Lisa Roy

Lisa Roy
Institute of Chemical Technology, Mumbai | ICT · IOC Bhubaneswar Campus

PhD

About

41
Publications
18,340
Reads
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373
Citations
Introduction
Our work is focused on the investigation and modeling of catalytic activities, in enzymes, synthetic complexes and on surfaces to derive meaningful insights about the mechanisms of these molecular machines. In our group we mainly utilize quantum chemical methodology to understand the following: Bio-inspired homogeneous catalytic reactions, Gas storage and heterogeneous catalysis, Non-covalent interaction guided catalysis and self-assembly
Additional affiliations
November 2018 - present
Institute of Chemical Technology, Mumbai
Position
  • Professor (Assistant)
October 2017 - October 2018
Central Mechanical Engineering Research Institute
Position
  • Fellow
July 2015 - October 2017
Max Planck Institute for Chemical Energy Conversion
Position
  • PostDoc Position

Publications

Publications (41)
Article
The development of synthetic nonequilibrium systems has gathered increasing attention due to their potential to illustrate the dynamic, complex, and emergent traits of biological systems. Simple building blocks capable of interacting via dynamic covalent chemistry and physical assembly in a reaction network under nonequilibrium conditions can contr...
Article
An electrochemical method for the synthesis of unsymmetrically substituted NH-pyrroles is described. The synthetic strategy comprises a challenging heterocoupling between two structurally diverse enamines via sequential chemoselective oxidation, addition, and cyclization processes. A series of aryl- and alkyl-substituted enamines were effectively c...
Article
C≡N bond scission can be a potential avenue for functionalization of chemical bonds. We have conducted a computational study, using density functional theory (DFT) and ab initio multireference CASSCF method, to unravel the intricate mechanistic pathways traversed in the copper-promoted, dioxygen assisted reaction for formation of aryl isocyanate sp...
Article
This article reports π-chromophore assemblies from three structurally related dipolar naphthalene monoimide (NMI) luminogens (M1, M2 and M3) by underexplored orthogonal dipole-dipole interaction and halogen bonding. Single crystal structure analysis...
Article
Full-text available
An acceptorless dehydrogenative strategy for the synthesis of polyfluoroalkylated bis‐indoles is described by employing an earth‐abundant nickel‐based catalytic system under air. The notable feature of the present transformation is the use of bench stable and easily affordable polyfluorinated alcohols without any pre‐functionalization for the intro...
Article
Merocyanine dye assembly in nonpolar solvents is driven by electrostatic dipole‐dipole interactions, which make hierarchical structures of merocyanine less favorable, due to the compensation of its dipole moment in the discrete antiparallel dimers. Herein, we describe the self‐assembly of a merocyanine dye ( MC‐OH ) into higher aggregates in aqueou...
Article
Full-text available
A diastereoselective allylation of N-tert-butane sulfinyl α-iminoesters using allylboronic acids is developed to obtain optically active non-proteinogenic α-amino acid precursors in good yields and diastereoselectivities. Gram-scale synthesis, broad tolerance of functional groups, excellent stereodivergence, post-synthetic modifications, and easy r...
Article
C≡N bond scission can be a potential avenue for functionalization of chemical bonds. We have conducted a computational study, using density functional theory (DFT) and ab initio multireference CASSCF method, to unravel the intricate mechanistic pathways traversed in the copper‐promoted, dioxygen assisted reaction for formation of aryl isocyanate sp...
Article
Stabilizing noncovalently encapsulated guest molecules inside a nanoassembly constructed from amphiphilic polymers has become a very challenging effort in the area of targeted drug delivery of biomedical applications. The unwanted...
Article
The role of solvents in the control over supramolecular interactions has been studied for decades in protein folding, soft material fabrication and long-range organization of functional organic π chromophores. Nonpolar...
Article
Full-text available
An electrochemical method for the synthesis of unsymmetrically substituted NH-pyrroles is described. The synthetic strategy comprises a challenging heterocoupling between two structurally diverse enamines via sequential chemoselective oxidation, addition, and cyclization processes. A series of aryl- and alkyl-substituted enamines were effectively c...
Article
A metal-free C-C bond activation strategy of 1,3-diynes has been described via an "extrusion and recombination"approach, which delivered structurally important 1,2-diketones. This phenomenon was performed using tetra-n-butylammonium iodide (TBAI) as a catalyst and peroxide as a radical initiator and oxidant. The C-C bond activation follows sequenti...
Preprint
