A new series of N,O-bidentate ligands, L1, L2, L3 and L4, and their Pd(II) complexes, PdL1, PdL2, PdL3
and PdL4 have been synthesised and characterised using various physico-chemical techniques, namely
elemental analyses, IR and 1
H and 13C NMR spectroscopies, and conductivity analysis. The molecular
geometries of PdL2 and PdL4 have been elucidated through single crystal X-ray crystallography revealing
2:1 molar equivalence of ligand: Pd with the Schiff bases that exhibited bidentate ligands behaviour,
in which they coordinated through the phenolic O donor atoms and imine N. Upon complexation, the
ν(C=N) around 1629-1639 cm-1 and ν(C-O) around 1251 to 1252 cm-1 shifted to lower frequencies by 4
to 23 cm-1. In this study, three parameters were chosen for the reaction conditions optimisation, which
were types of bases, loadings for the catalyst, and temperatures of the reaction. Pd(II) complexes exhibited
good catalytic activities for Heck coupling reaction with 100% conversion at 100°C within 12 hours of
reaction time. Reducing the reaction temperature to 80°C reduced the conversion to a maximum of 80%.