Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Jul 20;11(31):8145-8150.
doi: 10.1039/d0sc03223a.

An atropisomeric M2L4 cage mixture displaying guest-induced convergence and strong guest emission in water

Takahiro Tsutsui  1 , Lorenzo Catti  2 , Kenji Yoza  3 , Michito Yoshizawa  1
Affiliations

An atropisomeric M2L4 cage mixture displaying guest-induced convergence and strong guest emission in water

Takahiro Tsutsui et al. Chem Sci. .

Abstract

Introduction of atropisomeric axes into a bent bispyridine ligand leads to the quantitative formation of a complex mixture of atropisomeric M2L4 cages upon treatment with metal ions. Whereas the isomer ratio of the obtained cage mixture, consisting of up to 42 isomers, is insensitive to temperature and solvent, the quantitative convergence from the mixture to a single isomer is accomplished upon encapsulation of a large spherical guest, namely fullerene C60. The observed isomerization with other guests depends largely on their size and shape (e.g., <10 and 82% convergence with planar triphenylene and bowl-shaped corannulene guests, respectively). Besides the unusual guest-induced convergence, the present cage mixture displays the strongest guest emission (Φ F = 68%) among previously reported M n L m cages and capsules, upon encapsulation of a BODIPY dye in water.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts to declare.

Figures

Fig. 1
Fig. 1. Schematic representation of the self-assemblies of (a) a biological nanostructure, (b) an M2L4 cage from symmetrical ligands and metal ions, and (c) a complex mixture of M2L4 cage isomers from desymmetrized ligands and metal ions studied herein.
Fig. 2
Fig. 2. Schematic representation of (a) bispyridine ligand 1 (R = –OCH2CH2OCH3) and, (b) the optimized structures of the atropisomers in equilibrium (DFT calculation, B3LYP/6-31* level, R = –OCH3) and the formation of M2L4 cage 2 as a complex isomeric mixture.
Fig. 3
Fig. 3. Schematic representation of the possible 42 isomers of M2L4 cage 2. These isomers are in equilibrium in solution.
Fig. 4
Fig. 4. 1H NMR spectra (500 MHz, DMSO-d6, r.t.) of (a) ligand 1 and (b) a complex mixture of cage isomers 2. (c) 1H DOSY NMR (500 MHz, DMSO-d6, 298 K) and (d) ESI-TOF MS (DMSO, r.t.) spectra of isomers 2. Optimized structures of 2: (e) an all-syn isomer and (f and g) an all-anti isomer (substituents and counterions are omitted for clarity).
Fig. 5
Fig. 5. (a) Schematic representation of the guest-induced convergence of a complex mixture of 2. 1H NMR spectra (500 MHz, D2O, r.t.) of (b) cage 2, (c) 2·(Tp)2, (d) 2·Ad, (e) 2·(Cor)2, and (f) 2·C60. (g) ESI-TOF MS spectrum (H2O) of 2·C60 and the expansion and simulation of the [2·C60 – 4·NO3−]4+ signals.
Fig. 6
Fig. 6. X-ray crystal structure of 2·C60 (all-syn isomer): (a) space-filling representation for C60 and (b) space-filling representation for the naphthalene panels (the substituents are replaced by H atoms for clarity). (c) Optimized structure of 2·C60 (all-anti isomer, R = –H).
Fig. 7
Fig. 7. (a) Schematic representation of the formation of highly emissive host–guest complex 2′·PMB. (b) UV-visible spectra and photograph (H2O, r.t.) of 2′·PMB, 2′, and PMB (in CH3CN). (c) Optimized structure of 2′·PMB (R = –H, all-syn isomer). (d) Fluorescence spectrum (H2O, r.t., 80 μM based on 2′, λex = 500 nm) of 2′·PMB and its photograph (λex = 365 nm).
See this image and copyright information in PMC

