02116nas a2200217   4500008004100000022001400041245019300055210006900248260007100317300001400388490000800402520119800410100002101608700002401629700002301653700002401676700001701700700002301717700002601740856013201766       2014                        eng d  a1932-744700aSuperior grafting and state-of-the-art interfacial electron transfer rates for newly designed geminal dicarboxylate bound ruthenium(II)- and osmium(II)-polypyridyl dyes on TiO2 nanosurface0 aSuperior grafting and stateoftheart interfacial electron transfe  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a3864-38770 v1183 a<p>Two new Ru(II)-/Os(II)-polypyridyl based sensitizer dyes with geminal dicarboxylic acid group as the binding unit for superior grafting of the dye to TiO2 have been designed and synthesized. Steady-state photochemical studies of the two sensitizer dyes in presence of TiO2 in water confirm strong binding of the dyes to TiO2. Femtosecond transient absorption studies of these newly synthesized dyes on TiO2 nanosurface have been carried out in water and the results have been compared with those for the corresponding 4,4'-dicarboxy-2,2'-bipyridine analogues of the dyes. While the charge recombination rates are considerably slower, interestingly, the electron injection rates are very fast for multiple saturated C-C linkages present between the chromophoric core and the anchoring moiety. The origin and the consequences of such profound effects on the ultrafast interfacial dynamics are discussed. This is the first report on the ultrafast transient absorption studies of dyes with geminal dicarboxylic acid binding groups, which we believe will add significantly to the present research efforts toward the development of robust and efficient dyes for use in dye solar applications.</p>1 aBanerjee, Tanmay1 aBiswas, Abul, Kalam1 aReddy, Upendar, G.1 aSahu, Tuhin, Subhra1 aDas, Amitava1 aGanguly, Bishwajit1 aGhosh, Hirendra, Nath  uhttps://library.ncl.res.in/content/superior-grafting-and-state-art-interfacial-electron-transfer-rates-newly-designed-geminal-002773nas a2200241   4500008004100000022001400041245011700055210006900172260007100241300001600312490000800328520190000336100001502236700001702251700001902268700001902287700002202306700001502328700002302343700002502366700001702391856012302408       2015                        eng d  a1520-610600aSpecific reagent for Cr(III): imaging cellular uptake of Cr(III) in Hct116 cells and theoretical rationalization0 aSpecific reagent for CrIII imaging cellular uptake of CrIII in H  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT  a13018-130260 v1193 a<p>A new rhodamine-based reagent (L-1), trapped inside the micellar structure of biologically benign Triton-X 100, could be used for specific recognition of Cr(III) in aqueous buffer medium having physiological pH. This visible light excitable reagent on selective binding to Cr(III) resulted in a strong fluorescence turn-on response with a maximum at similar to 583 nm and tail of that luminescence band extended until 650 nm, an optical response that is desired for avoiding the cellular autofluorescence. Interference studies confirm that other metal ions do not interfere with the detection process of Cr(III) in aqueous buffer medium having pH 7.2. To examine the nature of binding of Cr(III) to L-1, various spectroscopic studies are performed with the model reagent L-1 which tend to support Cr(III)-eta(2)-olefin pi-interactions involving two olefin bonds in molecular probe L-1. Computational studies are also performed with another model reagent L-M to examine the possibility of such Cr(III)-eta(2)-olefin pi-interactions. Presumably, polar functional groups of the model reagent L-M upon coordination to the Cr(III) center effectively reduce the formal charge on the metal ion and this is further substantiated by results of the theoretical studies. This assembly is found to be cell membrane permeable and shows insignificant toxicity toward live colon cancer cells (Hct116). Confocal laser scanning microscopic studies further revealed that the reagent L-1 could be used as an imaging reagent for detection of cellular uptake of Cr(III) in pure aqueous buffer medium by Hct116 cells. Examples of a specific reagent for paramagnetic Cr(III) with luminescence ON response are scanty in the contemporary literature. This ligand design helped us in achieving the turn on response by utilizing the conversion from spirolactam to an acyclic xanthene form on coordination to Cr(III).</p>1 aAli, Firoj1 aSaha, Sukdeb1 aMaity, Arunava1 aTaye, Nandaraj1 aSi, Mrinal, Kanti1 aSuresh, E.1 aGanguly, Bishwajit1 aChattopadhyay, Samit1 aDas, Amitava  uhttps://library.ncl.res.in/content/specific-reagent-criii-imaging-cellular-uptake-criii-hct116-cells-and-theoretical-002218nas a2200217   4500008004100000245009700041210006900138260000800207300001600215490000700231520147200238100002401710700002401734700001901758700001901777700002301796700002401819700002501843700001701868856011501885       2016                        eng d00aSwitch-on NIR probe for specific detection of Hg2+ ion in aqueous medium and in mitochondria0 aSwitchon NIR probe for specific detection of Hg2 ion in aqueous   cNOV  a12052-120600 v553 aA new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based probe molecule (L) is synthesized for specific binding to Hg2+ ion in physiological condition with an associated luminescence ON response in the near-IR region of the spectrum. Appropriate functionalization in the 5-position of each of two pyrrole moieties with styryl functionality in a BODIPY core helped us in achieving the extended conjugation and a facile intramolecular charge transfer transition with a narrow energy gap for frontier orbitals. This accounted for a poor emission quantum yield for the probe molecule L. Binding to. Hg2+ helped in interrupting the facile intramolecular charge transfer (ICT) process that was initially operational for L. This resulted in a hypsochromic shift of absorption band and a turn-on luminescence response with lambda(Em)(max) of 650 nm on specific binding to Hg2+. Observed spectral changes are rationalized based on quantum chemical calculations. Interestingly, this reagent is found to be localized preferentially in the mitochondria of the live human colon cancer (Hct116) cells. Mitochondria is one of the major targets for localization of He2+, which actually decreases the mitochondrial membrane potential and modifies various proteins having sulfudryl functionality(ies) to cause cell apoptosis. Considering these, ability of the present reagent to specifically recognize Hg2+] in the mitochondrial region of the live Hct116 cells has significance.1 aAgarwalla, Hrideshg1 aMahajan, Pankaj, S.1 aSahu, Debashis1 aTaye, Nandaraj1 aGanguly, Bishwajit1 aMhaske, Santosh, B.1 aChattopadhyay, Samit1 aDas, Amitava  uhttps://library.ncl.res.in/content/switch-nir-probe-specific-detection-hg2-ion-aqueous-medium-and-mitochondria