MECHANOSYNTHESIS AND REACTIVITY STUDIES OF Pd(II) COMPLEXES

Mechanochemistry is aligned with green chemistry, involves chemical reactions driven by mechanical forces. Organometallic mechanochemistry remains relatively underexplored, and only recently key organometallic complexes have been synthesized via this method. Despite the widespread use of Pd(II) complexes in catalysis and medicinal chemistry, their mechanochemical synthesis and application have received limited attention. In this study, some Pd(II) complexes were synthesized via mechanochemistry from commercial halogenated and halogen-like Pd(II) precursors and commercial ligands. These compounds can be classified into three groups: [Pd(COD)X2] with 1,5-cyclooctadiene; [Pd(N⌒N)X2] and [Pd(N⌒N’⌒N)X]X with bidentate and tridentate N-ligands; [Pd(PPh3)2X2] and [Pd(P⌒P)X2] featuring mono- and bidentate P-ligands. The reactions proceed with high to quantitative yields and excellent product purity, supported by favorable green chemistry metrics. These complexes were subsequently evaluated in the mechanochemical oxidation of benzyl alcohol to the corresponding benzaldehyde. Several complexes showed promising conversion and selectivity, highlighting their potential for further development.