Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India.
Inorg Chem. 2020 Jan 6;59(1):801-809. doi: 10.1021/acs.inorgchem.9b03062. Epub 2019 Dec 26.
A clear and unambiguous rationalization of chirality induction, amplification, and subsequent inversion processes has been demonstrated using an achiral Mg(II)porphyrin dimer (host) and a series of chiral diols (guests) upon stepwise formation of a 1:1 host-guest polymer and 1:2 host-guest monomer via intermolecular assembling and disassembling processes. Crystallographic characterizations are reported here for both the polymer and the monomeric complexes, which enable us to completely scrutinize the structural and geometrical changes systematically in rationalizing their optical properties. The sign of the CD couplets for both the polymer and monomer are just opposite between and guests, which suggests that the chirality is dictated solely by the stereogenic projection of the chiral centers. Stronger intra- and intermolecular coupling in the polymeric complexes is responsible for the highly enhanced CD couplets as compared to the monomer and have only intramolecular coupling as also observed in their X-ray structures. DFT studies clearly support the experimental observations.
使用非手性 Mg(II)卟啉二聚体（主体）和一系列手性二醇（客体），通过分子间组装和拆卸过程，逐步形成 1:1 主体-客体聚合物和 1:2 主体-客体单体，对手性诱导、放大和随后的反转过程进行了明确而清晰的合理化解释。本文报道了聚合物和单体配合物的晶体学特征，这使我们能够系统地全面检查结构和几何变化，从而合理地解释它们的光学性质。聚合物和单体的 CD 偶合对在 和 客体之间正好相反，这表明手性仅由手性中心的立体投影决定。与单体相比，聚合物配合物中更强的分子内和分子间耦合导致 CD 偶合对显著增强，并且在它们的 X 射线结构中也观察到只有分子内耦合。DFT 研究清楚地支持了实验观察。
