Syntheses,Reactions, Characterization,and Antifungal Activities of Chloro-bis-(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth(III)

Abstract

Chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth(III) compounds have been synthesized by the reaction of bismuth trichloride with sodium 2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane in 1:2 molar ratio in benzene solution. Reactions of these chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)-bismuth(III) compounds with sodium tetraisopropoxyborate in equimolar ratio in benzene solution yield the corresponding heterobinuclear bismuth derivatives with boron. All compounds were characterized by elemental analyses and molecular weight measurements. Plausible structures are proposed on the basis of IR and ¹H, ¹¹B, ¹³C, and ³¹P spectroscopic studies. 2-Mercapto-2-thioxo-1,3,2-dioxaphospholanes-/dioxaphosphorinanes and the corresponding chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth (III) compounds show antifungal activities against Fusarium and Trichoderma.

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GRAPHICAL ABSTRACT      

An alternate route to substituted 6,7-dihydro 5H-dibenz[c,e]azepines from allylbenzamides derived from the Morita–Baylis–Hillman adducts

An acid-catalyzed modular synthesis of substituted 5H-dibenz[c,e]azepines from a biaryl allylbenzamides prepared from the MBH adducts via a cascade dearoylation and intramolecular cyclization is described. The utility of the product for preparing 7,9-dihydro-4bH-dibenz[c,e]pyrrolo[1,2-a]azepine is also presented.     

Polymerization of 3‐ethynylthiophene with homogeneous and heterogeneous Rh catalysts

3‐Ethynylthiophene (3ETh) was polymerized with Rh(I) complexes: [Rh(cod)acac], [Rh(nbd)acac], [Rh(cod)Cl]₂, and [Rh(nbd)Cl]₂ (cod is η²:η²‐cycloocta‐1,5‐diene and nbd η²:η²‐norborna‐2,5‐diene), used as homogeneous catalysts and with the last two complexes anchored on mesoporous polybenzimidazole (PBI) beads: [Rh(cod)Cl]₂/PBI and [Rh(nbd)Cl]₂/PBI used as heterogeneous catalysts. All tested catalyst systems give high‐cis poly(3ETh). In situ NMR study of homogeneous polymerizations induced with [Rh(cod)acac] and [Rh(nbd)acac] complexes has revealed: (i) a transformation of acac ligands into free acetylacetone (Hacac) occurring since the early stage of polymerization, which suggests that this reaction is part of the initiation, (ii) that the initiation is rather slow in both of these polymerization systems, and (iii) a release of cod ligand from [Rh(cod)acac] complex but no release of nbd ligand from [Rh(nbd)acac] complex during the polymerization. The stability of diene ligand binding to Rh‐atom in [Rh(diene)acac] catalysts remarkably affects only the molecular weight but not the yield of poly(3ETh). The heterogeneous catalyst systems also provide high‐cis poly(3ETh), which is of very low contamination with catalyst residues since a leaching of anchored Rh complexes is negligible. The course of heterogeneous polymerizations is somewhat affected by limitations arising from the diffusion of monomer inside catalyst beads. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2776–2787, 2008     

Mechanoluminescence excitation in alkali halide crystals and colouration decay in microcrystalline powders

The mechanoluminescence (ML) of NaCl, NaBr, NaF, LiCl and LiF crystals ceases at 105, 58, 170, 151 and 175°C respectively. Both the temperatureT _c at whichML disappears and the temperatureT _s required to induce a particular percentage of colouration decay in a given time, decreases with increasing nearest neighbour distance in alkali halide crystals. This perhaps suggests that similar processes cause the disappearance ofml in alkali halide crystals and the colouration decay in their microcrystalline powders. It is shown that mobile dislocations may cause the leakage of surface charge and the decay of colouration in microcrystalline powders.     

A separable approximation to the two-body t-matrix for short-range central local potentials

The S-wave potential in momentum space, V₀(p, p′), corresponding to a local two-body central short-range potential may be expanded in separable form with the help of suitable quadrature formulae. With a two-term separable expansion for a variety of nuclear potentials, the resulting t-matrix is found to be in close agreement with the corresponding result with a six-term expansion for small values of p and p′ which are important in the calculation of the trinucleon binding energy.     

Crystallographic determination of metal surfaces with helium scattering

Helium-surface diffraction data has been used to construct the interaction potential between a Helium atom and a metal surface. The constructed potential fits experimental data for all beam energies and angles of incidence and more importantly is independent of beam energy. Such a potential essentially consists of two parts: a short range repulsive corrugated potential due to electronic overlap, and a long range attractive potential due to dispersion forces. We have generated potentials for He scattering for Ni, Cu and Au and in all cases found excellent agreement with experiments. We also report that the repulsive part of the He scattering potential can be obtained rather simply from first principles without adjustable parameters. This suggests that one can determine surface crystallography from first principles without adjustable parameters.     

Adsorbate band formation: The chemisorption of CO on Pd (100)

In ordered overlayers of adsorbed gases on metal surfaces, high coverage situations can lead to overlap between orbitals on adjacent species and hence to adsorbate band formation. We conclusively demonstrate the existence of this effect in chemisorption by examining the dispersion of the 4α level in the u.v. photoelectron spectrum of the CO/Pd (100) system. The results agree well with a first principles extended tight binding calculation of the two-dimensional band structure.     

Impedance response of polycrystalline tungsten oxide

Polycrystalline tungsten oxide (WO₃) pellets were prepared by conventional ceramic processing technology. The ac small-signal electrical data acquired in the frequency (f) range 100 Hz≤f≤1 MHz at temperature (T) ranging the 31-100 °C revealed distinct semicircular relaxation in the impedance plane. This relaxation indicates device behavior originating from the grain boundaries. The lumped grain impedance associated with the device action remained too small to detect when the large resistance scale is realized. The semicircular relaxation is thermally activated indicating 0.58 eV as the activation energy for the relaxation time.