b>C≡N bond scission accomplished by protonation, reductive cleavage and metathesis techniques are well-known to execute nitrogen transfer reactions. Herein, we have conducted an extensive computational study, using DFT and molecular dynamics simulations, to unravel the mechanistic pathways traversed in CuCN and CuBr<sub>2</sub> promoted splitting o...
Article
Full-text available
An organophotoredox-catalyzed reduction/addition/oxidation cascade of N-protected maleimides and N-(acyloxy)phthalimides is documented. The mild and efficient redox-neutral process involves hitherto unknown Giese-type addition of aryloxy-alkyl radicals on the N-protected maleimides and a successive oxidation allowing an overall Z-alkenylation of N-...
Article
Density functional calculations have been performed to elucidate the mechanism of formation of N‐phenylbenzylamine (Am) from alkylation of aniline (An) with benzaldehyde (Bz), with the intermediacy of the imine, N‐benzylideneaniline (Im), catalyzed by the triaryl borane (BAr3), B(2,6‐Cl2C6H3)(p‐HC6F4)2, and utilizing H2 as the reductant. Our comput...
Chapter
Conversion of CO2 into liquid fuels and value-added fine chemicals has gained much attention in recent years to meet the ever-rising global energy demand and hence develop a sustainable solar fuel economy. This chapter enumerates feasible catalytic routes through which CO2 could be utilized as a C1 feedstock. First, we address CO2 functionalization...
Article
The conversion of CO2 into liquid fuels and value-added fine chemicals is of significant interest for both environment and global energy demand. In this frontier article, we highlight viable methods for transforming CO2 into valuable C1 feedstocks and summarize the key mechanistic aspects obtained by in-depth computational investigations of three i...
Article
Catalytic removal of H2 from boron‐nitride (BN)‐based nanomaterials at ambient conditions is of paramount importance in order to develop lightweight hydrogen storage media. Here, the DLPNO‐CCSD(T) technique is used to calculate accurate relative energies and activation barriers of Brønsted acid‐initiated removal of H2 from hydrogenated BN nanotubes...
Article
Post-synthetic modification of organic linkers embedded in a metal–organic framework (MOF) is a favourable strategy to improve the storage of hydrogen through physisorption at ambient conditions. Density functional and domain-based local pair natural orbital coupled cluster calculations are conducted to evaluate the feasibility of hydrogen adsorpti...
Article
Supra-amphiphiles constituted of non-covalent bonds have emerged as attractive systems for fabrication of stimuli-responsive self-assembled nanostructures. A unique supramolecular strategy utilizing halogen (X)-bonding interaction has been demonstrated for constructing emissive supra-π-amphiphiles in water from a hydrophobic pyridyl functionalized...
Article
Selective functionalization of C‐H bond provides a straightforward approach to a large variety of well‐defined derivatives. High‐valent mononuclear iron(IV)‐oxo complexes are proposed to carry out these C‐H activation reactions in enzymes or in biomimetic syntheses. In this present endeavor we aim to highlight the features that delineate the distin...
Article
Full-text available
Fixation and chemical reduction of CO 2 are important for utilization of this abundant resource, and understanding the detailed mechanism of CO cleavage is needed for rational development of CO 2 reduction methods. Here, we describe a detailed analysis of the mechanism of the reaction of a masked two-coordinate cobalt(I) complex, L tBu Co (where L...
Article
Selective C=C bond oxidation is a fundamental process in Nature and has potential utility in organic synthesis. Herein, we employ ab initio and density functional techniques to investigate the nature of the oxidant and mechanism in alkene oxidation by two H2O2 activating Rieske oxygenase inspired iron catalysts, one of which is more sterically encu...
Article
We employ quantum chemical calculations to study the hydrogenation of carbon dioxide by amine boranes, NMe3BH3(Me3AB) and NH3BH3(AB) weakly bonded to a bulkier Lewis acid, Al(C6F5)3(LA). Additionally, computations have also been conducted to elucidate the mechanism of hydrogenation of carbon dioxide byMe3AB while captured between one Lewis base (P(...
Article
Ligandenaustauschprozesse spielen eine Schlüsselrolle bei der Biosynthese von Eisen-Schwefel-Clustern, vor allem während des Transfers des gebildeten Clusters vom Gerüst- zum entsprechenden Zielprotein. Trotz wichtiger Erkenntnisse aus In-vivo- und In-vitro-Studien sind die mikroskopischen Details dieses Ligandenaustausches bisher nicht verstanden....
Article
Ligand exchange plays an important role in the biogenesis of Fe/S clusters, most prominently during cluster transfer from a scaffold protein to its target protein. Although in?vivo and in?vitro studies have provided some insight into this process, the microscopic details of the ligand exchange steps are mostly unknown. In this work, the kinetics of...
Article
Multiple-bonded iron-oxo and -nitrido species have been identified or proposed as key intermediates in a range of important chemical transformations. The reported model complexes feature various coordination geometries and distinct electronic structures, and therefore exhibit diverse reactivity. The present contribution highlights the synergy from...
