@article { ISI:000349902200001, title = {Computational investigation on the catalytic activity of Rh-6 and Rh4Ru2 clusters towards methanol activation}, journal = {Theoretical Chemistry Accounts }, volume = {134}, number = {1}, year = {2014}, month = {DEC}, pages = {1597}, publisher = {SPRINGER}, type = {Article}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Catalysis of molecular activation of small molecules through scission of strong chemical bonds is one of the major challenges faced by chemists. More specifically, activation of the strong C-H and O-H bonds of various alcohols, especially methanol, is one of the various important intermediate steps of key organic reactions. Our present work explores a suitable metal cluster catalyst towards methanol dissociation. In particular, we have examined the effect of ruthenium doping (Rh:Ru = 2:1) on the catalytic activity of Rh-6 cluster towards methanol dissociation. Density functional theory-based calculations illustrate two competitive pathways for methanol dissociation, which are via O-H and C-H bond breaking. Both the pathways are found to be energetically favourable in the presence of bimetallic and mono-metallic clusters. Importantly, energy barrier for O-H bond dissociation reduces considerably in doped cluster as compared to pure Rh-6 cluster and is smaller than the values reported for a number of other small metallic clusters.

}, keywords = {Bimetallic Clusters, Density Functional Theory (DFT), Doping, Methanol Activation, Rhodium Clusters}, issn = {1432-881X}, doi = {10.1007/s00214-014-1597-z}, author = {Ghatak, Kamalika and Sengupta, Turbasu and Krishnamurty, Sailaja and Pal, Sourav} } @article {43596, title = {Contriving a catalytically active structure from an inert conformation: a density functionalinvestigation of Al, Hf, and Ge doping of Au-20 tetrahedral clusters}, journal = {Journal of Physical Chemistry C}, volume = {120}, year = {2016}, month = {SEP}, pages = {19636-19641}, abstract = {

The transformation of an inert structure into a catalytically active conformation has immense potential from a structural engineering point of view. In the present work, we explored methods of achieving such a transformation through a density-functional-based study. Au-20 is known be one of the most stable and catalytically inert gold clusters, with a well-known tetrahedral structure. We demonstrate the transformation of the inert Au-20 conformation into a highly active catalytic cluster through selective doping with Hf and Ge atoms. Depending on the dopant, the inert tetrahedral Au-20 cluster evolves into either an endohedral or a hollow-cage-like conformation. The structural changes are manifested in the catalytic properties as well, with the result that the transformed doped cages exhibit extremely low activation barriers for the environmentally important CO oxidation reaction as compared to reported inert Au-20 cluster. The activation barriers for CO oxidation are particularly low (\<0.12 eV) when germanium is directly involved in the CO oxidation. Thus, the current work highlights the importance of engineering structural properties of metal nanoclusters with the help of heteroatom dopants for future applications in efficient catalysis.

}, doi = {10.1021/acs.jpcc.6b04305}, author = {Manzoor, Dar and Krishnamurty, Sailaja and Pal, Sourav} } @article {48490, title = {Can Li atoms anchored on boron- and nitrogen-doped graphene catalyze dinitrogen molecules to ammonia? a DFT study}, journal = {ChemPhysChem}, volume = {24}, year = {2023}, month = {JUN}, type = {Article}, abstract = {

The most successful electrochemical conversion of ammonia from dinitrogen molecule reported to date is through a Li mediated mechanism. In the framework of the above fact and that Li anchored graphene is an experimentally feasible system, the present work is a computational experiment to identify the potential of Li anchored graphene as a catalyst for N-2 to NH3 conversion as a function of (a) minimum number of Li atoms needed for anchoring on graphene sheets and (b) the role of chemical modification of graphene surfaces. The studies bring forth an understanding that Li anchored graphene sheets are potential catalysts for ammonia conversion with preferential adsorption of N-2 through end-on configuration on Li atoms anchored on doped and pristine graphene surfaces. This mode of adsorption being characteristic of Nitrogen Reduction Reaction (NRR) through enzymatic pathway, examination of the same followed by analysis of electronic properties demonstrates that tri-Li atoms (Tri Atom Catalysts, TACs) are more efficient as catalysts for NRR as compared to two Li atoms (Di Atom Catalysts, DACs). Either way, the rate determining step was found to be *NH2 -\>*NH3 step (mixed pathway) with Delta G(max)=1.02 eV and *NH2-*NH3 -\>*NH2 step (enzymatic pathway) with Delta G(max)=1.11 eV for 1B doped TAC and DAC on graphene sheet, respectively. Consequently, this work identifies the viability of Li anchored graphene based 2-D sheets as hetero-atom catalyst for NRR.

