Application of barycentric method for determination of free energy of liquid monodisperse system accomplishing diffusion

The barycentric method has been applied to determining the thermodynamic potential (the free energy) of a liquid rarefied monodisperse colloid system in which free unstationary diffusion under constant external conditions has been accomplished. Free energy at an arbitrary moment of time has been obtained as a function of horizontal mass center shift toward the cuvette cavity geometrical center of the liquid disperse system investigated. A very good coincidence between the numerical results from the proposed barycentric method and another classical thermodynamic method has been observed.     

New 5-bromo-2-hydroxybenzaldehyde S-ethylisothiosemicarbazone and its mixed-ligand Cu(II) complex with imidazole: synthesis, characterization and DFT calculation

A new Schiff base ligand of 5-bromo-2-hydroxybenzaldehyde S-ethyl-isothiosemicarbazone (H₂L) was synthesized and its mixed-ligand Cu(II) complex was also prepared by reaction of Cu(NO₃)₂·3H₂O with H₂L and imidazole. Their structures were fully characterized by elemental analysis, FT-IR, molar conductivity and UV-Vis methods. The analytical data suggest that the metal, H₂L and imidazole ratios in the Schiff base complex are 1:1:1. Single crystal diffraction was also used to better understand the molecular structure of the Cu(II) complex. The results of physico-chemical analyses of the Schiff base complex reveal the coordination geometry around the central atom is square planar. The H₂L ligand (NNO donor) is coordinated to the metal center as a tridentate bionegatively agent. Another position of the square planar geometry is occupied by the imidazole ligand. Furthermore, computational studies of the new complex were performed by carrying out DFT calculations. Geometry optimization and natural band analysis of the complex is discussed in further detail.      

Mixed Ligand Palladium(Ⅱ) Complex with NS-Bidentate S-Allyldithiocarbazate Schiff Base: Synthesis, Spectral Char-acterization, Crystal Structure and Decoding Intermolecular Interactions with Hirshfeld Surface Analysis

A new mixed ligand palladium(II) complex with bidentate NS‐donor chelate, [PdCl(PPh₃)L] (L: S‐allyl β‐N‐(benzylidene)dithiocarbazate), has been prepared and characterized using single crystal X‐ray diffraction and spectroscopic (electronic, IR, ¹H NMR and ¹³C NMR) techniques. The shorter Pd? P bond distance, 2.255(7) Å, than the sum of the single bond radii for palladium and phosphorus (2.41 Å), showed partial double bond character. Visualizing and exploring the crystal structure using Hirshfeld surface analysis showed the presence of π··· π, N··· π, C? H··· π, Cl···H and weak C? H···S interactions as most important intermolecular interactions in the crystal lattice, which are responsible to extension of the supramolecular network of the compound and stabilization of the crystal structure.     

Facile and green methodology for surface‐grafted Al2O3 nanoparticles with biocompatible molecules: preparation of the poly(vinyl alcohol)@poly(vinyl pyrrolidone) nanocomposites

The present work describes preparation of modified alumina with biocompatible, water soluble, and treating agents such as citric acid and ascorbic acid. Also, the influence of the modified nanoparticles (NPs) into the blend of poly(vinyl alcohol)@poly(vinyl pyrrolidone) (50/50) matrix was studied. At first, citric acid and ascorbic acid as environmental friendly agents were grafted on the surface of Al₂O₃ NPs. Then, nanocomposites (NCs) with different amounts of modified Al₂O₃ NPs were prepared via a simple ultrasonic method. The characterizations of the molecular structure of the NCs specified that chemical and physical interactions happened between inorganic and organic counterparts. The mutual effect of modified NPs into the polymer matrix was investigated on the structural, interfacial interaction, thermal stability, and optical properties. The results from morphological characterization confirmed changes in morphology of poly(vinyl alcohol) and poly(vinyl pyrrolidone) after loading NPs. Uniform dispersion of modified spherical Al₂O₃ NPs powders into the matrix of 50/50 polymers was detected by field emission scanning electron microscopy and energy‐dispersive X‐ray. Adding M‐NPs into the polymer matrix expressively improved the thermal stability of NCs. Peaks in ultraviolet–visible spectra were shifted to the higher absorption. Copyright © 2017 John Wiley & Sons, Ltd.     

Systematic Study of Two-Quasi-Particle Structure of Odd–Odd Thulium Nuclei

Physics of Atomic Nuclei - In this study, the nuclear structure properties of $${}^{160{-}166}$$ Tm isotopes with neutron numbers 91, 93, 95, and 97 were investigated using the projected shell...     

