An unusual phase transition in a non-Hermitian Su-Schrieffer-Heeger model.

This article studies a non-Hermitian Su-Schrieffer-Heeger model which has periodically staggered Hermitian and non-Hermitian dimers. The changes in topological phases of the considered chiral symmetric model with respect to the introduced non-Hermiticity are studied where we find that the system supports only complex eigenspectra for all values of ≠ 0 and it stabilizes only non-trivial insulating phase for higher loss-gain strength. Even if the system acts as a trivial insulator in the Hermitian limit, the increase in loss-gain strength induces phase transition to non-trivial insulating phase through a (gapless) semi-metallic phase.

Insights into the compositional and temperature-mediated magnetic characteristics of chromium-doped ZnO nanoparticles.

This study explores the influence of chromium content and temperature on the magnetic characteristics of ZnO synthesized via the cost-effective coprecipitation approach. The host ZnO structure is not significantly changed by chromium doping, even at 5 wt.% of chromium concentration, according to x-ray diffraction studies.

Heterocyclic fluorescent Schiff base chemosensors for the detection of Fe(III) and Cu(II) ions.

Two new Schiff bases were synthesized from 1-(2,4-dihydroxyphenyl)ethanone and pyridine derivatives. Both compounds were characterized using infrared, UV-Vis., H NMR, C NMR and mass spectral studies.

Synthesis, characterization, molecular modeling, binding energies of β-cyclodextrin-inclusion complexes of quercetin: Modification of photo physical behavior upon β-CD complexation.

We prepared a naturally occurring flavanoid namely quercetin from tea leaves and analyzed by Absorption, Emission, FT-IR, H, C nmr spectra and ESI-MS analysis. The inclusion behavior of quercetin in cyclodextrins like α-, β-, γ-, per-6-ABCD and mono-6-ABCD cavities were supported such as UV-vis., Emission, FT-IR and ICD spectra and energy minimization studies.

Arene Ruthenium(II)-Catalyzed Sustainable Synthesis of 2,4-Disubstituted Quinazolines Acceptorless Dual Dehydrogenative Coupling of Alcohols.

We demonstrate an efficient and sustainable strategy for the direct synthesis of 2,4-disubstituted quinazolines by arene Ru(II)benzhydrazone complex the eco-friendly sequential acceptorless dehydrogenative coupling of 2-aminobenzhydrol derivatives and benzyl alcohols for the first time. The new ruthenium(II) complex of the general formula [(η--cymene)Ru(L1)Cl] (L1-acenaphthenequinone hydrazone) has been synthesized and characterized by analytical, spectroscopic, and single-crystal X-ray diffraction techniques. A broad spectrum of 2,4-disubstituted quinazolines have been successfully derived (25 examples) from 2-aminobenzhydrol derivatives with various benzyl alcohols using 1 mol % of catalyst loading in the presence of NHOAc.

Synthesis, X-ray crystal structure, Hirshfeld surface analysis and DFT studies of ()-'-(2-bromo-benzyl-idene)-4-methylbenzohydrazide.

The title mol-ecule, CHBrNO, displays a configuration with respect to the C=N double bond. The dihedral angle between the bromo- and methyl-substituted benzene rings is 16.1 (3)°.

Co(II) Complexes of4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(thiazol-2-yl)benzenesulphonamide and 4-((pyridin-2-ylmethylene)amino)-N-(thiazol-2-tl)benzenesulfonamide: Synthesis, Fluorescence Properties and Anticancer Activity.

Two new Co(II) complexes of 4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(thiazol-2-yl)benzenesulphonamide and 4-((pyridin-2-ylmethylene)amino)-N-(thiazol-2-yl)benzene sulfonamide were synthesised. The structure of the complexes was identified by elemental analysis, FT-IR, electronic, EI mass, Powder XRD spectra and magnetic moment. The TG and DTA patterns of the complexes were supported the structures.

Isoquinolinium 5-(2,4-di-nitro-phen-yl)-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetra-hydro-pyrimidin-4-olate: crystal structure, Hirshfeld surface analysis and pharmacological evaluation.

