A study of the atmospherically important reactions between dimethyl selenide (DMSe) and molecular halogens (X2 = Cl2, Br2, and I2) with ab initio calculations.

The atmospherically relevant reactions between dimethyl selenide (DMSe) and the molecular halogens (X(2) = Cl(2), Br(2), and I(2)) have been studied with ab initio calculations at the MP2/aug-cc-pVDZ level of theory. Geometry optimization calculations showed that the reactions proceed from the reagents to the products (CH(3)SeCH(2)X + HX) via three minima, a van der Waals adduct (DMSe:X(2)), a covalently bound intermediate (DMSeX(2)), and a product-like complex (CH(3)SeCH(2)X:HX). The computed potential energy surfaces are used to predict what molecular species are likely to be observed in spectroscopic experiments such as gas-phase photoelectron spectroscopy and infrared matrix isolation s…

Temperature influence on the synthesis of pristine graphene oxide and graphite oxide

Abstract Derivative oxide carbon materials, such as graphene or graphite oxides, have been recently considered to be a promising material in a wide scenarios of emerging technologies due to their physical and chemical properties, as well as, for their low production costs. Even if apparently similar, these materials exhibit different physical and chemical properties. One of the critical issue is associated with the exfoliation process and contributes to the formation of graphene oxide and graphite oxide material. Here, we show a single synthetic wet method to produce graphene or graphite oxide by applying a control of the operational temperature during the reaction. The process was optimise…

Halloysite Nanotubes and Metal Corrosion Inhibitors: A Computational and Experimental Study

Halloysite nanotubes are widely used as a substrate for the controlled release of various types of molecules in an increasing number of applications. In this work, the interactions of halloysite silicic and aluminic surfaces with corrosion inhibitor compounds, such as benzotriazole, 8-hydroxyquinoline, 2-mercaptobenzimidazole, and 2-mercaptobenzothiazole, were investigated from a computational point of view. Two new halloysite compounds with salicylaldoxime and quinaldic acid were designed. Here we propose their synthesis, evaluate amounts of loading, and analyze the adsorption behavior.

Alkali-Metal Azides Interacting with Metal–Organic Frameworks

L-arabinose adsorption on hydrogenated and hydrated ruthenium catalyst

A study of the atmospherically important reactions of dimethylsulfide (DMS) with I2 and ICl using infrared matrix isolation spectroscopy and electronic structure calculations.

The reactions of dimethylsulfide (DMS) with molecular iodine (I(2)) and iodine monochloride (ICl) have been studied by infrared matrix isolation spectroscopy by co-condensation of the reagents in an inert gas matrix. Molecular adducts of DMS + I(2) and DMS + ICl have also been prepared using standard synthetic methods. The vapour above each of these adducts trapped in an inert gas matrix gave the same infrared spectrum as that recorded for the corresponding co-condensation reaction. In each case, the infrared spectrum has been interpreted in terms of a van der Waals adduct, DMS : I(2) and DMS : ICl, with the aid of infrared spectra computed for their minimum energy structures at the MP2 lev…

Molecular-Level Characterization of Heterogeneous Catalytic Systems by Algorithmic Time Dependent Monte Carlo

Monte Carlo algorithms and codes, used to study heterogeneous catalytic systems in the frame of the computational section of the NANOCAT project, are presented along with some exemplifying applications and results. In particular, time dependent Monte Carlo methods supported by high level quantum chemical information employed in the field of heterogeneous catalysis are focused. Technical details of the present algorithmic Monte Carlo development as well as possible evolution aimed at a deeper interrelationship of quantum and stochastic methods are discussed, pointing to two different aspects: the thermal-effect involvement and the three-dimensional catalytic matrix simulation. As topical app…

The complete basis set Full-CI roto-vibrational spectroscopic constants of AlH, AlH+ and AlH -

The spectroscopic constants of AlH, AlH + and AlH -, as well as their counterparts with H/D isotopic substitution, were obtained at the frozen core Full-CI/CBS limit and corrected for the core-correlation, relativistic and diagonal Born–Oppenheimer contributions, calculated by means of different high-level computational methods. On the basis of the obtained values, some accepted experimental result for these astrochemically relevant species is questioned.

