The self-assembly of small molecules with a suitable metal ion is a critical bottom-up approach for preparing solution-processable metallo-supramolecular polymers and to realize their potential as a photocatalyst. Herein, we report the design, synthesis, self-assembly, and gelation behavior of a low-molecular-weight gelator (LMWG) based on a pyrene core connected to four terpyridine units (TPY-PY) through amide linkages. TPY-PY forms an organogel (OG) in the DMSO/H2O mixed solvent with a nanofibrillar morphology. In contrast, the introduction of RuII with the LMWG resulted in a Ru-TPY-PY coordination polymer gel (CPG) with a cross-linked fibrillar nanostructure with a length of several micrometers. The Ru-TPY-PY CPG exhibited highly efficient photoreduction of CO2 to CO (yield: 10.79 mmol g-1, rate: 899.17 mu mol g-1 h-1) with 90% selectivity, under visible light irradiation, and in the presence of triethylamine (TEA) as a sacrificial electron donor. Moreover, metallo-supramolecular polymers with diverse nanomorphologies, formed at different RuII to TPY-PY ratios, showed different efficiencies in the photo reduction of CO2 to CO. Among these nanostructures, 1D nanofibers exhibited enhanced photocatalytic activity compared to the nanospheres for CO2 reduction, attributed to the abundance of catalytically active sites on their surface with facile CO2 diffusion capabilities. Furthermore, femtosecond transient absorption spectroscopy, in situ DRIFTS analysis, and DFT calculation help to understand the feasibility of the electron transfer pathway, and reaction mechanism in the overall process. The "soft" processable hybrid metal-organic supramolecular polymers that integrate both the catalytic site and the light-absorbing units are a class of catalysts showing efficient CO2 photoreduction to CO.

The intensifying climate emergency compels a rapid paradigm shift from fossil fuel-based energy systems toward sustainable, carbon-neutral alternatives. Among emerging strategies, the photocatalytic valorization of CO2 into energy-dense fuels and commodity chemicals by suitable photocatalysts presents a straightforward and economically viable solution for both greenhouse gas mitigation and renewable energy storage. In this context, covalent organic frameworks (COFs) have emerged as a highly promising class of crystalline, porous semiconductor photocatalysts for CO2 reduction reactions (CO2RR), owing to their structural regularity, modularity, and optoelectronic tunability. In this review, we comprehensively outline the recent progress in three distinct categories of COF-based photocatalytic systems: metal-free COFs, single-metal-atom based COFs, and COF-based composites. Key strategies such as the judicious incorporation of donor-acceptor architectures, rational post-synthetic functionalization, and heterojunction engineering are discussed. Insights from in situ operando characterization and theoretical calculations are also presented to highlight the roles of exciton dynamics, charge separation, active site engineering, and structure-function relationship in CO2RR. Finally, we propose future research directions for better utilization of COFs in solar fuel/chemical generation. Overall, this review aims to provide a comprehensive discussion on the advancement of COF-based photocatalysts and next-generation CO2 valorization materials.

ABSTRACT Developing a single material capable of driving simultaneous photoelectrochemical (PEC) water oxidation and dark CO 2 reduction offers an appealing strategy for solar‐fuel production, yet remains largely unexplored in soft metallo‐supramolecular systems. Herein, a porphyrin‐based Ni(II)‐coordinated metallo‐supramolecular gel (Ni‐CPG) is developed as a dual‐functional catalyst for PEC applications. In the PEC cell, Ni‐CPG enables visible‐light‐driven water oxidation acting as a photoanode. To boost the water oxidation performance, a TiO 2 electron‐transporting layer (ETL) was integrated with Ni‐CPG, creating a type‐II heterojunction (TiO 2 /Ni‐CPG) that facilitates interfacial charge separation and transport. Kelvin probe force microscopy (KPFM) and Mott‐Schottky analysis confirm a facile electron transfer pathway from Ni‐CPG to TiO 2 . The resulting hybrid photoanode delivered a remarkable photocurrent density (∼121.96 µA.cm −2 at 1.23 V vs. RHE), representing a ∼203‐fold improvement over pristine Ni‐CPG, with charge transfer efficiency exceeding 63%. In a H‐type PEC cell, Ni‐CPG is employed as heterojunction photoanode and dark cathode simultaneously, achieving a Faradaic efficiency >94% for selective CO 2 ‐to‐CO conversion at 1.57 V versus RHE. Furthermore, in‐situ FTIR spectroscopy and DFT calculations unveiled the CO 2 reduction pathway and key intermediates. This study highlights the potential of metallo‐supramolecular polymer gel as a dual functional catalyst for water oxidation and dark CO 2 ‐to‐fuel production.

