01827nas a2200241   4500008004100000022001400041245009800055210006900153260000800222300001400230490000700244520101400251653003201265653001001297653001501307653001801322653003001340100001701370700002601387700002501413700002001438856012701458       2020                        eng d  a1433-785100aNanoparticle size-fractionation through self-standing porous covalent organic framework films0 aNanoparticle sizefractionation through selfstanding porous coval  cJAN  a1161-11650 v593 a<p>Covalent organic frameworks (COFs) have attracted attention due to their ordered pores leading to important industrial applications like storage and separation. Combined with their modular synthesis and pore engineering, COFs could become ideal candidates for nanoseparations. However, the fabrication of these microcrystalline powders as continuous, crack-free, robust films remains a challenge. Herein, we report a simple, slow annealing strategy to construct centimeter-scale COF films (Tp-Azo and Tp-TTA) with micrometer thickness. The as-synthesized films are porous (SA(BET)=2033 m(2) g(-1) for Tp-Azo) and chemically stable. These COFs have distinct size cut-offs (ca. 2.7 and ca. 1.6 nm for Tp-Azo and Tp-TTA, respectively), which allow the size-selective separation of gold nanoparticles. Unlike, other conventional membranes, the durable structure of the COF films allow for excellent recyclability (up to 4 consecutive cycles) and easy recovery of the gold nanoparticles from the solution.</p>
10acovalent organic frameworks10afilms10ananofilter10aNanoparticles10asize-selective separation1 aDey, Kaushik1 aKunjattu, Shebeeb, H.1 aChahande, Anurag, M.1 aBanerjee, Rahul  uhttps://library.ncl.res.in/content/nanoparticle-size-fractionation-through-self-standing-porous-covalent-organic-framework01919nas a2200229   4500008004100000022001400041245016200055210006900217260000800286520105900294653002801353653002501381653002201406653001901428653001401447653001601461100002501477700002101502700002501523700001801548856012301566       2021                        eng d  a0302-893300aRed fluorescent ultra-small gold nanoclusters functionalized with signal molecules to probe specificity in quorum sensing receptors in gram-negative bacteria0 aRed fluorescent ultrasmall gold nanoclusters functionalized with  cJUN3 aUltra-small (size < 2 nm) gold nanoclusters (AuNCs) are used as fluorescent probes which have excellent applications in bioimaging and sensing due to their emission in visible and NIR spectral region. Here, this property is exploited for understanding the quorum sensing phenomenon in bacteria which is regulated by signal molecules which are specific to various species. AuNCs are then functionalized with the signal molecules, Acyl Homoserine Lactones (AHL) of varying carbon chain length, C-6, C-8, and C-12 without 3rd C modification, to sense different strains of gram-negative bacteria i.e., Escherichia coli, Cronobacter sakazakii and Pseudomonas aeruginosa. In the concentration employed, selectivity to a limited extent is observed between the three Gram-negative bacteria tested. E. coli showed emission with all the AHL conjugates and P. aeruginosa did not interact with any of the three conjugates, whereas C. sakazakii showed specificity to C-8AHL. This is probably due to selectivity for cognate AHL molecules of appropriate concentrations.10aacyl homoserine lactone10afluorescence imaging10aGold nanoclusters10aquorum sensing10aReceptors10aselectivity1 aChahande, Anurag, M.1 aLathigara, Disha1 aPrabhune, Asmita, A.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/red-fluorescent-ultra-small-gold-nanoclusters-functionalized-signal-molecules-probe02578nas a2200217   4500008004100000022001400041245015200055210006900207260000800276490000700284520173800291653003002029653003702059653003002096653001702126100002502143700002202168700002602190700001802216856012602234       2024                        eng d  a0934-086600aUltra-small Au nanoclusters with tailored photoluminescence properties using modified thiol ligands: a computational and experimental demonstration0 aUltrasmall Au nanoclusters with tailored photoluminescence prope  cOCT0 v413 a<p>
	Au nanoclusters with tailored photoluminescence can be obtained through controlled nanoparticle ligand interface chemistry. The present work reports molecular gold nanoclusters with tuneable photoluminescence emission from 600 to 700 nm using N,N `,N `'-trialkyl (11-mercaptoundecyl)ammonium chloride ligands as capping-agents. The tunability within red spectral region is regulated through specific interface chemistry between gold nanoclusters of molecular range and functional groups of the quaternary ammonium head over N,N `,N `'-trialkyl(11-mercaptoundecyl)ammonium chloride. Combined understanding obtained from the spectroscopy, microscopy, and density functional theory studies demonstrate that the functional group specific electronic interactions at the interfaces steer the emission characteristics of ``molecular'' Au nanoparticles. The study clearly identifies that bulkier functional groups, i.e., triethyl, tripropyl, tributyl, and dimethyl benzene over N+ (of thiol ligand) through their steric effects minimize the particle size giving rise to tunable photoluminescence emission in red spectral region. However, the red shift seen in the emission Au nanoclusters with N-(11-mercaptoundecyl)-N,N `-dimethylbenzenammonium chloride ligand in contradiction to particle size effect is computationally proved to be due to the delocalization of electron density from benzene aromatic ring to N+ of ammonium head leading to a reduction in the HOMO-LUMO energy gap. Fluorescence properties of water dispersible Au nanoclusters are tuned by varying the ammonium head group. Density Functional Theory studies correlate the distinction in emission when head group is phenyl to charge transfer characteristics. image</p>
10aDensity functional theory10aphotoluminescent Au nanoclusters10asurface plasmon resonance10athiol ligand1 aChahande, Anurag, M.1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja1 aDevi, Nandini  uhttps://library.ncl.res.in/content/ultra-small-au-nanoclusters-tailored-photoluminescence-properties-using-modified-thiol