Incoherent Nonreciprocal Absorbance Circular Dichroism of Uniaxial Assemblies
Incoherent Nonreciprocal Absorbance Circular Dichroism of Uniaxial Assemblies
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DOI：
10.1021/acs.jpcb.3c03104
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发表时间：
2023-09-18
影响因子：
3.3
通讯作者：
Simpson，Garth J.
中科院分区：
文献类型：
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作者：
Turner，Gwendylan A.;Hwang，Yechan;Simpson，Garth J.
分析理论提出预测显着大的和完全电偶极子允许的圆二色性（CD）在电子紫外-可见（UV-vis）吸收光谱的单轴表面组件。透射光束的部分去偏振为表面特异性和手性特异性不对称参数提供了一条途径，这些参数的数量级大于各向同性系统的类似测量。使用从头算量子化学计算产生的模型的预测，没有可调的参数同意与紫外-可见吸收CD测量的亲水性基板上制备的纳米微晶。值得注意的是，这些计算正确地预测了（i）关键的光谱特征，（ii）CD光谱中手性特异性峰的相对幅度，（iii）绝对CD符号，以及（iv）由仪器中样品重定向引起的倒数CD符号反转。这些结果连接的分子结构和取向的大CD可观察到的取向薄膜组件，进一步扩展到广泛的类别的手性特定的光谱分析的潜力。
Analytical theory is proposed predicting remarkably large and fully electric-dipole-allowed circular dichroism (CD) in electronic ultraviolet–visible (UV–vis) absorbance spectroscopy of uniaxial surface assemblies. Partial depolarization of the transmitted beam provides a pathway for surface-specific and chiral-specific dissymmetry parameters that are orders of magnitude greater than those from analogous measurements of isotropic systems. Predictions of the model generated using ab initio quantum chemical calculations with no adjustable parameters agreed with UV–vis absorbance CD measurements of naproxen microcrystals prepared on hydrophilic substrates. Notably, these calculations correctly predicted (i) the key spectroscopic features, (ii) the relative magnitudes of chiral-specific peaks in the CD spectrum, (iii) the absolute CD sign, and (iv) the reciprocal CD sign inversion arising from sample reorientation in the instrument. These results connect the molecular structure and orientation to large CD observable in oriented thin-film assemblies, with the potential for further extension to broad classes of chiral-specific spectral analyses.