scholarly journals Absolute configuration and host-guest binding of chiral porphyrin-cages by a combined chiroptical and theoretical approach

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiangkun Ouyang ◽  
Anne Swartjes ◽  
Marc Geerts ◽  
Pieter J. Gilissen ◽  
Danni Wang ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Polymer Chains ◽  
Vibrational Circular Dichroism ◽  
Cage Compounds ◽  
Guest Binding ◽  
Circular Dichroïsm

Abstract Porphyrin cage-compounds are used as biomimetic models and substrate-selective catalysts in supramolecular chemistry. In this work we present the resolution of planar-chiral porphyrin cages and the determination of their absolute configuration by vibrational circular dichroism in combination with density functional theory calculations. The chiral porphyrin-cages form complexes with achiral and chiral viologen-guests and upon binding one of the axial enantiomorphs of the guest is bound selectively, as is indicated by induced-electronic-dichroism-spectra in combination with calculations. This host-guest binding also leads to unusual enhanced vibrational circular dichroism, which is the result of a combination of phenomena, such as rigidification of the host and guest structures, charge transfer, and coupling of specific vibration modes of the host and guest. The results offer insights in how the porphyrin cage-compounds may be used to construct a future molecular Turing machine that can write chiral information onto polymer chains.

scholarly journals Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

2021 ◽  
Vol 16 (3) ◽  
pp. 1934578X2199616
Author(s):  
Rosa E. del Río ◽  
Pedro Joseph-Nathan
Keyword(s):  
Natural Products ◽  
Circular Dichroism ◽  
Absolute Configuration ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Research Field ◽  
Vibrational Circular Dichroism ◽  
Biological Molecules ◽  
Nitrogen Containing Compounds ◽  
Circular Dichroïsm

Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

Sign in / Sign up

Export Citation Format

Share Document