Thiophene-Based Covalent Organic Frameworks: Synthesis, Photophysics and Light-Driven Applications

Abstract

Porous crystalline materials, such as covalent organic frameworks (COFs), have emerged as some of the most important materials over the last two decades due to their excellent physicochemical properties such as their large surface area and permanent, accessible porosity. On the other hand, thiophene derivatives are common versatile scaffolds in organic chemistry. Their outstanding electrical properties have boosted their use in different light-driven applications (photocatalysis, organic thin film transistors, photoelectrodes, organic photovoltaics, etc.), attracting much attention in the research community. Despite the great potential of both systems, porous COF materials based on thiophene monomers are scarce due to the inappropriate angle provided by the latter, which hinders its use as the building block of the former. To circumvent this drawback, researchers have engineered a number of thiophene derivatives that can form part of the COFs structure, while keeping their intrinsic properties. Hence, in the present minireview, we will disclose some of the most relevant thiophene-based COFs, highlighting their basic components (building units), spectroscopic properties and potential light-driven applications.

A thienyl‐benzodithiophene‐based two‐dimensional conjugated covalent organic framework for fast photothermal conversion

“…The successful Schiff-base 2D polycondensation is confirmed by Fourier transform infrared (FT-IR) spectroscopy, where we observed the disappearance of the amine signals (3100-3600 cm À1 ) accompanied by the appearance of a new signal at 1581 cm À1 , which we assign to the C N stretching vibration (Figure 2A). This is further confirmed by solid-state 13 C cross-polarization magic-angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy, where the peak at $150 ppm can be attributed to the C atoms in the imine linkages (Figure 2B). Moreover, the predicted 13 C NMR spectrum in Figure S3 agrees well with the experimental result.…”

“…This is further confirmed by solid-state 13 C cross-polarization magic-angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy, where the peak at $150 ppm can be attributed to the C atoms in the imine linkages (Figure 2B). Moreover, the predicted 13 C NMR spectrum in Figure S3 agrees well with the experimental result. X-ray photoelectron spectroscopy (XPS) displays the core levels of C 1s, N 1s and S 2p in BDT-BP-COF (Figure S4).…”

“…Chemical tunability in the porous conjugated polymer backbone has enabled 2D c ‐COFs for broad electronic, optoelectronic and electrochemical applications such as organic field‐effect‐transistors, 5 organic light‐emitting diodes, 6 organic solar cells, 3b,7 electrochromism, 8 photothermal conversion, 9 and so forth. Very recently, various electro−/photo‐active building blocks such as pyrene, 10 porphyrin, 11 phthalocyanine, 1b isoindigo, 8,12 thiophene and its derivatives (bithiophene, thienothiophene, benzodithiophene (BDT)) 4c,13 have been incorporated into the 2D c ‐COF backbone. This has enabled nontrivial chemical and physical features such as electrical conductivity with high charge carrier mobility, photoactivity, and anisotropic charge transport 14 .…”

Ruthenium nanoparticles on covalent triazine frameworks incorporating thiophene for the electrocatalytic hydrogen evolution reaction

“…38 Various studies concerning thiophene-containing CTFs are published, since the triazine moiety as an electron withdrawing group together with electron donating thiophene could constitute donor-acceptor (DA) polymers with low band gap and improved conductivity. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] The primary route of CTF synthesis, the cyclotrimerization of oligo-nitrile precursors, is achieved via various ways, like ionothermal (ZnCl 2 ) or superacid-catalyzed polymerization, or amide condensation. Each way offers different advantages depending on the desired properties and intended applications.…”

Thiophenes—Naturally Occurring Plant Metabolites: Biological Activities and In Silico Evaluation of Their Potential as Cathepsin D Inhibitors

“…In our previous review, 96 natural thiophene derivatives were listed from various plant species belonging to the Asteraceae family till 2015, with a particular focus on their biosynthesis, bioactivities, and physical and spectral data [8]. Recently, several reviews dealing with synthetic thiophene-based derivatives, including their anti-inflammation and anticancer potentials, spectroscopic properties, and synthesis, were published [21][22][23][24]. On the other side, there is no available review on naturally occurring thiophene derivatives from plant sources.…”