Mass spectrometric characterization of oligomeric phosphaalkenes

Oligomeric phosphaalkenes are readily characterized using electrospray ionization mass spectrometry (ESI-MS). The high affinity of phosphines for silver ions permits the detection of the unadulterated polymer as [M + xAg](x+) ions (x = 2-3). When the oligomers are oxidized using H2O2, the resulting phosphine oxide polymer may be treated with sodium ions to produce [M + xNa](x+) ions ( x = 2-3). Both methods predict a similar distribution of oligomers: M-n values of 3450 +/- 100 Da and a PDI of 1.09 +/- 0.01 cover both analyses. This distribution represents oligomers of the general formula Me( PMesCPh(2))(n)H from n = 4-20, maximizing at similar to n = 10.