Photoelectrochemical (PEC) water splitting offers a promising solar-driven route for hydrogen production, but its efficiency is limited by poor semiconducting properties, sluggish kinetics, and high overpotential of the oxygen evolution reaction (OER). Herein, we explored a Ru-based coordination polymer gel (Ru-TTN-CPG), prepared by self-assembly of TTN low molecular weight gelator (TTN: naphthalenediimide (NDI) core connected with four terpyridine moieties through alkyl amide chains) with Ru2+ as a soft, processible hybrid photoanode material for PEC water oxidation. The crosslinked nanofibrous CPG promotes efficient photogenerated charge separation and transport while providing an abundant catalytic site, and the Ru-terpyridine units enable visible-light absorption through metal-to-ligand charge transfer. A type-II heterojunction photoanode is fabricated by introducing TiO2 as an electron-transporting layer, which facilitates charge separation, suppresses interface recombination, and significantly improves photocurrent density. Moreover, in situ FTIR spectroscopy reveals water oxidation on the Ru-TTN-CPG surface under illumination, enabling identification of key intermediates. Complementary in situ XAS measurements support oxidation state changes of the Ru2+-center under operating conditions, conclusively establishing Ru2+ as a catalytically active site. Guided by experimental observations, theoretical calculations elucidate the mechanistic pathway of water oxidation. Overall, this work highlights the potential of soft hybrid metallo-supramolecular polymers for advancing next-generation PEC energy-conversion systems.

This work demonstrates intrinsic lattice-driven chirality in CsPbBr3 nanorods, arising from strain-induced octahedral distortion, and fundamentally distinct from chiral-ligand-induced or molecule-driven chirality reported in most halide perovskites. The highly quantum-confined nanorods exhibit exceptionally large lattice strain nearly an order of magnitude higher than in previously reported systems which acts as the primary driving force for breaking local inversion symmetry. This strain-mediated symmetry breaking gives rise to strong circular dichroism (CD), natural circular dichroism (NCD), and robust polarization-dependent photoluminescence (PL), all persisting up to room temperature. Piezoresponse force microscopy confirms local ferroelectricity, magnetization measurement showed diamagnetic to superparamagnetic transition while magneto-optical measurements reveal nonlinear Zeeman response and zero-field magnetic signatures linked to the asymmetric chiral potential. Collectively, these results establish strain as a powerful route for inducing chirality, ferroelectricity, and magneto-optical coupling in achiral inorganic lattices, opening new pathways for chiral optoelectronics and spin-selective devices.

This study presents the development of a Co( ii ) single-atom-based conjugated microporous polymer, which achieves over 99% selectivity in CO 2 -to-CH 4 photoconversion, as supported by in situ DRIFTS and DFT studies.

Developing a single material capable of driving simultaneous photoelectrochemical (PEC) water oxidation and dark CO2 reduction offers an appealing strategy for solar-fuel production, yet remains largely unexplored in soft metallo-supramolecular systems. Herein, a porphyrin-based Ni(II)-coordinated metallo-supramolecular gel (Ni-CPG) is developed as a dual-functional catalyst for PEC applications. In the PEC cell, Ni-CPG enables visible-light-driven water oxidation acting as a photoanode. To boost the water oxidation performance, a TiO2 electron-transporting layer (ETL) was integrated with Ni-CPG, creating a type-II heterojunction (TiO2/Ni-CPG) that facilitates interfacial charge separation and transport. Kelvin probe force microscopy (KPFM) and Mott-Schottky analysis confirm a facile electron transfer pathway from Ni-CPG to TiO2. The resulting hybrid photoanode delivered a remarkable photocurrent density (∼121.96 µA.cm-2 at 1.23 V vs. RHE), representing a ∼203-fold improvement over pristine Ni-CPG, with charge transfer efficiency exceeding 63%. In a H-type PEC cell, Ni-CPG is employed as heterojunction photoanode and dark cathode simultaneously, achieving a Faradaic efficiency >94% for selective CO2-to-CO conversion at 1.57 V versus RHE. Furthermore, in-situ FTIR spectroscopy and DFT calculations unveiled the CO2 reduction pathway and key intermediates. This study highlights the potential of metallo-supramolecular polymer gel as a dual functional catalyst for water oxidation and dark CO2-to-fuel production.

