@article {43904, title = {Binding selectivity of vitamin K3 based chemosensors towards nickel(II) and copper(II) metal ions}, journal = {Journal of molecular Structure}, volume = {1143}, year = {2017}, month = {SEP}, chapter = {495-514}, abstract = {

The vitamin K3 derivatives 2-methyl-3-[(pyridin-2-ylmethyl)-amino]-1,4-naphthoquinone (M-1), 2-methyl-3-[(pyridin-2-ylethyl)-amino]-1,4-naphthoquinone (M-2), 2-methyl-3-((2-(thiophen-2-yl) methyl)amino)naphthalene-1,4-dione (M-3) and 2-methyl-3-((2-(thiophen-2-yl)ethyl)amino)naphthalene-1,4-dione (M-4) have been synthesized, characterized and studied for their chemosensor abilities towards transition metal ions. Crystal structures of M-1 to M-4 revealed a variety of N-H center dot center dot O, C-H center dot center dot center dot O, C-H center dot center dot center dot pi and pi center dot center dot center dot pi interactions. Minor variations in such interactions by chemical stimuli such as metal ions, results in change in color that can be visualized by naked eyes. It has been shown that electronic structure and H-1 NMR, vibrational as well as electronic spectra from the density functional theory agree well with the experiments. The metal ion binding in ethanol, ethanol-water and in mild base triethylamine brings forth recognizing ability of M-1 toward Ni2+ whereas M-2 exhibits large sensing ability for Cu2+ ion. Interestingly M-1 display varying metal ion binding specificity in different solvents with the association constant in ethanol being 11,786 M-1 for Ni2+ compared to 9462 M-1 for the Cu2+. A reversal in preferential binding of M-2 with the respective association constants being 4190 M-1 and 6370 M-1 is discernible. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {Aminonaphthoquinone Molecular-structures, Anthraquinone, Aqueous-solution, Chemosensor, Crystal-structures, Cu(II), Derivatives, DFT, Fluorometric Chemosensors, hydrogen bonding, Naphthoquinone, pi-pi stacking, Recognition, sensors}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2017.04.094}, author = {Patil, Amit and Lande, Dipali N. and Nalkar, Archana and (Gejji, Shridhar P. and Chakrovorty, Debamitra and Gonnade, Rajesh and Moniz, Tania and Rangel, Maria and Pereira, Eulalia and Salunke-Gawali, Sunita} } @article {46318, title = {Dimedone-based rigid organic scaffold for organizing symmetrical helical peptide chains.}, journal = {ChemistrySelect}, volume = {4}, year = {2019}, month = {OCT }, pages = {11518-11522}, type = {Article}, abstract = {

We describe herein design, synthesis and conformational investigations of polypeptides attached on a rigid dimedone template. Two identical peptide chains are attached on a single carbon containing dimedone as a scaffold. Dimedone assists in controlling the secondary interactions through strong intramolecular helical C-12 and C-15 membered bifurcated hydrogen bonding on both the peptide chains along with propagating the helical architecture of the peptide chains attached. There exists a C-6 hydrogen bonding for the single stranded peptides attached to dimedone. Extensive structural investigations involving single crystal X-ray diffraction, solution-state NMR and CD studies of oligopeptides have been undertaken.

}, keywords = {dimedone, Helical, hydrogen bonding, Peptides, template}, issn = {2365-6549}, doi = {10.1002/slct.201903087}, author = {Madica, Krishnaprasad and Lakshmi, Jerripothula K. and Madhu, Suresh and Nadimpally, Krishna Chaitanya and Gonnade, Rajesh and Jagadeesh, Bharatam and Sanjayan, Gangadhar J.} }