01933nas a2200193 4500008004100000022001400041245012000055210006900175260011000244300001400354490000700368520114000375100002001515700002001535700002101555700001501576700002001591856012801611 2010 eng d a0959-942800aSelective CO2 and H-2 adsorption in a chiral magnesium-based metal organic framework (Mg-MOF) with open metal sites0 aSelective CO2 and H2 adsorption in a chiral magnesiumbased metal aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a9073-90800 v203 a

A rare porous magnesium-based metal-organic framework, Mg-MOF-1 [Mg(3,5-PDC)(H2O)], was synthesized solvothermally in DMF. Structural determination by X-ray single-crystal diffraction technique reveals that this chiral MOF (space group P6(1)22) is constructed by helical assembly of Mg2+ ions with achiral 3,5-pyridine dicarboxylates and coordinating water molecules, to form a three-dimensional framework with parallel hexagonal channels. The structural detail of its 0D analogue Mg-MOF-2 [Mg(2,4-PDC)(H2O)(3)] has been discussed to show how subtle variation in the ligand architecture changes the resulting structure from 0D to 3D. Mg-MOF-1 remains robust and porous upon evacuation of the coordinating water molecules. This is the first report of a chiral hexagonal Mg-MOF synthesized from an achiral organic building unit. Open Mg metal sites show selective hydrogen (H-2) adsorption (ca. 0.8 wt% at 77 K) and carbon dioxide (CO2) uptake (ca. 0.7 mmol g(-1) at 298 K) over nitrogen at 1 atm. Ab initio quantum chemical calculation of adsorption energies and possible adsorption sites of hydrogen molecules are also reported.

1 aMallick, Arijit1 aSaha, Subhadeep1 aPachfule, Pradip1 aRoy, Sudip1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/selective-co2-and-h-2-adsorption-chiral-magnesium-based-metal-organic-framework-mg-mof-002010nas a2200193 4500008004100000022001400041245009200055210006900147260007100216300001400287490000700301520128800308100002001596700002001616700002101636700001501657700002001672856012401692 2011 eng d a0020-166900aStructure and gas sorption behavior of a new three dimensional porous magnesium formate0 aStructure and gas sorption behavior of a new three dimensional p a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB a1392-14010 v503 a

A new three-dimensional magnesium formate polymorph, namely, gamma-[Mg-3(O2CH)(6)] has been synthesized via in situ formate anion generation method. gamma-Mg-formate crystallizes in space group Pbcn, and structural determination by X-ray single crystal diffraction reveals a three-dimensional network of Mg2+ linked by formate anions. All formate anions possess similar binding mode to the metal center with one oxygen of a particular formate anion binds to one metal center (mu(1) oxygen) and other oxygen binds to two metal centers (mu(2) oxygen). N-2 adsorption studies indicate that the framework displays permanent porosity. The specific surface area of gamma-Mg-formate (BET, 120 m(2) gm(-1)) is lower than the alpha- polymorph (BET, 150 m(2) gm(-1)). However, the initial hydrogen uptake of gamma-Mg-formate reached almost 1.0 wt % when the adsorbate pressure approached 760 Torr at 77 K. This is higher than the hydrogen uptake of alpha-Mg-formate (0.6 wt %). gamma-Mg-formate, shows a moderate affinity and capacity for CO2 (3.4 angstrom kinetic diameter) at 298 K. The CO2 uptake at 760 Torr is 2.01 mmol gm(-1)(47.0 cc gm(-1)). Although this CO2 uptake is somewhat modest, it compares well with the CO2 uptake of several Mg-MOFs and ZIFs reported in the literature.

