Tarun Kumar Sahu

Amorphous coordination polymers offer distinct advantages over crystalline frameworks owing to their structural flexibility, high density of accessible coordination sites, and defect tolerance. Yet precise control over their nanoscale growth and dispersion remains a fundamental challenge. Herein, we report a biomolecule-driven supramolecular templating strategy for the generation of amorphous coordination polymer nanodot-embedded hydrogel. A guanosine monophosphate-based G-quadruplex supramolecular architecture, co-assembled with gallic acid, serves as an active template that spatially confines metal–polyphenol coordination. Upon Fe3+ incorporation, this supramolecular scaffold directs the formation of ultrasmall, uniformly dispersed coordination polymer nanodots, in contrast to the uncontrolled aggregation observed in non-templated systems. Spectroscopic and electrochemical analyses reveal that supramolecular confinement stabilizes mixed-valence Fe2+/Fe3+ species and enhances ligand-to-metal charge transfer, imparting efficient photothermal conversion under visible-light irradiation. As a proof-of-concept, the resulting hybrid material is shown to be an effective photothermal catalyst for solvent-free cycloaddition of CO2 to epoxides under ambient pressure, delivering cyclic carbonates with high efficiency. This work establishes G-quadruplex assembly as a versatile platform for regulating size-controlled growth of coordination polymers and highlights the functional advantages of biomolecular confinement for sustainable catalytic transformations.

Manipulating the coordination environment through hetero‐ligand incorporation induces controlled defects at catalytically active sites, offering a powerful route to regulate electronic structure and reactivity. Here, we present a supramolecular approach to defect engineering within a soft hydrogel matrix by confining a Bi ³⁺ ‐caffeic acid complex within a guanosine monophosphate‐based G‐quadruplex hydrogel. This confinement not only breaks local coordination symmetry and generates oxygen‐vacancy‐rich heterojunctions but also emulates the active‐site environments of enzymes. The G‐quadruplex fibrillar scaffold provides ion‐channel‐like pathways that facilitate charge transport, enhance substrate diffusion, and promote selective adsorption, while confinement ensures the uniform dispersion of catalytic sites. Together, these synergistic effects result in an exceptional N ₂ to NH ₃ conversion of 905.2 µmol h ⁻¹ g ⁻¹ _(cat) under visible light irradiation, 3.8 times higher than that of the pristine complex. This work introduces a versatile strategy that integrates defect engineering, heterojunction formation, and biomimetic confinement within a soft supramolecular assembly, establishing G‐quadruplex hydrogels as a powerful platform for sustainable photocatalytic nitrogen fixation and beyond.

Conductive polymer hydrogels combine the electrical conductivity of organic polymers with the high water content, porosity, and tissue-mimicking properties of hydrogels, making them ideal for bioelectronic interfaces. However, traditional polymer matrices often lack biocompatibility, self-healing ability, dynamic reconfigurability, and tunable mechanical properties. To address these challenges, herein we report a dimeric guanosine monophosphate (GMP)-based supramolecular hydrogel that self-assembles into a fibrillar network with intrinsic peroxidase-mimetic activity in a metal-free, microconfined environment. This unique catalytic property enables the in situ oxidative polymerization of aniline into polyaniline nanofibers, forming a hybrid conductive hydrogel with excellent mechanical strength, self-healing capability, stimuli-responsive sol-gel transitions, and high ionic conductivity. The resulting hydrogel was used to fabricate electrochromic energy-storing electrodes and "all-solid-state" supercapacitors with high capacitance (343 mF cm^-2) and energy density (93.36 Wh cm^-2). This work highlights the potential of small biomolecules as artificial enzyme mimics and structural matrices for transforming biomolecular self-assemblies into functionally conductive hydrogels. The integration of biomolecules for enzyme-mimetic catalysis for generating the conducting polymer hydrogels might provide a versatile platform for advancing bioelectronic technologies.