Analysis of the solid-state rearrangement of hydrido-alkynyl ruthenium complexes to their vinylidene tautomers

The solid-state tautomerization of the hydrido-alkynyl derivatives [Cp*RuH( C equivalent to CR)(dippe)][BPh4] (Cp* = C5Me5; R = SiMe3, Ph, H; dippe = 1 ,2-bis-(diisopropylphosphino)-ethane) to their vinylidene isomers [Cp*Ru=C= CHR(dippe)] [BPh4] was studied by IR spectroscopy. Characteristic isothermi c alpha vs. t curves for each individual rearrangement process were recorde d. Their shape, and hence the isomerization mechanism, depends strongly on the nature of the substituent R. The kinetic analysis of the above curves u sing the Avrami-Erofeev provided some mechanistic information about the iso merization process in the solid.