02700nas a2200217   4500008004100000245005900041210005700100260000800157300001400165490000700179520203200186100002002218700002402238700002602262700001902288700002302307700002802330700002002358700001702378856008702395       2011                        eng d00aFolding and unfolding movements in a [2]pseudorotaxane0 aFolding and unfolding movements in a 2pseudorotaxane  cDEC  a138–1440 v763 a<p>A new dibenzo[24]crown-8 derivative (1) was synthesized and functionalized with aromatic moieties such as naphthalene and coumarin units. These two fluorophores are known to form an effective FRET (Forster resonance energy transfer) pair, and this formed the basis for the design of this host crown ether derivative. Results of the steady-state and time-resolved fluorescence studies confirmed the resonance energy transfer between the donor naphthalene moiety and acceptor coumarin fragment, while NMR spectra and computational studies support a folded conformation for the uncomplexed crown ether 1. This was found to form an inclusion complex, a [2]pseudorotaxane type with imidazolium ion derivatives as the guest molecules with varying alkyl chain lengths ([C4mim]+ or [C10mim]+). The host crown ether (1) tends to adopt an open conformation on formation of the interwoven inclusion complex (1·[C4mim]+ or 1·[C10mim]+). This change in conformation, from the folded to a open one, was predicted by computational as well as 1H NMR studies and was confirmed by single crystal X-ray structure for one (1·[C4mim]+) of the two inclusion complexes. The increase in the effective distance between the naphthalene and coumarin moieties in the open conformation of these inclusion complexes was also supported by the decrease in the effective FRET process that was operational between naphthalene and coumarin moieties in the free molecule (1). Importantly, this inclusion complex formation was found to be reversible, and in the presence of a stronger base/polar solvent, such as triethyl amine/DMSO, the deprotonation/effective solvation of the cationic imidizolium ions ([C4mim]+ or [C10mim]+) resulted in decomplexation or dethreading with restoration of the original emission spectra for 1, which signifies the subsequent increase in the FRET process. Thus we could demonstrate that a molecular folding-unfolding type of movement in the crown ether derivative could be induced by chemical input as an imidazolium ion.</p>1 aSuresh, Moorthy1 aMandal, Amal, Kumar1 aKesharwani, Manoj, K.1 aAdarsh, N., N.1 aGanguly, Bishwajit1 aKanaparthi, Ravi, Kumar1 aSamanta, Anunay1 aDas, Amitava  uhttps://library.ncl.res.in/content/folding-and-unfolding-movements-2pseudorotaxane00951nas a2200205   4500008004100000245014100041210006900182260000800251300001400259490000700273520017900280100002300459700002300482700001500505700002800520700002300548700002700571700001700598856013000615       2018                        eng d00aFluorescent chemodosimeter for quantification of Cystathionine-y-synthase activity in plant extracts and imaging of endogenous biothiols0 aFluorescent chemodosimeter for quantification of Cystathionineys  cAUG  a9079-90820 v543 a<p>A new reagent for quantification of CgS in plant extracts using a generalized methodology suitable for recognition of homocysteine (Hcy) with luminescence ON response.</p>1 aAgarwalla, Hridesh1 aHoskere, Anila, A.1 aAli, Firoj1 aPradhan, Swaraj, Rashmi1 aGanguly, Bishwajit1 aPramanik, Sumit, kumar1 aDas, Amitava  uhttps://library.ncl.res.in/content/fluorescent-chemodosimeter-quantification-cystathionine-y-synthase-activity-plant-extracts