01326nas a2200181   4500008004100000022001300041245011300054210006900167260000900236300001700245490000700262520066700269100002100936700002400957700002200981700001701003856012401020       2018                        eng d  a1463907600aWhat drives the H-abstraction reaction in bio-mimetic oxoiron-bTAML complexes? A computational investigation0 aWhat drives the Habstraction reaction in biomimetic oxoironbTAML  cAPR   a13845-13850 0 v203 aMonomeric iron-oxo units have been confirmed as intermediates involved in the C–H bond activation in various metallo-enzymes. Biomimetic oxoiron complexes of the biuret modified tetra-amido macrocyclic ligand (bTAML) have been demonstrated to oxidize a wide variety of unactivated C–H bonds. In the current work, density functional theory (DFT) has been employed to investigate the hydrogen abstraction (HAT) reactivity differences across a series of bTAML complexes. The cause for the differences in the HAT energy barriers has been found to be the relative changes in the energy of the frontier molecular orbitals (FMOs) induced by electronic perturbation.1 aMukherjee, Anagh1 aPattanayak, Santanu1 aGupta, Sayam, Sen1 aVanka, Kumar  uhttps://library.ncl.res.in/content/what-drives-h-abstraction-reaction-bio-mimetic-oxoiron-btaml-complexes-computational01069nas a2200181   4500008004100000022001400041245009700055210006900152260000900221300001400230490000700244520042200251100002100673700002100694700001700715700002600732856012900758       2019                        eng d  a0022-326300aMetal-free regioselective cross dehydrogenative coupling of cyclic ethers and aryl carbonyls0 aMetalfree regioselective cross dehydrogenative coupling of cycli  cFEB   a2039-20470 v843 a<p>A highly regioselective, efficient, and metal-free oxidative cross dehydrogenative coupling (CDC) of aryl carbonyls with cyclic ethers has been developed. This method offers easy access to substituted alpha-arylated cyclic ethers with a high functional group tolerance in good to excellent yields. The regioselectivity of this CDC reaction was confirmed by density functional theory (DFT)-based calculations.</p>
1 aMane, Kishor, D.1 aMukherjee, Anagh1 aVanka, Kumar1 aSuryavanshi, Gurunath  uhttps://library.ncl.res.in/content/metal-free-regioselective-cross-dehydrogenative-coupling-cyclic-ethers-and-aryl-carbonyls02271nas a2200265   4500008004100000022001400041245010900055210006900164260000800233300001000241490000700251520135700258653003501615653001701650653001701667653003501684653000901719100002701728700003101755700002101786700002401807700002301831700002501854856012601879       2020                        eng d  a0268-260500aAnthrone-spirolactam and quinoline hybrid based sensor for selective fluorescent detection of Fe(3+)ions0 aAnthronespirolactam and quinoline hybrid based sensor for select  cOCT  ae58670 v343 a<p>The synthesis of a novel, and highly selective Fe(3+)ion sensor based on anthrone-spirolactam and its quinoline hybrid ligand is reported. The designed ligand displayed selective detection of Fe(3+)ions with enhanced fluorescence emission. The complexation of Fe(3+)ion led to a red shift of 32 nm from 420 nm to 452 nm, and a several fold increase in intensity with fluorescent green emission. The complexation (detection) of Fe(3+)ions with ligand resulted in chelation enhanced fluorescence and intramolecular charge transfer through the inhibition of C=N isomerization. This hybrid sensor shows high sensitivity and selectivity, spontaneous response, and works on a wide pH range a minimum detection limit of 6.83 x 10(-8)M. Importantly, the sensor works through the fluorescence turn-on mechanism that overcomes the paramagnetic effect of Fe(3+)ions. The binding mechanism between the ligand and the Fe(3+)ions was established from the Job's plot method, optical studies, Fourier transfor infrared spectroscopy, NMR titration, fluorescence life-time studies, and density functional theory optimization. The sensor displayed excellent results in the quantification of Fe(3+)ions from real water samples. Furthermore, due to its biocompatibility nature, fluorescent spotting of Fe(3+)ions in live cells revealed its bioimaging applications.</p>
10aanthrone-spirolactam-quinoline10aCell imaging10afluorescence10aintramolecular charge transfer10airon1 aDarole, Ratanamala, S.1 aLeslee, Denzil, Britto Chr1 aMukherjee, Anagh1 aGonnade, Rajesh, G.1 aKaruppannan, Sekar1 aSenthilkumar, Beeran  uhttps://library.ncl.res.in/content/anthrone-spirolactam-and-quinoline-hybrid-based-sensor-selective-fluorescent-detection01563nas a2200265   4500008004100000022001400041245014800055210006900203260000900272300001100281490000700292520063500299653001600934653002200950653003100972653001901003653002901022100002201051700002101073700001901094700001901113700001701132700002001149856012801169       2020                        eng d  a0040-402000aHighly efficient chemoselective N-tert butoxycarbonylation of aliphatic/aromatic/heterocyclic amines using diphenylglycoluril as organocatalyst0 aHighly efficient chemoselective Ntert butoxycarbonylation of ali  cJUN   a1312230 v763 a<p>An efficient approach for the Chemoselective N-tert-butoxycarbonylation of a variety of amines using diphenylglycoluril as organocatalyst has been described. For the first time, a plausible mechanism for the N-tert-butoxycarbonylation has been proposed using density functional theory (DFT) calculations supported by NMR studies. The reusability of the organocatalyst and observation of the desired N-Boc protected amines being formed without the formation of side products like urea, oxazolidinone, isocyanate, and N, N-di-Boc derivatives makes the present protocol desirable. (C) 2020 Elsevier Ltd. All rights reserved.</p>
