quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of o-aminoarylketones and carbonyl compounds utilizing niobium (v) chloride / polyethylenglycole(nbcl5.peg) and niobium(v)chloride (nbcl5) as available and inexpensive catalysts. the quinoline derivatives were prepared in glycerol, an excellent solvent in terms of environmental impact, with hig...

Epoxide ring opening is a frequently required transformation in Organic Synthesis. In this paper we describe the application of NbCl5 for this purpose using three different substrates. Chlorohydrins, 1,2-diols, products containing solvent residues as well as rearrangement products are obtained, depending on both the substrate structure and reaction conditions. Rationalizations to account for so...

Quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of O-aminoarylketones and carbonyl compounds utilizing niobium (V) chloride / polyethylenglycole(NbCl5.PEG) and niobium(V)chloride (NbCl5) as available and inexpensive catalysts. The quinoline derivatives were prepared in glycerol, an excellent solvent in terms of environmental impact, with hig...

Graphite is widely used in technology because of its unique properties. A drawback of graphite is its low heat resistance in oxidizing atmospheres. To increase its heat resistance, Nb-Hf protective coatings were synthesized. Electrodeposition of niobium coatings on graphite with subsequent precise surface alloying of niobium with hafnium was studied. Electrochemical synthesis of Nb-Hf coatings ...

modern vehicle bodies make intensive use of high strength steel grades to meet the contradicting demand of lighter weight and simultaneously better mechanical performance. for many steel grades microalloying by niobium is the key to achieve their characteristic property profile. in hsla steels niobium enhances the strength primarily by grain refinement. in interstitial free high strength steels...

Measurements at 8.6 GHz on TM mode superconducting niobium cavities have been carried out at SLAC in an attempt to establish definitive conditions for reproducibly attaining high peak electric and magnetic fields and high residual &Is. Four cavities, processed by techniques which insure thepresence of an oxi& layer on the niobium surface before final high temperature outgassing, have given peak...

Compared to the large number of main group Zintl compounds there are only a few that contain transition metals.[1] This is not surprising since the traditional definition of Zintl phases automatically excludes transition metals. However, many such compounds with transition metals can qualify for Zintl phases when a broader definition is used. The latter includes compounds of transition metals w...

Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR(2))(3)(N-t-Bu)] (, R = Me; , R = Et) starting out from [NbCl(3)(N-t-Bu)(py)(2)] and the respective LiNR(2) reagent (py = pyridine). ...

We have successfully synthesized niobium monophosphide and tantalum monophosphide crystals by a chemical vapor transport technique. We report resistivity vs. temperature of both materials in the temperature range from 2 K to 300 K. We have also performed electronic structure calculations and present the band structure and density of states of these two compounds. The calculations show that both...