In the present work, reaction of chloro?bridged complex [Pd{? 2 ( C,C )-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}(µ-Cl)] 2 ( A ) with NaN 3 (1:2 molar ratio) in methanol afforded the corresponding azido-bridged dimer [Pd{? 2 ( C,C )-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}(µ-N 3 )] 2 ( 1 ) as a mixture of isomers, which underwent bridge cleavage reactions with monodentate ligands to afford the monomeric, neutral Pd(II) complexes [Pd{? 2 ( C,C )-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}N 3 (L)] [L = PPh 3 ( 2 ) Me 3 Py ( 3 ), Py ( 4 )]. The C,C- orthometallated complexe [Pd{? 2 ( C,C )-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}(µ-Br)] 2 ( B ) is easily cleaved with monodentate ligand Phenyl isothiocyanate, to afford the mononuclear complexe: [Pd{? 2 (C,C)-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}Br(SCN-Ph)] ( 5 ). The chloro bridge in the dimeric orthopalladated complex ( A ) is easily cleaved by neutral ligand thiourea, to afford mononuclear complexe: [Pd{? 2 (C,C)-C 6 H 4 PPh 2 C(H)CO(C 6 H 4 -NO 2 -4)}Cl(tu)] ( 6 ). The complexes were identified and fully characterized by elemental analysis and spectroscopic studies (IR and multi nuclear NMR). In the first section of the project, the biological activity of 2 and 3 has been evaluated by examining their ability to bind to fish sperm DNA ( FS -DNA) with UV and fluorescence spectroscopy. The results suggested that both complexes interact with FS -DNA through the intercalation mode and follow the binding affinity order of 3 2. Moreover, to explore the Potential medicinal value of the new complexes, binding interaction of 2 and 3 with bovine serum albumin (BSA) was studied at normal physiological conditions using fluorescence and UV–Vis spectral techniques. The reactivity towards protein BSA revealed that the quenching of BSA fluorescence by the two complexes are static quenching, and complex 3 exhibits a higher BSA-binding ability than that of complex 2 . In the second section, a series of palladium complexes bearing monodentate and bidentate ligands were applied in the Suzuki reaction of aryl halides with phenylboronic acid. The complexes were found to be effective catalysts for these reactions affording the cross-coupled products in moderate to excellent yields.
