00896nas a2200193 4500008004100000245008100041210006900122260000800191300001400199490000700213520024200220100001800462700002400480700002600504700002400530700002300554700001700577856010800594 2011 eng d00aReceptor design and extraction of inorganic fluoride ion from aqueous medium0 aReceptor design and extraction of inorganic fluoride ion from aq cMAY a7398-74000 v473 a

A receptor with acidic methylene hydrogens is found to act as an efficient binding mode for F−. This reagent could as well be used for selective and quantitative extraction of F− from the aqueous solution of NaF and sea water.

1 aDas, Priyadip1 aMandal, Amal, Kumar1 aKesharwani, Manoj, K.1 aSuresh, Eringathodi1 aGanguly, Bishwajit1 aDas, Amitava uhttps://library.ncl.res.in/content/receptor-design-and-extraction-inorganic-fluoride-ion-aqueous-medium01981nas a2200157 4500008004100000245017200041210006900213260000800282300001800290490000800308520132800316100002201644700001701666700001701683856012301700 2012 eng d00aRare example of TICT based optical responses for the specific recognition of Cr3+ by a 2,2?:6?,2?-terpyridine derivative and demonstration of multiple logic operations0 aRare example of TICT based optical responses for the specific re cJUL a17448–174570 v1163 a

Chemosensor L showed a nonlinear fluorescence response on specific binding to Cr3+ ion in the presence of various alkali, alkaline-earth, transition, and lanthanide metal ions. A luminescence band with maxima at 512 nm for L was observed (λext = 330 nm) for a twisted intramolecular charge transfer (TICT) transition following antienergy gap law behavior. However, normal energy gap law behavior prevailed on formation of a new nonluminescent charge transfer complex, Mn+·L. For paramagnetic metal ions, paramagnetism induced luminescence quenching could have also contributed to this. A new switched on fluorescence response at λems of 356 nm (λext of 330 nm) was observed due to Franck–Condon charge transfer (FC-CT) transition only on the formation of a complex, (Cr3+)2·L. Spectral studies revealed a unique dynamic coordination behavior and migration of Cr3+ from the terpyridyl fragment to the NNMe2 center of L as a function of the varying concentration of another ion (Zn2+) and the subtle difference in the binding affinities of the terpyridyl moiety toward Cr3+ and Zn2+. Further, spectral responses of L toward Zn2+, different concentration of Cr3+, H+ and on subsequent addition of F– as different ionic inputs could be correlated well for demonstrating various basic and combinatorial circuits.

1 aMahato, Prasenjit1 aSaha, Sukdeb1 aDas, Amitava uhttps://library.ncl.res.in/content/rare-example-tict-based-optical-responses-specific-recognition-cr3-2262-terpyridine01765nas a2200229 4500008004100000245009600041210006900137260000800206300001600214490000700230520098300237100002201220700001701242700001501259700001901274700002801293700002701321700002601348700002301374700001701397856012101414 2012 eng d00aRatiometric detection of Cr3+ and Hg2+ by a naphthalimide-rhodamine based fluorescent probe0 aRatiometric detection of Cr3 and Hg2 by a naphthalimiderhodamine cJAN a1769–17770 v513 a

Newly synthesized rhodamine derivatives, L1 and L2, are found to bind specifically to Hg2+ or Cr3+ in presence of large excess of other competing ions with associated changes in their optical and fluorescence spectral behavior. These spectral changes are significant enough in the visible region of the spectrum and thus, allow the visual detection. For L1, the detection limit is even lower than the permissible [Cr3+] or [Hg2+] in drinking water as per standard U.S. EPA norms; while the receptor, L2 could be used as a ratiometric sensor for detection of Cr3+ and Hg2+ based on the resonance energy transfer (RET) process involving the donor naphthalimide and the acceptor Cr3+/Hg2+-bound xanthene fragment. Studies reveal that these two reagents could be used for recognition and sensing of Hg2+/Cr3+. Further, confocal laser microscopic studies confirmed that the reagent L2 could also be used as an imaging probe for detection of uptake of these ions in A431 cells.

