Cyclometalation of N-(4-methoxyphenyl)-.alpha.-benzoylbenzylideneamine with palladium(II) acetate. Evidence for a new kind of diastereoisomerism

Abstract

The reaction of Pd(OAc)2 with N-(4-methoxyphenyl)-α-benzoylbenzylideneamine yielded two different acetate-bridged ortho-palladated compounds, Pd2[4-OCH3C6H4N=C(COC 6H5)C6H5]2(μ-OAc) 2 (2 and 3), depending on the relative ratio of the reagents. Both diastereoisomeric complexes exhibit a nonplanar, open-book shape, differing only in the dihedral angle formed between the C6H5C=O and the C6H5C=N planes; i.e., they are atropisomers around the CO-CN bond, as could be established from X-ray diffraction data. Both complexes crystallize in the centrosymmetric triclinic space group P1, with Z = 2. Unit cell parameters are as follows: compound 2, a = 14.206 (9) Å, b = 15.764 (5) Å, c = 11.149 (3) Å, α = 92.46 (2)°, β = 95.31 (4)°, γ = 116.03 (4)°; compound 3, a = 11.889 (15) Å, b = 13.209 (23) Å, c = 15.436 (9) Å, α = 87.34 (1)°, β = 78.51 (7)°, γ = 87.73 (1)°. © 1992 American Chemical Society.