Rhodium(I) complexes of β-diketonates and related ligands as homogeneous hydrogenation catalysts

Article abstract of DOI:10.1016/0304-5102(91)80018-X

Rhodium(I) complexes of β-diketonates such as bis(η²-ethene)[1,3-(1-phenyl)-butanedionato-O,O′]rhod ium(I) and related (O...O) ligands are active catalysts for the hydrogenation of unhindered alkenes at 30°C (1 atm H₂). Substrates such as α-acylaminocinnamic acid are not hydrogenated under these conditions, a result that can be used as a test for homogeneity in these catalytic systems. The crystal structures of two catalysts are described: bis(η²-ethene)[1,3-(1-ferrocenyl)-butanedionato-O, O′]rhodium(I), orthorhombic, space group P2₁2₁2₁, with a = 7.8550(4), b = 9.8400(4), c = 21.5093(7) A, and Z = 4. R = 0.037 and R_w = 0.042 for 2993 reflections with I > 3?(I). (1,5-cyclooctadiene)(2′-acetylphenoxy-O,O′)rhodium(I), triclinic, space group P1ˉ with a = 7.6634(5), b = 9.7831(3), c = 10.1112(6) A, α = 104.763(3), β = 73.668(6), γ = 98.470(4)°, and Z = 2. R = 0.028 and R_w = 0.034 for 5174 reflections with I > 3 ?(I).