Although the above mechanistic studies focussed on intermediates in the HDF of 1, similar observations were made in other reactions. For example, when perfluorotoluene was reacted with Ph2SiH2 at 20 o C in MeCN with P n Bu3 as the catalyst (10 mol%), after 10 minutes the formation of a phosphonium ion was seen ( 31 P  = -38.1, apparent septet, ca. 4 Hz; F  = -58.0 (t, 4 JFF = 18 Hz), -126.8