Comparative Raman spectroscopy study of sulfonate-substituted triphenylphosphines

A comparative Raman spectroscopy study of triphenylphosphine (TPP), monosul fonated triphenylphosphine (TPPMS) and trisulfonated triphenylphosphine (TP PTS) is reported. The characteristic modes for each molecule were evidenced and we suggest assignments for the majority of the modes. A detailed study of the phenyl breathing mode (around 1000 cm(-1)) shows that in the case o f TPP, the three rings are nonequivalent, whereas for TPPTS, the sulfonate substituant seems to contribute to stabilise the molecule structure so as t he rings are equivalent. The TPPMS spectrum is a medium case between the ex treme cases of TPP and TPPTS and presents the characteristics of the two pr evious spectra. (C) 1999 Elsevier Science B.V. All rights reserved.