Extension of the Pd-catalyzed CN bond forming reaction to the synthesis of large polydentate ligands containing NH functions

The use of Pd(0) mediated CN coupling reaction for the synthesis of large polydentate ligands functionalized with NH groups is described. The protocol has been applied to the synthesis of polycarboxylic ligands and polypyridyl ligands, starting from common aryl halides containing a central phenyl or biphenyl core as electrophiles. Different aromatic amines or isonicotinamide have been used as nucleophiles. In all cases the ligands have been isolated in high yields and purity. The products have been characterized by means of FTIR, 1H NMR, 13C(1H) NMR, EI-MS or CI-MS and elemental analysis. The X-ray structure of N,N'-(biphenyl-4,4'-diyl)diisonicotinamide has also been solved.