Synthesis of Ru alkylidene complexes.

The present work describes the robust synthesis of Ru alkylidene complexes (PCy(3))(2)Cl(2)Ru=CHR - precursors for metathesis catalysts. Moreover, the dynamic behavior of complexes where R = 2-naphthyl and 2-thienyl was studied. (1)H NMR techniques were employed to establish the preferred conformations in solution for both complexes and the energy barrier for rotation around single (Ru=)CH-C(thienyl) bond was estimated (ΔG(≠) (303K) = 12.