Spectroscopic studies of aryl substituted 1-phenyl-2-pyrazolines: Steric and electronic substitution effects
作者:Marzieh Soltani、Hamid R. Memarian、Hassan Sabzyan
DOI:10.1016/j.molstruc.2018.07.052
日期:2018.12
Abstract A series of aryl substituted 1-phenyl-2-pyrazolines containing electron-donating and electron-withdrawing substituents on different positions of the C3 or C5-aryl groups were synthesized and their steric and electronic effects on characteristic spectral data were investigated by experimental spectroscopic methods (UV–Vis, IR and NMR) and DFT computations. Whereas the C5-aryl group of the heterocyclic
Photooxidation of various 2-pyrazolines is studied experimentally and computationally. Experimental results show that the electron-donating/withdrawing substituents increases/decreases the rate of this photoreaction. The proposed light-induced electron-transfer mechanism explains the steric and electronic effects of the substituents, co-planarity of the aryl rings substitutions, orientations of the
实验和计算研究了各种2-吡唑啉的光氧化作用。实验结果表明,给电子/吸电子取代基增加/降低了这种光反应的速率。拟议的光诱导电子转移机理解释了取代基的空间和电子效应,芳基环取代基的共面性,C 3-芳基环向C 3 = N 2的方向双键与溶剂在照射时间上反应完全。计算(TD)B3LYP / 6-311 ++ G(d,p)结果,包括前沿轨道能量,UV-可见跃迁,静电势,CHELPG电荷,用于发现和描述隧道电子转移过程及其相关结构弛豫形成反应的速率决定步骤,并证明取代对反应速率的影响是正确的。第一次电子转移后形成的中间体络合物仅在其三重态下才进行质子转移步骤。2-吡唑啉的三重态激发态可能对电子转移步骤几乎没有贡献。循环伏安法测量结果支持了光化学结果。
Electronic and steric substituent effects on the fluorescence emission of 2‐pyrazoline derivatives
aryl rings. In addition, the effects of the concentration and the solvent polarity on the fluorescence emission were studied. Density functional theory (DFT) calculations were carried out to gain insight into the geometric, electronic, and spectroscopic properties of the pyrazoline derivatives. The results of both experimental and computational studies explain the effects of the geometrical orientation