Title
Supramolecular Chirogenesis In Bis-Porphyrin: Crystallographic Structure And Cd Spectra For A Complex With A Chiral Guanidine Derivative
Abstract
The complexation of (3aR,7aR)-N-(3,5-bis(trifluoromethyl)phenyl)octahydro-2H-benzo[d]imidazol-2-imine (BTI), as a guest, to ethane-bridged bis(zinc octaethylporphyrin), bis(ZnOEP), as a host, has been studied by means of ultraviolet-visible (UV-Vis) and circular dichroism (CD) absorption spectroscopies, single crystal X-ray diffraction, and computational simulation. The formation of 1:2 host-guest complex was established by X-ray diffraction and UV-Vis titration studies. Two guest BTI molecules are located at the opposite sides of two porphyrin subunits of bis(ZnOEP) host, which is resting in the anti-conformation. The complexation of BTI molecules proceed via coordination of the imine nitrogens to the zinc ions of each porphyrin subunit of the host. Such supramolecular organization of the complex results in a screw arrangement of the two porphyrin subunits, inducing a strong CD signal in the Soret (B) band region. The corresponding DFT computational studies are in a good agreement with the experimental results and prove the presence of 1:2 host-guest complex as the major component in the solution (97.7%), but its optimized geometry differs from that observed in the solid-state. The UV-Vis and CD spectra simulated by using the solution-state geometry and the TD-DFT/omega B97X-D/cc-pVDZ + SMD (CH2Cl2) level of theory reproduced the experimentally obtained UV-Vis and CD spectra and confirmed the difference between the solid-state and solution structures. Moreover, it was shown that CD spectrum is very sensitive to the spatial arrangement of porphyrin subunits.
Year
DOI
Venue
2021
10.3390/sym13020275
SYMMETRY-BASEL
Keywords
DocType
Volume
porphyrin, guanidine, host&#8211, guest binding, chirality, supramolecular chemistry, circular dichroism, DFT, TD-DFT simulation
Journal
13
Issue
Citations 
PageRank 
2
0
0.34
References 
Authors
0
8
Name
Order
Citations
PageRank
Irina Osadchuk100.34
Nele Konrad200.34
Khai-Nghi Truong300.34
Kari Rissanen400.34
Eric Clot500.34
Riina Aav600.68
Dzmitry Kananovich700.34
Victor Borovkov800.34