Application of electrospray mass spectrometry to the characterisation of sulfonated and ferrocenyl phosphines

A range of ferrocenyl-containing and sulfonated triphenylphosphines have been investigated by electrospray mass spectrometry. In situ formation of hydroxymethyl phosphonium salt derivatives of the ferrocenyl phosphines and in situ formation of silver(I) adducts of both the ferrocenyl and sulfonated phosphines provided a means of characterising such compounds. Results are discussed in terms of fragmentation and aggregation of the parent molecular ion species, Sulfonated phosphines, including their sodium adducts, were easily characterised by their negative-ion spectra. Aminoalkyl-ferrocenyl phosphines form strong [M+H](+) ions in their positive-ion spectra. Ferrocenyl phosphines without amino functions give weaker [M+H](+) ions and may also be complicated by the existence of [M](+) ions. Less complex positive-ion mass spectra of these ferrocenyl phosphines can be observed following treatment with either a solution of AgNO3 or a mixture of formaldehyde and HCl. (C) 1998 Elsevier Science Ltd. All rights reserved.