František Tureček

Angle-resolved neutralization-reionization mass spectrometry

Neutralization -reionization mass spectra of 2-propenal, isomeric butenes, and isomeric n-hexenes have been found to depend significantly on the z-axis scattering angle of the neutralization event. As shown by Cooks for ion dissociations, increasing scattering angles generally favor products of higher activation-energy reactions. For isomeric butenes and n-hexenes, these reactions provide more definitive information for isomeric characterization.

Neutralization-reionization and ab initio study of the CH2CHSOH ⇄ CH3CHSO rearrangement

Abstract Ethenesulfenic acid and ethanethial-S-oxide cation radicals (1+ and 2+ ) and molecules (1 and 2) were generated in the gas phase and their collisionally activated isomerizations were studied by tandem and neutralization-reionization (NR) mass spectrometry, and by ab initio quantum chemical calculations. Consistent with experiments, ion 1+ is calculated to be more stable than 2+ (ΔE = −96 kJ mol−1), while a reverse order of stabilities is found for the molecules 1 and 2 (ΔE = 12 kJ mol−1). Significant energy barriers are calculated for the isomerization of 1+ to 2+ (186 kJ mol−1) and 1 to 2 (137 kJ mole−1). NR spectra were also utilized to analyze mixtures of 1 and 2 produced by flash-vacuum pyrolysis of vinyl tert-butyl sulfoxide. Thiirane-S-oxide cation radical and its ring-opened distonic isomer, .CH2CH2SO+, are also found as stable structures giving characteristic collisionally activated dissociation and neutralization-reionization spectra.

Carbonylation of n-alkylallylamines with CO/H2 mixtures

Abstract The homogeneously catalyzed carbonylation of N -alkylallylamines to N -alkyl-2-pyrrolidones has been studied and the effects of reaction variables have been evaluated. Contrary to expectations, the reaction proceeded at milder conditions with a CO/H 2 1:1 mixture than with pure carbon monoxide, and with phosphine-free rhodium complexes than in the presence of phosphines, which enhanced simultaneous double-bond hydroformylation. Studies of the reaction of Rh(I) complexes with amines indicate that the carbonylation proceeds via Rh(0) clusters.

Relative ionization cross-sections of oxygenated C(4) molecules

Abstract A method is presented for the determination of relative electron impact ionization cross-sections for polar and less volatile compounds. The compound is generated in the gas phase by flash-vacuum pyrolysis of a norbornene precursor, whereby the cyclopentadiene co-formed in a stoichiometric amount serves as internal standard. Cross-sections of 31 oxygenated C (4) molecules have been measured and tested for correlation with several molecular and bulk parameters

Isomerization of allyldiphenylphospine to (Z)-1-propenyldiphenylphospine in rhodium(I) complexes

Abstract Allylic double bonds in CH 2 CHCH 2 PPh 2 Rh I complexes undergo slow spontaneous isomerization to give (Z)-CH 3 CHCHPPh 2 Rh I complexes.