@article { ISI:000375631300006, title = {Correlating Nitrile IR frequencies to local electrostatics quantifies noncovalent interactions of peptides and proteins}, journal = {Journal of Physical Chemistry B}, volume = {120}, number = {17}, year = {2016}, month = {MAY}, pages = {4034-4046}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Noncovalent interactions, in particular the hydrogen bonds and nonspecific long-range electrostatic interactions are fundamental to biomolecular functions. A molecular understanding of the local electrostatic environment, consistently for both specific (hydrogen-bonding) and nonspecific electrostatic (local polarity) interactions, is essential for a detailed understanding of these processes. Vibrational Stark Effect (VSE) has proven to be an extremely useful method to measure the local electric field using infrared spectroscopy of carbonyl and nitrile based probes. The nitrile chemical group would be an ideal choice because of its absorption in an infrared spectral window transparent to biomolecules, ease of site-specific incorporation into proteins, and common occurrence as a substituent in various drug molecules. However, the inability of VSE to describe the dependence of IR frequency on electric field for hydrogen-bonded nitriles to date has severely limited nitrile{\textquoteright}s utility to probe the noncovalent interactions. In this work, using infrared spectroscopy and atomistic molecular dynamics simulations, we have reported for the first time a linear correlation between nitrile frequencies and electric fields in a wide range of hydrogen-bonding environments that may bridge the existing gap between VSE and H-bonding interactions. We have demonstrated the robustness of this field-frequency correlation for both aromatic nitriles and sulfur-based nitriles in a wide range of molecules of varying size and compactness, including small molecules in complex solvation environments, an amino acid, disordered peptides, and structured proteins. This correlation, when coupled to VSE, can be used to quantify noncovalent interactions, specific or nonspecific, in a consistent manner.

}, issn = {1520-6106}, doi = {10.1021/acs.jpcb.6b02732}, author = {Deb, Pranab and Haldar, Tapas and Kashid, Somnath M. and Banerjee, Subhrashis and Chakrabarty, Suman and Bagchi, Sayan} } @article {44374, title = {Catalytic enantioselective 1,3-alkyl shift in alkyl aryl ethers: efficient synthesis of optically active 3,3 {\textquoteright}-diaryloxindoles}, journal = {Angewandte Chemie-International Edition}, volume = {57}, year = {2018}, month = {MAY}, pages = {5735-5739}, abstract = {Reported is the first organocatalytic asymmetric 1,3-alkyl shift in alkyl aryl ethers for the synthesis of chiral 3,3{\textquoteright}-diaryloxindoles using a chiral Bronsted acid catalyst. Preliminary results showed that each enantiomer of the 3,3{\textquoteright}-diaryloxindole, and a racemic mixture, showed different antiproliferative activities against HeLa cell lines by using an MTT assay.}, doi = {10.1002/anie.201801650}, author = {Gade, Amol B. and Bagle, Pradip N. and Shinde, Popat S. and Bhardwaj, Vipin and Banerjee, Subhrashis and Chande, Ajit and Patil, Nitin T.} } @article {48383, title = {Computational insights into hydroboration with acyclic alpha-Borylamido-germylene and stannylene catalysts: Cooperative dual catalysis the key to system efficiency}, journal = {Polyhedron}, volume = {222}, year = {2022}, month = {AUG}, pages = {115907}, type = {Article}, abstract = {

The chemistry of low valent main group compounds has grown as an alternative to the chemistry of less abundant and less green transition metal complexes. It has been found that low valent compounds such as carbenes, silylenes, stannylenes and germylenes are efficient for activating small molecules and for catalysis. However, the reaction mechanism and the factors that affect the rate of reaction are not completely understood. In this computational investigation with density functional theory (DFT), we investigate and demonstrate the efficiency of a new mechanism for the hydroboration of aldehydes by germylenes and stannylenes, in the presence of the common hydroborating agent, pinacolborane, HBpin. This mechanism involves an HBpin molecule as an additional catalyst that cooperates with the germylene or stannylene catalyst to efficiently carry out the hydroboration. This mechanism is first demonstrated to work for experimentally reported systems, and then shown to be efficient for newly proposed germylene and stannylene systems. These new systems are alpha-Borylamido-germylene ((2,6-iPr(2)C(6)H(3)NBCy(2))(2)Ge(II)) and alpha-Borylamido-stannylene((2,6-iPr(2)C(6)H(3)NBCy(2))(2)Sn(II)). These new insights will help researchers look into low valent germylene and stannylene chemistry from a new perspective.

}, keywords = {Catalysis of hydroboration, computational chemistry, Germylenes and stannylenes, Main group chemistry, New mechanism}, issn = {0277-5387}, doi = {10.1016/j.poly.2022.115907}, author = {Banerjee, Subhrashis and Vanka, Kumar} } @article {48263, title = {Controlled reduction of isocyanates to formamides using monomeric magnesium}, journal = {Chemical Communications}, volume = {59}, year = {2023}, month = {FEB}, pages = {2255-2258}, type = {Article}, abstract = {

This work describes a transition metal-free methodology involving an efficient and controlled reduction of isocyanates to only formamide derivatives using pinacolborane (HBpin) as the hydrogenating agent and a bis(phosphino)carbazole ligand stabilized magnesium methyl complex (1) as the catalyst. A large number of substrates undergo selective hydroboration and give exclusively N-boryl formamides.

}, issn = {1359-7345}, doi = {10.1039/d3cc00036b}, author = {Kumar, Rohit and Sharma, Vishal and Banerjee, Subhrashis and Vanka, Kumar and Sen, Sakya S.} }