Theoretical investigation of magnetic properties in Cu(II) complexes with bridging azide ions

MOF DERIVATIVES AS MOLECULAR TOOLS TO TRAP METAL AZIDES

HPS-based catalysts: a computational study

Investigation of Polyol Adsorption on Ru, Pd, and Re Using vdW Density Functionals

Biomass-based feedstocks are often oxygenated compounds characterized by large amounts of hydroxyls. As an example, polyols and sugar alcohols are largely employed as reactants for different chemical catalytic transformations such as oxidation, dehydration, and hydrodeoxigenation, which usually occur in aqueous medium. With the goal of gaining new insights into processes that could be industrially relevant, the adsorption of the OH groups on metal surfaces and in the presence of water has to be correctly reproduced and described, within a chosen theoretical framework. Toward this goal, several tests were performed on the catalytically relevant metal Ru, Pd, and Re, benchmarking their bulk a…

Adsorption Studies of Molecules on the Halloysite Surfaces: A Computational and Experimental Investigation

We report the results of joint computational and experimental investigations on the adsorption capability of halloysite toward a set of common molecules (water, alcohols, halides, and carboxylic acids). The halloysite system has been modelized by means of a cluster approach choosing a portion of a spiral nanotube; it has a slight curvature, with a convex aluminic layer. The adsorption geometries are described in terms of hydrogen bond network structures; calculated interaction energies invariably indicate that the inner aluminic surface is the place for preferential adsorption of polar molecules. The presence of substitutional defects on the outer or inner surface of the halloysite model ca…

The SIESTA method applied to the study of renewable fuel synthesis

Low-Cost Synthesis of Smart Biocompatible Graphene Oxide Reduced Species by Means of GFP.

The aim of this work is focused on the engineering of biocompatible complex systems composed of an inorganic and bio part. Graphene oxide (GO) and/or graphite oxide (GtO) were taken into account as potential substrates to the linkage of the protein such as Anemonia sulcata recombinant green fluorescent protein (rAsGFP). The complex system is obtained through a reduction process between GO/GtO and rAsGFP archiving an environmentally friendly biosynthesis. Spectroscopic measurements support the formation of reduced species. In particular, photoluminescence shows a change in the activity of the protein when a bond is formed, highlighted by a loss of the maximum emission signal of rAsGFP and a …

Clay nanotubes for designing eco-compatible smart materials

Synthesis, photophysical properties and structures of organotin-Schiff bases utilizing aromatic amino acid from the chiral pool and evaluation of the biological perspective of a triphenyltin compound

Abstract Five new organotin(IV) complexes of compositions [Me 2 SnL 1 ] ( 1 ), [Me 2 SnL 2 ] n ( 2 ), [Me 2 SnL 3 ] ( 3 ), [Ph 3 SnL 1 H] n ( 4 ) and [Ph 3 SnL 3 H] ( 5 ) (where L 1  = (2 S )-2-(( E )-(( Z )-4-hydroxypent-3-en-2-ylidene)amino)-3-(1 H -indol-3-yl)propanoate, L 2  = (2 S )-( E )-2-((2-hydroxybenzylidene)amino)-3-(1 H -indol-3-yl)propanoate and L 3  = (2 S )-( E )-2-((1-(2-hydroxyphenyl)ethylidene)amino)-3-(1 H -indol-3-yl)propanoate were synthesized and spectroscopically characterized. The crystal structures of 1 – 4 were determined. For the dimethyltin derivative 2 , a polymeric chain structure was observed as a result of a long Sn∙∙∙O contact involving the exocyclic carbony…

MOF derivatives as cage for alkali-metal azides: a DFT study

Modeling of the Halloysite Spiral Nanotube

A computational SCC-DFTB investigation dealing with the structure of hydrated and anhydrous halloysite nanotubes with a spiral geometry is reported. The peculiar characteristics of these systems are described in terms of tetrahedral and octahedral distortions, of hydrogen bonds geometries involving water molecules and the surfaces in the hydrated nanotube, and of the interlayer interactions in the anhydrous one. When the properties of the spiral nanotube are compared with those of the kaolinite sheet, a certain degree of intrinsic disorder in the halloysite systems is revealed, due to the intrinsic nature of the spiral folding. This is particularly evident in the hydrogen bonds network occu…

Structural and Kinetic DFT Characterization of Materials to Rationalize Catalytic Performance

