Hydrothermal synthesis, structure and properties of a new arsenotungstate

A new arsenotungstate, Na[{Cu(2,2′-bpy)(imi)}{Cu(2,2′-bpy)}₂AsW₉O₃₃As(OH)]·8H₂O (1) (2,2′-bpy=2,2′-bipyridine, imi=imidazole), has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The compound 1 represents the first example of an unusual trilacunary arsenotungstate substituted simultaneously arsenide fragment and copper complexes. The compound 1 was used as solid bulk modifier to fabricate bulk-modified carbon paste electrodes (1-CPE) by direct mixing. The electrochemical behavior and electrocatalysis of 1-CPE have been studied in detail. Magnetic measurement for 1 shows the presence of antiferromagnetic interactions within the Cu²⁺ cations.     

Structure and biological activity of a new rotenoid from Pongamia pinnata

Pongarotene (1), a new rotenoid and karanjin (2), a known flavonol, were isolated from the seeds of Pongamia pinnata. The structure determination of these compounds were based on spectral analyses including 2D-NMR. The antifungal, antibacterial and phytotoxicity results of pure compounds 1 and 2 as well as of the methanol (M) and ethyl acetate (E) crude extracts are also being reported.     

Development of Poly(urethane esteramide) Coatings from Pongamia glabra Oil as Anticorrosive Applications

In this study, ethylene glycol polyesteramide (Eg-PEA) was synthesized from N,N-bis (2-hydroxy ethyl) pongamia oil fatty amide and ethylene glycol tetraacetic acid (EGTA) through condensation polymerization. It was further modified by toluene 2,4-diisocynate in different wt.% (20, 25, 30, and 35) to obtain urethane-modified polyesteramide (Eg-UPEA). The synthesized resins were characterized using FT-IR, ¹H NMR, and ¹³C NMR spectroscopic techniques, and molecular weight was determined by gel permeation chromatography (GPC). Physico-chemical and physico-mechanical analyses were carried out by standard laboratory methods. Thermal studies of Eg-UPEA were undertaken by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. To evaluate corrosion prevention performance Eg-UPEA-coated mild steel strips were investigated by potentiodynamic polarization in different corrosive media (5 wt.% NaCl, 3 wt.% HCL, 2.5 wt.% NaOH, and tap water) at room temperature. Thermal analysis revealed that Eg-UPEA30 may find application as an environmentally friendly corrosion protective coating and may be safely used up to 250°C.     

The synthesis and crystal structure of a new diprotonated Schiff base cryptand

Abstract

The synthesis and crystal structure of the diprotonated cryptand derived from the reaction of tren and 2,6-diacetyl pyridine is reported. The imino nitrogens of the Schiff base linkages are directed so that the dicarbimine functions are in trans, trans geometry relative to the pyridine C-N bond. This configuration has not previously been reported in related pyridine-derived Schiff base macrocycles.     

新型萜烯马来酸酐醇酸树脂的合成与结构表征

利用廉价工业松节油与顺丁烯二酸酐、多元醇。油酸等原料,合成了一种色泽浅,性能良好的萜烯马来酸酐醇酸树脂。研究了合成反应条件,用FTIR谱、^1^HNMR、TGA等手段对产物结构进行了表征,并测定了树脂的性能。     

Total synthesis of a new cytotoxic acetogenin, jimenezin, and the revised structure

The first total synthesis of jimenezin was achieved by using carbohydrates as chiral building blocks, thus revising the proposed structure 1 to 2. The key steps in this synthesis include an efficient construction of the THP-THF fragments 3 and 16 through a stereoselective condensation between the pyranyl aldehyde 5 and the acetylene derivative 6, and a palladium-catalyzed coupling reaction of 3 or 16 with a terminal butenolide 4.     

The synthesis,structure, magnetic and luminescent properties of a new tetranuclear dysprosium (III) cluster

The synthesis and characterization of [Dy₄(dhampH₃)₄(NO₃)₂](NO₃)₂ (1), a new tetranuclear dysprosium (III) complex, is described. The compound was characterized by its X-ray structure, magnetic properties as well as the luminescent spectra. The compound crystallizes in a P1? space group with a zig-zag linear form of geometry. The ac magnetic susceptibilities of the molecule indicate that it is a magnetic molecule with a slow magnetization relaxation. The molecule also exhibits an emission spectrum that was confirmed to be ligand based. These results indicate that this molecule has both a slow magnetization relaxation (that could be potentially a SMM) and luminescent properties.     

