The reaction of triptycene haloquinones with alkoxides. An unusual route to pentiptycene quinones

Triptycene haloquinones 3 react with sodium alkoxides in refluxing alcohol to afford, besides the expected substitution products, pentiptycene quinone 4. This approach to 4 is compared with a Diels-Alder strategy to the same compound.     

THERMODYNAMIC AND PARTICLE-DYNAMIC STUDIES ON SYNTHESIS OF SILICA NANOPARTICLES USING MICROWAVE-INDUCED PLASMA CVD

1. Introduction1.1 Silica nanoparticles and synthesis methods Silica (SiO2) nanoparticles are widely used in industry asan active filler for polymer reinforcement, a rheologicaladditive in fluids, a free flow agent in powders, and anagent for chemical mechanical polishing during IC (inte-grated circuit) fabrication (Sniegowski & de Boer, 2000).Silica powder is also used for producing silicon carbide(Koc & Cattamanchi, 1998) or opaque silica aerosols (Leeet al., 1995). Many methods can …     

Nonlinear compression of optical solitons

In this paper, we consider nonlinear Schrödinger (NLS) equations, both in the anomalous and normal dispersive regimes, which govern the propagation of a single field in a fiber medium with phase modulation and fibre gain (or loss). The integrability conditions are arrived from linear eigen value problem. The variable transformations which connect the integrable form of modified NLS equations are presented. We succeed in Hirota bilinearzing the equations and on solving, exact bright and dark soliton solutions are obtained. From the results, we show that the soliton is alive, i.e. pulse area can be conserved by the inclusion of gain (or loss) and phase modulation effects.     

Triptycene quinones in synthesis: preparation of triptycene cyclopentenedione and its reactivity as a dienophile

Triptycenene quinone 1 was converted to triptycene cyclopentenedione 5 through hydroxyquinone-phenyliodonium ylide formation and thermal ring contraction of the latter. Cyclopentenedione 5 reacts as a dienophile and as a dipolarophile with dienes and nitrile oxides, affording polycyclic adducts bearing the triptycene moiety.     

Symplectic supercuspidal representations and related problems

In this paper, we summarize the basic structures and properties of irreducible symplectic supercuspidal representations of GLn(F) over a p-adic local field F with characteristic zero, and explore possible topics for further investigation.     

Biological studies of organotin(IV) complexes with 2-mercaptopyrimidine

The known organotin(IV) complexes with 2-mercaptopyrimidine (L) [Me₂SnL₂] (1), [Buⁿ ₂SnL₂] (2), [Ph₂SnL₂] (3), and [Ph₃SnL] (4) were synthesized using a new approach. The effect of the synthesized compounds on peroxidation of fatty acids (oleic and linoleic) was studied. Complexes 1–4 promote the peroxidation of oleic acid. Their effect on the enzymatic peroxidation of linoleic acid with lipoxygenase was compared with that of cisplatin and in vitro cytoxicity against sarcoma cancer cells was determined. The antiproliferative effect of complexes 2–4 was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–743, April, 2007.     

Ultra-low-frequency dust-electromagnetic modes in self-gravitating magnetized dusty plasmas

Obliquely propagating altra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic field and dustmagnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays stabilizing role.     

Synthesis and characterization of a new chloro-di-phenyltin(IV) complex with 2-mercapto-nicotinic acid: Study of its influence upon the catalytic oxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase

The complex [(C₆H₅)₂SnCl(HMNA)] (1) where H₂MNA is thioamide 2-mercapto-nicotinic acid has been synthesized by reacting a methanolic solution of di-chloro-di-phenyltin(IV) Ph₂SnCl₂ with an aqueous solution of 2-mercapto-nicotinic acid, containing twofold amount of potassium hydroxide. The Sn/ligand molar ratio is 2:1. The complex was characterized by elemental analysis, FT-IR and Mössbauer spectroscopic techniques. In addition the crystal structure of the molecule was determined by an X-ray diffraction at 293(2) K. C₁₈H₁₄ClNO₂SSn is monoclinic, space group P2₁/n, a = 15.089(3) Å, b = 15.846(3) Å, c = 16.691(3) Å, β = 105.57(3)°, Z = 8. The ligand coordinates to the metal center through the exocyclic sulfur and the heterocyclic nitrogen atoms, forming a four membered ring. The coordination sphere around the tin(IV) ion is completed with two carbon atoms from the two phenyl groups and one chlorine atom. The geometry around the tin atom can be described either as trigonal bipyramidal or tetragonal pyramidal. Finally, the influence of the complex [(C₆H₅)₂SnCl(HMNA)] (1) upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was also kinetically and theoretically studied and the results compared with the ones of the corresponding binuclear complex [(C₆H₅)₃Sn(MNA)Sn(C₆H₅)₃ · (acetone)] (2) reported in the literature.     

Crystallographic report: Diphenylbis(Hpiroxicam)tin(IV), [Ph2Sn(Hpir)2]

The crystal structure of complex [Ph₂Sn(Hpir)₂ ·CH₃CN] shows for the first time chelation to a metal atom of piroxicam through the keto‐enolate oxygen atoms. Copyright © 2004 John Wiley & Sons, Ltd.