Recent advancements in single-site heterogeneous catalysis have attracted immense attention due to molecular-level control over structure-support interactions. Herein, a high-surface-area, thermally stable Hf-MOF-808, {[Hf6(μ3-O)5(μ3-OH)3(H2O)2(BTC)2(HCOO)5]}n (Hf-MOF), is postmodified with catalytically active NiII sites, and the photosensitizing [Ru(MBA)(bpy)2]Cl2 (MBA: 2-(5'-methyl-[2,2'-bipyridin]-5 yl)acetic acid, bpy: 2,2'-bipyridine) moiety via covalent grafting to develop the single-integrated photocatalytic system named Hf-Ni-MBA-Ru-MOF. Postsynthetic NiII metalation in the secondary building unit (SBU) and its coordination environment are characterized by several techniques, including X-ray absorption spectroscopy (XAS). The catalyst showed highly selective multielectron-proton CO2 reduction to methanol, yielding 404 μmol·g-1 after 10 h of visible-light irradiation. The high selectivity and production rate depicted by Hf-Ni-MBA-Ru-MOF in aqueous media under visible light are highly promising for sustainable CO2 conversion. The confinement of the [Ru(MBA)(bpy)2]2+ photosensitizer inside the MOF enhances the lifetime of the photoexcited electron, thereby increasing the efficacy of the catalytic CO2 reduction by transferring the excited-state electron to catalytically active NiII centers grafted to the Hf6-SBU . The excited-state electron transfer to the catalytic NiII site is explored by femtosecond transient absorption spectroscopy (FSTA) analysis supported by density functional theory (DFT) calculations. Furthermore, the intermediates in the multielectron reduction of CO2 to methanol are identified by the in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy study.

This study establishes the participation of neighbouring electron-donating atoms in stabilizing the weakly adsorbed *CO intermediate, enabling metal-free photocatalytic CO 2 reduction beyond CO.

ABSTRACT Ferroelectricity has long been of great scientific interest due to its tremendous potential for information storage technologies and wide‐ranging applications. Metal‐organic frameworks (MOFs) or porous coordination polymers (PCPs), with their structural tunability and dynamic host‐guest chemistry, offer a powerful platform for engineering next‐generation ferroelectrics. However, progress in ferroelectric MOFs/PCPs has been limited by their intrinsically weak polarization, restricting the realization of non‐trivial switchable ferroelectricity feasible at room temperature. We address this limitation, reporting a series of flexible PCPs with mixed donor‐acceptor (D‐A) stacks designed to achieve room‐temperature ferroelectricity via strong charge‐transfer interactions. The 3D Zn‐based PCP, {[Zn( o ‐phen)(2,6‐ndc)]·DMF} n , having a supramolecular dynamic nano‐space for D‐A stacking, exhibits intrinsic flexibility that endows structural adaptation to the guest molecules of varying shape, size, and chemical nature. The encapsulation of electron‐rich aromatic amine guests like N , N ′‐dimethyl aniline and N , N ′‐dimethyl‐ p ‐toluidine results in the formation of extended D‐A stacks with acceptor motifs of the framework along a particular crystallographic axis. Peierls‐like distortion of these 1D extended D‐A stacks gives rise to spontaneous polarization, ultimately resulting in room‐temperature ferroelectricity. We furthermore show that the ferroelectric features of the PCP are closely related to the packing and geometry of the guest molecules incorporated.

