Conjugated microporous polymers (CMPs) are a unique class of materials that combine extended π-conjugation with a permanently microporous skeleton. Since their discovery in 2007, CMPs have become established as an important subclass of porous materials. A wide range of synthetic building blocks and network-forming reactions offers an enormous variety of CMPs with different properties and structures. This has allowed CMPs to be developed for gas adsorption and separations, chemical adsorption and encapsulation, heterogeneous catalysis, photoredox catalysis, light emittance, sensing, energy storage, biological applications, and solar fuels production. Here we review the progress of CMP research since its beginnings and offer an outlook for where these materials might be headed in the future. We also compare the prospect for CMPs against the growing range of conjugated crystalline covalent organic frameworks (COFs).

Advances in Conjugated Microporous Polymers.

Recent progress in metal-organic frameworks-based hydrogels and aerogels and their applications

We have developed model light-emitting metallogels functionalized with lanthanide metal-ligand coordination complexes via a terpyridyl-end-capped four-arm poly(ethylene glycol) polymer. The optical properties of these highly luminescent polymer networks are readily modulated over a wide spectrum, including white-light emission, simply by tuning of the lanthanide metal ion stoichiometry. Furthermore, the dynamic nature of the Ln-N coordination bonding leads to a broad variety of reversible stimuli-responsive properties (mechano-, vapo-, thermo-, and chemochromism) of both sol-gel systems and solid thin films. The versatile functional performance combined with the ease of assembly suggests that this lanthanide coordination polymer design approach offers a robust pathway for future engineering of multi-stimuli-responsive polymer materials.

White-Light-Emitting Lanthanide Metallogels with Tunable Luminescence and Reversible Stimuli-Responsive Properties.

With the ambition of solving the challenges of the shortage of fossil fuels and their associated environmental pollution, visible-light-driven splitting of water into hydrogen and oxygen using semiconductor photocatalysts has emerged as a promising technology to provide environmentally friendly energy vectors. Among the current library of developed photocatalysts, organic conjugated polymers present unique advantages of sufficient light-absorption efficiency, excellent stability, tunable electronic properties, and economic applicability. As a class of rising photocatalysts, organic conjugated polymers offer high flexibility in tuning the framework of the backbone and porosity to fulfill the requirements for photocatalytic applications. In the past decade, significant progress has been made in visible-light-driven water splitting employing organic conjugated polymers. The recent development of the structural design principles of organic conjugated polymers (including linear, crosslinked, and supramolecular self-assembled polymers) toward efficient photocatalytic hydrogen evolution, oxygen evolution, and overall water splitting is described, thus providing a comprehensive reference for the field. Finally, current challenges and perspectives are also discussed.

Recent Advances in Conjugated Polymers for Visible‐Light‐Driven Water Splitting

The rapid detection of antibiotics and organic explosives has gradually garnered great attention, due to concerns about sustainability and the environment. In this work, a luminescent Tb-based metal organic gel (MOG(Tb) gel) was prepared by Al-based MOG induced in situ replacement of Al3+ with Tb3+. Remarkably, the strong emission of the post-synthesized MOG(Tb) xerogel can be quenched efficiently by using trace amounts of sulfamethazine (SMZ) and sulfadiazine (SDZ) even in the presence of other competing antibiotics. Furthermore, the MOG(Tb) xerogel has shown its application as a chemosensor for the highly selective detection of nitroaromatics such as 2,4-dinitrophenol (2,4-DNT) and 2,6-dinitrophenol (2,6-DNT). To further verify the recyclability of MOG(Tb), detection experiments were carried out with recovered xerogel to give a satisfactory result.

