Rhodium(I) and palladium(II) complexes with the Schiff base 2,2-bis((4S)-4-benzyl-2-oxazoline)

The Schiff base 2,2^′-bis((4S)-4-benzyl-2-oxazoline) (I) and its coordination complexes with rhodium(I) and palladium(II) (and with 1,5-cyclo-octadiene and allyl ligands) have been characterised by single-crystal X-ray diffraction, mass spectrometry, ¹³C and ¹H NMR spectroscopy: Rh(C₂₀H₂₀N₂O₂)(C₈H₁₂)]Rh₂(C₂₀H₂₀N₂O₂)₂](CF₃SO₃)₃ · (CH₃CH₂O) (II) and Pd(C₂₀H₂₀N₂O₂)(C₃H₅)]CF₃SO₃ (III). We discuss the reasons for the formation of two complex cations for Rh(I), Rh(C₂₀H₂₀N₂O₂)(C₈H₁₂)]⁺ (IIa) and Rh₂(C₂₀H₂₀N₂O₂)₂]²⁺ (IIb), and only one for Pd(II).