}, keywords = {computational chemistry, Graphene Sheet, heterogeneous catalysis, Li Nanoparticles, Nitrogen Reduction Reaction}, issn = {1439-4235}, doi = {10.1002/cphc.202200750}, author = {Verma, Tushar Singh and Samal, Pragnya Paramita and Selvaraj, Kaliaperumal and Krishnamurty, Sailaja} } @article {48678, title = {Catalyst-assisted selective vinylation and methylallylation of a quaternary carbon center using tert-butyl acetate}, journal = {Journal of Organic Chemistry}, volume = {88}, year = {2023}, month = {JUL}, pages = {9686-9703}, type = {Article}, abstract = {

The In-(OTf)(3)-catalyzed \& alpha;-vinylationof varioushydroxy-functionalized quaternary carbon centers using in situ generatedisobutylene from tert-butyl acetate is presentedas a novel synthetic methodology. Moreover, tert-butylacetate is a nonflammable feed stock and is a readily available sourcefor the in situ production of vinyl substituents, as demonstratedby the vinylation reaction with quaternary hydroxy/methoxy compounds.Moreover, an excellent selectivity for methylallylation over vinylationwas obtained with Ni-(OTf)(2) as a catalyst. In the case ofperoxyoxindole, methylallyl-functionalized 1,4-benzoxazin-3-one derivativeswere formed through the sequential rearrangement of peroxyoxindolefollowed by the nucleophilic attack by isobutylene. The detailed mechanismfor this reaction and rationalization for the selectivity are providedusing kinetics and density functional theory studies.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.2c03072}, author = {Mohanta, Nirmala and Samal, Pragnya Paramita and Pandey, Akanksha M. and Mondal, Shankhajit and Krishnamurty, Sailaja and Gnanaprakasam, Boopathy} } @article {48818, title = {Chemical bridge-mediated heterojunction electron transport layers enable efficient and stable perovskite solar cells}, journal = {ACS Applied Materials and Interfaces}, volume = {15}, year = {2023}, month = {JUN}, pages = {29597-29608}, type = {Article}, abstract = {

Perovskite solar cells (PSCs) emerged as potential photovoltaicenergy-generating devices developing in recent years because of theirexcellent photovoltaic properties and ease of processing. However,PSCs are still reporting efficiencies much lower than their theoreticallimits owing to various losses caused by the charge transport layerand the perovskite. In this regard, herein, an interface engineeringstrategy using functional molecules and chemical bridges was appliedto reduce the loss of the heterojunction electron transport layer.As a functional interface layer, ethylenediaminetetraacetic acid (EDTA)was introduced between PCBM and the ZnO layer, and as a result, EDTAsimultaneously formed chemical bonds with PCBM and ZnO to serve asa chemical bridge connecting the two. DFT and chemical analyses revealedthat EDTA can act as a chemical bridge between PCBM and ZnO, passivatedefect sites, and improve charge transfer. Optoelectrical analysisproved that EDTA chemical bridge-mediated charge transfer (CBM-CT)provides more efficient interfacial charge transport by reducing trap-assistedrecombination losses at ETL interfaces, thereby improving device performance.The PSC with EDTA chemical bridge-mediated heterojunction ETL exhibiteda high PCE of 21.21\%, almost no hysteresis, and excellent stabilityto both air and light.

