6^th International Conference on Physical and Theoretical Chemistry September 02-03, 2019 Holiday Inn Express Zurich Airport | Zurich, Switzerland

Biography:

Jiri Kozelka is Directeur de Recherche Emeritus in the laboratory « Dynamique des Systèmes et Interactions des Macromolécules Biologiques » (Université Paris Diderot, France) and Professor of biophysics at Masaryk university in Brno, Czech Republic. His domains of research include platinum antitumor drugs, DNA and

protein structure, and weak interactions in chemistry and biology. In the present work, his team took profit from the availability of QM/MM models for the formate oxidation inside formate dehydrogenase to analyze the energy components of the interaction between the substrate (formate) and the cofactor (NAD⁺), in the orientation that the reaction partners have in the active site.

Abstract:

NAD-dependent formate dehydrogenase (FDH) uses NAD+ as cofactor to catalyze the oxidation of  formate to CO₂ (Figure 1). The interaction between the formate anion and NAD+ is a case of an anion-p interaction. It has expectedly a strong electrostatic component, however, the low-lying empty p orbitals of NAD+ make this oxidant also a potential acceptor for donor-acceptor covalent bonding. In the present work, we used two energy decomposition schemes, EDA1 and NEDA2 to monitor the physical nature of  the substrate-cofactor interaction during  the reaction (H-COO- + NAD+ ® CO₂ + NADH). The coordinates of the substrate-cofactor pair were taken from a QM/MM simulation of the reaction inside the Candida boidinii FDH by Guo et al.;3 these coordinates enabled us to study the interaction in the reactants state, transition state, and products state  in the conformation and orientation the reacting partners have in the active site of the enzyme.

Biography:

Eugene Ustinov, Doctor in Physical Chemistry, Professor, is now a Leading Researcher at Ioffe Institute of Russian Academy of Sciences (Saint Petersburg, Russian Federation). He received his Doctor degree (1990) from the Institute of Physical Chemistry, Russian Academy of Sciences. His research interests focus on molecular modeling of the gas adsorption on surfaces and in confined volume of nanoporous materials at cryogenic temperatures; phase coexistence; two-dimensional first-order phase transition and orientational transition in molecular layers on solid surfaces. Eugene Ustinov has proposed a methodology for determination of the chemical potential and other thermodynamic functions of crystalline molecular layers using molecular simulation with a renewed version of the kinetic Monte Carlo method. He worked several times at the University of Queensland, Australia as a Visiting Professor. Eugene Ustinov has published more than 140 papers in peer-reviewed journals.

Abstract:

There is a significant progress in the part of physical chemistry dealing with thin films, adsorption, coating and other surface phenomena. Sophisticated methods have been developed for the design networks of organic molecules, visualization and description of the structure of molecular layers. However, not much is known on thermodynamics of two-dimensional crystalline phases. The aim of this study is to show how the chemical potential of the crystalline molecular layer can be determined. We developed a methodology based on a kinetic Monte Carlo simulation of the gas-solid system in the cell with a variable external potential imposed on the gas phase. At equilibrium the chemical potential is the same over the cell and, therefore, this technique guaranties its reliable determination in the solid phase as that in the gas phase is easily evaluated. This approach proved to be very efficient in studying thermodynamic properties of contact layers of argon, krypton, nitrogen and hydrogen on solid surfaces and confined in nanoporous materials at cryogenic temperatures, as well as the melting and orientational (N₂) long-to-short order transitions. The most challenging task is thermodynamic behavior of orientationally ordered layers formed by relatively large organic molecules. The reason is an extremely small primary molecular flux from the crystal and, therefore, its negligible contribution to the chemical potential compared to the secondary (reflected) flux. Nonetheless, the presence of the gas-solid interface allows us to circumvent the problem. Thus, we have successfully modeled the structures formed by trimesic acid and determined thermodynamic potentials and entropy of the chicken-wire structure and several flower-like polymorphs. From our viewpoint, the method has a significant potential for analysis of 2D crystals, their growth, thermodynamic stability, orientational and first order transitions.

