Negative-ion fast atom bombardment mass spectrometry in the characterization of deoxyfluorinated sugars

Negative-ion fast atom bombardment mass spectrometry and metastable ion studies were applied to the characterization of three isomeric fluorine-containing sugars. Peculiar fragmentation processes were evidenced for each isomer, enabling their differentiation. Comparison with the behaviour of a non-fluorinated analogue allowed investigation of the role of fluorine in the decomposition processes of these compounds.     

Fast atom bombardment mass spectrometry of new polydentate schiff bases. 2. The case of mono- and bisaldimines containing pyridine groups

The mass spectrometric behaviour of seven polydentate Schiff bases derived from the condensation of formyl or diformyl precursors (2,3-dihydroxy- or 2,5-dihydroxy-benzaldehyde, 3-metoxy- or 3-ethoxy-salicylaldehyde, 3-formyl-salicyclic acid, 4-methoxy- or 4-chloro-2,6-diformylphenol) with 2-aminomethylpyridine have been investigated by fast atom bombardment mass spectrometry and metastable ion studies.     

The X-ray diffraction crystal structure determination and electron impact fragmentations of the gaseous ions of 3-(p-chlorophenyl)-1-methyltriazene-1-oxide and its 3-methyl derivative

The decomposition of the gaseous positive ions of the title compounds obtained by electron impact have been completely mapped. The X-ray structural determinations of these two substances established their identity definitively and allowed to reveal some interesting features of these molecules of pharmaceutical interest.     

Photoinitiated substitution reactions of 2 and 4-pyridinecarbonitrile with cyclopentene

The photoreactions of 4 and 2-pyridinecarbonitrile with cyclopentene carried out in acetone or in acetonitrile solutions lead, respectively, to 4-(2 cyclopentenyl)-pyridine $\text{1}$ and 2-(2 cyclopentenyl)pyridine $\text{2}$. From 2-pyridinecarbonitrile a little amount of ketone $\text{3}$ is obtained.     

DFT computational study of the mechanism of allyl halides carbonylation catalyzed by nickel tetracarbonyl

A theoretical investigation at the DFT(B3LYP) level on the carbonylation reaction of allyl bromide catalyzed by nickel tetra-carbonyl Ni(CO)(4) is discussed. The computational results show the following: (i) Three main steps characterize the catalytic cycle: (a) an oxidative addition step, (b) a carbonylation step, and (c) a reductive elimination step where the acyl product is obtained and the catalyst is regenerated. (ii) Both Ni(CO)(3) and Ni(CO)(4) complexes can behave as "active" catalytic species. (iii) The oxidative addition leads to the formation of either eta(3) or eta(1)-allyl nickel complexes, which are involved in a fast equilibrium. (iv) The carbonylation occurs much more easily on the eta(1) than on the eta(3) intermediates.     

Relatively regular ideals in semiprime Banach algebras

Nella prima parte di questo lavoro vengono studiate le relazioni che intercorrono tra il concetto di relativa regolarità in un'algebra non necessariamente unitaria ed alcuni ideali (radicale, zoccolo, prezoccolo) che intervengono nello sviluppo della teoria di Fredholm in algebre di Banach. Nella seconda parte del lavoro viene dimostrato che in certe algebre di BanachA complesse semiprime l'esistenza di un ideale relativamente regolare chiuso implica cheA è unitaria e di dimensione finita.