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Porous covalent organic nanotubes and their assembly in loops and toroids

A Publisher Correction to this article was published on 22 April 2022

This article has been updated


Carbon nanotubes, and synthetic organic nanotubes more generally, have in recent decades been widely explored for application in electronic devices, energy storage, catalysis and biosensors. Despite noteworthy progress made in the synthesis of nanotubular architectures with well-defined lengths and diameters, purely covalently bonded organic nanotubes have remained somewhat challenging to prepare. Here we report the synthesis of covalently bonded porous organic nanotubes (CONTs) by Schiff base reaction between a tetratopic amine-functionalized triptycene and a linear dialdehyde. The spatial orientation of the functional groups promotes the growth of the framework in one dimension, and the strong covalent bonds between carbon, nitrogen and oxygen impart the resulting CONTs with high thermal and chemical stability. Upon ultrasonication, the CONTs form intertwined structures that go on to coil and form toroidal superstructures. Computational studies give some insight into the effect of the solvent in this assembly process.

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Fig. 1: Design and synthesis of covalent organic nanotubes.
Fig. 2: Characterization of nanotubes.
Fig. 3: Intertwining of the CONTs.
Fig. 4: Stability of CONT-1.
Fig. 5: Multiscale molecular models of the CONT-1 system.
Fig. 6: Characterization of toroidal structures.

Data availability

All data supporting the findings of this study, including synthesis, experimental procedures and compound characterization, are available within the article and its Supplementary Information. Structure and parameter files for the AA and CG models of the CONT-1 tubules used in the simulations are available at (ref. 40) Supplementary Information is available in the online version of the paper. Reprints and permissions information is available online at Correspondence and requests for materials should be addressed to R.B. Source data are provided with this paper.

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K.K. acknowledges University Grants Commission for a senior research fellowship, and Shayan Karak acknowledges IISER Kolkata for an Integrated PhD fellowship. R.B. acknowledges funding from the DST-Swarna Jayanti Fellowship grant (DST/SJF/CSA-02/2016–2017), DST Mission Innovation (DST/TM/EWO/MI/CCUS/17 and DST/TMD(EWO)/IC5-2018/01(C)) and DST SERB (CRG/2018/000314). G.M.P. acknowledges funding received from the Swiss National Science Foundation (grants IZLIZ2_183336) and the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement number 818776–DYNAPOL). We thank G. Sheet for collecting the AFM data and P.R. Rajamohanan for discussion about the NMR results. G.M.P., L.L., C.P., R.C. and L.P. also acknowledge the computational resources provided by the Swiss National Supercomputing Center and by CINECA. We thank C. Empereur-Mot and A. Cardellini for useful discussions. M.M. and M.B. acknowledge a DST-Swarna Jayanti Fellowship grant (DST/SJF/PSA01/2015-16).

Author information

Authors and Affiliations



K.K., Sharath Kandambeth and R.B. designed and choose the building blocks. K.K. and Shayan Karak synthesized all the materials. K.K. performed the SEM, TEM and AFM. N.T. and T.G.A. perfomed the solid-state NMR. M.M. and M.B. collected the AFM images in Fig. 1 and Supplementary Fig. 15. Sharath Kandambeth constructed the nanotube architecture. C.P., L.L., L.P., R.C. and G.M.P. undertook the theoretical calculation of intertwining and the role of the solvents. K.K., Sharath Kandambeth, Suvendu Karak and R.B. planned all the experiments. R.B. supervised the whole project. K.K., Sharath Kandambeth, Suvendu Karak and R.B. analysed all the results and co-wrote the manuscript with input from all co-authors.

Corresponding authors

Correspondence to Suvendu Karak, Giovanni M. Pavan or Rahul Banerjee.

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Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Chemistry thanks Ramesh Jasti, Peyman Moghadam and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–41, discussion and Tables 1 and 2.

Supplementary Video 1

Coarse-grained model for intertwined CONT-1.

Supplementary Video 2

Model for CONT-1 in DCM.

Supplementary Video 3

Model for CONT-1 in water.

Supplementary Video 4

Zoomed video of CONT-1 in DCM.

Supplementary Video 5

Zoomed video of CONT-1 in water.

Supplementary Data 1

Source data for Supplementary Fig. 12: pore size distribution of CONT-1 from N2 adsorption isotherm.

Supplementary Data 2

Source data for Supplementary Fig. 26: DLS study for toroids.

Supplementary Data 3

Source data for Supplementary Fig. 31: calculation of yield of toroids.

Source data

Source Data Fig. 2

The Excel sheet contains FTIR data, solid state 13C NMR, solid state 13C HPDEC NMR, N2 adsorption isotherm and pore size distribution of CONT-1.

Source Data Fig. 4

N2 adsorption isotherm of pristine CONT-1 and CONT-1 after water treatment (immersed in water) for 7 days.

Source Data Fig. 5

Angle 1 and angle 2 distribution for CONT-1 in DCM, THF, water and vacuum.

Source Data Fig. 6

DLS data for toroids and histogram plot for radius of toroids from SEM images.

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Koner, K., Karak, S., Kandambeth, S. et al. Porous covalent organic nanotubes and their assembly in loops and toroids. Nat. Chem. 14, 507–514 (2022).

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