Stable crystalline lattices in two-dimensional binary mixtures of dipolar particles

The phase diagram of binary mixtures of particles interacting via a pair potential of parallel dipoles is computed at zero temperature as a function of composition and the ratio of their magnetic susceptibilities. Using lattice sums, a rich variety of different stable crystalline structures is identified including $A_mB_n$ structures. [$A$ $(B)$ particles correspond to large (small) dipolar moments.] Their elementary cells consist of triangular, square, rectangular or rhombic lattices of the $A$ particles with a basis comprising various structures of $A$ and $B$ particles. For small (dipolar) asymmetry there are intermediate $AB_2$ and $A_2B$ crystals besides the pure $A$ and $B$ triangular crystals. These structures are detectable in experiments on granular and colloidal matter.Comment: 6 pages - 2 figs - phase diagram update

Structural investigation of a new cadmium coordination compound prepared by sonochemical process: Crystal structure, Hirshfeld surface, thermal, TD-DFT and NBO analyses

The final publication is available at Elsevier via https://doi.org/10.1016/j.ultsonch.2018.11.024. © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/A new nanostructured cadmium complex containing a tridentate Schiff base ligand was sonochemically synthesized and characterized by XRPD, FT/IR, NMR, and single crystal X-ray crystallography. Structural data showed that cadmium(II) ion is surrounded by three nitrogen atoms of Schiff base ligand and two iodide anions. The crystal packing was contained the intermolecular interactions such as CH⋯O, CH⋯I and π⋯π interactions organizing the self-assembly process. Hirshfeld surfaces and corresponding fingerprint plots have been used for investigation of the nature and proportion of interactions in the crystal packing. FT/IR, NMR and XRD data were in agreement with the X-ray structure and confirm the phase purity of the prepared sample. The molecular structure of the complex was optimized by density functional theory (DFT) calculation at the B3LYP/LANL2DZ level of theory and the results were compared with experimental ones. For more concise study of structure and spectral aspects of the complex, natural bond orbital (NBO) analysis and time-dependent density functional theory (TD-DFT) have been also performed. Thermal stability of the cadmium iodide complex was investigated by thermogravimetric analysis (TGA). Finally, cadmium oxide nanoparticles was prepared by direct calcination of CdLI2 complex as a new precursor.Partial support of this work by Yasouj University is appreciated

Dynamical correlations and collective excitations of Yukawa liquids

In dusty (complex) plasmas, containing mesoscopic charged grains, the grain-grain interaction in many cases can be well described through a Yukawa potential. In this Review we summarize the basics of the computational and theoretical approaches capable of describing many-particle Yukawa systems in the liquid and solid phases and discuss the properties of the dynamical density and current correlation spectra of three- and two-dimensional strongly coupled Yukawa systems, generated by molecular dynamics simulations. We show details of the $\omega(k)$ dispersion relations for the collective excitations in these systems, as obtained theoretically following the quasilocalized charge approximation, as well as from the fluctuation spectra created by simulations. The theoretical and simulation results are also compared with those obtained in complex plasma experiments.Comment: 54 pages, 31 figure

IR and N-IR spectrometry characterizations of LGS crystal and family

Middle and near infrared (MIR/NIR) spectrometry has been used to characterize series of samples of LGx family and GaPO$_{4}$. Since OH impurities influence the material properties, their spectroscopy is investigated in detail. The [190–3200 nm] region is measured in transmission. Furthermore, the study of spectra made at Nitrogen liquid temperature is used to follow the modification in the signature of some defects present in the lattice and induced by treatments as $\gamma$ irradiation or annealing. At least, we show that these “new” materials contain less OH-groups than quartz crystal