Biography:

Cesare Oliviero Rossi was born in 1974 in Cosenza, Italy. He received his Degree in Chemistry, cum laude, in 1997 at the University of Calabria, and his Ph.D. in “Chemical Sciences” in 2002 at the same University, working on the structural characterization of lyotropic systems. His publication track record, including more than 100 papers in international peer reviewed journals, is impressive. His major area of expertise is the study of colloidal systems. In particular, he has recently been focusing on the chemistry of bitumen and its additives, approaching the open challenges in this area of research from a chemical point of view, also making use of investigation and analytical techniques never used before to study asphalt binders. He was awarded the gold medal for contribution to the Road Science by the High Research Institute of Kazakhstan

Abstract:

ILT is particularly useful when the signal is characterized by multi-exponential decay, for example in spin relaxation or in the dephasing of the NMR spin echo signal associated with sopra molecular aggregation under the influence of pulsed magnetic or internal field gradients. In this study, an Inverse Laplace Transform of the NMR spin-echo decay (T2) was applied as novel approach to observe the real rejuvenating effect of the potential additive. The potentialities of a new, non-toxic and eco-friendly biocompatible additive on aged bitumen are explored for the first time as bitumen rejuvenator, by means of advanced rheological and Relaxometry-NMR measurements. Pristine, aged, and doped aged bitumen morphology have also been investigated by SEM. The new rejuvenator helps to rearrange the structure of the aged bitumen (aiming at the original one), and this mechanism can be observed by ILT/NMR analysis.

Biography:

Jean-Christophe Poully is assistant professor at the University of Caen (France) since 2010. His research is focused on the intrinsic properties of biologically-relevant molecular systems, by means of experimental techniques such as mass and ion mobility spectrometries, but also quantum-chemical calculations. It allows shedding light on processes occurring after electron capture, photoabsorption or ion collision, but also on structural properties of biomolecules. These last years, he worked on direct effects of ionizing radiation to understand the first physical and chemical steps underlying radio- and hadrontherapy. In particular, he collaborates with radiobiologists to know more about the side-effects of irradiating cartilage, through investigations on collagen mimetic peptides. One of his future projects is going towards probing conformational changes triggered by ionizing radiation, because these processes can lead to denaturation of proteins or DNA strands.

Abstract:

To understand the effects of ionizing radiation on biological molecular systems, it is crucial to control the experimental conditions, especially in terms of temperature and phase. Irradiation of a solution at room temperature mainly leads to the formation of free radicals from the solvent. These species then chemically react with biomolecules, leading to secondary processes such as bond cleavage, cross-linking and generally quenching of biological activity. All these indirect effects require diffusion of free radicals from the solvent to the biomolecule, which occurs at rates that decrease by several orders of magnitude from room to cryogenic temperatures. To study direct effects, frozen, lyophilized, crystallized or dried samples can be used. These last years, at the CIMAP lab, we have investigated the structure and stability of isolated collagen mimetic peptides and antibiotic/receptor non-covalent complexes of controlled mass and stoichiometry, by means of home-made experimental set-ups and through international collaborations. Our main findings are the following. First, the collagen triple helix exists in the gas phase, and its stability is not due to solvent. Second, interaction with one carbon ion at the Bragg-peak energy or ionizing photon in the VUV-X range mainly leads to ionization, vibrational energy deposition and intermolecular followed by intramolecular fragmentation. Radical-mediated mechanisms such as loss of neutral molecules from amino acid side chains have been found to play a big role. Our most recent studies suggest that non-covalent interactions underlying molecular recognition between the antibiotic vancomycin and its receptor are affected by ionizing radiation in a very different way depending on pH: indeed, our results show that the protonated complex does not survive, and fragments mainly via glycosidic bond cleavage, whereas the deprotonated complex mainly loses CO₂ after electron detachment. In a near future, we aim at probing the radiation-induced denaturation of biomolecular systems by tandem ion-mobility spectrometry.

