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[BOND]C6H3CH[DOUBLE BOND]NC6H4-4-CH3)]2

The 2′-cyclopalladated imine complex equation image, reacts with CO in MeOH to afford the 2′-substituted aryl imine 2′-CO2CH3-5′-OCH3[BOND]C6H3CH[DOUBLE BOND]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 equation image is obtained. [Pd(μ-OAc)(1a)]2 with 2 equiv. of Ph3P and CO (1 atm) gives the heterocyclic equation image which arises from two CO insertion reactions, whereas [PdX(1a)]2 (X = AcO, Cl) with 4 equiv. of C[TRIPLE BOND]NBut and 4 equiv. of Ph2PCH2CH2PPh2 affords the heterocyclic ketenimine equation image [PdCl(1a)]2 reacts with CH2[DOUBLE BOND]CHCO2CH2CH3 to afford 2′([BOND]CH[DOUBLE BOND]CHCO2CH2CH3)-5′-OCH3C6H3CHO, and [Pd(μ-OAc)(1a)]2 with I2 to give 2′-I-5′-OCH3C6H3CHO. Excess CH3O2CC[TRIPLE BOND]CCO2CH3 reacts with various substituted cyclopalladated Schiff's bases in MeOH to afford equation image which we formulate as possessing two Pd[BOND]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[BOND]O(1), 2.139(6), Pd[BOND]O(2), 2.026(6), Pd[BOND]N, 2.039(6), Pd[BOND]C(2′), 1.951(8), Pd[BOND]Pd, 3.113(1), N[BOND]Pd[BOND]C(2′), 80.9(3), N[BOND]Pd[BOND]O(1), 97.5(2), C(2′)[BOND]Pd[BOND]O(2), 91.7(3), O(1)[BOND]Pd[BOND]O(2), 89.2(2).