1 aMallick, Arijit1 aSaha, Subhadeep1 aPachfule, Pradip1 aRoy, Sudip1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/structure-and-gas-sorption-behavior-new-three-dimensional-porous-magnesium-formate-001631nas a2200157 4500008004100000022001400041245013000055210006900185260007100254300001400325490000800339520096400347100002401311700001501335856012301350 2012 eng d a1520-610600aStructural, dynamical, and thermodynamical properties of carbon nanotube polycarbonate composites: a molecular dynamics study0 aStructural dynamical and thermodynamical properties of carbon na a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a3083-30910 v1163 a

All-atom molecular dynamics simulations are performed on pure monomer and trimer of polycarbonate and their mixtures with different molecular weight percentages of embedded single walled carbon nanotubes at different temperatures to study the structural and dynamical properties of the composite system. The diffusion behaviors of monomer, trimer of polycarbonate and carbon nanotubes in composite matrices are investigated and compared with pure matrices in details. Both structural and dynamical properties indicate the weak interaction between the nanotubes and matrix molecules. The high tendency of nanotubes to form bundles is observed during simulation. The bundle formation free energy has been calculated from the potential of mean force calculations. The mechanism and energetics of bundle formation is explored in the atomistic scale. The formation of the carbon nanotube bundle is a favorable process in the oligomeric polycarbonate matrix.

1 aChakraborty, Souvik1 aRoy, Sudip uhttps://library.ncl.res.in/content/structural-dynamical-and-thermodynamical-properties-carbon-nanotube-polycarbonate-002034nas a2200157 4500008004100000022001400041245013800055210006900193260011000262300001400372490000600386520130800392100003001700700001501730856013101745 2013 eng d a1744-683X00aStructural and dynamical properties of polyethylenimine in explicit water at different protonation states: a molecular dynamics study0 aStructural and dynamical properties of polyethylenimine in expli aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN a2269-22810 v93 a

PEI is a pH sensitive polymer which acts as a proton sponge in acidic conditions. Despite many experimental and theoretical efforts, a fundamental understanding of the structure and dynamics of linear PEI chains on the atomistic level at different protonation states in dilute solutions remains a topic of discussion. This report analyses the structural properties of PEI at different protonation states, which are representative of different pH, using all atomistic molecular dynamic simulations. The structural properties revealed that the polymer at high pH (basic medium) is highly coiled, while at low pH (strong acidic conditions) the chains are elongated. We studied the dynamics and ordering of water molecules that are part of the solvation shells of the PEI chains at different protonation states. We observe that the water molecules are ordered along the polymer backbone for a completely protonated PEI chain (i.e. in the case of acidic pH) and hop to the neighbouring solvation shell. The residence time and the self-diffusion of water molecules in the solvation shells and their activation barriers were also calculated and analysed further. We concluded the study by correlating the solvation shell water dynamics and the structure of the PEI chain at different protonation states.

1 aChoudhury, Chandan, Kumar1 aRoy, Sudip uhttps://library.ncl.res.in/content/structural-and-dynamical-properties-polyethylenimine-explicit-water-different-protonation-001465nas a2200157 4500008004100000022001400041245005200055210005100107260011000158300001600268490000700284520089600291100002201187700001501209856008301224 2015 eng d a1463-907600aSelf-assembly of phospholipids on flat supports0 aSelfassembly of phospholipids on flat supports aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a31152-311600 v173 a

The current study deals with the self-assembly of phospholipids on flat supports using the Martini coarse grain model. We reported here the effect of the hydrophilic and hydrophobic nature of the solid supports on the lipid self-assembly. The hydrophilic and hydrophobic supports were modeled on the basis of water droplet simulations. The present work addresses the self-assembly mechanism of lipids on eight different supports with different strengths of hydrophilicity and hydrophobicity. We demonstrated how interplay between the interactions of lipid and water with the support can guide the lipid self-assembly process. Thereafter, we calculated the energetics of the components of the system to quantify the competitions between water and a lipid head-group with hydrophilic supports. Finally, the properties of the self-assembled bilayers were also analyzed and reported here.

