含双腈基分子的振动光谱和计算化学表征

Vibrational and Computational Characterization of a Dual Nitrile-Containing Compound

利用傅里叶变换红外光谱、结合计算化学手段,研究了2,2’-azobisobutyronitrile(AIBN)中的腈基(C≡N—)的红外光谱特性。发现其双C≡N—伸缩振动指纹(峰值和半峰宽)都具有一定的溶剂依赖性。密度泛函水平上的计算化学预测了该分子的C≡N—伸缩振动的二重简并度,与实验结果一致。可以预期,在引发聚合反应(如合成传统的基于多肽的水凝胶)过程中,上述红外振动光谱特性将发生改变,C≡N—的振动光谱会表现出与基态不同的振动特性。在此情形下,C≡N—伸缩振动可兼做原位红外光谱探针,用于监测化学反应的进行。

In this work,infrared characteristics of the C≡N— group in 2,2'-azobisobutyronitrile(AIBN)were examined using FTIR spectroscopy and computational chemistry methods.Solvent-dependent C≡N stretching vibrational signatures(peak position and FWHM)were observed.Computation at the level of DFT predicted a doubly degenerate C≡N— stretching mode,which explained experimental results.It is expected that the IR signature would change in the course of a polymerization reaction of classical peptide-based hydrogels,in which AIBN often serves as initiator,and can be used as an IR probe for monitoring the polymerization reactions.