Biography:

Tadashi Ogitsu has his expertise in ab-initio simulations and computational spectroscopy, and is interested in applying these skills and investigate on fundamental aspect of electrochemical processes relevant for energy applications such as renewable hydrogen production. He is a deputy group leader of Quantum Simulation Group at Lawrence Livermore National Laboratory and is the point of contact for DOE/EERE HydroGEN consortium which is designed to facilitate sustainable hydrogen production R&D by providing highly diverse and complemental research capabilities

Abstract:

Electrochemical processes are ubiquitously seen in problems relevant for our life, yet, extremely challenging to gain an accurate atomistic information due to its complex and dynamical nature. However, recent progresses on ab-initio computer simulation techniques combined with the advancement in high performance computing made direct simulations of complex electrochemical interfaces possible albeit connection to the corresponding real problem often is not apparent. On the other hand, there are many experimental probes that provides chemical and physical information of such problems albeit interpretation of such experimental data tends not to be straightforward. In this presentation, we will demonstrate how a combination of ab-initio simulations and in-operando characterization techniques such as ambient-pressure X-ray photoemission spectroscopy (AP-XPS) can be used to gain atomistic insights into electrochemical problems. We will discuss how AP-XPS data taken for oxidation of III-V semiconductors (GaP/InP) induced by chemical agents such as oxygen and/or water can be interpreted with the help of ab-initio simulations. Most importantly, ab-initio simulations provide information regarding relation between thermodynamic stability of structural models and their spectroscopic signatures that will give us confidence in interpreting the experimental data. This is particularly the case, when comprehensive set of spectroscopic information for the given problem is available. We show that one can effectively narrow down the candidate surface oxidation models based on systematic theory-experiments comparisons on O1s, P2p core-level binding energies, surface workfunction shift as well as their stabilities. Such a comprehensive theory-experiments comparison will lead to deeper understanding of electrochemical processes such as hydrogen/oxygen evolution and/or material corrosions that will facilitate improvements of the energy conversion/storage technologies.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office.

Biography:

Valeria Loise was born in 1986 in Cosenza, Italy. She received her Master’s degree in Chemistry, in 2016 at the University of Calabria. She has attended her PhD in “Life of Sciences” at the same University, working on the effects of the rejuvenator on the bitumen, since 2017. Her major area of expertise is the study of colloidal systems. In particular, she focuses on the chemistry of bitumen and its additives, approaching the open challenges in this area of research from a chemical point of view, also making use of investigation and analytical techniques never used before to study asphalt binders.

Abstract:

The present work aims to investigate the role of multi-walled carbon nanotubes MWCNTs on the structure of bitumen and their use as modifiers for binder. Since Iijima discovered them in 1991, CNTs have attracted enormous research attention due their amazing effects on properties of MWCNTs based composites. A MWCTs are a special CNTs where multiple single-walled carbon nanotubes are nested inside one another. They are characterized by high Young’s modulus, good tensile stability, high thermal conductivity and surface density. The bitumen is a colloidal system, where the asphaltenes (polar phase) are dispersed in the maltene (oil phase), it is possible to increase mechanical performances by using MWCTs as modifier. The MWCNTs change the microstructure of bitumen generally characterized by nano-meter sized aggregates of polar molecules (asphaltenes) organized in hierarchical structures, stabilized by resins and dispersed in an apolar phase of paraffins and aromatic oils (maltene) inducing high resistance effect to mechanical stresses. Two different types of MWCNTs were tested: one is a product obtained by laboratory synthesis through Catalytic Chemical Vapour Deposition (CCVD) technique and other one is a commercial one.  Microstructures of multi-walled carbon nanotubes and the rheological behaviour of modified and unmodified bitumens were investigated. The two different type of MWCNTs were characterized from structural and morphological point of view by TEM, micro –Raman spectroscopy and TGA techniques. Hence, the bitumens modified by MWCNTs were analysed through DSR experiments

Biography:

Leonid Rubinovich completed his PhD from Tomsk University, Russia. He is Researcher under KAMEA program at the Chemistry Department of Ben-Gurion University of the Negev, ISRAEL. L. R. published over 60 scientific articles.

Abstract:

Chemical-equilibrium involving a small number of molecules inside a confined nanospace can exhibit considerable deviations from the macroscopic thermodynamic limit due to reduced mixing entropy, as was predicted in several of our works using statistical-mechanics canonical partition-functions and the lattice-gas [1-3] as well as non-lattice [4] models. In particular, for exergonic addition and dimerization a considerable shift of the bimolecular reaction extent towards product formation is expected. This “nanoconfinement entropic effect on chemical-equilibrium” (NCECE) was verified by revised analysis [5] of reported measurements of DNA hybridization inside confined nano-fabricated chambers. More recently, we predicted enhancement of Ir dimerization inside Pd-Ir nanoparticles that can affect their catalytic properties [4].

