Publications by authors named "Chandrasekhar Naisa"

The chemistry of the on-water surface, characterized by enhanced reactivity, distinct selectivity, and confined reaction geometry, offers significant potential for chemical and materials syntheses. However, the utilization of on-water surface synthesis is currently limited by the requirement for a stable air-water interface, which restricts its broader synthetic applications. In this work, we present a approach that mimics on-water surface chemistry using micelles.

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Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are emerging as a unique subclass of layer-stacked crystalline coordination polymers that simultaneously possess porous and conductive properties, and have broad application potential in energy and electronic devices. However, to make the best use of the intrinsic electronic properties and structural features of 2D c-MOFs, the controlled synthesis of hierarchically nanostructured 2D c-MOFs with high crystallinity and customized morphologies is essential, which remains a great challenge. Herein, we present a template strategy to synthesize a library of 2D c-MOFs with controlled morphologies and dimensions via insulating MOFs-to-c-MOFs transformations.

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Electrochemical proton storage plays an essential role in designing next-generation high-rate energy storage devices, e.g., aqueous batteries.

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A general approach to promote IR light-driven CO reduction within ultrathin Cu-based hydrotalcite-like hydroxy salts is presented. Associated band structures and optical properties of the Cu-based materials are first predicted by theory. Subsequently, Cu(SO)(OH) nanosheets were synthesized and are found to undergo cascaded electron transfer processes based on d-d orbital transitions under infrared light irradiation.

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Emerging rechargeable aluminium batteries (RABs) offer a sustainable option for next-generation energy storage technologies with low cost and exemplary safety. However, the development of RABs is restricted by the limited availability of high-performance cathode materials. Herein, we report two polyimide two-dimensional covalent organic frameworks (2D-COFs) cathodes with redox-bipolar capability in RAB.

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Organic frameworks with carbon-carbon (CC) linkage are an important class of materials owing to their outstanding chemical stability and extended π-electron delocalization resulting in unique optoelectronic properties. In the first part of this review article, the design principles for the bottom-up synthesis of 2D and 3D sp/sp CC linked organic frameworks are summarized. Representative reaction methodologies, such as Knoevenagel condensation, Aldol condensation, Horner-Wadsworth-Emmons reaction, Wittig reaction, and coupling reactions (Ullmann, Suzuki, Heck, Yamamoto, etc.

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Rechargeable aqueous Zn-ion energy storage devices are promising candidates for next-generation energy storage technologies. However, the lack of highly reversible Zn-storage anode materials with low potential windows remains a primary concern. Here, we report a two-dimensional polyarylimide covalent organic framework (PI-COF) anode with high-kinetics Zn-storage capability.

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Organic electrode materials are of long-standing interest for next-generation sustainable lithium-ion batteries (LIBs). As a promising cathode candidate, imide compounds have attracted extensive attention due to their low cost, high theoretical capacity, high working voltage, and fast redox reaction. However, the redox active site utilization of imide electrodes remains challenging for them to fulfill their potential applications.

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Cyano-substituted polyphenylene vinylenes (PPVs) have been the focus of research for several decades owing to their interesting optoelectronic properties and potential applications in organic electronics. With the advent of organic two-dimensional (2D) crystals, the question arose as to how the chemical and optoelectronic advantages of PPVs evolve in 2D compared with their linear counterparts. In this work, we present the efficient synthesis of two novel 2D fully sp -carbon-linked crystalline PPVs and investigate the essentiality of inorganic bases for their catalytic formation.

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Covalent organic frameworks (COFs) have garnered immense scientific interest among porous materials because of their structural tunability and diverse properties. However, the response of such materials toward laser-induced nonlinear optical (NLO) applications is hardly understood and demands prompt attention. Three novel regioregular porphyrin (Por)-based porous COFs-Por-COF-HH and its dual metalated congeners Por-COF-ZnCu and Por-COF-ZnNi-have been prepared and present excellent NLO properties.

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Porous organic polymers (POPs) have attracted significant attention towards molecular adsorption in recent years due to their high porosity, diverse functionality and excellent chemical stability. In this work, we present a systematic case study on the formation of thiazolo[5,4-d]thiazole (TzTz) linkages through model compounds and its integration to synthesize a set of three novel, thermo-chemically stable TzTz-linked POPs, namely TzTz-POP-3, TzTz-POP-4, and TzTz-POP-5 with triphenylbenzene, tetraphenylpyrene and tetra(hydroxyphenyl)methane cores, respectively. Interestingly, the integrated TzTz moiety of the represented TzTz-POP-3 renders chemoselective removal of organic dye fluorescein (FL) from a mixture with parafuchsine (FU) in aqueous solution.

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Carbon electrocatalysts consisting of metal complexes such as MN or MS are promising alternatives to high-cost Pt catalysts for the hydrogen evolution reaction (HER). However, the exact HER active sites remain elusive. Here, molecular metal dithiolene-diamine (MS N , M=Co and Ni), metal bis(dithiolene) (MS ), and metal bis(diamine) (MN ) complexes were selectively incorporated into carbon-rich 2D metal-organic frameworks (2D MOFs) as model carbon electrocatalysts.

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Self-assembled hexagonal organic submicrotubes, upon electronic excitation with an UV laser, display an active type polarized whispering gallery mode (WGM) resonance in the visible (Vis) range (400-600 nm). Due to the photonic cavity effect the tubes show fluorescence (FL) signal intensity 5× greater than the corresponding powder state. Furthermore, the same tubes, which are passive to a visible laser, produce yellow-orange emitting carbonaceous lumps when burnt with an intense laser beam (42 mW) forming a chemically binary heterogeneous structure.

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This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers with two counter anions from a novel back-to-back coupled hybrid ligand. The spin cross-over (SCO) temperature of polymers with BF4 and ClO4 counter anions is T1/2 = 313 K and T1/2 = 326 K, respectively. By following the top-down approach, one of the polymers (with ClO4 counter anion) is successfully solution processed using a lithographically controlled wetting technique to create laser readable high-resolution Archimedean (4,8(2) ) nanolattices (consist of diamagnetic octagons and SCO squares).

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We have fabricated nearly monodispersed nanocrystalline sheet waveguides from a well-known red emitting meso-tetratolylporphyrin molecule (1) by following a bottom-up solvent assisted self-assembly technique. The nano-sheets thickness is in the range of 110-180 nm. Localized laser illumination showed excitation position dependent exciton polariton (653 and 719 nm) propagation behavior of the sheets.

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A series of novel "super hybrid tridentate ligands" based on (2-(1-butyl-1H-1,2,3-triazol-4-yl)-6-(1H-pyrazol-1-yl)pyridine (tpp) derivatives were synthesized. Their Fe(ii) complexes display around (T(½) = 287 K) and above room temperature (T(½)≫ 375 K) spin transition temperatures.

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This paper presents an eight-step synthetic method for the preparation of a series of new back-to-back coupled 2,6-bis(triazol-1-yl)pyridine (btp) molecules (L1-L3). These L1-L3 molecules displayed fluorescent emission at 381, 381, and 457 nm, respectively. We also demonstrated the self-assembly of these fluorescent molecules with Eu(3+) ions to obtain Eu(3+) centered red-orange luminescent solids via "antenna effect".

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Fluorescent elongated nanotapes and nearly monodispersed short submicrotubes were successfully prepared in a controlled manner from two tailor-made pi-conjugated organic building blocks 1 and 2, respectively in dichloromethane solvent via a supramolecular self-assembly approach.

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