Gao Tianyue, Lei Juncheng, Zou Siyu, Wang Chenxu, Xu Xuefang, Gou Qian
Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331 Chongqing, China.
Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China.
Phys Chem Chem Phys. 2023 Oct 18;25(40):27798-27804. doi: 10.1039/d3cp03712f.
The rotational spectrum of the isoprene-maleic anhydride complex has been investigated by pulsed jet Fourier transform microwave spectroscopy and interpreted with complementary quantum chemical calculations. Theoretical predictions have yielded four plausible isomers, all residing within an energy window of 12 kJ mol. However, two distinct isomers characterized by a π-π stacked configuration have been experimentally observed in pulsed jets, which have differed in the orientation of isoprene over maleic anhydride. The relative population ratio of the two detected isomers has been estimated to be / ≈ 3/1 from rigorous measurements of the relative intensity on a set of -type transitions. Remarkably, this study underscores the pivotal role played by the interaction between the CC bonding orbital (π) of isoprene and the CC antibonding orbital (π*) of maleic anhydride in stabilizing the target complex.
通过脉冲喷射傅里叶变换微波光谱对异戊二烯 - 马来酸酐配合物的转动光谱进行了研究，并用互补的量子化学计算进行了解释。理论预测得到了四种可能的异构体，它们都处于12 kJ/mol的能量范围内。然而，在脉冲喷射中通过实验观察到了两种以π - π堆积构型为特征的不同异构体，它们在异戊二烯相对于马来酸酐的取向上有所不同。通过对一组Q型跃迁相对强度的严格测量，估计这两种检测到的异构体的相对丰度比约为3/1。值得注意的是，这项研究强调了异戊二烯的CC键合轨道(π)与马来酸酐的CC反键轨道(π*)之间的相互作用在稳定目标配合物中所起的关键作用。
