Adeniyi Adebayo A, Ajibade Peter A
Department of Chemistry, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.
Department of Chemistry, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Dec 10;133:831-45. doi: 10.1016/j.saa.2014.06.030. Epub 2014 Jun 13.
The electronic and spectroscopic properties of seven pyrazole derivatives are presented in order to give a clear understanding of their distinguishing features. Four out of the seven ligands are synthesised and are also characterised experimentally. A very high correlation was observed between the experimental and the theoretical IR, (1)H NMR and (13)C NMR, which help in the characterisation of the ligands. The excitation properties computed using the TDDFT shows that most of experimentally observed absorptions of the ligands are predominantly form either the HOMO or HOMO-1 to LUMO or LUMO+1. The characteristic features of the ()N atoms (i.e. metal available coordinating centre) shows that the carboxylic unit may possibly decrease the metal affinity of the pyrazole unit while the pyridine unit will increase the affinity. The conductivity properties of the seven ligands are found to be in the order of bdmpzpy>bpzpy>bphpza>bdcpzpy>phpz>dcpz. The J-coupling of ()NN can give an insight into the variation in their bond distance, bond stretch and bond strength in the ligands. Also the atomic properties of the ()N atoms and their ()NN bonds can help in the molecular characterisation, differentiation and in prediction of the non-linear optical properties of the ligands as conductive materials.
为了清晰地了解七种吡唑衍生物的独特性质，本文介绍了它们的电子和光谱性质。七种配体中的四种已合成并通过实验进行了表征。实验值与理论值的红外光谱、¹H NMR和¹³C NMR之间存在非常高的相关性，这有助于配体的表征。使用TDDFT计算的激发性质表明，配体的大多数实验观察到的吸收主要来自最高占据分子轨道（HOMO）或HOMO - 1到最低未占据分子轨道（LUMO）或LUMO + 1。（）N原子（即金属可配位中心）的特征表明，羧基单元可能会降低吡唑单元的金属亲和力，而吡啶单元会增加亲和力。发现七种配体的电导率性质顺序为bdmpzpy>bpzpy>bphpza>bdcpzpy>phpz>dcpz。（）NN的J - 耦合可以深入了解配体中它们的键长、键伸缩和键强度的变化。此外，（）N原子及其（）NN键的原子性质有助于分子表征、区分以及预测配体作为导电材料的非线性光学性质。