Abstract The intensifying climate emergency compels a rapid paradigm shift from fossil fuel‐based energy systems toward sustainable, carbon‐neutral alternatives. Among emerging strategies, the photocatalytic valorization of CO 2 into energy‐dense fuels and commodity chemicals by suitable photocatalysts presents a straightforward and economically viable solution for both greenhouse gas mitigation and renewable energy storage. In this context, covalent organic frameworks (COFs) have emerged as a highly promising class of crystalline, porous semiconductor photocatalysts for CO 2 reduction reactions (CO 2 RR), owing to their structural regularity, modularity, and optoelectronic tunability. In this review, we comprehensively outline the recent progress in three distinct categories of COF‐based photocatalytic systems: metal‐free COFs, single‐metal‐atom based COFs, and COF‐based composites. Key strategies such as the judicious incorporation of donor–acceptor architectures, rational post‐synthetic functionalization, and heterojunction engineering are discussed. Insights from in situ operando characterization and theoretical calculations are also presented to highlight the roles of exciton dynamics, charge separation, active site engineering, and structure–function relationship in CO 2 RR. Finally, we propose future research directions for better utilization of COFs in solar fuel/chemical generation. Overall, this review aims to provide a comprehensive discussion on the advancement of COF‐based photocatalysts and next‐generation CO 2 valorization materials.

Introduction Hypothyroidism is a common side effect in head and neck cancer (HNC) patients treated with radiotherapy (RT). Conformal RT reduces the dose to normal tissues while delivering higher doses to tumors. However, hypothyroidism remains a significant toxicity in these patients. This study evaluates the incidence of hypothyroidism, thyroid dosimetric parameters, and their correlation with radiation-induced hypothyroidism in HNC patients treated with conformal RT at a regional cancer center in India. Methods Fifty patients with histologically confirmed squamous cell carcinoma of the head and neck, treated with conformal RT, and who underwent pre- and post-treatment thyroid function tests were included in the study. All patients were euthyroid before treatment. The thyroid gland was contoured retrospectively in the approved RT plan. The volume of the contoured thyroid gland and the thyroid dosimetric parameters (Dmean, Dmax, Dmin, and V30-V60) were recorded. Pre- and post-treatment thyroid function test results were compared to look for the incidence of hypothyroidism, and dosimetric data were compared to establish a relation with the incidence of hypothyroidism. Results The median age was 53 years. Most patients had oral cavity primaries (60%), stage III/IVA disease (86%), and received definitive (64%) or adjuvant (36%) RT. Two-thirds underwent concurrent chemotherapy. After a median follow-up of four months, 24% developed hypothyroidism, with a median onset of 16 weeks post-treatment. Pharyngeal primary and concurrent chemotherapy were significant risk factors. Dosimetric analysis revealed Dmean > 57 Gy, V55 > 80%, and V60 > 37% as predictors of hypothyroidism. Conclusion Pharyngeal cancers, concurrent chemoradiotherapy, and higher thyroid doses significantly increase the risk of hypothyroidism. Optimizing RT planning is essential to minimize thyroid toxicity, particularly in high-risk patients.

The production of green H2 fuel by photocatalytic water splitting has emerged as a potential solution to mitigate challenges related to the energy crisis. The inherent electric field generated within piezoelectric materials under mechanical stress offers a promising avenue for enhancing charge separation in photocatalysis through piezo-phototronic effect. Herein, we develop a photo-piezocatalyst leveraging [Ce6(µ3-O)4(µ3-OH)4(HCOO)6]6+ cluster modification via post-synthetic multistep integration of a donor-acceptor (D-A) dyad within Ce-based MOF-808 (Ce-MOF). This supramolecular D-A charge transfer (CT) complex inside the confined nanopore of Ce-MOF functions as an efficient light-harvesting unit. Concomitantly, light-mediated electron transfer from the CT complex, results in a mixed valence Ce4+/Ce3+ state  which creates local distortion within the Ce-oxo cluster, transitioning it from an ideal cubic state to a non-centrosymmetric configuration, giving rise to piezoelectric polarization. The synergistic interplay between piezoelectric polarization and enhanced CT driven light-harvesting capabilities culminates in an ultrahigh H2 production with a rate of 12.7 mmol g-1h-1, achieved through overall water splitting under photo-piezocatalytic conditions. This work not only highlights the immense potential of MOFs as efficient catalysts for water splitting but also paves the way for harnessing both solar and mechanical energy through photo-mediated piezocatalytic reactions.