1 aMahato, Prasenjit1 aSaha, Sukdeb1 aSuresh, E.1 aDi Liddo, Rosa1 aParnigotto, Pier, Paolo1 aConconi, Maria, Teresa1 aKesharwani, Manoj, K.1 aGanguly, Bishwajit1 aDas, Amitava uhttps://library.ncl.res.in/content/ratiometric-detection-cr3-and-hg2-naphthalimide-rhodamine-based-fluorescent-probe01954nas a2200217 4500008004100000245014700041210006900188260000800257300001400265490000700279520116100286100001701447700002201464700002301486700001501509700002501524700001801549700002101567700001701588856013101605 2012 eng d00aRecognition of Hg 2+ and Cr 3+ in physiological conditions by a rhodamine derivative and its application as a reagent for cell-imaging studies0 aRecognition of Hg 2 and Cr 3 in physiological conditions by a rh cDEC a336–3450 v513 a

A new rhodamine-based receptor, derivatized with an additional fluorophore (quinoline), was synthesized for selective recognition of Hg2+ and Cr3+ in an acetonitrile/HEPES buffer medium of pH 7.3. This reagent could be used as a dual probe and allowed detection of these two ions by monitoring changes in absorption and the fluorescence spectral pattern. In both instances, the extent of the changes was significant enough to allow visual detection. More importantly, the receptor molecule could be used as an imaging reagent for detection of Hg2+ and Cr3+ uptake in live human cancer cells (MCF7) using laser confocal microscopic studies. Unlike Hg(ClO4)2 or Hg(NO3)2 salts, HgCl2 or HgI2 failed to induce any visually detectable change in color or fluorescence upon interaction with L1 under identical experimental conditions. Presumably, the higher covalent nature of HgII in HgCl2 or HgI2 accounts for its lower acidity and its inability to open up the spirolactam ring of the reagent L1. The issue has been addressed on the basis of the single-crystal X-ray structures of L1·HgX2 (X– = Cl– or I–) and results from other spectral studies.

1 aSaha, Sukdeb1 aMahato, Prasenjit1 aReddy, Upendar, G.1 aSuresh, E.1 aChakrabarty, Arindam1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/recognition-hg-2-and-cr-3-physiological-conditions-rhodamine-derivative-and-its-application01290nas a2200205 4500008004100000245011900041210006900160260000800229300001600237490000700253520056400260100002400824700002000848700001800868700001500886700001800901700002100919700001700940856012700957 2012 eng d00aRecognition of Hg2+ion through restricted imine isomerization: crystallographic evidence and imaging in live cells0 aRecognition of Hg2ion through restricted imine isomerization cry cJUN a2980–29830 v143 a

A newly synthesized imine-based receptor (L) showed remarkable specificity toward the Hg2+ ion in aqueous media over other metal ions. Coordination of L to Hg2+ induces a turn-on fluorescence response. This was explained based on the restricted imine isomerization along with PET on coordination to Hg2+. X-ray structural evidence tends to favor a C–C bond rotation rather than C═N isomerization for adopting a favorable conformation in L for coordination to Hg2+. This reagent could be used for imaging the accumulation of Hg2+ ions in HeLa cells.

1 aMandal, Amal, Kumar1 aSuresh, Moorthy1 aDas, Priyadip1 aSuresh, E.1 aBaidya, Mithu1 aGhosh, Sudip, K.1 aDas, Amitava uhttps://library.ncl.res.in/content/recognition-hg2ion-through-restricted-imine-isomerization-crystallographic-evidence-and01866nas a2200169 4500008004100000245014500041210006900186260000800255300001600263490000700279520120700286100002401493700002001517700001801537700001701555856012401572 2012 eng d00aRestricted conformational flexibility of a triphenylamine derivative on the formation of host-guest complexes with various macrocyclic hosts0 aRestricted conformational flexibility of a triphenylamine deriva cMAR a3906–39170 v183 a

Herein, we report the host–guest-type complex formation between the host molecules cucurbit[7]uril (CB[7]), β-cyclodextrin (β-CD), and dibenzo[24]crown-8 ether (DB24C8) and a newly synthesized triphenylamine (TPA) derivative 1X3 as the guest component. The host–guest complex formation was studied in detail by using 1H NMR, 2D NOESY, UV/Vis fluorescence, and time-resolved emission spectroscopy. The chloride salt of the TPA derivative was used for recognition studies with CB[7] and β-CD in an aqueous medium. The restricted internal rotation of the guest molecule on complex formation with either of these two host molecules was reflected in the enhancement of the emission quantum yield and the average excited-state lifetime for the triphenylamine-based excited states. Studies with DB24C8 as the host molecule were performed in dichloromethane, a medium that maximizes the noncovalent interaction between the host and guest fragments. The Förster resonance energy transfer (FRET) process involving DB24C8 and 1(PF6)3, as the donor and acceptor fragments, respectively, was established by electrochemical, steady-state emission, and time-correlated single-photon counting studies.