A water-stable Tb(III)-based metal–organic gel (MOG) for detection of antibiotics and explosives

Coordination polymer gels: soft metal–organic supramolecular materials and versatile applications

Tunable emission in lanthanide coordination polymer gels based on a rationally designed blue emissive gelator

The process of assembling astutely designed, well-defined metal-organic cube (MOC) into hydrogel by using a suitable molecular binder is a promising method for preparing processable functional soft materials Here, we demonstrate charge-assisted H-bonding driven hydrogel formation from Ga3+-based anionic MOC ((Ga8(ImDC)12)12−) and molecular binders, like, ammonium ion (NH4+), N-(2-aminoethyl)-1,3-propanediamine, guanidine hydrochloride and β-alanine The morphology of the resulting hydrogel depends upon the size, shape and geometry of the molecular binder Hydrogel with NH4+ shows nanotubular morphology with negative surface charge and is used for gel-chromatographic separation of cationic species from anionic counterparts Furthermore, a photo-responsive luminescent hydrogel is prepared using a cationic tetraphenylethene-based molecular binder (DATPE), which is employed as a light harvesting antenna for tuning emission colour including pure white light This photo-responsive hydrogel is utilized for writing and preparing flexible light-emitting display A possible route to producing processable soft materials is by assembling metal organic cubes into hydrogels Here the authors show charge-assisted H-bond driven self-assembly of Ga3+-based anionic metal organic cubes and suitable molecular binders towards multi-functional hydrogels

/pdf/binder-driven-self-assembly-of-metal-organic-cubes-towards-4p5y3qmjqh.pdf

Binder driven self-assembly of metal-organic cubes towards functional hydrogels.

Bandgap engineering in donor-acceptor conjugated microporous polymers (CMPs) is a potential way to increase the solar-energy harvesting towards photochemical water splitting. Here, the design and synthesis of a series of donor-acceptor CMPs [tetraphenylethylene (TPE) and 9-fluorenone (F) as the donor and the acceptor, respectively], F0.1 CMP, F0.5 CMP, and F2.0 CMP, are reported. These CMPs exhibited tunable bandgaps and photocatalytic hydrogen evolution from water. The donor-acceptor CMPs exhibited also intramolecular charge-transfer (ICT) absorption in the visible region (λmax =480 nm) and their bandgap was finely tuned from 2.8 to 2.1 eV by increasing the 9-fluorenone content. Interestingly, they also showed emissions in the 540-580 nm range assisted by the energy transfer from the other TPE segments (not involved in charge-transfer interactions), as evidenced from fluorescence lifetime decay analysis. By increasing the 9-fluorenone content the emission color of the polymer was also tuned from green to red. Photocatalytic activities of the donor-acceptor CMPs (F0.1 CMP, F0.5 CMP, and F2.0 CMP) are greatly enhanced compared to the 9-fluorenone free polymer (F0.0 CMP), which is essentially due to improved visible-light absorption and low bandgap of donor-acceptor CMPs. Among all the polymers F0.5 CMP with an optimum bandgap (2.3 eV) showed the highest H2 evolution under visible-light irradiation. Moreover, all polymers showed excellent dispersibility in organic solvents and easy coated on the solid substrates.

Regulating Charge‐Transfer in Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution

The recent upsurge in research on coordination polymer gels (CPGs) stems from their synthetic modularity, nanoscale processability, and versatile functionalities. Here we report self-assembly of an amphiphilic, tripodal low-molecular weight gelator (L) that consists of 4,4′,4-[1,3,5-phenyl-tri(methoxy)]-tris-benzene core and 2,2′:6′,2″-terpyridyl termini, with different metal ions toward the formation of CPGs that show controllable nanomorphologies, tunable emission, and stimuli–responsive behaviors. L can also act as a selective chemosensor for ZnII with very low limit of detection (0.18 ppm) in aqueous medium. Coordination-driven self-assembly of L with ZnII in H2O/MeOH solvent mixture results in a coordination polymer hydrogel (ZnL) that exhibits sheet like morphology and charge-transfer emission. On the other hand, coordination of L with TbIII and EuIII in CHCl3/tetrahydrofuran solvent mixture results in green- and red-emissive CPGs, respectively, with nanotubular morphology. Moreover, precise stoichi...

Papri Sutar

Papers

Coordination polymer gels: soft metal–organic supramolecular materials and versatile applications

Tunable emission in lanthanide coordination polymer gels based on a rationally designed blue emissive gelator

Binder driven self-assembly of metal-organic cubes towards functional hydrogels.

Regulating Charge‐Transfer in Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution

Coordination Polymer Gels with Modular Nanomorphologies, Tunable Emissions, and Stimuli-Responsive Behavior Based on an Amphiphilic Tripodal Gelator.