}, keywords = {charge transfer, chemical bridge, electron transport layer, ethylenediaminetetraacetic acid, Perovskite solar cells, trap-assisted recombination}, issn = {1944-8244}, doi = {10.1021/acsami.3c04852}, author = {Patil, Pramila and Maibam, Ashakiran and Sangale, Sushil S. and Mann, Dilpreet Singh and Lee, Hyun-Jung and Krishnamurty, Sailaja and Kwon, Sung-Nam and Na, Seok-In} } @article {48268, title = {Chemically modified graphene sheets as potential sensors for organophosphate compounds(pesticide): A DFT study}, journal = {Applied Surface Science}, volume = {619}, year = {2023}, month = {MAY}, pages = {156745}, type = {Article}, abstract = {

Owing to the extensive use of pesticides in agriculture and the threat posed to the environment and humankind, attention is drawn toward the need for its remediation from various sources, in particular from water. The adsorption characteristics of hydrophobic graphene and its BN doped counterparts are evaluated using DFT methodology, to assess their sensing potential towards notable pesticide molecules (Organophosphate pesticides (OPs) such as chlorpyriphos, parathion, methyl-parathion, and fenitrothion). To accomplish this, various elec-tronic properties such as band structure, DOS, Bader charge analysis, and CDD have been calculated. Interest-ingly, exothermic interactions (-0.1 eV to-2 eV) have been noted for all the OPs with NB doped single vacancy defect induced graphene surfaces. With an exception of FTN, all the other OPs showed significant changes in the electronic properties of surfaces as apparent from the change in band gap and nature of the band from indirect to direct. The appreciable adsorption energy, higher charge transfer, and notable variation in the band gap are the decisive factors behind the strong interaction exhibited by NB doped surfaces especially dg-(NB-2)2 (except FTN). These findings demonstrate the suitability of NB doped single vacancy defect induced graphene sheets for the detection of the studied OPs.

}, keywords = {Adsorption, BN doped graphene surfaces, Charge density difference, Density functional theory, Organophosphate pesticides}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2023.156745}, author = {Shivankar, Bhavana R. and Singh, Chandrodai Pratap and Krishnamurty, Sailaja} } @article {49055, title = {Computational identification of most potent atom pair catalysts for electrocatalytic nitrogen reduction reaction over hydrogen evolution reaction}, journal = {Inter.}, volume = {58}, year = {2024}, month = {MAR }, pages = {1345-1358}, type = {Article}, abstract = {

Robust electrocatalytic atom pair compositions (APCs) where Nitrogen Reduction Reaction (NRR) is more enhanced over competing Hydrogen Evolution Reaction (HER) is searched for using computational studies based on Density Functional Theory based methods. Atomic pairs are anchored on mechanically and thermally stable graphene surfaces. A wide range of transition metal based atom pair compositions from 3d, 4d, and 5d groups are systematically investigated for reduction of dinitrogen molecule with lower reduction barrier as compared to HER. APR compositions of Ni-Rh with an overall limiting potential of -0.22 V, Fe-W with an overall limiting potential of -0.26 V and Co-Pt with an overall limiting potential of -0.28 V are identified as the most potent atomic pairs for enhanced nitrogen reduction reaction over the HER. Finally, the performance of most potent composition, viz., Ni-Rh is validated to be consistent with respect to their thermodynamic stability and performance within the solvent effects.

}, keywords = {Atom pair catalysts, Density Functional Theory (DFT), Electrochemical nitrogen reduction reaction (eNRR), hydrogen evolution reaction (HER), IR stretching frequencies, N-N bond length}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2024.01.203}, author = {Verma, Tushar Singh and Dar, Afshana Hassan and Dar, Manzoor Ahmad and Selvaraj, Kaliaperumal and Krishnamurty, Sailaja} } @article {49726, title = {Clove essential oil-supported disposable in-tip cellulose paper (DICP) device for facile extraction of anesthetic drugs from postmortem samples: a white analytical toxicology (WAT) approach}, journal = {Sustainable Chemistry and Pharmacy}, volume = {45}, year = {2025}, month = {JUN}, pages = {102010}, type = {Article}, abstract = {