1 aMandal, Amal, Kumar1 aSuresh, Moorthy1 aDas, Priyadip1 aDas, Amitava uhttps://library.ncl.res.in/content/restricted-conformational-flexibility-triphenylamine-derivative-formation-host-guest00902nas a2200193 4500008004100000245013700041210006900178260000800247300001400255490000700269520018100276100001700457700002500474700002200499700001600521700002200537700001700559856013200576 2012 eng d00aRhodamine-alginate conjugate as self-indicating gel beads for efficient detection and scavenging of Hg 2+ and Cr 3+ in aqueous media0 aRhodaminealginate conjugate as selfindicating gel beads for effi cNOV a1659-16610 v483 a

Effective extraction of Hg2+ and Cr3+ ions from aqueous media by novel rhodamine–alginate polymer-based highly fluorogenic, as well as colorimetric, chemosensor beads.

1 aSaha, Sukdeb1 aChhatbar, Mahesh, U.1 aMahato, Prasenjit1 aPraveen, L.1 aSiddhanta, A., K.1 aDas, Amitava uhttps://library.ncl.res.in/content/rhodamine-alginate-conjugate-self-indicating-gel-beads-efficient-detection-and-scavenging-hg02505nas a2200205 4500008004100000022001400041245016500055210006900220260007100289300001600360490000700376520165600383100001802039700002802057700002102085700002302106700002302129700001702152856013002169 2013 eng d a0020-166900aRole of metal ion in specific recognition of pyrophosphate ion under physiological conditions and hydrolysis of the phosphoester linkage by alkaline phosphatase0 aRole of metal ion in specific recognition of pyrophosphate ion u a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a11034-110410 v523 a

Complexes synthesized from Zn(II), Cu(II), and Cd(II), using a dipicolyl amine derivative (L), showed unique specificity toward pyrophosphate ion (PPi or P4O74-) among all other common anionic analytes, including different biologically significant phosphate ion (PO43-, H2PO42-) or phosphate-ion-based nucleotides, such as AMP, ADP, ATP, and CTP. However, the relative affinities of PPi toward these three metal complexes were found to vary and follow the order K-a(L.Zn-PPi) > are given in units of (L.Cu-PPi)(a) >= K-a(L.Cd-PPi). Luminescence responses of the receptor L were substantial on binding to Zn2+ and Cd2+, while relatively a much smaller luminescence response was observed in the presence of Cu2+. Luminescence responses of L.M-PPi (M is Zn2+, Cd2+, and Cu2+) were further modified on binding to the PPi ion. This could be utilized for quantitative detection of PPi in physiological condition as well as for developing a real time ``turn-on'' (for L.Zn and L.Cu) and ``turn-off'' (for L.Cd) fluorescence assay for evaluating the enzymatic activity of alkaline phosphatase (ALP). Experimental results revealed how the subtle differences in the binding affinities between PPi and M in L.M (M is Zn2+, Cd2+, and Cu2+), could influence the cleavage of the phosphoester linkage in PPi by ALP. The DFT calculations further revealed that the hydrolytic cleavage of the metal ion coordinated phosphoester bond is kinetically faster than that for free PPi and thus, rationalized the observed difference in the cleavage of the phosphoester bond by an important mammalian enzyme such as ALP in the presence of different metal complexes.

