@article { ISI:000310215400007, title = {Conformational modulation of Ant-Pro oligomers using chirality alteration of proline residues}, journal = {Organic \& Biomolecular Chemistry}, volume = {10}, number = {42}, year = {2012}, month = {SEP}, pages = {8426-8433}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Structural modulation of Ant-Pro (anthranilic acid-proline) oligomers has been carried out by chirality alteration of the proline residues. The results suggest that the chirality altered oligomers show well-defined helical conformation featuring nine-membered hydrogen bonding interactions - without compromising conformational rigidity.

}, issn = {1477-0520}, doi = {10.1039/c2ob26132d}, author = {Kale, Sangram S. and Kotmale, Amol S. and Dutta, Achintya Kumar and Pal, Sourav and Rajamohanan, P. R. and Sanjayan, Gangadhar J.} } @article { ISI:000317327900022, title = {Carboxamide versus sulfonamide in peptide backbone folding: a case study with a hetero foldamer}, journal = {Organic Letters}, volume = {15}, number = {7}, year = {2013}, month = {APR}, pages = {1504-1507}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Strikingly dissimilar hydrogen-bonding patterns have been observed for two sets of closely similar hetero foldamers containing carboxamide and sulfonamides at regular intervals. Although both foldamers maintain conformational ordering, the hydrogen-bonding pattern and backbone helical handedness differ diametrically.

}, issn = {1523-7060}, doi = {10.1021/ol4002762}, author = {Ramesh, Veera V. E. and Kale, Sangram S. and Kotmale, Amol S. and Gawade, Rupesh L. and Puranik, Vedavati G. and Rajamohanan, P. R. and Sanjayan, Gangadhar J.} } @article { ISI:000329299200005, title = {Comparison of sodium zirconium phosphate and calcium zirconium phosphate structures for the retention of fluoride}, journal = {Journal of Radioanalytical and Nuclear Chemistry}, volume = {299}, number = {1}, year = {2014}, month = {JAN}, pages = {19-24}, publisher = {SPRINGER}, type = {Article}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

Fluoride anion interaction has been explored for the first time to investigate how the structure of sodium zirconium phosphate (NZP) and calcium zirconium phosphate (CZP) can be altered in its presence. Different compositions were made by adding NaF and CaF2 in CZP and NZP matrices respectively. Fluoride interaction differs with NZP and CZP structure as suggested by F-NMR data. The addition of fluoride to the NZP or CZP structure enables to stabilize the structure at a low temperature of 600-700 A degrees C under microwave conditions.

}, keywords = {F-NMR, Fluoride characterization, Microwave, NZP, PIGE}, issn = {0236-5731}, doi = {10.1007/s10967-013-2741-2}, author = {Dey, Ambarish and Das Gupta, Amit and Basu, Debrata and Ambashta, Ritu D. and Wattal, P. K. and Kumar, Sanjiv and Body, Monique and Rajamohanan, P. R.} } @article { ISI:000331895900018, title = {Conformational modulation of peptide secondary structures using beta-aminobenzenesulfonic acid}, journal = {Chemical Communications}, volume = {50}, number = {22}, year = {2014}, month = {JAN}, pages = {2886-2888}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

This communication describes the influence of beta-aminobenzenesulfonic acid ((S)Ant) on the conformational preferences of hetero foldamers. The designed (Aib-(S)Ant-Aib)(n) and (Aib-(S)Ant-Pro)(n) oligomers display a well-defined folded conformation featuring intramolecular mixed hydrogen bonding (7/11) and intra-residual (6/5) H-bonding interactions, respectively.

}, issn = {1359-7345}, doi = {10.1039/c3cc48850k}, author = {Kale, Sangram S. and Kunjir, Shrikant M. and Gawade, Rupesh L. and Puranik, Vedavati G. and Rajamohanan, P. R. and Sanjayan, Gangadhar J.} } @article {44111, title = {Chiral discrimination through h-1 nmr and luminescence spectroscopy: dynamic processes and solid strip for chiral recognition}, journal = {Chemistry-A European Journal}, volume = {23}, year = {2017}, month = {DEC}, pages = {18303-18313}, type = {Article}, abstract = {The appropriate choice of the host molecules with well-defined optical activity (S-H/R-H) helps in the differentiation between two secondary ammonium ion-derivative guest molecules with different optical activities (R-G/S-G) based on the fluorescence resonance energy transfer (FRET)based luminescence responses. Crown ether-based host molecules with opposite chiral configurations (R-H, S-H) have been derived from 1,1{\textquoteright}-bi-2-naphthol (BINOL) derivatives that have axially chiral biaryl centers. These chiral crown ethers form host-guest complexes (i.e., [2] pseudoro-taxanes) with chiral secondary ammonium ion derivatives (R-G, S-G). NMR spectroscopic studies show that the complexes are in a dynamic equilibrium in solution. Results of the H-1 NMR and fluorescence spectroscopic studies indicate a head-on orientation of the host and guest in the [2] pseudorotaxanes. The difference in the efficiency in the FRET-based responses between anthracene and the BINOL derivatives allow efficient chiral discrimination of the guests. Isothermal titration calorimetry and NMR investigations reveal that inclusion complexes between hosts and guests of the same chirality (R-H center dot R-G, S-H center dot S-G) are more stable relative to those of opposite chirality (R-H center dot S-G, S-H center dot R-G). However, FRET-based energy-transfer efficiency is higher for R-H center dot S-G and S-H center dot R-G complexes. NMR spectroscopic studies show that the relative orientation of the guest in the host cavity is significantly different when the host binds a guest of the same or opposite chirality; furthermore, the latter is more favorable for FRET, thus enabling discrimination between enantiomers. Interestingly, chiral discrimination of guest ions could also be achieved by using silica surfaces modified with chiral host molecules.}, doi = {10.1002/chem.201704837}, author = {Gangopadhyay, Monalisa and Maity, Arunava and Dey, Ananta and Rajamohanan, P. R. and Ravindranathan, Sapna and Das, Amitava} }