Ligacija U+ u plinskoj fazi. Usporedba pirena, fenantridina i fenantrena kao liganada

Ligation of U+ with phenanthrene in an FT ICR MS instrument is compared with previous results on U+ with pyrene and phenanthridine. All investigated processes compete with U+ oxidation by water and oxygen traces in the instrument. The comparison indicates that oxidation preferentially involves dehydrogenated ligation products.Ligacija U+ fenantrenom u FT ICR spektrometru masa uspoređuje se s ranijim rezultatima na U+ s pirenom i fenantridinom. Svi istraženi procesi su u kompeticiji s oksidacijom U+ tragovima vode i kisika u instrumentu. Usporedba pokazuje da oksidacija preferira dehidrogenirane produkte ligacije

Deuterium Labeling Study of the Gas-phase Reaction of Fe+/Cr+ with Pyrene by FTMS

A ~ 10 :1 mixture of deuterated with undeuterated pyrene was used to study the product composition in the reaction with various ratios of Fe+ and Cr+ (10 :1 to 1: 10) ions in a Fourier-transform mass spectrometer. None of the products FePy+, CrPy+, Py+, FePy2+, CrPy2+ and Py2+ showed deviation from the statistically expected composition

Gas phase kinetics of metal ion ligation by pyrene

Investigation of simple ligation reactions of metal M+ ions with pyrene (Py) within the ICR FT mass spectrometer indicates relatively fast consecutive formation of MPy+ and MPy2+ ions, and if E-i(M+) > E-i(Py) accompanied also by formation of Py+ due to charge exchange. The much slower reaction and equilibrium Py+ + Py reversible arrow Py-2(+), for which the thermodynamic parameters are known, makes it possible to determine the concentration of Py during the ligation reactions and to calculate the second order rate constants from the set of pseudo first order constants obtained by iterative nonlinear least square fitting of experimental snapshot mass spectral data with the proposed kinetic scheme

Solvent and Temperature Effects in π-Route Cyclization

endo-Bicyclo[3.3.1]non-6-ene-3-carboxylic acid (1) was prepared and the solvent and temperature effects on the n-route cyclization were studied. The stereochemistry of the products strongly depends on the reaction temperature and the solvent used. The interpretation of the mechanism and product distribution based on experimental data is supported by theoretical investigation

Kinetike ligacije metalnih monokationa s pirenom u plinskoj fazi

The gas-phase ligation of M+ ions with pyrene is reviewed. The M+ (M = Al, K, V, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Sn, Ta, W, Re, Pt, Au, Hg, Pb, Bi and U) were produced by a single laser shot. Gaseous pyrene was already present in the Fourier transform mass spectrometer (FTMS). The reaction proceeded by consecutive ligations, sometimes accompanied by expulsion of a part (usually H2) of the ligand. Charge transfer (when the neutral metal has a higher ionization energy than the pyrene), pyrene dimerization, oxidation by residual oxygen, and protonation by ubiquitous water in the instrument may also take place. Reaction progression was followed by varying the delay time between the shot and the mass-spectrometric assay of the ions. If electronically-excited M+, which might have been produced by the laser pulse, was interfering with the reaction, these ions and their products were swept out of the FTMS chamber prior to initiation of the time delay specified above.Istraživana je ligacija različitih metalnih monokationa M+ s pirenom u plinskoj fazi. M+ (M = Al, K, V, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Sn, Ta, W, Re, Pt, Au, Hg, Pb, Bi and U) nastaju pojedinačnim udarima lasera na metalne mete unutar spektrometra masa uz Fourierovu transformaciju (FTMS) u kojem je već prisutan piren u plinskoj fazi. Do ligacije dolazi konsekutivnim adicijama uz ili bez gubitka dijela (obično H2) liganda. Ukoliko je energija ionizacije metala veća od energije ionizacije pirena dolazi do izmjene naboja. Također se opažaju reakcije dimerizacije, oksidacije s preostalim kisikom i protoniranje s prisutnom vodom u instrumentu. Napredovanje reakcija je praćeno snimanjem svih iona uz različita vremena zadržavanja u spektrometru nakon (i) udara lasera; (ii) dodatnoga izbacivanja trenutno stvorenih produkata s elektronički pobu|enim M+

An FTMS Investigation of the Competition between Uranium Oxidation and Ligation Reactions

An unexpected formation of oxidation products in the gas-phase reaction of U+ ions with pyrene and 9-azaphenanthrene in a Fourier transform mass spectrometer is reported. The products and reactions are described, but structures and mechanisms are not discussed