@article {42536, title = {Receptor design and extraction of inorganic fluoride ion from aqueous medium}, journal = {Chemical Communications}, volume = {47}, year = {2011}, month = {MAY}, pages = {7398-7400}, abstract = {

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.

}, doi = {10.1039/C1CC11458A}, author = {Das, Priyadip and Mandal, Amal Kumar and Kesharwani, Manoj K. and Suresh, Eringathodi and Ganguly, Bishwajit and Das, Amitava} } @article {42500, title = {Recognition of Hg2+ion through restricted imine isomerization: crystallographic evidence and imaging in live cells}, journal = {Organic Letters}, volume = {14}, year = {2012}, month = {JUN}, pages = {2980{\textendash}2983}, abstract = {

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{\textendash}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.

}, doi = {10.1021/ol3009733}, author = {Mandal, Amal Kumar and Suresh, Moorthy and Das, Priyadip and Suresh, E. and Baidya, Mithu and Ghosh, Sudip K. and Das, Amitava} } @article {42509, title = {Restricted conformational flexibility of a triphenylamine derivative on the formation of host-guest complexes with various macrocyclic hosts}, journal = {Chemistry a European Journal}, volume = {18}, year = {2012}, month = {MAR}, pages = {3906{\textendash}3917}, abstract = {

Herein, we report the host{\textendash}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{\textendash}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 F{\"o}rster 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.

}, doi = {10.1002/chem.201103079}, author = {Mandal, Amal Kumar and Suresh, Moorthy and Das, Priyadip and Das, Amitava} } @article { ISI:000326319800045, title = {Role of metal ion in specific recognition of pyrophosphate ion under physiological conditions and hydrolysis of the phosphoester linkage by alkaline phosphatase}, journal = {Inorganic Chemistry}, volume = {52}, number = {19}, year = {2013}, month = {OCT}, pages = {11034-11041}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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 {\textquoteleft}{\textquoteleft}turn-on{\textquoteright}{\textquoteright} (for L.Zn and L.Cu) and {\textquoteleft}{\textquoteleft}turn-off{\textquoteright}{\textquoteright} (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.

}, issn = {0020-1669}, doi = {10.1021/ic401243h}, author = {Das, Priyadip and Chandar, Nellore Bhanu and Chourey, Shishir and Agarwalla, Hridesh and Ganguly, Bishwajit and Das, Amitava} }