Preparation of an efficient catalyst through injection of CuI on modified poly (styrene-co-maleic anhydride) and theoretical investigation of the structural and electronic properties of catalyst

A novel polymer supported [poly (styrene-co-maleic imide) (SMI)]Cu(I) nano-particles was prepared via in situ reaction of 4-amino-5-methyl-4H-1,2,4-triazole-3-thione with [poly (styrene-co-maleic anhydride)] (SMA) along with immobilization of CuI. These nano-particles were fully characterized by using scanning electron microscopy (SEM), energy dispersive spectroscopy analysis, Xray (EDAX), inductively coupled plasma (ICP) analysis, ¹H NMR and FT-IR techniques. Moreover, the structural and electronic features of metal–ligand interactions in the complex model of polymer-supported copper nanocatalyst were assessed using density functional theory calculations. The catalytic activity of these supported Cu(I) nonoparticles was examined in one of the classiest name reaction so–called “click reaction” which is coined K. B Sharpless for the regioselective synthesis of 1,2,3-triazole derivatives using a multicomponent reaction (MCR) involving benzyl halides, sodium azide and terminal alkynes in water as a green solvent. This heterogeneous catalyst showed excellent catalytic activity and was separated by simple filtration and was used at least in five consecutive runs without a significant decrease in its activity.     

Synthesis,crystal structure of new linear trinuclear isovalence Co(II)([Co<Subscript>3</Subscript>(H–L)<Subscript>2</Subscript>(L)<Subscript>2</Subscript>]), and visualizing intermolecular interactions with Hirshfeld surface method

S-allyl-β-N-[(2-hydroxyphenyl)methylene]hyrazinecarbodithioate) (1, H₂L), the Schiff base of dithiocarbazate with unsaturated allyl substitution, can act as a new tridentate SNO ligand H₂–L and react with cobalt(II) nitrate hexahydrate to form the novel linear trinuclear isovalence Co(II) complex, [Co₃(H–L)₂(L)₂] 2C₂H₅OH (2). The compounds were characterized by elemental analysis, infrared, and ultraviolet spectroscopy. Compound 2 was also characterized by single-crystal X-ray analysis and crystallizes in the orthorhombic space group, Pbcn, with a = 30.643(1) Å, b = 9.118(4) Å, c = 19.017(7) Å, α = β = γ = 90°, V = 5312.95 Å³, Z = 4, and R ₁ = 0.0790, (wR ₂) = 0.1223. The six-coordinate central Co(II) atom is bonded to two deprotonated metal-containing ligands. The terminal Co(II) atoms are in a square planar SNON four-coordinate environment and connected to the central Co(II) by N-atoms from the ligand backbone. For quantifying the intermolecular interactions in crystal lattice, the new d _norm surface and the breakdown of fingerprint plots have been used for visualizing and exploring the compound 2.     

Synthesis and X-ray crystal structures of some isothiosemicarbazone complexes

Transition Metal Chemistry - Four complexes of a new isothiosemicarbazone ligand have been prepared and characterized as μ2-pip-(NiL)2 (1), MnL2 (2), UO2L(BrSal)BuOH (3) and (μ2-MoO2L)2...     

Molecular structures and spectroscopic characterization of cobalt(III) and nickel(II) complexes of <Emphasis Type="Italic">N</Emphasis>-(2-hydroxyethyl)-2-(thiophene-2-ylmethylene)-hydrazinecarbothioamide

Two complexes of a thiosemicarbazone ligand, namely N-(2-hydroxyethyl)-2-(thiophene-2-ylmethylene)-hydrazinecarbothioamide (HL), have been synthesized. The complexes have been characterized by physico-chemical and spectroscopic methods. The crystal and molecular structures of [CoL₃]·2MeOH (1) and [NiL₂] (2) have been determined by X-ray diffraction studies. For both complexes, the metal is coordinated through the sulfur and azomethine nitrogen atoms of the thiosemicarbazone. The ligand exists in its thiolate tautomeric form, and the central Co(III) and Ni(II) atoms have distorted octahedral and square planar geometries, respectively, with five-membered chelate rings formed by the ligand. The lattice of 1 shows infinite oxygen donor/acceptor hydrogen bonds in the ab plane and weak interactions between rings along the c axis, respectively, giving a supramolecular network. The molecular units in 2 are linked together by hydrogen bonds between the hydroxyl oxygen and hydrazone N proton, giving rise to an infinite ribbon extended along the c-axis. These chains are connected by N3–H3···O1 interactions that form a sheet within the ac plane.     

Molecular theory of thermal conductivity of the Lennard-Jones fluid

In this paper the thermal conductivity of the Lennard-Jones fluid is calculated by applying the combination of the density-fluctuation theory, the modified free volume theory of diffusion, and the generic van der Waals equation of state. A Monte Carlo simulation method is used to compute the equilibrium pair-correlation function necessary for computing the mean free volume and the coefficient in the potential-energy and virial contributions to the thermal conductivity. The theoretical results are compared with our own molecular dynamics simulation results and with those reported in the literature. They agree in good accuracy over wide ranges of density and temperature examined in molecular dynamics simulations. Thus the combined theory represents a molecular theory of thermal conductivity of the Lennard-Jones fluid and by extension simple fluids, which enables us to compute the nonequilibrium quantity by means of the Monte Carlo simulations for the equilibrium pair-correlation function.