Synthesis and surface reactivity of phosphide nanocrystals

Gap and InP nanocrystals were synthesized from Na₃P and GaCI₃ at low temperature (80–100°C) and atmospheric pressure. The samples were characterized by XRD and TEM measurements. The surface reactivity of Gap nanocrystals was studied by heating in N₂. The weight of the nanocrystals increased at the temperature between 370°C and 480°C. It can be concluded that N, molecule was absorbed and reactivated on the surface of Gap nanocrystals. Keywords: gallium phosphide, indium phosphide, nanocrystal, surface reactivity.     

Ring-closing metathesis of 2,2-diallyl derivatives of pyrrolidine and piperidine: a route to azaspiroheterocyclic structures

Transformations of 1-benzyl-2,2-di(2-propenyl)pyrrolidine and 1-benzyl-2,2-di(2-propenyl)piperidine into the corresponding 1-azaspiro[4.n]alkenes via ring-closing metathesis using accessible homogeneous catalytic systems WCl₆—H₂SiPh₂, WOCl₄—H₂SiPh₂, and Ru(=CHPh)(PCy₃)₂Cl₂ (Cy is cyclohexyl) were performed for the first time.     

On the reactions of molybdenum and tungsten carbonyls with trimethyl- and triethyl-aluminium

Reactions of hexacarbonylmolybdenum, hexacarbonyltungsten and arene complexes of tricarbonylmolybdenum and tricarbonyltungsten with trimethyl- and triethyl-aluminium have been studied. It has been found, based on IR and NMR spectra, that trialkylaluminium does not form complexes with hexacarbonyls of molybdenum and tungsten. Arene (mesitylene, toluene and benzene) complexes of tricarbonylmolybdenum form 1 : 1 complexes with triethylaluminium, and arene complexes of tricarbonyltungsten form complexes with trimethyl- and triethyl-aluminium. Regardless of the molar ratios of reactants (arene)M(CO)₃/AlEt₃, only one of the three CO groups bonded to molybdenum or tungsten forms a complex with AlEt₃. Fast exchange between free and complexed trialkylaluminium and an exchange of trialkylaluminium between all three carbonyl groups have been observed in benzene, toluene and decalin solutions. In the ¹H NMR spectra of the products of the reactions of (mesitylene)Mo(CO)₃ with AIEt₃ and AIMe₃, signals at –9 to –14ppm (characteristic for molybdenum hydrides) were present. It confirmed an alkylation of molybdenum followed by β- or α-hydrogen elimination with the formation of the corresponding molybdenum hydrides, the actual catalyst of aromatic hydrocarbon hydrogenation.