Synthesis and characterisation of 5,6-bis(salicylideneimino)-1,10-phenanthroline and its trinuclear complexes

Abstract

As a multidonor ligand with phenanthroline and salicylaldimine functionalities on the same molecule, 5,6-bis(salicylideneimino)-1,10-phenanthroline (LH2) has been,synthesized by the reaction of 5,6-diamino-1,10-phenanthroline with salicylaldehyde and its metal complexes with Ni(II) and Cu(II) have been prepared. Both of the isolated complexes are trinuclear with metal/ligand ratio of 3:2. Protonation constants of LH2 which have been determined by potentiometric titration in solution are log K-1=8.96, log K-2=15.88, log K-3=8.73 and log K-4=2.78. The newly synthesized compounds have been verified by IR, H-1 NMR and mass spectra together with elemental analysis.