The chemistry and catalytic activity of new cationic ruthenium(II) complexes in the hydrogenation of cyclohexene. Crystal structure of [RuH(CO)(PPh₃)(P(OMe)₃)(Ph₂PCH ₂CH₂AsPh₂)]ClO₄·n - C₅H₁₂

Interaction of neutral ruthenium(II) complexes of the type [RuHCl(CO)(PPh₃) (L-L′)] [where L-L′= Ph₂PCH₂CH₂PPh₂ (dppe), 1 ; Ph₂PCH₂CH₂CH₂PPh₂ (dppp), 2 ; Ph₂PCH₂CH₂AsPh₂ (arphos), 3] with AgClO₄ in the presence of L″ [L″ = P(OMe)₃ or PMe₃] yielded the new cationic ruthenium(II) complexes [RuH(CO)(PPh₃)(L″)(L-L′)]ClO₄ [where L-L′ = dppe, 4 ; dppp, 5 ; arphos, 6 ; L″ = PMe₃, 4 ; P(OMe)₃, 5 and 6]. All the complexes have been characterized by both analytical and spectroscopic (IR and ¹H NMR) methods. The structure of a cationic complex 6, [RuH(CO)(PPh₃)(P(OMe)₃) (arphos)]ClO₄·n -C₅H₁₂, has been confirmed by single-crystal X-ray diffraction. The Ru atom is octahedrally coordinated with CO, PPh₃ and arphos in the equatorial plane and H and P(OMe)₃ in the axial positions. In the hydrogenation of cyclohexene, some relations between structures and catalytic activities have been studied. The cationic complexes have shown lower catalytic activities than their neutral analogues.