01827nas a2200253 4500008004100000245013400041210006900175260000800244300001600252490000700268520093800275100002201213700002301235700001801258700002001276700002101296700001801317700002101335700002501356700002101381700002101402700002101423856012901444 2016 eng d00aUltrahydrophobic fluorous metal-organic framework derived recyclable composite as apromising platform to tackle marine oil spills0 aUltrahydrophobic fluorous metalorganic framework derived recycla cJUL a10937-109430 v223 aDerived from a strategically chosen hexafluorinated dicarboxylate linker aimed at the designed synthesis of a superhydrophobic metal-organic framework (MOF), the fluorine-rich nanospace of a water-stable MOF (UHMOF-100) exhibits excellent water-repellent features. It registered the highest water contact angle (approximate to 176 degrees) in the MOF domain, marking the first example of an ultrahydrophobic MOF. Various experimental and theoretical studies reinforce its distinc-tive water-repellent characteristics, and the conjugation of superoleophilicity and unparalleled hydrophobicity of a MOF material has been coherently exploited to achieve real-time oil/water separation in recyclable membrane form, with significant absorption capacity performance. This is also the first report of an oil/water separating fluorinated ultrahydrophobic MOF-based membrane material, with potential promise for tackling marine oil spillages.1 aMukherjee, Soumya1 aKansara, Ankit, M.1 aSaha, Debasis1 aGonnade, Rajesh1 aMullangi, Dinesh1 aManna, Biplab1 aDesai, Aamod, V.1 aThorat, Shridhar, H.1 aSingh, Puyam, S.1 aMukherjee, Arnab1 aGhosh, Sujit, K. uhttps://library.ncl.res.in/content/ultrahydrophobic-fluorous-metal-organic-framework-derived-recyclable-composite-apromising01365nas a2200205 4500008004100000022001400041245006300055210006300118260000800181300001400189490000800203520073300211100002400944700002100968700001700989700001901006700002101025700001801046856009501064 2019 eng d a1520-610600aArresting an unusual amide tautomer using divalent cations0 aArresting an unusual amide tautomer using divalent cations cOCT a8419-84240 v1233 a

Ion-specific effects on peptides and proteins are key to biomolecular structure and stability. The subtle roles of the cations are far less understood, compared to the pronounced effects of the anions on proteins. Most importantly, divalent cations such as Ca2+ and Mg2+ are crucial to several biological functions. Herein, we demonstrate that an amide-iminolate equilibrium is triggered by the binding of the divalent cations to the amide oxygen in aqueous solution. The excellent agreement between the experimental and theoretical results confirms the arrest of an unusual amide tautomer by the divalent cations, which is a rarely known phenomenon that might open up an array of applications in chemistry and biology.

1 aKashid, Somnath, M.1 aSingh, Reman, K.1 aKwon, Hyejin1 aKim, Yung, Sam1 aMukherjee, Arnab1 aBagchi, Sayan uhttps://library.ncl.res.in/content/arresting-unusual-amide-tautomer-using-divalent-cations06213nas a2200217 4500008004100000022001400041245009500055210006900150260000800219300001400227490000800241520546200249100002405711700002105735700001705756700001905773700001905792700002105811700001805832856014505850 2020 eng d a1520-610600aReply to “comment on ‘arresting an unusual amide tautomer using divalent cations’”0 aReply to comment on arresting an unusual amide tautomer using di cDEC a479–4830 v1253 a

In our publication, we assigned the blue-shifted shoulder of N-methylacetamide (NMA) in the infrared (IR) spectrum (∼1645 cm–1) to an iminolate tautomer stabilized in the presence of divalent metal cations (e.g., 5 M Ca2+).(1) Cremer and co-workers comment that this shoulder arises from the dehydration of the amide oxygen upon interaction with the metal cations.(2,3) Their assignment is based on three interesting experimental observations: (1) the IR spectrum of 15N-isotope-labeled NMA does not show any considerable red-shift compared to that of NMA; (2) a new peak appears for NMA at 1680 cm–1 in the presence of 1 M DCl, which shows a 17 cm–1 red-shift for 15N-labeled NMA; and (3) the IR spectrum of acetone C═O stretch also demonstrates a blue-shifted shoulder in the presence of a high concentration of CaCl2.

1 aKashid, Somnath, M.1 aSingh, Reman, K.1 aKwon, Hyejin1 aSeol, Jin, Gyu1 aKim, Yung, Sam1 aMukherjee, Arnab1 aBagchi, Sayan uhttps://library.ncl.res.in/content/reply-%E2%80%9Ccomment-%E2%80%98arresting-unusual-amide-tautomer-using-divalent-cations%E2%80%99%E2%80%9D01632nas a2200217 4500008004100000022001400041245007300055210006900128260000800197300001600205490000800221520094400229100001901173700002401192700001601216700002101232700001801253700002101271700001901292856010301311 2022 eng d a1520-610600aWater-controlled keto-enol tautomerization of a prebiotic nucleobase0 aWatercontrolled ketoenol tautomerization of a prebiotic nucleoba cJUL a5735–57430 v1263 a

Barbituric acid is believed to be a proto-RNA nucleobase that was used for biological information transfer on prebiotic earth before DNA and RNA in their present forms evolved. Nucleobases have various tautomeric forms and the relative stability of these forms is critical to their biological function. It has been shown that barbituric acid has a tri-keto form in the gas phase and an enol form in the solid state. However, its dominant tautomeric form in aqueous medium that is most relevant for biology has been investigated only to a limited extent and the findings are inconclusive. We have used multiple approaches, namely, molecular dynamics, quantum chemistry, NMR, and IR spectroscopy to determine the most stable tautomer of barbituric acid in solution. We find a delicate balance in the stability of the two tautomers, tri-keto and enol, which is tipped toward the enol as the extent of solvation by water increases.

1 aDatar, Avdhoot1 aPaithankar, Harshad1 aDeb, Pranab1 aChugh, Jeetender1 aBagchi, Sayan1 aMukherjee, Arnab1 aHazra, Anirban uhttps://library.ncl.res.in/content/water-controlled-keto-enol-tautomerization-prebiotic-nucleobase