03074nas a2200265 4500008004100000022001400041245008500055210006900140260009200209300001200301490000700313520211500320653001902435653002602454653003002480653002202510653002802532653003002560653001602590100001702606700002602623700001702649700002702666856011502693 2016 eng d a0892-702200aDFT based assay for tailor-made terpyridine ligand-metal complexation properties0 aDFT based assay for tailormade terpyridine ligandmetal complexat a4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLANDbTAYLOR & FRANCIS LTDcMAY a618-6270 v423 a

Electron-rich terpyridine ligand and its metal complexes have a potential to grow as responsive surfaces by adapting their physicochemical properties as a function of environment. The responsiveness is brought about by judicious molecular level designing that is currently hindered due to lack of information and control on terpyridine (TPy)-metal (M) interactions at single molecule level. So far there is no organised understanding on the binding of different metals with TPy ligand and ways to modulate it. Being a large conjugated [GRAPHICS] system, TPy has a large scope to be functionalised with electron exchanging groups to alter its electronic structure and consequently its binding with metal atoms. In first report of such a kind, using density functional theory (DFT), we demonstrate that convenient modulation of TPy-M binding is possible through functionalisation of TPy for [GRAPHICS] , Ru, Fe, Mo and Au. Electron donating groups viz., CH [GRAPHICS] , OCH [GRAPHICS] , C [GRAPHICS] H [GRAPHICS] , NH [GRAPHICS] and electron withdrawing groups viz., CF [GRAPHICS] , COOH, CN and NO [GRAPHICS] are considered for functionalisation of TPy ligand. Significantly, the present work focuses on the functionalisation at 4 and 4 [GRAPHICS] positions of TPy molecule. The role of such a functionalisation in influencing the ligands structure-property correlation is missing in the literature to the best of our knowledge. The present investigation quantifies that by pertinent functionalisation of TPy, TPy-M binding energies can be modified up to [GRAPHICS] 60kcal/mol. Our results reveal that functionalisation leads to a considerable charge redistribution within the TPy-M complex with carbon atoms in pyridine rings functioning as major electron sink/source with a corresponding red/blue shift of [GRAPHICS] stretching frequency. This modifies the red-ox, optical and other chemical properties of TPy-M complexes. In brief, the present report illustrates a way to design ligands such as TPy for diverse applications through tailor-made functionalisation using electronic structure methodology.

10aBinding energy10acharge redistribution10aDensity functional theory10afunctionalisation10aMetal organic complexes10ametal-ligand interactions10aterpyridine1 aJoshi, Krati1 aKrishnamurty, Sailaja1 aSingh, Iksha1 aSelvaraj, Kaliaperumal uhttp://library.ncl.res.in/content/dft-based-assay-tailor-made-terpyridine-ligand-metal-complexation-properties01894nas a2200157 4500008004100000022001400041245004600055210004300101260000800144300001400152490000700166520144700173100001701620700002601637856007301663 2018 eng d a1463-907600aAu26: a case of fluxionality/co-existence0 aAu26 a case of fluxionalitycoexistence cAPR a8616-86230 v203 a

The Au26 cluster is one of the widely studied gold clusters in the size range of n = 21–30. It has been proposed in a more recent combined experimental and theoretical study that the neutral Au26 cluster is fluxional. The fluxionality of a cluster is relevant to its catalytic applications. In this context, to explore the extent of fluxionality, Born Oppenheimer Molecular Dynamical (BOMD) simulations are carried out on experimentally and theoretically proposed fluxional Au26 conformations (three compact or core–shell structures and a high symmetry cage structure). The simulations reveal that the high energy golden tube outperforms the ground state structure (compact C2v conformation) as well as the other two low-symmetry compact conformations in terms of thermal stability. The enhancement in the thermal stability is explained on the basis of structural integrity imposed by the open skeleton of shortest bond distances within Au26-Tube. In addition to this, the homogeneous distribution of charges and the strong s–d hybridization exhibited by FMOs are seen to play a pivotal role in increasing the stability of Au26-Tube. The present investigation also reveals that the characteristic fluxionality proposed to exist in the Au26 system is noted only above 400 K and it is missing at room temperature. The simulations also bring forth the question of how relevant a ground state conformation is at working temperatures.

