Recent trends and challenges for the emerging materials class of microporous polymers are reviewed. See the main article for graphical abstract image credits.

Recently, covalent organic frameworks (COFs) have emerged as an interesting class of porous materials, featuring tunable porosity and fluorescence properties based on reticular construction principles. Some COFs display highly emissive monocolored luminescence, but attaining white-light emission from COFs is difficult as it must account for a wide wavelength range. White-light emission is highly desired for solid-state lighting applications, and obtaining it usually demands the combination of red-, green-, and blue-light components. Hence, to achieve the targeted white-light emission, we report for the first time grafting of lanthanides (Eu 3+ /Tb 3+ ) on a two-dimensional imine COF (TTA-DFP-COF). We studied the luminescence properties of the hybrid materials prepared by anchoring Eu 3+ (red light) and Tb 3+ (green light) β-diketonate complexes onto the TTA-DFP-COF. Reticular construction is exploited to design strong coordination of Eu 3+ and Tb 3+ ions into nitrogen-rich pockets of the imine COF. Mixed Eu 3+ /Tb 3+ materials are then prepared to incorporate red and green components along with the inherent blue light from the organic moieties of the COF to produce white-light emission. We show that COFs have the potential for hosting Eu 3+ and Tb 3+ complexes, which can be tuned to obtain desired excitations for applications in the field of optoelectronics, microscopy, optical sensing, and bioassay.

We present, for the first time, covalent triazine frameworks functionalized with acetylacetonate group (acac-CTFs). They are obtained from the polymerization of 4,4′-malonyl­dibenzonitrile under ionothermal conditions and exhibit BET surface areas up to 1626 m2/g. The materials show excellent CO2 uptake (3.30 mmol/g at 273 K and 1 bar), H2 storage capacity (1.53 wt % at 77 K and 1 bar), and a good CO2/N2 selectivity (up to 46 at 298 K). The enhanced CO2 uptake value and good selectivity are due to the presence of dual polar sites (N and O) throughout the material. In addition, acac-CTF was used to anchor VO­(acac)2 as a heterogeneous catalyst. The V@acacCTF showed outstanding reactivity and reusability for the modified Mannich-type reaction with a higher turnover number than the homogeneous catalyst. The higher reactivity and reusability of the catalyst come from the coordination of the vanadyl ions to the acetyl acetonate groups present in the material. The strong metalation is confirmed from Fourier transform infrared analysis, 13C MAS NMR spectral analysis, and X-ray photoelectron spectroscopy measurement. Detailed characterization of the V@acac-CTF reveals that electron donation from O∧O of the acetylacetonate group to VO­(acac)2, combined with the very high surface area of acac-CTF, is responsible for the stabilization of the catalyst. Overall, this contribution highlights the necessity of stable catalytic binding sites on heterogeneous supports to fabricate greener catalysts for sustainable chemistry.

Mesoporous graphitic carbon nitride (mpg-C3 N4 ) was found to be an efficient heterogeneous photocatalyst for the metal-free radical cyclization of 2-bromo-1,3-dicarbonyl compounds. Reactions leading to functionalized cyclopentanes proceed under mild conditions and can be conducted in a continuous flow photoreactor. Compared to the batch reaction, the use of a continuous flow reactor resulted in a significant reduction in reaction time (complete conversion of 0.04 mmol of substrate in a batch was achieved after 4 h, whereas in a flow reactor the same amount of substrate was fully converted into a product within 40 min). Mechanistic studies of the reaction showed that THF plays not only the role of solvent, but is also a crucial hydrogen and electron donor.

An iridium dihydride pincer complex [IrH 2-(POCOP)] is immobilized in a hydroxy-functionalized microporous polymer network using the concepts of surface organometallic chemistry. The introduction of this novel, truly innocent support with remote OH-groups enables the formation of isolated active metal sites embedded in a chemically robust and highly inert environment. The catalyst maintained high porosity and without prior activation exhibited efficacy in the gas phase hydrogenation of ethene and propene at room temperature and low pressure. The catalyst can be recycled for at least four times.

Lithium‐sulphur (Li−S) batteries are a promising alternative power source, as they can provide a higher energy density than current lithium‐ion batteries. Porous materials are often used as cathode materials as they can act as a host for sulphur in such batteries. Recently, covalent organic frameworks (COFs) have also been used, however they typically suffer from stability issues, resulting in limited and thus insufficient durability under practical conditions and applications. Herein, we report the synthesis of a crystalline and porous imine‐linked triazine‐based dimethoxybenzo‐dithiophene functionalized COF (TTT‐DMTD) incorporating high‐density redox sites. The imine linkages were further post‐synthetically transformed to yield a robust thiazole‐linked COF (THZ‐DMTD) by utilizing a sulphur‐assisted chemical conversion method, while maintaining the crystallinity. As a synergistic effect of its high crystallinity, porosity and the presence of redox‐active moieties, the thiazole‐linked THZ‐DMTD exhibited a high capacity and long‐term stability (642 mAh g−1 at 1.0 C; 78.9 % capacity retention after 200 cycles) when applied as a cathode material in a Li−S battery.

An iridium dihydride pincer complex [IrH 2-(POCOP)] is immobilized in a hydroxy-functionalized microporous polymer network using the concepts of surface organometallic chemistry. The introduction of this novel, truly innocent support with remote OH-groups enables the formation of isolated active metal sites embedded in a chemically robust and highly inert environment. The catalyst maintained high porosity and without prior activation exhibited efficacy in the gas phase hydrogenation of ethene and propene at room temperature and low pressure. The catalyst can be recycled for at least four times.

The use of a flow reactor significantly reduces the reaction time.