This review shortly discusses recent results obtained by the application of density functional theory for the calculations of the adsorption and diffusion properties of small molecules and their reactivity on heterogenous catalytic systems, in the ambit of the Nanocat project. Particular focus has been devoted to palladium catalysts, either in atomic or small cluster form. Some protocols have been tested to obtain efficient ways able to treat the electronic and geometric influence of supports like zeolites and carbon nanotubes on the catalytic properties of palladium. The hydroisomerization of cis-but-2-ene is discussed as model reaction on supported and unsupported Pd clusters. Some prelim…

Studio teorico sul confinamento delle azidi di metalli alcalino-terrosi nella cavità di un aggregato tubolare ciclopeptidico

Computational Study on Cesium Azide Trapped in a Cyclopeptidic Tubular Structure

The structures and the electronic properties of host-guest complexes formed by a cyclopeptidic tubular aggregate and the species CsN3, CS2(N-3)(2), and CS2N6 have been investigated by means of density functional theory. Taking advantage of the azide property to act as a bridge ligand between two or more metal cations, it may be possible to trap N-3(-) ions inside a confined space. This could be important for the preparation of polynitrogen molecules N-n. Results show that there are significant attractive interactions between the azide ion and the cavity walls, which make the ion stay inside the inner empty space of the cyclopeptidic aggregate. The confinement of the species CS2(N-3)(2) forc…

Physical properties of waterlogged wood. Measurements with Accupyc 1330, Helium pycnometer

COMPUTATIONAL APPROACHES EMPLOYED IN THE SusFuelCat PROJECT

Processo di invecchiamento chimico dei legni: verifica dell'efficacia del trattamento da misure di densità

Studio teorico dell’interazione host-guest fra un sistema tubolare ciclopeptidico e la cesio azide

Confined But-2-ene catalytic isomerization inside H-ZSM-5 models: A DFT study

The isomerization of cis-but-2-ene to trans-but-2-ene within a 22T H-ZSM-5 zeolite model, also in the presence of two adsorbed Pd atoms, has been studied by DFT calculations. The results obtained allow us to state that the cis/trans but-2-ene isomerization can easily proceed inside unsupported zeolite cavities. In this case, differently than in the gas phase reaction, the trans-but-2-ene is less stable than the cis-but-2-ene, when adsorbed on the zeolite inner surface. Excluding the adsorption-desorption steps, the isomerization process involves two intermediates and three transition states, whose energy content is always very low with respect to that of reagents and intermediate species. T…

MODELING OF SPIRAL HALLOYSITE NANOTUBES

Computational approaches used in the POLYCAT EU project

INSIGHTS WITHIN APR PROCESS USING VDW-DF FUNCTIONAL

CCDC 1431712: Experimental Crystal Structure Determination

Related Article: Tushar S. Basu Baul, Pelesakuo Kehie, Andrew Duthie, Nikhil Guchhait, Nune Raviprakash, Raveendra B. Mokhamatam, Sunil K. Manna, Nerina Armata, Michelangelo Scopelliti, f, Ruimin Wang, Ulli Englert|2017|J.Inorg.Biochem.|168|76|doi:10.1016/j.jinorgbio.2016.12.001

CCDC 1431713: Experimental Crystal Structure Determination

Related Article: Tushar S. Basu Baul, Pelesakuo Kehie, Andrew Duthie, Nikhil Guchhait, Nune Raviprakash, Raveendra B. Mokhamatam, Sunil K. Manna, Nerina Armata, Michelangelo Scopelliti, f, Ruimin Wang, Ulli Englert|2017|J.Inorg.Biochem.|168|76|doi:10.1016/j.jinorgbio.2016.12.001

CCDC 1431715: Experimental Crystal Structure Determination

Related Article: Tushar S. Basu Baul, Pelesakuo Kehie, Andrew Duthie, Nikhil Guchhait, Nune Raviprakash, Raveendra B. Mokhamatam, Sunil K. Manna, Nerina Armata, Michelangelo Scopelliti, f, Ruimin Wang, Ulli Englert|2017|J.Inorg.Biochem.|168|76|doi:10.1016/j.jinorgbio.2016.12.001

CCDC 1431714: Experimental Crystal Structure Determination

Related Article: Tushar S. Basu Baul, Pelesakuo Kehie, Andrew Duthie, Nikhil Guchhait, Nune Raviprakash, Raveendra B. Mokhamatam, Sunil K. Manna, Nerina Armata, Michelangelo Scopelliti, f, Ruimin Wang, Ulli Englert|2017|J.Inorg.Biochem.|168|76|doi:10.1016/j.jinorgbio.2016.12.001