Neutral palladium(II) complexes with P,N Schiff-base ligands: Synthesis, characterization and catalytic oligomerisation of ethylene

New N-functionalised 2-phosphinobenzaldimino (P^N) ligands bearing 3-picolyl, furfuryl, thiophene-2-methyl, thiophene-2-ethyl, and benzyl groups have been prepared in good yield. The 2-phosphinobenzaldimino ligands were reacted with PdCl2(COD) to give the corresponding metal complexes of the type Pd(L)Cl2 (L = 2-phosphinobenzaldimino (P^N) ligand). All compounds were fully characterized using spectroscopic and analytical techniques, including 1H, 13C, and 31P NMR and IR spectroscopies, mass spectrometry and elemental analysis. Selected neutral palladium complexes were evaluated as catalyst precursors in ethylene oligomerisation reactions, after activation with a co-catalyst (MMAO, EtAlCl2, or Et2AlCl).