Redox-active covalent organic frameworks (COFs) with metal binding sites are increasingly recognized for developing cost-effective, eco-friendly organic electrodes in rechargeable energy storage devices. Here, we report a microwave-assisted synthesis and characterization of a triazine-based polyimide COF that features dual redox-active sites (-C=O from pyromellitic and -C=N- from triazine) and COF@CNT nanocomposites (COF@CNT-X, where X=10, 30, and 50 wt % of NH2-MWCNT) formed through covalent linking with amino-functionalized multiwalled carbon nanotubes. These composites are evaluated as cathode materials for the sodium-ion batteries (SIBs). The amine functionalization renders the covalent bond between COF and CNT, improving electronic conductivity, structural rigidity, and long-term stability. The interfacial growth of COF layers on CNTs increases accessible redox-active sites, enhancing sodium diffusion kinetics during sodiation/desodiation. The COF@CNT-50 composite exhibits outstanding Na+ ion storage performance (reversible capacity of 164.3 mAh g-1 at 25 mA g-1) and excellent stability over 1000 cycles at ambient temperature. At elevated temperature (65 °C), it also maintains good capacity and cycle stability. Ex situ XPS analysis confirms the importance of dual active sites in the Na+ diffusion mechanism. Density functional theory (DFT) calculations reveal insights into Na+ binding sites and corresponding binding energies into COF structure, elucidating the experimental storage capacity and voltage profile.

Metal-organic frameworks (MOFs) with mixed proton and electron conductivity (MPEC) are promising materials for electrochemical energy systems, yet few examples merge these properties within a single phase. Here, we report a series of breathable 3D MOFs featuring mixed conduction with the general formula H12-M2-(DOBDP)3 (wherein M(Ill) = Fe, Al, SC, and In and H6-DOBDP = 2,5-dihydroxy-1,4-benzenediphosphonic acid). The metal-phosphonate nodes and uncoordinated phosphonate (P-OH) groups enable the structure dynamics as well as proton conductivity, assisted by water channels. High proton conductivity (1.6 x 10-4 S/cm) and moderate electron conductivity (8.3 x 10-7 S/cm) are measured for the hydrated state of the Fe-MOF phase, whereas the Al phase exhibits only proton conductivity, highlighting the critical role of the Fe center in enabling MPEC. These findings advance the understanding of dual-conductive MOFs and establish a framework for designing next-generation materials with combined ion and electron transport.

Piezocatalysis has emerged as a promising technique for the production of green H 2 fuel by harvesting mechanical energy. A metal‐free, highly porous covalent–organic framework (COF) as a piezocatalyst that produces H 2 at an ultra‐high rate of 6.6 mmol g −1 h −1 under ultrasonication is reported. This activity originates from the electron–hole carriers generated in “nested” nearly degenerate conduction and valence bands driving ferrielectric ordering of dipoles whose coupling with soft torsional phonons facilitates absorption of energy from the mechanical stress fields. Conformationally flexible donor tris(4‐aminophenyl)amine (TAPA) moiety in COF introduces soft torsional lattice modes that interact with pyromellitic dianhydride (PDA) acceptor to generate stress tunable dipoles and surface charges. As electron–hole pairs generated throughout the bulk ferrielectric are available at the pore surfaces of the COF, they are readily accessible to the water molecules to be split. The work provides a design concept based on donor–acceptor based frameworks showing conformational flexibility‐driven symmetry breaking for piezocatalysis.

