The behaviour of [Pt(eta(3)-allyl)XP(C6H5)(3)] complexes in electrospray ionization conditions compared with those achieved by other ionization methods

Three Pt(II) eta3-allylic compounds, [Pt(eta3-allyl)XP(C6H5)3] (X = Cl, Br, I) have been studied under electrospray ionization (ESI) conditions. Unexpected behaviour, such as the complete lack of either [M]+. or [MH]+ ions, the formation of complexes with the solvent and bis-triphenylphosphino-containing species, was observed. To rationalize such results, a series of parallel measurements on the same compounds have been performed under electron impact, fast-atom bombardment and field ionization conditions. The data so obtained suggest that molecular species are not produced by ESI, probably due to the action of strong electric fields and collisionally induced decompositions occurring in different regions of the instrument. Complexes with the solvent originate through gas-phase ion–molecule reactions, while the bis-triphenylphosphino-containing species are formed by reaction of ions with triphenylphosphine formed by thermal decomposition inside the heated capillary line, just after the electrospray ionization source.