Phase transition studies in 9O.6 and 9O.8

The variation of density with temperature across different phases for two homologues of the N(4-n-alkyloxybenzylidene)-4'-n-alkylanilines (9O.6 and 9O.8) exhibiting the S_AS_CS_FS_G phase variant is determined. The influence of pretransitional effects in the fluctuation dominated non-linear region in the vicinity of the isotropic-smectic A transition and the nucleation growth analogy of this transition are discussed.     

Reactions on solid supports part I: Novel preparation of α-formyl pyrroles from α-methylpyrroles by oxidation with thallium (III) nitrate on clay

Treatment of α-methylpyrroles with thallium (III) nitrate/Montmorillonite clay affords the corresponding α-formylpyrroles in excellent yields.     

Cathodic synthesis of 2-amino-2-propene-1-ones electrolytical studies on vinylazides,VII

The cathodic preparation of enamino ketones from enazidoketones has been generalised to include heteroaromatic and aliphatic derivatives. Mechanistically the role of different sites of protonation, either on N¹ of the N₃-group or on carbonyl depending on electrolysis potential and acid strength, apparent by product distribution, is clarified. Aldehydic groups are preferentially reduced compared to the vinylazide part. Purely aliphatic azidoketones yield conjugated dienes under reductive acetylation, which might be useful for cycloaddition reactions.Die kathodische Synthese von Enaminoketonen aus ungesättigten Azidoketonen wurde auf heteroaromatisch substituierte und auf rein aliphatische Derivate übertragen. Zum Reduktionsmechanismus wurde der Einfluß verschiedener Stellen der Protonierung (am N¹ der N₃-Gruppe bzw. an der Carbonylgruppe), abhängig von Potential und Säurestärke, untersucht. Aldehydische Gruppen als weitere funktionelle Gruppen im Enazid werden leichter als die Vinylazide reduziert. Die rein aliphatischen Enazidoketone ergeben bei reduktiver Acylierung konjugierte Diene.

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Elektrolytische Untersuchungen an Vinylaziden, 7. Mitt.: Kathodische Synthese von 2-Amino-2-propen-1-onen

     

Absorption spectrum of VO2+ ion doped in caesium cadmium sulphate hexahydrate single crystal

Results of the optical absorption spectrum of VO²⁺ ion doped in caesium cadmium sulphate hexahydrate studied at room (300 K) and liquid nitrogen (77 K) temperatures are reported. The site symmetry of the ion is found to be C_4ν. Correlating the optical and ESR spectral data, the molecular orbital coefficients are evaluated.     

Dalpanio,AC-glycosylisoflavanone fromDalbergia paniculata

Dalpanin, isolated from the flowers ofDalbergia paniculata (Roxb.) has been characterised as aC-glycosylisoflavanone by chemical and spectral evidence. A provisional structure (IV) is assigned to this new compound.     

Study of isotope shifts,isotone shifts and nuclear compressibility from the analysis of muonic x-ray transitions

Muonic x-ray transitions in various spherical nuclei in the region 13?Z?83 have been analysed and the isotope and isotone shifts in charge radiusR are investigated. AssumingR=r ₀ A ^1/3, the isotopic and isotonic behaviour of the parameterr ₀ (=RA ^?1/3) is also studied. The variation ofr ₀ with mass numberA reveals the variation of average nucleon density, which in turn sheds light on the compressibility of nuclear matter. The isotope and isotone shifts inR exhibit the shell effects in the vicinity of magic neutron and proton numbers: 20, 28, 50, 82 and 126. The results indicate that neutron-proton interaction is maximum at the beginning of a major neutron shell and decreases gradually as the shell gets filled up. The behaviour of parameterr ₀ clearly suggests that low-Z nuclei are highly compressible while high-Z nuclei are more or less incompressible. The parameterr ₀ too is observed to exhibit profound shell effects.     

Symmetrizations of Markov processes

Two methods for symmetrizing Markov processes are discussed. Letu ^a(x, y) be the potential density of a Lévy process on a compact Abelian groupG. A general condition is given that guarantees thatv(x, y)=u^a(x, y)+u^a(y, x) is the potential density of a symmetric Lévy process onG. The second method arises by considering the linear space of one-potentialsU ¹ f, withf inL ², endowed with the inner product (U ¹ f,U ¹ g)=fU ¹ g+gU ¹ f. If the semigroup ofX(t) is normal, then the completionH of this space is the Dirichlet space of a symmetric processY(t). A set that is semipolar forX(t) is polar forY(t).