A novel disposable in-tip cellulose paper (DICP) device, enhanced with clove essential oil (CEO), was developed for the extraction of four anesthetic drugs (lidocaine, prilocaine, ropivacaine, and bupivacaine) from postmortem blood and urine samples. The DICP device, equipped with 1 x 3 cm CEO-impregnated cellulose paper (CP) strips (prepared via a simple dip-coating process), is attached to a 1000 mu L micropipette. The findings from density functional theory (DFT) study reveals that CEO-impregnated cellulose demonstrates stronger and more diverse interactions with anesthetic drugs, as evidenced by more negative adsorption energy (-0.62 eV) and enhanced non-covalent interactions compared to cellulose alone. The procedure involves aspirating and dispensing diluted biological samples through the DICP device for 30 cycles, adsorbing the analytes onto the CEO-impregnated CP strips. The adsorbed analytes are subsequently eluted with 0.5 mL of ethyl acetate through 40 aspirating-dispensing cycles and analyzed by GC-MS. The method achieved limits of quantification as low as 0.01 mu g/mL, with intra-day and inter-day precisions below 10.2 \% and 14.6 \%, respectively, and accuracy ranging from 90.5 \% to 110.7 \%. Relative recoveries ranged from 66 \% to 87.6 \%, while matrix effects remained consistently below 11.9 \%. The DICP-GC-MS method demonstrated exceptional sustainability, achieving a whiteness score of 97.2 \%, underscoring its alignment with green analytical chemistry principles and operational simplicity. Applicability was demonstrated through the successful analysis of postmortem cardiac blood in a suspected anesthetic drug overdose case, highlighting its potential as a robust, high-throughput, and eco-friendly approach for routine forensic toxicological screening.

}, keywords = {Anesthetic drugs, Clove essential oil, Disposable in-tip cellulose paper (DICP) device, Green sample preparation, White analytical toxicology (WAT)}, doi = {10.1016/j.scp.2025.102010}, author = {Jain, Rajeev and Shivankar, Bhavana R. and Krishnamurty, Sailaja and Al-Khateeb, Lateefa A. and Sheetal, Sarah and Alharthi, Sarah} } @article {50055, title = {CO2, N2 and H2 adsorption in Zn2+-containing zeolites and metal-organic frameworks}, journal = {Physical Chemistry Chemical Physics}, volume = {28}, year = {2026}, month = {FEB}, pages = {5161-5174}, type = {Article}, abstract = {

We employ a chemically accurate (+/- 4 kJ mol-1) embedding approach to calculate enthalpies for CO2, N2, and H2 adsorption in the Zn2+-containing zeolites FAU and CHA, and for CO2 and H2 in the metal-organic frameworks (MOFs) Zn-MOF-74 and CALF-20. Using MP2 as the high-level method and PBE+D4 as the periodic low-level method (MP2:PBE+D4), we obtain CO2 adsorption enthalpies of -46, -34, and -36 kJ mol-1 for Zn-CHA, Zn-MOF-74, and CALF-20, respectively, all within chemical accuracy limits of the experimental values of -42, -30, and -39 kJ mol-1. For CO2 in Zn-FAU, where no experimental data exist, we provide an MP2:PBE+D4 prediction of -49 kJ mol-1. For N2, we predict MP2:PBE+D4 adsorption enthalpies of -41 and -39 kJ mol-1 in Zn-CHA and Zn-FAU, respectively. CO2 adsorption is stronger in the zeolites than in the studied MOFs. Across all systems, CO2 adsorption tends to be stronger than N2 adsorption and both are largely favoured over H2. We observe inconsistent accuracy of PBE+D4 for the two MOFs, despite their similar characteristics, underscoring the need for high-level approaches in predictive screening. Additionally, we conclude that Zn2+ cations with open coordination sites act as the primary binding sites and that these cations preferentially occupy 6-membered rings in zeolites.

}, issn = {1463-9076}, doi = {10.1039/d5cp04169d}, author = {Samal, Pragnya Paramita and Berger, Fabian and Krishnamurty, Sailaja and Sauer, Joachim} }