Photoelektronenspektroskopische untersuchung von tris(trimethylelement(IV)aminen, -phosphinen, -arsinen und -stibinen

The PE spectra of [(CH₃)₃Sn]₃N, [(CH₃)₃E]₃P (E = C, Si, Sn), [(CH₃)₃Si]₃As and [(CH₃)₃E]₃Sb (E = C, S, Ge, Sn) are analyzed. The constant level of the ionization potentials of the n-hybrid orbitals of N, P, As, and Sb, together with changes in the hybridization and interactions with ligand MO's is discussed by qualitative MO investigations.     

Stanniokomplexe oxa-verbrückter stannylene

Complexes of the type C₅H₅Ni(P(NR₂)₃)X (X = Cl, Br, CH₃) and [C₅H₅Ni-(P(NR₂)₃)₂]PF₆ (R = CH₃, C₂H₅) are prepared. CH₃OH cleaves the phospohorusnitrogen bond.     

Austauschreaktionen an organostannylphosphinen: Identifizierung einer stabilen zwischenstufe

Monomeric 1 : 1 adducts of di-t-butyl(chlorodimethylstannyl)phosphine and dimethyltin dichloride are formed in solution by mixing equimolar amounts of the two components or by mixing dimethyltin dichloride and di-t-butyl(trimethylsilyl)phosphine in a 2 : 1 molar ratio. NMR, IR, Raman and ^{119 m}Sn Mössbauer data are in agreement with a symmetrical structure with two equivalent (CH₃)₂SnCl groups bridged by di-t-butylphosphine and chloro groups. The bonding and stability of the adduct are discussed.     

Microwave-enhanced synthesis of new (-)-steganacin and (-)-steganone aza analogues

[reaction: see text]. A novel, microwave-enhanced, highly efficient protocol for the synthesis of hitherto unknown (-)-steganacin and (-)-steganone 7-aza analogues containing a 1,2,3-triazole ring has been presented. Microwave irradiation was found to be highly beneficial in promoting the Suzuki reaction and the 1,3-dipolar cycloaddition reaction to generate the highly strained medium-sized ring system of the title molecules.     

Dimere Dialkylphosphanylgermylene: Ylidische Diphosphadigermetane

Dimeric Dialkylphosphanylgermylenes: Ylidic Diphosphadigermetanes The dichlorogermylene triphenylphosphane complex ( 1 ) reacts with di-t-butyl(trimethylsilyl)phosphane ( 2 a ) only in a 1 : 1 stoichiometry providing dimeric chloro(di-t-butylphosphanyl)germylene ( 3 a ); with two equivalents of diisopropyl(trimethylsilyl)phosphane ( 2 b ), however, 1 (or the dichlorogermylene dioxane complex) provide straightforwardly dimeric bis(diisopropylphosphanyl)germylene ( 5 b ) as yellow crystals. The trans-dimeric structures of 3 a and 5 b are confirmed by spectroscopic data and by X-ray diffraction. Dialkylphosphanylgermylenes 3 a and 5 b are ylide-type diphosphadigermetanes in solution and in the solid state.     

A one-pot microwave-assisted synthesis of pyrido[2,3-d]pyrimidines

A high yield multicomponent reaction providing multifunctionalized pyrido[2,3-d]pyrimidines with up to four diversity centers in a one-pot microwave-assisted cyclocondensation of alpha,beta-unsaturated esters, amidine systems and malononitrile (or ethyl cyanoacetate) is described.