5-MEMBERED AND 6-MEMBERED EXO-CYCLOPALLADATED COMPOUNDS OF N-BENZYLIDENEAMINES - SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF [PDBR(PARA-MEOC6H3(CH2)2N=CH(2,6-CL2C6H3))(PPH3)] AND [PDBR(C6H4CH2N=CH(2,6-CL2C6H3))(PET3)2]

The reaction of N-(2,6-dichlorobenzylidene)amines, 2,6-Cl2C6H3CH=N(CH2)nC6H4-p-R (n = 1, 2; R = H, MeO), with Pd(AcO)2 in refluxing acetic acid has been studied. With N-benzylidenebenzylamines (n = 1) exo five-membered derivatives were obtained. From N-benzylidene(2-phenylethyl)amines (n = 2) endo five-membered cyclopalladated compounds were formed by oxidative addition of C‒Cl bonds of the ligand to Pd(0) formed in situ. Under milder conditions (acetic acid at 80 °C) the exo six-membered compound [inline formula omitted] was obtained. All exo derivatives contain the imine ligand in the syn form. By reaction with PR3 (R = Et, Ph), monophosphine complexes [inline formula omitted] and bisphosphine derivatives [inline formula omitted], where the Pd‒N bond has been broken, can be obtained. [inline formula omitted] (6f) crystallizes in the monoclinic space group P21/n with a = 20.321 (4) Å, b = 12.561 (3) Å, c = 12.608 (3) Å, β = 97.50 (2)°, and Z = 4. The exo six-membered ring displays a boat conformation with Pd and C(7) atoms out of the plane defined by the remaining atoms. [PdBr{C6H4CH2N═CH(2,6-Cl2C6H3)}(PEt3)2] (9c) has been characterized by X-ray crystallography; it crystallizes in the monoclinic space group P2l/a with a = 45.352 (6) Å, b = 8.884 (2) Å, c = 7.556 (2) Å, β = 99.02 (3)°, and Z = 4. The Pd atom has a roughly planar coordination, and the imine ligand is in the anti form. © 1990, American Chemical Society. All rights reserved.