SYNTHESIS AND CHARACTERIZATION OF DOUBLE CYCLOPALLADATED COMPLEXES OFSCHIFF-BASES AND AZINE-OXIDATIVE ADDITION OF ARYL-HALOGEN BOND

The oxidative addition of aryl-halogen bonds of Schiff bases (2-ClC6H4 CH=N-CH2-)(2) (1), (2-BrC6H4CH=N-CH2-)(2) (2), 1,4-(2-BrC6H4CH=N-)(2)C 6H4 (3), 4,4'-(2-BrC6H4CH=N-C6H4)(2) (4) and the azine (2-BrC6H4CH=N-) (2) (5) to Pd(dba)(2) has been carried out in benzene. Insoluble halog eno-bridged polymeric complexes [{Pd(C6H4CH=N-CH2-)Cl}(n)] (1a), [{Pd( C6H4CH=N-CH2-) Br}(n)] (2a), [1,4-{BrPd (C6H4CH=N-C6H4-N=CHC6H4)PdBr}( n)] (3a), [4,4'-{Pd(C6H4CH=N-C6H4)Br}(n)] (4a) and [{Pd(C6H4CH=N-)Br}( n)] (5a) were formed. The bridge-splitting reactions of halogeno-bridg ed complexes were studied with different ligands like triphenylphosphi ne, triethylphosphite, 4-picoline, diethyldithiocarbamate and N-(2-hyd roxy) benzylideneamine. All the double cyclopalladated complexes obtai ned were analysed by means of H-1 NMR and C-13 NMR spectroscopy.