@article {44558, title = {What drives the H-abstraction reaction in bio-mimetic oxoiron-bTAML complexes? A computational investigation}, journal = {Physical Chemistry and Chemical Physics}, volume = {20}, year = {2018}, month = {APR }, pages = {13845-13850 }, type = {Journal Article}, abstract = {Monomeric iron-oxo units have been confirmed as intermediates involved in the C{\textendash}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{\textendash}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.}, issn = {14639076}, doi = {10.1039/C8CP01333K}, author = {Mukherjee, Anagh}, editor = {Pattanayak, Santanu} } @article {46194, title = {Metal-free regioselective cross dehydrogenative coupling of cyclic ethers and aryl carbonyls}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {FEB }, pages = {2039-2047}, type = {Article}, abstract = {

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.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b03048}, author = {Mane, Kishor D. and Mukherjee, Anagh and Vanka, Kumar and Suryavanshi, Gurunath} } @article {46796, title = {Anthrone-spirolactam and quinoline hybrid based sensor for selective fluorescent detection of Fe(3+)ions}, volume = {34}, year = {2020}, month = {OCT}, pages = {e5867}, type = {Article}, abstract = {

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{\textquoteright}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.

}, keywords = {anthrone-spirolactam-quinoline, Cell imaging, fluorescence, intramolecular charge transfer, iron}, issn = {0268-2605}, doi = {10.1002/aoc.5867, Early Access Date = JUL 2020}, author = {Darole, Ratanamala S. and Christopher Leslee, Denzil Britto and Mukherjee, Anagh and Gonnade, Rajesh G. and Karuppannan, Sekar and Senthilkumar, Beeran} } @article {46834, title = {Highly efficient chemoselective N-tert butoxycarbonylation of aliphatic/aromatic/heterocyclic amines using diphenylglycoluril as organocatalyst}, journal = {Tetrahedron}, volume = {76}, year = {2020}, month = {JUN }, pages = {131223}, type = {Article}, abstract = {

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.

}, keywords = {DFT studies, Diphenylglycouril, N-tert butoxycarbonylation, organocatalyst, Proton shuttle mechanism}, issn = {0040-4020}, doi = {10.1016/j.tet.2020.131223}, author = {Awasthi, Amardeep and Mukherjee, Anagh and Singh, Mandeep and Rathee, Garima and Vanka, Kumar and Chandra, Ramesh} } @article {46691, title = {Unraveling the hidden role of the counteranion in {\textquoteleft}{\textquoteleft}cation in a cage{\textquoteright}{\textquoteright} systems}, journal = {Journal of Physical Chemistry A}, volume = {124}, year = {2020}, month = {OCT }, pages = {8040-8049}, type = {Article}, abstract = {

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 {\textquoteleft}{\textquoteleft}non-coordinating{\textquoteright}{\textquoteright} counterion employed in such systems) during entry and subsequent existence at the center of the cage. Hence, what is actually present is a {\textquoteleft}{\textquoteleft}pseudomonocation{\textquoteright}{\textquoteright}. 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 {\textquoteleft}{\textquoteleft}isoionicity{\textquoteright}{\textquoteright} is introduced, demonstrating that the counterion-coordinated dications are isoionic with a monocation, such as Li(I), isolated in the same ionophore.

}, issn = {1089-5639}, doi = {10.1021/acs.jpca.0c06995}, author = {Mukherjee, Anagh and Ghule, Siddharth and Tiwari, Mrityunjay K. and Vanka, Kumar} } @article {47608, title = {Computational insights into the role of external and local electric fields in macrocyclic chemical and biological systems}, journal = {ChemPhysChem}, volume = {22}, year = {2021}, month = {DEC}, pages = {2484-2492}, type = {Article}, abstract = {The 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+.}, keywords = {counter anions, Density functional calculations, electric field, ion selectivity, macrocyclic systems}, issn = {1439-4235}, doi = {10.1002/cphc.202100581}, author = {Mukherjee, Anagh and Ghule, Siddharth and Vanka, Kumar} }