 和 3211 cm-1 附近。第二个波段是位于 2212-2209 cm-1 区域的尖锐吸收带,是氰基的吸收。第三个是 1611-1603 cm-1 区域的吸收带,归因于 C=N 的吸收。密度泛函理论(DFT)对相对能量、相对焓和自由能的计算表明,除体系 3 外,E 异构体是最稳定的,其中最稳定的是 Z 异构体。构象能谱显示,N1-N2-C1-C2 扭转角在(-90 和 90o)附近有两个最大值,在(-180、0 和 180)处有三个局部最小值。最高占位分子轨道(HOMOs)集中在整个分子上,而最低未占位分子轨道(LUMOs)则分布在三腈上。