10aDFT studies10aDiphenylglycouril10aN-tert butoxycarbonylation10aorganocatalyst10aProton shuttle mechanism1 aAwasthi, Amardeep1 aMukherjee, Anagh1 aSingh, Mandeep1 aRathee, Garima1 aVanka, Kumar1 aChandra, Ramesh  uhttps://library.ncl.res.in/content/highly-efficient-chemoselective-n-tert-butoxycarbonylation-aliphaticaromaticheterocyclic01752nas a2200181   4500008004100000022001400041245008300055210006900138260000900207300001400216490000800230520115100238100002101389700002101410700002701431700001701458856009501475       2020                        eng d  a1089-563900aUnraveling the hidden role of the counteranion in ``cation in a cage'' systems0 aUnraveling the hidden role of the counteranion in cation in a ca  cOCT   a8040-80490 v1243 a<p>The current work showcases general principles at play in systems consisting of cations present inside molecular cages. Such systems, relevant to chemistry and biology, have been carefully investigated by computational methods. The important Ge(II)-encapsulating cage systems have been studied first. The very fact that such compounds exist appears highly unlikely, given the highly reactive nature of the Ge(II) dication. Our studies reveal what really occurs in solution when such complexes are formed: the Ge(II) dications are actually present as [Ge-X](+) (where X is the ``non-coordinating'' counterion employed in such systems) during entry and subsequent existence at the center of the cage. Hence, what is actually present is a ``pseudomonocation''. Interestingly, such pseudomonocation-encapsulated cages are seen to be equally relevant in systems of biological importance, such as for dicationic s block-based ionophores. In explaining such cases, the concept of ``isoionicity'' is introduced, demonstrating that the counterion-coordinated dications are isoionic with a monocation, such as Li(I), isolated in the same ionophore.</p>
1 aMukherjee, Anagh1 aGhule, Siddharth1 aTiwari, Mrityunjay, K.1 aVanka, Kumar  uhttps://library.ncl.res.in/content/unraveling-hidden-role-counteranion-cation-cage-systems02326nas a2200229   4500008004100000022001400041245012600055210006900181260000800250300001400258490000700272520151300279653001901792653003601811653001901847653002001866653002401886100002101910700002101931700001701952856012701969       2021                        eng d  a1439-423500aComputational insights into the role of external and local electric fields in macrocyclic chemical and biological systems0 aComputational insights into the role of external and local elect  cDEC  a2484-24920 v223 aThe investigation of the role of the electric field in systems of widespread interest employing computational techniques is an emerging area of research. The outcome of applying an oriented external electric field (OEEF) on the geometric and electronic properties of the chemically unique pi-conjugated cyclic carbon ring compounds has been explored with density functional theory (DFT). Distinct changes in the structural and electronic features of such ring compounds are observed upon the application of OEEFs. Importantly, the calculations indicate that a mixed aliphatic-aromatic conjugated ring converts from a singlet to a triplet after the application of an OEEF, suggesting potential applications in optoelectronics for such molecules, without the need for photochemically induced change in the spin state. Furthermore, the influence of built-in local electric fields (LEFs) present in naturally occurring macrocyclic systems such as valinomycin has also been explored. Static and ab initio molecular dynamics (AIMD) calculations indicate that LEFs are the primary driving factor in determining the energetically favoured position of counter anions such as chloride (Cl-) in the potassium (K+) and sodium (Na+) coordinated valinomycin macrocycle structures: they exist inside the cage in the case of K+ sequestration by valinomycin and outside for Na+. This divergence has been proposed to be the determining factor for the selectivity of the valinomycin macrocycle for binding a K+ cation over Na+.10acounter anions10aDensity functional calculations10aelectric field10aion selectivity10amacrocyclic systems1 aMukherjee, Anagh1 aGhule, Siddharth1 aVanka, Kumar  uhttps://library.ncl.res.in/content/computational-insights-role-external-and-local-electric-fields-macrocyclic-chemical-and