Energy Conservation for a Scalar Field in Linear Gravity

In this paper we derive a Gaussian flux integral for a metric in the weak field limit. We shall prove that the energy integral for an approximately linear metric due to a scalar field, will possess a same form for the Newtonian mass.     

Synthesis,Crystal Structure,and Characterization of Na7Cu4(AsO4)5

Abstract

Sodium copper (II) arsenate Na₇Cu₄(AsO₄)₅ has been grown by conventional high-temperature, solid-state methods in molten-salt media. It was characterized by single crystal X-ray diffraction (XRD), thermal analysis (DTA–TGA), scanning electron microscopy (SEM), semiquantitative energy dispersive spectroscopy analysis (EDS), and vibrational spectroscopy. Na₇Cu₄(AsO₄)₅ exhibits a three-dimensional framework built up of CuO₅, CuO₄, and AsO₄ polyhedra, with intersecting channels in which the Na⁺ cations are located. The three-dimensional cohesion of the framework results from Cu–O–As bridges. CuO₅ and CuO₄ polyhedra are elongated due to the Jahn–Teller effect, whereas AsO₄ tetrahedra are almost regular. This new structural model is validated by the charge distribution (CD) analysis. The infrared and Raman spectra confirmed the presence of AsO₄ tetrahedra.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional tables and figures.]     

Many-body and quantum effects in the surface tension and surface energy of liquid neon and argon using the Fowler’s approximation

The Fowler’s expression for calculation of the reduced surface tension and surface energy has been used with Lennard-Jones (LJ) and two-body Hartree-Fock dispersion (HFD)-like potentials for neon and argon, respectively. The required radial distribution functions (RDFs) have been used from two recently determined expressions in the literature and a new equation proposed in this work. Quantum corrections for neon system have been considered using the Feynman-Hibbs (FH) and Wigner-Kirkwood (WK) approaches. To take many-body forces into account for argon system, the simple three-body potentials of Wang and Sadus (2006) [33] and Hauschild and Prausnitz (1993) [30] used with the HFD-like potential without requiring an expensive three-body calculation. The results show that the quantum and three-body effects improve the prediction of the surface tension of liquid neon and argon using the Fowler’s expression.     

Synthetic Studies Towards Taxol Analogs: Chemoselective Cleavage of C-5 Cinnamoyl Group in Taxane Group of Diterpenoids with Hydroxylamine

Taxane group of diterpenoids 2 and 3 which possess cinnamoyl moiety at C-5 position underwent selective cleavage to C-5 hydroxy compounds 4 and 5 on treatment with hydroxylamine. The resulting compounds were characterised based on their spectral data.     

Thermally Stable and Organo-soluble Polyamides Containing Triazine Rings and Ether Linkages in the Main Chain: Synthesis and Characterization

In order to synthesize new polyamide(PA) 5 and copolyamides(Co PA) 7a-7d, a new-type of dicarboxylic acid containing triazine ring was successfully synthesized from 2,4-dichloro-6-methoxy-s-triazine 1 and 4-aminobenzoic acid. New polyamide 5 containing triazine moiety was prepared from 4,4'-(6-methoxy-1,3,5-triazine-2,4-diyl)bis(azanediyl)dibenzoic acid 3 and 4,4′-diaminodiphenylether by direct polycondensation reaction. Then new series thermally stable copolyamides 7a-7d with high solubility in common organic solvents were synthesized from the direct polycondensation reaction of diacid 3 as a first monomer, aliphatic-aromatic diacids 6a-6d as second diacids and 4,4′-diaminodiphenylether. All of the above polymers were fully characterized by 1H-NMR and FTIR spectroscopy, elemental analysis(CHN), inherent viscosity, solubility tests, gel permeation chromatography(GPC), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). The resulted Co PAs 7a-7d have shown good inherent viscosities, solubility and thermal properties.     

Catalyst-free,aqueous and highly diastereoselective synthesis of new 5-substituted 1H-tetrazoles via a multi-component domino Knoevenagel condensation/1,3 dipolar cycloaddition reaction

An approach for the synthesis of new 5-substituted-tetrazoles via multi-component domino Knoevenagel condensation/1,3 dipolar cycloaddition reaction of carbonyl compounds, malononitrile and sodium azide in water without assistance of any catalyst has been reported. This general protocol provides a wide variety of 5-substituted 1H-tetrazoles in good yields under mild reaction conditions.     

Triphenylphosphine-Catalyzed Simple Synthesis of Dimethyl 1-Aryl-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylates

Ethyl 2-arylamino-2-oxo-acetates undergo a complex reaction with dimethyl acetylenedicarboxylate in the presence of triphenylphosphine to produce dimethyl 1-aryl-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylates in good yields. Dynamic NMR study of dimethyl 1-(2-methylphenyl)-4-ethoxy-5-oxo-4,5-dihydro-1 H -pyrrole-2,3-dicarboxylate shows a fairly high energy barrier ( j G p = 53.2 kJmol m 1 ) for rotation around the N-aryl single bond, which leads to an observable atropisomerism.     

Silphox [POCl3−n (SiO2) n ] as a New,Efficient, and Heterogeneous Reagent for the Synthesis of Benzimidazole Derivatives Under Microwave Irradiation

Silphox [POCl_3-n(SiO₂)_n] efficiently catalyzes the condensation of benzene-1,2-diamine with mono and dicarboxylic acids under microwave irradiation to afford benzimidazole derivatives in high yields and short reaction times.     

Preparation and Characterization of New Optically Active Poly(amide-imide)s from N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine and Aromatic Diamines

Five new optically active aromatic poly(amide-imide)s (PAIs) 5a–e were prepared from a direct polycondensation reaction of a new diacid of N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine 3 with various aromatic diamines 4a–e in a medium consisting of triphenyl phosphite (TPP), calcium chloride (CaCl₂), pyridine (Py) and N-methyl-2-pyrrolidone (NMP). The polycondensation reaction produced a series of novel poly(amid-imide)s 5a–e in quantitative yields with inherent viscosities of 0.39–0.51 dL/g. The resulting polymers were fully characterized by means of ¹H-NMR, FT-IR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of them were investigated using TGA/DTG and differential scanning calorimeter (DSC). The diacid 4 was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6- tetracarboxylic dianhydride 1 with L-isoleucine 2 in acetic acid solution.     

Synthesis and antitumor activity evaluation of some 1, 2, 4-triazine and fused triazine derivatives

Reactions of 3-hyrazino-5,6-diphenyl-1,2,4-triazine with various carbonyl compounds such as ethyl acetoacetate, acetylacetone, benzoin, isatin, phthalic anhydride, phenyl isocyanate and acetic anhydride were discussed. Its reactions with α, β unsaturated compounds such as arylidinemalononitrile, diethyl acetylenedicarboxylate, dibenzylidine hydrazine were studied. These reactions led to the formation of various triazine and fused-triazine derivatives. The antitumor activity of the synthesized compounds was tested against HePG2 and MCF-7 cell lines. Some of the tested compounds were most active, whereas other compounds exhibited little or no activity.