High-spin supramolecular pair of Mn(II)/thiazyl radical complexes

TheMn(hfac)2 complex of the paramagnetic 4-(benzoxazol-20-yl)-1,2,3,5-dithiadiazolyl ligand is reported (hfac = 1,1,1,5,5,5- hexafluoroacetylacetonato-). The Mn(II) and radical ligand spins are coupled antiferromagnetically (AF) in the coordination complex. Short sulfur–oxygen contacts between molecules provide an efficient pathway for AF coupling between the radical ligand of one molecule and the Mn(II) of a neighbouring molecule, resulting in a large total spin ground state (ST = 4) for a pair of molecules

The structure , magnetism and EPR spectra of a (μ-thiophenolato)(μ-pyrazolato-N,N') double bridged dicopper(II) complex

A new binuclear copper(II) complex, namely [Cu2L(pz)(DMSO)], where L = 2,6-bis[(2-phenoxy)iminomethyl]-4-methylthiophenolate(3-) and pz = pyrazolate ligand, has been synthesized by a one-pot synthesis involving copper(II) acetate monohydrate, the S-protected ligand precursor 2-(N,Ndimethylthiocarbamato)-5-methylisophthalaldehyde di-2?-hydroxy anil, (I), and pyrazole, in which a metal-promoted S-deprotection reaction occurs during the formation of the complex. This was characterized by routine physicochemical studies, single crystal X-ray diffraction and electron paramagneticresonance (EPR) techniques. The structure analysis reveals that there are copper centres in two different environments, a slightly distorted square planar and a distorted square-pyramidal, arranged in binuclear units. The EPR study of these binuclear units performed at 9.4 GHz in the temperature range between 4 and 293 K shows an antiferromagnetic interaction between CuII ions, and allows evaluating g factors gx = 2.068(1), gy = 2.091(1) and gz = 2.165(1), with = 2.108(1), an exchange coupling parameter J0 = -26(1) cm−1 (defined as Hex = - J0 S1 S2), and a zero field splitting of the ground triplet state described by D = 86(2) × 10-4 cm-1 and E = -48(3) × 10-4 cm-1. These results are discussed and compared with the existing literature.Fil: Khadir, Narjes. Sharif University of Technology. Department of Chemistry; IránFil: Boghaei, Davar M.. Sharif University of Technology. Department of Chemistry; IránFil: Assoud, Abdeljalil. University of Waterloo. Department of Chemistry; CanadáFil: Nascimento, Otaciro R.. Universidade de São Paulo. Instituto de Física de São Carlos. Departamento de Física e Ciência Interdisciplinar. Grupo de Biofísica Molecular Sergio Mascarenhas; BrasilFil: Nicotina, Amanda. Universidade Federal do Rio de Janeiro. Instituto de Física; BrasilFil: Ghivelder, Luis. Universidade Federal do Rio de Janeiro. Instituto de Física; BrasilFil: Calvo, Rafael. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentin

Synthesis and characterization of two binuclear nickel(II) complexes of thiophenol-based “end-off” compartmental ligands and their application as catalysts for selective oxidation of sulfides

<div><p></p><p>Reaction of the binucleating S-protected ligand precursors 2-(<i>N,N</i>-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′-hydroxy anil (<b>I</b>) and 2-(<i>N,N</i>-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′-hydroxy 5′-methyl anil (<b>II</b>) with nickel(II) acetate tetrahydrate in the presence of pyrazole afforded the binuclear nickel(II) complexes [L^<b>I</b>Ni₂(pz)] (<b>1</b>) and [L^<b>II</b>Ni₂(pz)] (<b>2</b>), respectively. The complexes have been characterized by routine physicochemical studies as well as by X-ray single crystal structure analysis. In both complexes, Ni(II) ions are doubly bridged by the thiophenolic sulfur of the pentadentate Schiff base ligand and a pyrazolate group. Efficient protocols for the oxidation of sulfides to sulfoxides with high selectivities, catalyzed by binuclear μ-thiophenolato-μ-pyrazolatonickel(II) in the presence of urea hydrogen peroxide (UHP) were explored. We obtained predominantly the monooxygenated product. The resulting products are obtained in good to excellent yields within a reasonable time.</p></div