Mass spectrometry of polystyrene and polypropene ruthenium complexes. A new tool for polymer characterization

The use of organometallic fragments as cationization reagents for matrix-assisted laser-desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS) of polystyrene (PS) and polypropene (PP) is reported. Reaction of [Ru(C5H5)(NCCH3)3][PF6] (1a) with PS samples of numerical mass average Mn 1430–135 000 in a ratio [Ru]/[PS]=1/1 to 3/1 favours effective ionization of the polymer by MALDI-MS techniques and leads to an increase in signal intensity over that obtained by use of Ag+ salts. PP samples of Mn 2700 and 6100 are ionized after reaction with the trinuclear ruthenium pentahydride derivative (RuC5Me5)3H5, thus affording the first observation of MALDI-MS signals for this polymer. Reactions of the cations [Ru(C5H5)(NCCH3)3]+ and [Ru(C5Me5)(NCCH3)3]+ with 1,3-diphenylpropane and of (RuC5Me5)3H5 with 1-eicosene were studied as models for the corresponding reactions with PS and PP, respectively.