1 aJoshi, Krati1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/au26-case-fluxionalityco-existence02276nas a2200253 4500008004100000022001400041245010300055210006900158260000900227300001100236490000900247520140000256653002301656653001601679653001901695653001601714653004201730653002101772100002901793700001701822700002701839700002601866856013001892 2019 eng d a2210-271X00aProbing the catalytic activity of pristine and doped Pd and Ni metal clusters towards H2O molecule0 aProbing the catalytic activity of pristine and doped Pd and Ni m cDEC  a1126240 v11703 a

Electrolysis of H2O to produce molecular hydrogen, the most environment friendly and energy efficient fuel, using cost effective catalysts is one of the major global research challenges. To date, Pt remains the best suitable and yet highly expensive electro-catalyst for hydrogen evolution reaction. Design of an alternative cost-effective catalyst requires a fundamental molecular level understanding of the water molecule adsorption and its activation. In that context, we examine the adsorption and activation of water molecule on model alternative catalysts namely, Ni-6 and Pd-6 clusters using density functional theory based methodology. Ni-6 and Pd-6 clusters and their singly doped counterparts are used for this study. Mo, W, Fe, Co and Cu are used as doping elements. To quantify the influence of medium (neutral and alkaline) on the activation of the water molecule, Ni based clusters are considered in neutral and anionic states, respectively. The activity of these clusters towards H2O molecule is evaluated in terms of the adsorption energy, charge transfer, bandgap, red shift in O-H stretching frequency and dissociation barriers for H2O. The studies demonstrate that doping with Co in all the studied clusters (Pd-6, Ni-6 and anionic Ni-6) increases their activity. Best activity is noted for Fe doped neutral Ni b clusters with a dissociation barrier of 5.76 kcal/mol.

10aActivation barrier10aNi clusters10aO-H activation10aPd clusters10aRed shift of O-H stretching frequency10aWater adsorption1 aSamal, Pragnya, Paramita1 aJoshi, Krati1 aKaliaperumal, Selvaraj1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/probing-catalytic-activity-pristine-and-doped-pd-and-ni-metal-clusters-towards-h2o-molecule01783nas a2200229 4500008004100000022001400041245010700055210006900162260000900231300001200240490000700252520098500259100003001244700001701274700001501291700002701306700001701333700001901350700003001369700002401399856013001423 2019 eng d a1948-718500aRole of structural distortion in stabilizing electrosynthesized blue emitting phosphorene quantum dots0 aRole of structural distortion in stabilizing electrosynthesized  cMAR  a973-9800 v103 a

Luminescent phosphorene quantum dots (PQDs) have emerged as fascinating nanomaterials for potential applications in optoelectronics, catalysis, and sensing. Herein, we investigate the structural distortion of black phosphorus (BP) under an applied electric field to yield blue luminescent PQDs [average diameter 8 +/- 1.5 nm (N = 60)]. The electrosynthesized PQDs exhibit photoluminescence emission independent of excitation wavelength with 84% quantum efficiency. Structural distortion that occurred during the transformation of BP to PQDs is confirmed by results obtained during transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Further, using first-principles-based density functional theory, calculations on oxygenated and nonoxygenated PQDs augment the experimental observations that an optimum oxygen content maintains the structural integrity of PQDs, above which the structural robustness of PQDs is drastically diminished.