Using the grand-canonical ensemble, the modeling has been recently extended to the more common “quasi-confined nanosystems” exchanging molecules with a macroscopic environment. As exemplified by dimerization of alkali metal vapors trapped inside pores by potential wells, the following conditions facilitate product-stabilizing NCECE effects under quasi-confinement (QNCECE): (i) limited nanospace capacity; (ii) significant host-guest interactions (deep potential wells); (iii) high-coverage of the nanospace (e.g., due to high external pressure or to low temperatures). In the case of low-coverage product destabilization is predicted because of monomer deficiency effects (opposite to the QNCECE).

The unique chemical-equilibria under confinement and quasi-confinement are anticipated for a wide range of nanospaces (nanopores, zeolites, nanotubes, fullerenes, micelles), and thus can have implications for the growing nanotechnological utilization of chemical syntheses conducted within nanoreactors

Biography:

Abstract:

RNA macromolecules perform various enzymatic and gene regulatory functions, which requires their specific stable three-dimensional structures. Specific structures of RNA is always stabilized by base pairing and stacking interactions and RNA showed various types of base pairing in addition to canonical Watson-Crick or wobble GU types. Analysis of all available RNA structures by detecting all types of base pairs, stabilized by two or more hydrogen bonds, show there are huge variations of  non canonical base pairs appearing frequently, such as A:A, A:G, etc, through their Hoogsteen or Sugar edge interactions as well. These base pairs are often seen within double helices, stacked on top of another base pair with good stacking geometry. These data have been organized in a database (http://hdrnas.saha.ac.in/rnabpdb) along with their orientation parameters. The data now can be used for generation of structures of various functional RNA, such as miRNA, using our RNAHelix software, which can lead to better predictions of their functions. Further analysis using ab initio quantum chemical calculations indicate possibility of double helix formation by some of the non-canonical base pairs. Some of the base pairs show bimodal distributions in their structural parameters, which appears to have great implication. Structural data analysis augmented by stacking energy analysis, using dispersion corrected DFT and MP2 methods, and all-atom molecular dynamics simulations further indicate possibility of Intrinsically Disordered Structure of RNA for certain sequence. This indicates that perhaps all types of base pairing modes may not give stable double helical structures.

Biography:

Man Yao was born in Liaoning, China. She received her PhD (material processing engineering, in 1998) at Dalian University of Technology, China, she joined the faculty at Dalian University of Technology as a lecturer in1989, and as a professor in 2001. In 2005, she began to work in University of Florida, America as a visiting scholar for three years. She has her expertise in multi-scale modeling and simulation of functional materials in photoelectricity and catalysis. Recent years, her research interest mainly focuses on the theoretical investigation and design of high-efficiency electrocatalysts for energy storage and conversion, and molecular self-assembly.

Abstract:

Lithium-oxygen (Li-O₂) batteries have recently attracted extensive attention due to their high theoretical energy density and practically available energy density, which are essential for future electric vehicles and other high-energy storage devices. However, the sluggish charging and discharging kinetic rates limit its practical application, and suffers from many issues such as high ORR/OER overpotential, short cycle life, low current density, unstable electrode material, and electrolyte instability. One of the approaches to accelerate the sluggish electrochemical reactions is using electrocatalysts. In this paper, the first-principles calculation method is used to study the cathode catalysts in Li-O₂ batteries based on transition-metal carbides (TMCs) system, including: to study the reaction mechanism during charging and discharging processes in lithium-air batteries; to build the theoretical model coupling of electron, ion, and interface in electrochemical reaction to determine the thermodynamics evaluation parameters of catalytic activity; to exploit the structure-activity relationship in electrochemical reactions, thereby determining the intrinsic properties affecting the catalytic activity. Finally, our work provides reliable information for the design, screening and development of new materials for Li-O₂ batteries. The detailed studies are as follows:  oxidized TiC surface as the potential state of TiC cathode is analyzed   during OER, in which O layer helps O₂^2- oxidation and Li-O bond activation, showing smaller O₂ evolution barrier and lower charge voltage; doping effect on the catalytic activity of TiC; correlations between material properties relative to the adsorption/desorption behavior of active molecules and the catalytic activity of 3d-TMCs and early TMCs are constructed, in which the ORR overpotentials are inversely proportional to the Li₄O₂/LiO₂ adsorption energies, meanwhile, the ORR overpotentials are proportional to the desorption energies of Li⁺ and the OER overpotentials are proportional to the O₂ desorption energies. Besides, the study on catalytic activity of Ti₂C MXene in Li-O₂ is under way.