The asymmetric unit of the title salt C9H8N(+)·C12H9N4O7 (-), which exhibits anti-convulsant and hypnotic activities, comprises one anion and one cation inter-acting via an N-H⋯O hydrogen bond. In the anion, the six-membered rings are inclined each to other at 42.78 (9)°.

Crystal structure of creatininium 5-(2,4-di-nitro-phen-yl)-1,3-di-methyl-barbiturate monohydrate: a potential anti-convulsant agent.

In the anion of the title hydrated mol-ecular salt, C4H8N3O(+)·C12H9N4O7 (-)·H2O [systematic name: 2-amino-1-methyl-4-oxo-4,5-di-hydro-1H-imidazol-3-ium 5-(2,4-di-nitro-phen-yl)-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetra-hydro-pyrimidin-4-olate monohydrate], the 2,4-di-nitro-phenyl ring is inclined to the mean plane of the pyrimidine ring [r.m.s.

Crystal structure of a second triclinic polymorph of 2-methyl-pyridinium picrate.

The title mol-ecular salt, C6H8N(+)·C6H2N3O7 (-) (systematic name: 2-methyl-pyridinium 2,4,6-tri-nitro-phenolate), crystallizes with two cations and two anions in the asymmetric unit. In the crystal, the cations are linked to the anions via bifurcated N-H⋯(O,O) hydrogen bonds, generating R 1 (2)(6) graph-set motifs. Numerous C-H⋯O hydrogen bonds are observed between these cation-anion pairs, which result in a three-dimensional network.

Crystal structure of 3-methyl-pyridinium picrate: a triclinic polymorph.

The title mol-ecular salt, C6H8N(+)·C6H2N3O7 (-) (systematic name: 3-methyl-pyridinium 2,4,6-tri-nitro-phenolate), crystallizes in the triclinic space group P-1. The crystal structure of the monoclinic polymorph (space group P21/n) has been reported [Stilinovic & Kaitner (2011 ▸). Cryst.

Crystal structure of 1,10-phenanthrolinium 3-hy-droxy-2,4,6-tri-nitro-phenolate.

In the title molecular salt, C12H9N2 (+)·C6H2N3O8 (-), the cation and anion are connected by an N-H⋯O hydrogen bond. In the anion, an intra-molecular O-H⋯O hydrogen bond with an S(6) ring motif is observed. The planes of two of the nitro groups are approximately parallel to the plane of the benzene ring, making dihedral angles of 3.

Crystal structure and biological evaluation of 4-methyl-morpholin-4-ium 1,3-dimethyl-2,6-dioxo-5-(2,4,6-tri-nitro-phen-yl)-1,2,3,6-tetra-hydro-pyrimidin-4-olate.

The title mol-ecular salt, C5H12NO(+)·C12H8N5O9 (-) [common name: 4-methyl-morpholin-4-ium 1,3-dimethyl-5-(2,4,6-tri-nitro-phen-yl)barbiturate], possesses noticeable anti-convulsant and hypnotic activity. In the anion, the 1,3-di-methyl-barbituric acid ring and the symmetrically substituted tri-nitro-phenyl ring, linked via a C-C bond, are not coplanar but subtend an angle of 44.88 (7)°.

A new chalcone structure of (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one: Synthesis, structural characterizations, quantum chemical investigations and biological evaluations.

The structure of (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one (C19H13BrO) crystallized in the triclinic system of P-1 space group. The unit cell dimensions are: a=5.8944 (9)Å, b=7.

Crystal structure and thermal behaviour of pyridinium styphnate.

In the crystal structure of the title mol-ecular salt, C5H6N(+)·C6H2N3O8 (-) (systematic name: pyridinium 3-hy-droxy-2,4,6-tri-nitro-phenolate), the pyridin-ium cation and the 3-hy-droxy-2,4,6-tri-nitro-phenolate anion are linked through bifurcated N-H⋯(O,O) hydrogen bonds, forming an R 1 (2)(6) ring motif. The nitro group para with respect to phenolate ion forms an intra-molecular hydrogen bond with the adjacent phenolic -OH group, which results in an S(6) ring motif. The nitro group flanked by the phenolate ion and the phenolic -OH group deviates noticeably from the benzene ring, subtending a dihedral angle of 89.

