Reactions of Cyclopalladated Benzylidene-aniline Schiff's Base Complexes. Selective Synthesis of 2′-Substituted Schiff's Base Derivatives and the X-Ray Crystal Structure of the Dimer [Pd(μ-OAc)(5′-OCH3?C6H3CHNC6H4-4-CH3)]2

The 2′-cyclopalladated imine complex , reacts with CO in MeOH to afford the 2′-substituted aryl imine 2′-CO₂CH₃-5′-OCH₃? C₆H₃CH?NTol (Tol = C₆H₄-4-CH₃). The product of this reaction can be altered by changing the bridging ligand from AcO to Cl, in which case only the 5-membered ring heterocyclic compound is obtained. Pd(μ-OAc)( 1a )]₂ with 2 equiv. of Ph₃P and CO (1 atm) gives the heterocyclic which arises from two CO insertion reactions, whereas PdX( 1a )]₂ (X = AcO, Cl) with 4 equiv. of C?NBu^t and 4 equiv. of Ph₂PCH₂CH₂PPh₂ affords the heterocyclic ketenimine PdCl( 1a )]₂ reacts with CH₂?CHCO₂CH₂CH₃ to afford 2′(? CH?CHCO₂CH₂CH₃)-5′-OCH₃C₆H₃CHO, and Pd(μ-OAc)( 1a )]₂ with I₂ to give 2′-I-5′-OCH₃C₆H₃CHO. Excess CH₃O₂CC?CCO₂CH₃ reacts with various substituted cyclopalladated Schiff's bases in MeOH to afford which we formulate as possessing two Pd? C bonds, and one coordinated ester O atom. The X-ray crystal structure of Pd(μ-OAc)( 1a )]₂ has been determined; relevant bond lengths Å] and bond angles °] are: Pd? O(1), 2.139(6), Pd? O(2), 2.026(6), Pd? N, 2.039(6), Pd? C(2′), 1.951(8), Pd? Pd, 3.113(1), N? Pd? C(2′), 80.9(3), N? Pd? O(1), 97.5(2), C(2′)? Pd? O(2), 91.7(3), O(1)? Pd? O(2), 89.2(2).