On a new calcium vanadate: synthesis, structure and Li insertion behavior

A synthetic form of the mineral hewettite was prepared via a new route in aqueous medium, starting either from the crystalline compound Li_1.1V₃O₈, or from its amorphous precursor. The anhydrous, crystalline derivative Ca_0.5V₃O₈ was obtained by heating the synthetic hewettite at 250°C under dynamic vacuum. The diffraction studies show that the 2D structure of Ca_0.5V₃O₈ involves the same V₃O₈ layers as in the hewettite or in Li_1+αV₃O₈. The stacking of the layers is similar to that in the metahewettite. A structural model is proposed, where the Ca²⁺ ions occupy octahedral sites in the interlayer space. The electrochemical behavior of Ca_0.5V₃O₈ vs. lithium insertion is presented. It is original and reveals particularly good performances in terms of stability during cycling at C/5 rate. The homologues obtained with Mg or Ba, instead of Ca, are briefly presented.     

The structure of a new antibiotic,hygrolidin

The structure of a new antibiotic, hygrolidin has been determined as shown in fig. 3.     

The structure of a new antibiotic,chromoxymycin

Based on ¹H- and ¹³C-NMR spectral data, the planar structure of chromoxymycin, a new antitumor antibiotic, has been determined as shown in Fig. 1.     

Cu4Mo6Se8: synthesis, crystal structure, and electronic structure of a new Chevrel phase structure type

Cu4Mo6Se8 has been synthesized by intercalation of Cu into Cu2Mo6Se8 at room temperature, and its crystal structure has been determined. This compound crystallizes in the triclinic space group P, with a = 6.7609(8) A, b = 6.8122(7) A, c = 7.9355(10) A, alpha = 70.739(4) degrees , beta = 72.669(4) degrees , gamma = 84.555(5) degrees , and Z = 1. Instead of residing in the voids between corners or edges of Mo6Se8 clusters as in the classic R Chevrel structure, the Cu atoms in Cu4Mo6Se8 fully occupy four sites between faces of two adjacent Mo6Se8 clusters. Thus, two of the six Mo atoms in each cluster do not have capping Se atoms from neighboring clusters. This represents a new triclinic structure type for Chevrel phases. In addition to the synthesis and crystal structure, we present and discuss results from electronic structure calculations using both extended Hückel and density functional theory. These calculations predict Cu4Mo6Se8 to be metallic. We also report results from Cu intercalation into Chevrel phase sulfides and tellurides. Preliminary experiments suggest that a telluride analogue of Cu4Mo6Se8 exists.     

Hydrothermal synthesis, crystal structure, and magnetic properties of a new inorganic vanadium(III) phosphate with a chain structure

A new vanadium(III) phosphate, Na3V(OH)(HPO4)(PO4), has been synthesized by using mild hydrothermal conditions under autogeneous pressure. This material represents a very rare example of sodium vanadium(III) phosphate with a chain structure. The crystal structure has been determined by refinement of powder X-ray diffraction data, starting from the atomic coordinates of an isotypic compound, Na3Al(OH)(HPO4)(PO4), which was obtained under high temperature and high pressure. The phase crystallizes in monoclinic space group C2/m (No. 12) with lattice parameters a = 15.423(9) A, b = 7.280(0) A, c = 7.070(9) A, beta = 96.79(7) degrees, V = 788.3(9) A(3), and Z = 4. The structure consists of one-dimensional chains composed of corner-sharing VO5(OH) octahedra running along the b direction. They are decorated by isolated PO4 and HPO4 tetrahedra sharing two of their corners with the ones of the vanadium octahedra. The interconnection between the chains is assured by three crystallographically distinct Na(+) cations. Magnetic investigation confirms the 3+ oxidation state of the vanadium ions and reveals an antiferromagnetic arrangement between those ions through the chain.     

The GdPS structure,a new PbFCl-type derivative

The structure of GdPS is orthorhombic, space group Pmnb; a = 5.3620(5), b = 5.4079(6), c = 16.742(2)Å, Z = 8. It is a distorted derivative of the tetragonal PbFCl structure (a₀, c₀) with $\text{a ≈ b ≈ 2}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{a}{}_0\text{, c = 2c}{}_0$. The distortions are due to the formation of phosphorus chains. This structure type is found also in other rare-earth sulfopolyphosphides, e.g., with Ln = La···Sm, Tb···Tm, Y.     

新型Pd系聚吡咯配合物的合成、结构和吸附行为的研究

本文首次报道了一种新的二氯-二聚吡咯合钯(简称DCBPP)配合物的合成、结构和吸附H~2行为的实验和理论研究。确定了DCBPP的稳定性结构,探究了吸附过程的表面行为和微观机制,理论计算和实验测定的结果符合较好,圆满合理地说明一些实验现象。     

The structure of a new isotetracenone antibiotic,capoamycin

Based on ¹H and ¹³C NMR spectral data and chemical degradation, the structure of capoamycin, a new isotetracenone antibiotic has been determined as shown in Fig. 1.