1 aValappil, Manila, Ozhukil1 aJoshi, Krati1 aJohn, Lisa1 aKrishnamurthy, Sailaja1 aJana, Bikash1 aPatra, Amitava1 aPillai, Vijayamohanan, K.1 aAlwarappan, Subbiah uhttp://library.ncl.res.in/content/role-structural-distortion-stabilizing-electrosynthesized-blue-emitting-phosphorene-quantum01231nas a2200169 4500008004100000022001400041245012300055210006900178260000900247300001600256490000700272520058700279100001700866700002600883700002400909856012800933 2020 eng d a1463-907600aSurface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters0 aSurface functionalization an efficient alternative for promoting cOCT  a23351-233590 v223 a

{Surface functionalization through adsorption of ligands or non-metal atoms is considered to be an interesting and viable approach for tuning the physicochemical properties of gold clusters. Highly stable and magic numbered electronic configurations of thiolate protected gold clusters such as Au-25(SR)(18), Au-38(SR)(24)etc. with intriguing properties are the direct manifestation of the rich chemistry of the Au-S interface. The present investigation discerns the CO oxidation activity of structurally well characterized sulphur functionalized gold cluster anions AumS4-

1 aJoshi, Krati1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttp://library.ncl.res.in/content/surface-functionalization-efficient-alternative-promoting-catalytic-activity-closed-shell02700nas a2200265 4500008004100000022001400041245016000055210006900215260000800284300001100292490000800303520172400311653003002035653003202065653001702097653001902114653003702133100002202170700001902192700001702211700002502228700002602253700002702279856012802306 2020 eng d a0304-389400aUnravelling the distinct surface interactions of modified graphene nanostructures with methylene blue dye through experimental and computational approaches0 aUnravelling the distinct surface interactions of modified graphe cAPR a1217550 v3883 a

Nanoscopic modifications leading to multi-dimensional graphene structures are known to significantly influence their candidature for several applications including catalysis, energy storage, molecular sensing and most significantly adsorption and remediation of harmful materials such as dyes. The present work attempts to identify the key trajectories that connect the structural qualification with a chosen application, viz., the interactive forces in dye remediation. Various physico-chemically Modified Graphene Nanostructures (MGNs) such as 2 dimensional Graphite, Graphene Oxide (GO), reduced GO (rGO), holey rGO, and 3 dimensional GO hydrogel and Holey GO hydrogel are chosen and synthesised herein. These represent varieties of physicochemical features with respect to their dimensionality, surface features such as oxygen functionality, nanoscopic holes etc., that contribute to their characteristic overall surface interactions. Methylene Blue (MB), a popular industrial effluent posing major environmental concern is chosen to be a probe adsorbate in this case study. An exclusive real time in-situ UV visible spectral experiment provides the revealing reasons behind the outstanding performance of 2D GO sheets with an adsorption capacity of greater than 92 % even at high MB concentrations (>2000 ppm). A complex dependency of various factors such as surface oxygen, morphology, nanoporosity etc. on the unique overall interaction with an adsorbent such as MB by all these adsorbates is demonstrated using experimental and DFT based computational studies. Electrostatics and hydrogen bonding are understood to be the two dominant forces driving the MB adsorption on the best performing GO here.

10aDensity functional theory10aIn-situ UV-vis spectroscopy10aInteractions10aMethylene blue10aModified Graphene Nanostructures1 aManappadan, Zinoy1 aKumar, Shubham1 aJoshi, Krati1 aGovindaraja, Thillai1 aKrishnamurty, Sailaja1 aSelvaraj, Kaliaperumal uhttp://library.ncl.res.in/content/unravelling-distinct-surface-interactions-modified-graphene-nanostructures-methylene-blue02150nas a2200181 4500008004100000022001400041245010700055210006900162260000800231300001400239490000700253520149300260100002201753700002601775700001701801700002601818856012401844 2021 eng d a1144-054600aExploring edge functionalised blue phosphorene nanoribbons as novel photocatalysts for water splitting0 aExploring edge functionalised blue phosphorene nanoribbons as no cFEB a3570-35800 v453 a