References

    1. Mateu M. G. Arch. Biochem. Biophys. 2013;531:65–79. doi: 10.1016/j.abb.2012.10.015. - DOI - PubMed

    1. Representative examples:

    2. Meissner R. Mendoza J. d. Rebek Jr J. Science. 1995;270:1485–1488. doi: 10.1126/science.270.5241.1485. - DOI - PubMed
    3. MacGillivray L. R. Atwood J. L. Nature. 1997;389:469–472. doi: 10.1038/38985. - DOI
    4. Rebek Jr J. Acc. Chem. Res. 1999;32:278–286. doi: 10.1021/ar970201g. - DOI

    1. Representative examples:

    2. Tominaga M. Suzuki K. Kawano M. Kusukawa T. Ozeki T. Sakamoto S. Yamaguchi K. Fujita M. Angew. Chem., Int. Ed. 2004;43:5621–5625. doi: 10.1002/anie.200461422. - DOI - PubMed
    3. Sun Q.-F. Iwasa J. Ogawa D. Ishido Y. Sato S. Ozeki T. Sei Y. Yamaguchi K. Fujita M. Science. 2010;328:1144–1147. doi: 10.1126/science.1188605. - DOI - PubMed
    4. Fujita D. Ueda Y. Sato S. Mizuno N. Kumasaka T. Fujita M. Nature. 2016;540:563–566. doi: 10.1038/nature20771. - DOI - PubMed
    1. Debata N. B. Tripathy D. Chand D. K. Coord. Chem. Rev. 2012;256:1831–1945. doi: 10.1016/j.ccr.2012.04.001. - DOI
    2. Schmidt A. Casini A. Kühn F. E. Coord. Chem. Rev. 2014;275:19–36. doi: 10.1016/j.ccr.2014.03.037. - DOI

    1. For recent reviews:

    2. Harris K. Fujita D. Fujita M. Chem. Commun. 2013;49:6703–6712. doi: 10.1039/C3CC43191F. - DOI - PubMed
    3. Cook T. R. Stang P. J. Chem. Rev. 2015;115:7001–7045. doi: 10.1021/cr5005666. - DOI - PubMed
    4. Brown C. J. Toste F. D. Bergman R. G. Raymond K. N. Chem. Rev. 2015;115:3012–3035. doi: 10.1021/cr4001226. - DOI - PubMed
    5. Yoshizawa M. Yamashina M. Chem. Lett. 2017;46:163–171. doi: 10.1246/cl.160852. - DOI
    6. Vasdev R. A. S. Preston D. Crowley J. D. Chem.–Asian J. 2017;12:2513–2523. doi: 10.1002/asia.201700948. - DOI - PubMed
    7. Chen L.-J. Yang H.-B. Shionoya M. Chem. Soc. Rev. 2017;46:2555–2576. doi: 10.1039/C7CS00173H. - DOI - PubMed
    8. Chakraborty S. Newkome G. R. Chem. Soc. Rev. 2018;47:3991–4016. doi: 10.1039/C8CS00030A. - DOI - PubMed
    9. Sinha I. Mukherjee P. S. Inorg. Chem. 2018;57:4205–4221. doi: 10.1021/acs.inorgchem.7b03067. - DOI - PubMed
    10. Rizzuto F. J. von Krbek L. K. S. Nitschke J. R. Nat. Rev. Chem. 2019;3:204–222. doi: 10.1038/s41570-019-0085-3. - DOI
    11. Yoshizawa M. Catti L. Acc. Chem. Res. 2019;52:2392–2404. doi: 10.1021/acs.accounts.9b00301. - DOI - PubMed
    12. Sepehrpour H. Fu W. Sun Y. Stang P. J. J. Am. Chem. Soc. 2019;141:14005–14020. doi: 10.1021/jacs.9b06222. - DOI - PMC - PubMed
    13. Lewis J. E. M. Crowley J. D. ChemPlusChem. 2020;85:815–827. doi: 10.1002/cplu.202000153. - DOI - PubMed