Article
Full-text available
The role of pendant boron ligands in ammonia-borane (AB) dehydrogenation have been investigated using hybrid density functional theory for two very efficient Ruthenium based catalysts, developed by Williams and co-workers (J. Am. Chem. Soc. 2011, 133, 14212–14215). Our findings reveal that the catalytic action initiates through opening of the labil...
Article
Aerial Oxidation of Hydrazine In an attempt to unearth the mechanism for the century old known phenomenon of the degradation of hydrazine by aerial O2, we have found that this oxidation process propagates through an unprecedented aromatic 4c–2e bonded intermediate with unusually long N−O bonds. The graphic focuses on the 4c–2e bonded species, it's...
Article
Oxidation by dioxygen has a rich repertoire of mechanistic intricacies. Herein, we report a hitherto unknown paradigm of dioxygen activation reaction which propagates through a 4 center 2 electron (4c-2e) bound species. Using static DFT and ab initio quantum chemical techniques we have unraveled the oxidation pathway for hydrazine and its methylate...
Article
Through carefully calibrated density functional studies we predict that Ir pincer complexes, previously known to effectuate simultaneous proton and hydride transfer from ammonia-borane at ambient conditions, are equally efficient catalysts for the concerted dehydrogenation and subsequent release of H2 from hydrogenated boron nitride nanotubes overc...
Article
Chemisorbed hydrogen on boron nitride nanotubes (BNNT) can only be released thermally at very high temperatures above 350 °C. However, no catalyst has been identified that could liberate H2 from hydrogenated BN nanotubes under moderate conditions. Using different density functional methods we predict that the desorption of chemisorbed hydrogen from...
Article
Chemisorbed hydrogen on boron nitride nanotubes (BNNT) can only be released thermally at very high temperatures above 350 C. However, no catalyst has been identified that could liberate H2 from hydrogenated BN nanotubes under moderate conditions. Using different density functional methods we predict that the desorption of chemisorbed hydrogen from...
Article
Self-assembly of a series of carboxylic acid-functionalized naphthalene diimide (NDI) chromophores with a varying number (n=1-4) of methylene spacers between the NDI ring and the carboxylic acid group has been studied. The derivatives show pronounced aggregation due to the synergistic effects of H-bonding between the carboxylic acid groups in a syn...
Article
We have conducted a hybrid density functional study to explore the mechanism of oligo-polymerization of aminoborane, NH2BH2 formed immediately after dehydrogenation of NH3BH3 (Ammonia borane) both in nucleophilic and non-nucleophilic solvent medium. We find that the nucleophilicity of donor solvents and an in-situ generated intermediate, B-(cyclodi...
Article
Chemical hydrogen storage: Theoretical investigations showed that the dehydrogenation of chemisorbed hydrogen atoms on boron nitride nanotubes (BNNT) could be triggered by appropriate reagents through simultaneous proton and hydride transfer. The computed free-energy of the activation barrier for the reduction of formaldehyde to methanol by chemiso...
Article
Chemischer Wasserstoffspeicher: Rechnungen zufolge wird die Dehydrierung von auf Bornitrid-Nanoröhren (BNNTs) chemisorbierten Wasserstoffatomen durch geeignete Reagentien unter zeitgleichem Protonen- und Hydridtransfer ausgelöst (siehe Bild). Für die Reduktion von Formaldehyd zu Methanol durch Wasserstoffatome, die auf einer zickzackförmigen BNNT c...
Article
Theoretical investigations showed that the dehydrogenation of chemisorbed hydrogen atoms on boron nitride nanotubes (BNNT) could be triggered by appropriate reagents through simultaneous proton and hydride transfer. The computed free-energy of the activation barrier for the reduction of formaldehyde to methanol by chemisorbed hydrogen atoms on a zi...
Article
The chameleon reductant: CO2 trapped by a frustrated Lewis pair is predicted to undergo BH activation mediated reduction by NH3BH3, in contrast to concerted NH3BH 3 reduction of free CO2 (see figure). This mechanism provides further fundamental understanding of novel CO2 reduction processes that could lead to environmentally friendly and economi...

Questions

Question (1)
Question
I am trying to find out a transition state with NwChem. I have used the following format
start newts
charge 0
geometry
.
.
.
end
stepper
TS
maxiter 1000
end
basis "ao basis" spherical
* library 6-31G**
end
dft
mult 1
convergence energy 1e-6
XC B3LYP
end
driver
loose
end
task DFT saddle
However, every time I submit this job, it lands upon the initial intermediate. Can anybody tell me what are the correct keywords for doing a transition state with NwChem? In Gaussian calculations, we have to compute the Hessian initially before doing the transition state optimization. Is it necessary here also?   

Projects

Project (1)
Project
To identify efficient 3d transition metal catalyst for 2 electron reduction of CO2