Vibrational spectra (experimental and theoretical), molecular structure, natural bond orbital, HOMO-LUMO energy, Mulliken charge and thermodynamic analysis of N'-hydroxy-pyrimidine-2-carboximidamide by DFT approach.

The FT-IR, FT-Raman, (1)H, (13)C NMR and UV-Visible spectral measurements of N'-hydroxy-pyrimidine-2-carboximidamide (HPCI) and complete analysis of the observed spectra have been proposed. DFT calculation has been performed and the structural parameters of the compound was determined from the optimized geometry with 6-311+G(d,p) basis set and giving energies, harmonic vibrational frequencies and force constants. The results of the optimized molecular structure are presented and compared with the experimental.

Synthesis of a new class of carbon-bonded anionic sigma complexes with 1,3-dimethyl-2,6-dioxo-5-(2,4,6-trinitrophenyl)-1,2,3,6-tetrahydropyrimidin-4-olate moiety as insensitive high energy density materials -- implications from impact sensitivity and thermal testings.

Background: Poly nitro aromatic compounds are high energy density materials. Carbon-bonded anionic sigma complexes derived from them have remarkable thermal stability. At present there is a strong requirement for thermally stable insensitive high energy density materials (IHEDMs) in the energetic field which necessitates the present investigation.

Crystal structure of 2-{[(2-chloro-phen-yl)imino]-meth-yl}phenol.

In the title compound, C13H10ClNO, the dihedral angle between the planes of the aromatic rings is 51.42 (9)° and an intra-molecular O-H⋯N hydrogen bond closes an S(6) ring. The Cl atom and the N atom are syn.

Crystal structure of tri-methyl-ammonium 5-(2,4-di-nitro-phen-yl)-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetra-hydro-pyrimidin-4-olate.

The asymmetric unit of the title mol-ecular salt, C3H10N(+)·C12H9N4O7 (-) [alternative name: tri-methyl-ammonium 5-(2,4-di-nitro-phen-yl)-1,3-dimethyl barbiturate], contains one anion and two half-occupancy cations. The cations are disordered about inversion centres. The tetra-hydro-pyrimidine ring is essentially planar [maximum deviation = 0.

Crystal structure of 4-amino-pyridinium 5-(5-chloro-2,4-dinitrophenyl)-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate hemihydrate.

The title mol-ecular salt, C5H7N2 (+)·C12H8ClN4O7 (-)·0.5H2O, crystallizes as a hemihydrate. The two rings in the barbiturate anion are not coplanar but make a dihedral angle of 43.

Comparative in vitro Cytotoxic Studies of Novel 8-(4'/2'-Methoxy/Unsubstituted phenylcarbamoyl)bicyclo[3.3.1]nonane Derivatives on Ehrlich Ascites Carcinoma Cell Line.

Novel bicyclo[3.3.1]nonane derivatives were synthesized by an efficient methodology from acetoacetanilide, 2-methoxy and 4-methoxyacetoacetanilides, 1,3,5-trinitrobenzene and triethylamine.

Synthesis, crystal structure and theoretical studies of a Schiff base 2-[4-hydroxy benzylidene]-amino naphthalene.

The molecular structure of a new Schiff base, 2-[4-hydroxy benzylidene]-amino naphthalene (HBAN) has been examined by HF and B3LYP/6-311++G(d,p) calculations. The X-ray structure was determined in order to establish the conformation of the molecule. The compound, C17H13NO, crystallizes in the orthorhombic, P212121 space group with the cell dimension, a=6.

Theoretical and experimental calculations, Mulliken charges and thermodynamic properties of 4-chloro-2-nitroanisole.

The FT-IR and FT-Raman spectra of 4-chloro-2-nitroanisole were recorded and analyzed. The vibrational wavenumbers were examined theoretically with the aid of the GAUSSIAN 09 package of programs using the B3LYP/6-311G(d,p) and 6-311++G(d,p) levels of theory. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in IR and Raman spectroscopy of the studied molecule.