Abstract
Chiral zirconium(IV) double cage sandwich complex Zr(1)2 has been synthesized in one step from porphyrin cage H21. Zr(1)2 was obtained as a racemate, which was resolved by HPLC and the enantiomers were isolated in >99.5 % ee. Their absolute configurations were assigned on the basis of X‐ray crystallography and circular dichroism spectroscopy. Vibrational circular dichroism (VCD) experiments on the enantiomers of Zr(1)2 revealed that the chirality around the zirconium center is propagated throughout the whole cage structure. The axial conformational chirality of the double cage complex displayed a VCD fingerprint similar to the one observed previously for a related chiral cage compound with planar and point chirality. Zr(1)2 shows fluorescence, which is quenched when viologen guests bind in its cavities. The binding of viologen and dihydroxybenzene derivatives in the two cavities of Zr(1)2 occurs with negative allostery, the cooperativity factors α (=4 K2/K1) being as low as 0.0076 for the binding of N,N’‐dimethylviologen. These allosteric effects are attributed to a pinching of the second cavity as a result of guest binding in the first cavity.
Highlights
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not
The same trend is visible for to prepare Zr (TPP) and Zr(TPP)2.[54]. This increase in energy observed for the porphyrins in zirconium(IV) sandwich complexes might be explained by the distortion in the porphyrin plane, which causes a reduction of the aromaticity of the porphyrin
Its enantiomers have been resolved with excellent enantiomeric excesses and their absolute configurations could be assigned based on the crystal structure of ( )-Zr(1)2, and were confirmed by circular dichroism spectroscopy
Summary
Wybren Jan Buma, Jean-Valere Naubron, Jeanne Crassous, Johannes A. J. Gilissen, et al. Allosteric Guest Binding in Chiral Zirconium(IV) Double Decker Porphyrin. European Journal of Organic Chemistry, Wiley-VCH Verlag, 2021, 2021 (4), pp.607617. HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.