Catalytic Activity of Bis-phosphine Ruthenium(II)−Arene Compounds: Structure−Activity Correlations

摘要: The phosphine dissociation characteristics of a range bis-phosphine ruthenium(II)−arene complexes, [Ru(PPh3)(PR3)(η6-arene)]PF6 (arene = p-cymene:  PR3 PPhMe2, PPh3, P(p-tol)3, PPh2iPr; arene PhMe:  PPh3), [Ru(PPh3)(η2-PPh2(C6H4O))(η6-p-cymene)]PF6, and [RuCl(PPh3)(η7-PPh2(CH2)3Ph)]PF6, have been investigated by combination ligand exchange kinetics (with P(p-tol)3 in THF) tandem electrospray ionization mass spectrometry (ESI-MS/MS). Trends reactivity established from these studies were rationalized terms steric bulk, on the or phosphine, conformational freedom ligands. A good correlation is found between trends, especially ESI-MS/MS data, activity complexes as catalyst precursors for hydrogenation styrene to ethyl benzene (in THF). most active show under comparatively mild conditions (e.g., TOF ≥ 2000 h-1 THF at 50 °C bar H2). The...