Auf dem Gebiete der Spectralanalyse

Ohne Zusammenfassung     

A semiempirical model for the two-center repulsion integrals in the NDDO approximation

A self-consistent formalism is proposed for the two-center electron repulsion integrals in the NDDO approximation, based on their expansion in terms of multipole-multipole interactions and free from adjustable parameters.     

New heteroaromatic compounds—XII Further evidence for the aromaticity of the borazarenes

Snyder and his co-workers² have reported that the cyclic boric ester (I) is stable to hydrolysis and may be nitrated. These observations suggests that the stability of the heterocyclic boron compounds described in previous papers of this series might be due to their cyclic nature rather than to aromatic resonance. Their reactions with bases, and a comparison of the properties of 2:1-borazaronaphthalenes with those of their 3:4-dihydro derivatives seem to make this unlikely.     

Stereochemistry of diastereoisomeric propionyl esters of 4-(2-furyl)-3-methyl-1-phenethyl-piperidin-4-ols and the analgesic ether derived from their acid-catalysed ethanolysis

The stereochemistry of diastereoisomeric propionyl esters of 4-(2-furyl)-3-methyl-1-phenethylpiperidin-4-ols has been established by ¹³C NMR analysis. Both isomers, after acid-catalysed ethanolysis, are converted to the corresponding 4-ethoxy derivative of configuration (t-3-Me, r-4-OEt) that correlates with its analgesic properties.     

Homothetic packings of centrally symmetric convex bodies

Geometriae Dedicata - We estimate the bottom of the $$L^2$$ spectrum of the Laplacian on locally symmetric spaces in terms of the critical exponents of appropriate Poincaré series. Our main...     

Aromaticity and Pericyclic Reactions

Pericyclic reactions formally resemble the conversion of one Kekulé structure into another; the transition state may be “aromatic”, “nonaromatic”, or “antiaromatic”. Thermally induced pericyclic reactions proceed preferentially via aromatic transition states whereas their photochemical counterparts lead to products that are formed via antiaromatic transition states.     

Ueber die Wellenl?nge der Spectrallinien der Metalle in dem ultravioletten Theil des Spectrums

Ohne Zusammenfassung