Hydrogen gas, a highly combustible and eco-friendly fuel is stealing the limelight and its production is one of the major areas of research. An efficient and green method for producing clean hydrogen gas with no harmful by-product is water splitting. With the introduction of low dimensional materials, water splitting has become an easier and cost-effective process. The present work demonstrates the application of one such low dimensional material viz., edge functionalised Blue Phosphorene Nano-Ribbons (BPNRs) as potential photocatalysts. With a carrier mobility of 10(3) cm(2) V-1 s(-1) and a band gap of 1.5-3.0 eV, BPNRs are an attractive candidate for photocatalysis. BPNRs with different edge oreintations, viz. zigzag and armchair are functionalised with CH3O, COOCH3, CHO, COOH, OH, NH2, CONH2, SH, C6H5, and NO2 groups. Their performance towards activating water molecules at different sites on the nanoribbon is studied. The functionalised edges of the BPNRs are the active sites showing similar to 1.2% to 3.2% efficiency in activating the O-H bond of the water molecule. Among the different groups explored, CONH2 functionalised zigzag BPNR clearly exhibits a higher potential towards the adsorption of water molecules (-0.98 eV) and activation of O-H bonds with an elongation of 3.2% and a red shift of 500.6 cm(-1). This is attributed to the lone pair of electrons on the nitrogen atom contributing to the electron donating nature of the CONH2 functional group.

1 aMaibam, Ashakiran1 aChakraborty, Debalina1 aJoshi, Krati1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/exploring-edge-functionalised-blue-phosphorene-nanoribbons-novel-photocatalysts-water02724nas a2200169 4500008004100000022001400041245017900055210006900234260000800303300001400311490000700325520202600332100001702358700002202375700002602397856013102423 2021 eng d a1144-054600aFinite temperature behavior of carbon atom-doped silicon clusters: depressed thermal stabilities, coexisting isomers, reversible dynamical pathways and fragmentation channels0 aFinite temperature behavior of carbon atomdoped silicon clusters cMAY a8217-82270 v453 a

Silicon carbide clusters are significant due to their predominant occurrence in meteoric star dust, particularly in carbon-rich asymptotic giant branch stars. Of late, they have also been recognized as nanoclusters with potential applications in technology. Them both being elements of the same group, there is excellent potential for precise control over the physico-chemical properties of such molecular length-scale materials through atomic engineering and this has been explored recently by various experimentalists. This report simulates one of the significant physical properties, viz. conformational stability, of various carbon-doped silicon clusters as a function of temperature using Born-Oppenheimer molecular dynamics methodology. Single carbon atom-doped silicon clusters with 4-9 atoms (i.e., Si3C-Si8C) are chosen for this study as the gas phase geometries of these clusters have been characterized using a combination of experimental and theoretical methods in the recent past. The simulations ratify that various conformations do not interconvert among themselves at 300 K. The interconversion occurs at 500 K or above, thereby ratifying the possibility of the coexistence of multiple conformations of a given cluster, which are generally synthesized under subroom temperature conditions. Furthermore, the above single carbon atom-doped silicon clusters: (a) have depressed thermal stabilities as compared to their pristine counterparts with the exception of a Si5C conformation; (b) undergo multifarious evolution of the cluster, through the reversible dynamical and fragmentation pathways as a function of temperature and (c) single carbon atom-doped silicon clusters with 7 atoms (starting from Si6C) and above undergo a fragmentation at nearly 2000 K. The underlying electronic and structural properties of various clusters are discussed to explain the above observations with a note on critical fragmentation energy barriers required for the segmentation of clusters with seven or more atoms.

