Solid state chemical transformations through ring-opening polymerization of ferrocene-based conjugated microporous polymers in host-guest complexes with benzoxazine-linked cyclodextrin

Herein, we describe two ferrocene-derived conjugated microporous polymers (FFC-CMPs) prepared through Sonogashira couplings of 9-ferrocenylidene-2,7-dibromo-9H-fluorene (FFC) with tetraethynylpyrene (Py-T) and tetrakis(4-ethynylphenyl)ethene (TPE-T), respectively, and their properties determined using various spectroscopic techniques. These two FFC CMPs formed inclusion complexes (ICs) with a benzoxazine-linked beta-cyclodextrin (CD-BZ), with host-guest interactions occurring between the ferrocene and beta-CD units. We used Fourier transform infrared spectroscopy, X-ray diffraction, two-dimensional nuclear Overhauser enhancement NMR spectroscopy, solid-state beta-C CP/MAS NMR spectroscopy, and thermogravimetric analysis to characterize these FFC-CMP/CD-BZ ICs. The BZ units in the FFC-CMP/CD-BZ ICs underwent thermal ring-opening polymerization to form new Mannich bridges featuring both intermolecular (OH center dot center dot center dot O) and intramolecular (OH center dot center dot center dot N) hydrogen bonds; the resulting TPE-FFC-CMP/poly(CD-BZ) and Py-FFC-CMP/poly (CD-BZ) ICs exhibited outstanding thermal stability, with the latter having the higher CO2 uptake ability (1.42 mmol g(-1)) and capacitance (46 F g(-1) at 0.5 A g(-1)). Background: Host-guest complexes formed from macrocyclic hosts possessing hydrophobic cavities such as cyclodextrins (CDs) and various guest molecules have been studied widely for their fascinating characteristics. The interaction of ferrocene-containing CMPs with hydrophobic cavities of CDs to form inclusion complexes materials with excellent thermal properties and these materials can be used in different fields including energy storage and gas capture. Methods: Two ferrocene-based fluorene CMPs-TPE-FFC CMP and Py-FFC-CMP-through Sonogashira couplings of 9-ferrocenylidene-2,7-dibromo-9H-fluorene (FFC), as the main block, with tetraethynylpyrene (PyT) and tetrakis(4-ethynylphenyl)ethene (TPE-T), were successfully synthesized through Sonogashira couplings. Then, the two FFC CMPs were attached to a benzoxazine-functionalized beta-cyclodextrin (CD-BZ) through host-guest complexation. The successful synthesis of two FFC CMPs and FFC-CMP/CD-BZ ICs was investigated by using Fourier transform infrared spectroscopy, X-ray diffraction, two-dimensional nuclear Overhauser enhancement NMR spectroscopy, solid-state C-13 CP/MAS NMR spectroscopy, and thermogravimetric analysis. Significant Findings: The present work offers a new and facile strategy for the preparation CMPs/CD inclusion complexes through supramolecular chemistry and using these materials as an electrode in the energy devices and CO2 uptake. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, two ferrocene-derived conjugated microporous polymers (FFC-CMPs) were prepared and formed inclusion complexes with a benzoxazine-linked beta-cyclodextrin (CD-BZ). The properties of these FFC-CMP/CD-BZ complexes were characterized using various spectroscopic techniques. The complexes exhibited outstanding thermal stability and CO2 uptake ability.