Biography:

Kiran Soni was born in Haryana, India in 1983. She received her Ph.D. (2014) from the BITS Pilani. After completing postdoctoral research at University of Delhi, She joined the faculty at Maitreyi College, University of Delhi in 2017 where She is currently working as Assistant professor. Kiran Soni has her proficiency in synthesis of glycoconjugates, nano materials and their use in organic transformation as well as in metal ion sensing and in molecular recognition. Her work is based on the synthesis of all the natural moieties which does not hazard to our environment. Now a days She is using different nanoparticles also for purifying water and in HER reaction. In the above mentioned work She has synthesized the N2O2 types ligands which are helpful for the sensing different metals ion and amino acids in water.

Abstract:

Glycoconjugates are the molecules in which sugar is connected to other organic species such as protein, peptide, amino acids etc via covalent interaction. They are divided in three classes O type, N type and C type. It is of general concern to produce the molecules that can imitate like biological system. Several reports have appeared on structural and function mimicking of biological activities. Protein and Carbohydrate are linked by an amido linkage between the carboxyl group of L-aspartic acid and the amino group of 2-acetamido-2-deoxy-β-D-glucopyranosylamine which is extracted either from hen egg albumin or from other source. N-(2-Hydroxybenzoyl)-L-alanyl-4,6-O-ethylidene-β-D-glucopyranosylamine was interacted with transition metal ions but solid product was not isolated, even though the solution phase study supported the interactions between them. A series of alanyl-(4,6-O-ethylidene-b-D-glucopyranosylamine) derived new chiral receptors have been synthesized.  Metallochemistry of the ligands  has been explored. N-(2-Hydroxybenzylidene)-L-alanyl-4,6-O-ethylidene-β-D-glucopyranosylamine (K1) interacts with the acetates of Zn(II), Cu(II), Ni(II), Mn(II) and Co(II) ions in ground state but the interaction remains conserved in excited state for Zn²⁺ ion only. K1 has been also used for the molecular recognition of naturally occurring amino acids. All the interactions studies were explored using UV-visible, fluorescence and mass spectroscopy.

Biography:

Abstract:

This paper presents about Energy Dispersive X-Ray Fluoresce (EDXRF) Spectrometry, it is one of the most accurate economical chemical analytical technique, which can determine the proportional and identity of the major oxides of widely used for routine chemical analysis such: silicates, carbonates, sulphate, phosphates, rocks, cement, ceramic metallurgical samples, plastics, environmental and virtually any substance that can be adequately present to the x-ray Bearn. The analysis is rapid and non-destructive, but is generally impractical for determining elements lighter than fluorine. Major oxides analysis by XRF can be carried out on as little few grams of material. The sample material can be analyze as a pressed powder of fused into a glass disk using a suitable flux, such as lithium tetra borate. Using fused sample allows an evenly dispersed solid solution, which enables s wide range of matrix compositions to be accurately. Determined through the normalization of both particle size and inter – element (matrix) effects.

Biography:

Abstract:

This paper presents about Energy Dispersive X-Ray Fluoresce (EDXRF) Spectrometry, it is one of the most accurate economical chemical analytical technique, which can determine the proportional and identity of the major oxides of widely used for routine chemical analysis such: silicates, carbonates, sulphate, phosphates, rocks, cement, ceramic metallurgical samples, plastics, environmental and virtually any substance that can be adequately present to the x-ray Bearn. The analysis is rapid and non-destructive, but is generally impractical for determining elements lighter than fluorine. Major oxides analysis by XRF can be carried out on as little few grams of material. The sample material can be analyze as a pressed powder of fused into a glass disk using a suitable flux, such as lithium tetra borate. Using fused sample allows an evenly dispersed solid solution, which enables s wide range of matrix compositions to be accurately. Determined through the normalization of both particle size and inter – element (matrix) effects.