01981nas 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-application00902nas 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-hg02501nas 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-0