1 aMhashal, Anil, R.1 aRoy, Sudip uhttps://library.ncl.res.in/content/self-assembly-phospholipids-flat-supports-001825nas a2200157 4500008004100000022001400041245007500055210006900130260007100199300001400270490000800284520123700292100002401529700001501553856009901568 2015 eng d a1520-610600aStructure of nanorod assembly in the gyroid phase of diblock copolymer0 aStructure of nanorod assembly in the gyroid phase of diblock cop a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN a6803-68120 v1193 a

Diblock copolymers undergo microphase separation to form various microstructures, for example, lamellar, gyroid, cylindrical, cubic phases depending on compostion and segregation strength (Flory-Huggins parameter chi). Thus, it can act as template to organize doped nanomaterials into different 3D self-assembled structures located within the block copolymer matrix. Gyroid phase is One of the microstructures formed by block copolymer. It has a curved interfacial surface providing confinements throughout the matrix and thus can regulate the shape and sizes of self-assembled nanorods doped in it. Mesoscale simulation of model systems has been performed to explore the structure and dynamics of self-assembly of bundles formed by nanorods of different flexibilities in the gyroid phase of diblock copolymer matrix. Bundles of different shapes and sizes have been found to be formed depending on the nanorod bending flexibility and copolymer-nanorod interactions. The shape anisotropy (kappa(2)) and radius of gyration (R-g(2)) of bundles situated at different interfacial confining locations of block copolymer-matrices have been investigated as a function of nanorod flexibility and nanorod-diblock copolymer miscibility.

1 aChakraborty, Souvik1 aRoy, Sudip uhttps://library.ncl.res.in/content/structure-nanorod-assembly-gyroid-phase-diblock-copolymer-002001nas a2200157 4500008004100000245013200041210006900173260000800242300001200250490000700262520138100269100003001650700001901680700001501699856012901714 2016 eng d00aScalability of coarse-grained potentials generated from iterative boltzmann inversion forpolymers: case study on polycarbonates0 aScalability of coarsegrained potentials generated from iterative cMAY a274-2860 v253 aUsing systematic coarse-grained (CG) techniques such as iterative Boltzmann inversion (IBI) is an efficient means to simulate high molecular weight polymer melts within reasonable computational time. One drawback of such an approach is however the need to carry out extensive atomistic simulations in order to extrapolate the necessary distributions to derive the inter and intrabead force field parameters. Here it is shown that it is possible to use atomistic simulations of relative short oligomers to develop the CG model for high molecular weight polymers. In particular for the specific case of polycarbonates, it is found that the structural properties (end-to-end distance, radius of gyration and their distributions) are similar irrespective of whether the CG potentials are derived from 5-mer or 10-mer melt systems. Dynamical properties of the CG systems are smoother and faster than the atomistic ones. Scaling factor, derived by overlapping the CG mean square displacement curves (obtained from different CG IBI potentials) over the atomistic ones, also scales the autocorrelation functions. A prediction of the dynamical scaling factor in the case of the unavailability of atomistic simulations is also discussed. The dynamical properties of the CG melts are modeled reasonably well by all the CG potentials derived from atomistic simulations of short oligomers.1 aChoudhury, Chandan, Kumar1 aCarbone, Paola1 aRoy, Sudip uhttps://library.ncl.res.in/content/scalability-coarse-grained-potentials-generated-iterative-boltzmann-inversion-forpolymers02168nas a2200157 4500008004100000022001400041245014700055210006900202260011000271300001400381490000600395520144800401100002001849700001501869856012601884 2016 eng d a2046-206900aStructural and conformational properties of polybenzimidazoles in melt and phosphoric acid solution: a polyelectrolyte membrane for fuel cells0 aStructural and conformational properties of polybenzimidazoles i aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcDEC a8211-82210 v63 a

Poly[2,2'-(p-phenylene)-5,5'-bibenzimidazole (PBI) and poly(2,5-benzimidazole) (ABPBI) doped with phosphoric acid (PA) are considered as potential polymer electrolyte membranes for high temperature fuel cells. Conformational and structural properties of polymer chains in the presence of PA govern the function of the membrane. Therefore, in this work, a single chain conformational analysis of ABPBI and PBI in melt as well as in PA was performed using classical molecular dynamics simulations. End-to-end distance and the radius of gyration reveal significant changes in the conformations of PBI and ABPBI in PA. The structural changes are analyzed locally segment-wise as well as globally in these polymers. The shape and nature of the curvature along the chain is found to be significantly different for ABPBI and PBI. The role of the solvent (PA) on the chain backbone structure is explored for PA doped ABPBI and PBI chains. The PA arrangement along the backbone confirms that benzimidazole density in the case of both of the polymers determines the PA absorbing capacity. The H-bonding interactions between various atoms of the polymer backbone and the atoms of the PA molecules are evaluated along the polymer chain which relates to the arrangement of PA along the backbone. The reasons for the varying number of H-bonds along ABPBI and PBI which in turn has a significant effect on the stiffness of the chains are investigated.

