APPLICATION OF ELECTROSPRAY MASS-SPECTROMETRY TO THE CHARACTERIZATIONOF HYDROXYMETHYLPHOSPHONIUM SALTS, HYDROXYMETHYLPHOSPHINES, AND THEIROXIDE, SULFIDE AND SELENIDE DERIVATIVES

Air-stable hydroxymethylphosphonium salts, readily synthesized from th e appropriate primary, secondary or tertiary phosphine, formaldehyde a nd HCl, provide an excellent means of characterizing phosphines by ele ctrospray mass spectrometry. Results are discussed in terms of fragmen tation and aggregation of the parent molecular ion species, where loss of a CH2OH group is a common fragmentation route. For monophosphonium salts, parent ions M(+) were typically observed as the base peaks in positive-ion spectra, with the tendency to aggregate to form species o f the type [M(2)Cl](+), [M(3)Cl(2)](+) and [M(4)Cl(3)](+) (M = phospho nium ion) increasing with the number of CH2OH groups. Related aggregat es, e.g. [M(2)Cl(3)](-), were observed in the negative-ion spectra. In situ formation of silver(I) adducts of a number of phosphines and the ir sulphide derivatives provides an additional means of characterizati on, though this method was not applicable to phosphine selenides. For phosphine oxides, adducts are readily detected with alkali metal ions.