1 aJoshi, Krati1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/finite-temperature-behavior-carbon-atom-doped-silicon-clusters-depressed-thermal-stabilities02861nas a2200205 4500008004100000022001400041245009900055210006900154260000800223300001600231490000700247520213700254100002402391700002602415700002202441700002202463700002602485700001702511856012702528 2023 eng d a1463-907600aQuantum dot (Aun/Agn, n=3-8) capped single lipids: interactions and physicochemical properties0 aQuantum dot AunAgn n38 capped single lipids interactions and phy cAUG a22294-223030 v253 a

Realizing the potential of nano-hybrid biomaterials in various applications (nanoprobes to drug delivery), special attention has been devoted towards their synthesis and development. Nonetheless, several questions pertaining to the interface chemistry between the constituent entities (biomolecules and organic/inorganic part) of these hybrids, still remain unresolved. Keeping these unsolved issues in mind, the present theoretical investigation focuses on determining the electronic/physicochemical properties and interactions within gold and silver quantum dot-capped single lipid molecules. Quantum dots of varying sizes and shapes have been chosen and then coupled with lipid molecules (1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol, sodium salt (DMPG)), at the choline/glycerol, carboxylate and phosphate site. It has been identified that Au Qds interact strongly as compared to Ag clusters. In addition to the type, the shape and size of the Qd also influences their attachment with lipids. Among various sites, the phosphate site provides a considerably stronger platform for the coupling of Qds. On the other hand, attachment at the choline site leads to significantly lower interaction energies. The trend noted in interaction energies coincides with the structure-electronic property analysis (interatomic bond distances, charge transfer, PO2- stretching frequencies), which further helps in deducing the nature of interactions. The molecular dynamics simulations performed on selected Qd-lipid complexes established that the Qd interacting with lipids at the phosphate site remains fairly stable at room temperature without undergoing fragmentation into individual components. On the other hand, at the choline site, the Qd-to-lipid coupling is unstable and therefore they experience disintegration at 300 K temperature. Additionally, a unique glycerol-to-phosphate site crossover is evidenced, which reaffirms that the phosphate site is selectively preferred by Qds for binding with lipid molecules.

1 aManeri, Asma, H. H.1 aVarode, Shruti, Suhas1 aMaibam, Ashakiran1 aRanjan, Priyatosh1 aKrishnamurty, Sailaja1 aJoshi, Krati uhttp://library.ncl.res.in/content/quantum-dot-aunagn-n3-8-capped-single-lipids-interactions-and-physicochemical-properties01926nas a2200169 4500008004100000022001400041245009000055210006900145260000800214300001600222490000600238520133100244100002401575700002601599700001701625856011401642 2023 eng d a2470-134300aUnderstanding the stability of an unprecedented Si-Be bond within quantum confinement0 aUnderstanding the stability of an unprecedented SiBe bond within cAPR a14814-148220 v83 a

As of today, the Si-Be bond remains underexplored in the literature, and therefore its anomalous behavior continues to be an unsolved puzzle to date. Therefore, the present study aims at evaluating the integrity of an unprecedented Si-Be bond within quantum confinement. To accomplish this, first-principles-based calculation are performed on Be-doped silicon clusters with atomic sizes 6, 7, and 10. Silicon clusters are sequentially doped with one, two, and three Be atoms, and their thermal response is registered in the temperature range of 200-1500 K, which discloses several research findings. During the course of the simulations, the clusters face various thermal events such as solid cluster phase, rapid structural metamorphosis, and fragmentation. Si-Be nanoalloy clusters are noted to be thermally stable at lower temperatures (200-700 K); however, they begins to disintegrate earlier at a temperature as low as 800 K. This lower stability is attributed to the weak nature of Si and Be heteroatomic interactions, which is corroborated from the structural and electronic property analysis of the doped clusters. In addition to this, the performance of Be-doped clusters at finite temperatures is also compared with the thermal response of two other popular systems, viz., C-and B-doped silicon clusters.

1 aManeri, Asma, Harun1 aKrishnamurty, Sailaja1 aJoshi, Krati uhttp://library.ncl.res.in/content/understanding-stability-unprecedented-si-be-bond-within-quantum-confinement