1 aDas, Priyadip1 aChandar, Nellore, Bhanu1 aChourey, Shishir1 aAgarwalla, Hridesh1 aGanguly, Bishwajit1 aDas, Amitava uhttps://library.ncl.res.in/content/role-metal-ion-specific-recognition-pyrophosphate-ion-under-physiological-conditions-and-002501nas a2200193 4500008004100000022001400041245009100055210006900146260011000215300001600325490000700341520174100348100001802089700002202107700001702129700002702146700001702173856011702190 2015 eng d a1463-907600aRapid conductometric sensor for the analysis of cyanide using imidazole based receptor0 aRapid conductometric sensor for the analysis of cyanide using im aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a26790-267960 v173 a

A specific and efficient hydrogen bonding interaction between cyanide and the HN-H [imidazole] in an aqueous medium has been utilized for the selective recognition of cyanide under physiological conditions. The possibility of utilizing such an interaction for developing any practical device for the specific detection of cyanide in an aqueous environment has not been explored to date. We now report a simple dip and read conductometric sensor for cyanide ions using a tailored electrode in aqueous media. The purpose built reagent, 2-phenyl-1H-anthra-[2,3-d]-immidazole-5,10 dione was immobilized in a polyaniline matrix to fabricate this conductometric device. The homogeneous immobilization of the receptor in polyaniline was confirmed by FT-IR mapping. The proposed transduction mechanism is charge neutralization on the polyaniline moiety, which ultimately inhibits the protonation resulting in a decrease in the conductance of polyaniline. The sensor response was measured in three ranges of cyanide concentration (10(-10) M to 10(-8) M; 10(-8) M to 10(-6) M and 10(-6) M to 10(-3) M). Whereas the device is found insensitive in the first range, it acts as a detector in the second range and as a proportional sensor in the third range. The minimum detection limit of this device was found to be 10 nmol L-1 (2.6 ppt), which is significantly less than the WHO guideline values. The responses have been investigated under various conditions such as different pH and the electrochemical state of the polymer. The current device has been found to be better close to neutral pH and at a 400 mV vs. Ag/AgCl potential. The reproducibility and repeatability of the sensor was investigated and interference studies were performed.

1 aPaul, Anirban1 aPerween, Mosarrat1 aSaha, Sukdeb1 aSrivastava, Divesh, N.1 aDas, Amitava uhttps://library.ncl.res.in/content/rapid-conductometric-sensor-analysis-cyanide-using-imidazole-based-receptor-001209nas a2200205 4500008004100000022001400041245015300055210006900208260011000277300001600387490000700403520034900410100001800759700002300777700001500800700001900815700002500834700001700859856012700876 2015 eng d a1359-734500aReagent for specific recognition of cysteine in aqueous buffer and in natural milk: imaging studies, enzymatic reaction and analysis of whey protein0 aReagent for specific recognition of cysteine in aqueous buffer a aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG a15592-155950 v513 a

We report a new chemodosimetric probe (L) for specific recognition of cysteine (Cys) in aqueous buffer and in whey protein isolated from fresh cow's milk. Using this reagent we could develop a luminescence-based methodology for estimation of Cys released from a commercially available Cys-supplement drug by aminoacylase-1 in live cells.

1 aAnila, H., A.1 aReddy, Upendar, G.1 aAli, Firoj1 aTaye, Nandaraj1 aChattopadhyay, Samit1 aDas, Amitava uhttps://library.ncl.res.in/content/reagent-specific-recognition-cysteine-aqueous-buffer-and-natural-milk-imaging-studies-001610nas a2200193 4500008004100000022001400041245008600055210006900141260000900210300001400219490000700233520095900240100002401199700001601223700003001239700001701269700002001286856011001306 2017 eng d a1477-922600aRatiometric sensor for DNA based on a dual emission Ru(dppz) light-switch complex0 aRatiometric sensor for DNA based on a dual emission Rudppz light cMAY  a6079-60860 v463 a

Herein we describe the DNA binding properties of two new water-soluble ruthenium complexes; experimental and computational data reveal that both complexes display dual emission from MLCT and LLCT excited states. The interaction of the new complexes with DNA was also investigated. Although one of the complexes only binds DNA though groove binding, the second complex has separate ligands capable of groove binding and intercalation. Nevertheless, it was found that both complexes interact with duplex DNA with high affinity. DNA induced distinctive changes in the emission of the complexes; although the groove binding complex only displays a modest increase in emission on binding, the complex that contains the intercalating Ru-II(dppz) moiety displays a large increase in MLCT-based emission on DNA binding while emission from the LLCT excited state is unaffected. This means that the complex functions as the first ratiometric sensor for DNA.

1 aWalker, Michael, G.1 aRamu, Vadde1 aMeijer, Anthony, J. H. M.1 aDas, Amitava1 aThomas, Jim, A. uhttps://library.ncl.res.in/content/ratiometric-sensor-dna-based-dual-emission-rudppz-light-switch-complex