The supramolecular self-assembly of peptides offers a promising avenue for both materials science and biological applications. Peptides have garnered significant attention in molecular self-assembly, forming diverse nanostructures with α-helix, β-sheet, and random coil conformations. These self-assembly processes are primarily driven by the amphiphilic nature of peptides and stabilized by non-covalent interactions, leading to complex nanoarchitectures responsive to environmental stimuli. While extensively studied in biomedical applications, including drug delivery and tissue engineering, their potential applications in the fields of piezoresponsive materials, conducting materials, catalysis and energy harvesting remain underexplored. This review comprehensively elucidates the diverse material characteristics and applications of self-assembled peptides. We discuss the multi-stimuli-responsiveness of peptide self-assemblies and their roles as energy harvesters, catalysts, liquid crystalline materials, glass materials and contributors to electrical conductivity. Additionally, we address the challenges and present future perspectives associated with peptide nanomaterials. This review aims to provide insights into the versatile applications of peptide self-assemblies while concisely summarizing their well-established biomedical roles that have previously been extensively reviewed by various research groups, including our group.

Developing photoelectrochemical catalysts to convert CO2 into chemical feedstocks presents a promising approach for clean energy storage by harnessing solar energy. This study examines the potential of a Zn-based coordination polymer gel (CPG), incorporating terpyridine (TPY) and tetrathiafulvalene (TTF) moieties (Zn-TPY-TTF CPG), for artificial photosynthesis. In this novel approach, Zn-TPY-TTF CPG serves as both photoanode and dark cathode material in a photoelectrochemical (PEC) cell. When combined with BiVO4 (BVO) nanostructures to fabricate a heterojunction photoanode, Zn-TPY-TTF CPG significantly enhances PEC water-oxidation, delivering a fourfold increase in photocurrent density at 0.6 V versus Ag/AgCl compared to pristine BVO. Kelvin Probe Force Microscopy (KPFM) confirms improved carrier separation and transport due to favorable band alignment between BVO and Zn-TPY-TTF CPG. PEC CO2 reduction experiments in an H-cell demonstrate a remarkable 43% Faradaic efficiency for ethanol production at 1.4 V versus Ag/AgCl. The simultaneous water-oxidation and CO2 reduction capabilities of Zn-TPY-TTF CPG position it as a highly promising candidate for solar energy conversion. Operando FTIR and Raman spectroscopy reveal crucial reaction intermediates, while Density Functional Theory (DFT) calculations provide deeper insights into ethanol formation. This study highlights the potential of Zn-TPY-TTF CPG-based PEC cells to mimic natural photosynthesis and produce valuable chemical products.

Photochromic soft metallo-supramolecular materials undergo precise, reversible transformations in structure and electronic properties under light irradiation, offering potential applications in optoelectronics, sensing, and molecular switches. Herein, we report the synthesis, characterization, and investigation of light-induced reversible morphological transformations in a Zn(II)-based photochromic coordination polymer gel (Zn-pcCPG), integrated with a dithienylethene (DTE) unit. Upon UV irradiation (λ = 365 nm), Zn-pcCPG undergoes morphological transformation from nanofibers in the gel state to spherical nanoparticles in the sol state, involving reversible photoswitching with distinct color change. To explore the charge transport properties of these metallo-supramolecular polymers, we created a EGaIn/GaOX//Zn-pcCPG//AuTS junction using the nanostructures of Zn-pcCPG on a template-stripped gold substrate (AuTS) and a soft conformal EGaIn as the top electrode. These measurements show a reversible conductance photoswitching between the "open" and "closed" states of the coordination polymer gel containing a DTE core with an on/off ratio of ≈58 at -1 V. Additionally, we have also demonstrated the on-surface photoswitching of morphology and conductance properties. Interestingly, thermoelectric property measurements reveal a HOMO-dominated charge transport for both "open" and "closed" forms of Zn-pcCPG, with a reversible thermopower switching from +163 μV/K (open form) to +21 μV/K (closed form) and vice versa. By employing UV-Vis and ultraviolet photoelectron spectroscopy measurements, we have explained the experimental conductance and thermopower trends. This is the first study to demonstrate reversible conductance and thermopower switching with morphological transitions in a photochromic coordination polymer gel (pcCPG), paving the way for advancements in CPG-based supramolecular electronics.