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 als o 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 P y during the ligation reactions and to calculate the second order rate cons tants from the set of pseudo first order constants obtained by iterative no nlinear least square fitting of experimental snapshot mass spectral data wi th the proposed kinetic scheme.