1 aPahari, Swagata1 aRoy, Sudip uhttps://library.ncl.res.in/content/structural-and-conformational-properties-polybenzimidazoles-melt-and-phosphoric-acid-101831nas a2200229 4500008004100000022001400041245009800055210006900153260007900222300001200301490000800313520098400321653001801305653001801323653001801341653002801359100002501387700002201412700003001434700001501464856012201479 2016 eng d a0942-935200aStructural insight into self assembly of sophorolipids: a molecular dynamics simulation study0 aStructural insight into self assembly of sophorolipids a molecul aGENTHINER STRASSE 13, D-10785 BERLIN, GERMANYbWALTER DE GRUYTER GMBHcMAY a819-8360 v2303 a

Sophorolipids contain hydrophilic head groups at the ends of a long hydrophobic tail. As a result, sophorolipids can self assemble into variety of structures in water. Atomistic self assembly simulations of sophorolipids are performed in water. Two sophorolipids, oleic acid sophorolipid and linolenic acid sophorolipid, differing in number of double bonds in the hydrophobic tail are considered for this study. Long time self assembly simulations are performed considering 1 :3 lipid to water ratio by weight for both oleic and linolenic acid sophorolipids. In addition to 1 : 3 ratio, long time self assembly simulations are also performed with 1 : 1 and 1 : 2 ratios for linolenic acid sophorolipids. Distinctions in structural arrangements of sophorolipid molecules in the self assembled configuration for all the systems are investigated. The present study aims to provide structural insight into the different self assembled configurations of sophorolipids in water.

10aMD Simulation10aself assembly10asophorolipids10aUnited Atom Force Field1 aPandey, Prithvi, Raj1 aDhasaiyan, Prabhu1 aPrasad, Bhagavatula L. V.1 aRoy, Sudip uhttps://library.ncl.res.in/content/structural-insight-self-assembly-sophorolipids-molecular-dynamics-simulation-study02011nas a2200289 4500008004100000022001400041245008000055210006900135260007100204300001400275490000800289520102800297100001901325700002401344700002301368700002201391700003001413700002101443700002001464700002501484700002101509700001901530700001501549700002201564700002001586856011501606 2017 eng d a0002-786300aSelf-exfoliated guanidinium-based ionic covalent organic nanosheets (iCONs)0 aSelfexfoliated guanidiniumbased ionic covalent organic nanosheet a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a2823-28280 v1383 a

Covalent organic nanosheets (CONs) have emerged as functional two-dimensional materials for versatile applications. Although pi-pi stacking between layers, hydrolytic instability, possible restacking prevents their exfoliation on to few thin layered CONs from crystalline porous polymers. We anticipated rational designing of a structure by intrinsic ionic linker could be the solution to produce self-exfoliated CONs without external stimuli. In an attempt to address this issue, we have synthesized three self-exfoliated guanidinium halide based ionic covalent organic nanosheets (iCONs) with antimicrobial property. Self-exfoliation phenomenon has been supported by molecular dynamics (MD) simulation as well. Intrinsic ionic guanidinium unit plays the pivotal role for both self-exfoliation and antibacterial property against both Gram-positive and Gram-negative bacteria. Using such iCONs, we have devised a Mixed matrix membrane which could be useful for antimicrobial coatings with plausible medical benefits.

1 aMitra, Shouvik1 aKandambeth, Sharath1 aBiswal, Bishnu, P.1 aKhayum, Abdul, M.1 aChoudhury, Chandan, Kumar1 aMehta, Mihir, R.1 aKaur, Gagandeep1 aBanerjee, Subhrashis1 aPrabhune, Asmita1 aVerma, Sandeep1 aRoy, Sudip1 aKharul, Ulhas, K.1 aBanerjee, Rahul uhttps://library.ncl.res.in/content/self-exfoliated-guanidinium-based-ionic-covalent-organic-nanosheets-icons-0