MULTINUCLEATING 2,2'/6',2''-TERPYRIDINE LIGANDS AS BUILDING-BLOCKS FOR THE ASSEMBLY OF COORDINATION POLYMERS AND OLIGOMERS

The co-ordination properties of the tridentate ligand 2,2':6',2''-terpyridine (terpy) make it an ideal structural unit from which to assemble co-ordination oligomers and polymers with a linear connectivity about the metal centre. The dinucleating 'back-to-back' 2,2':6'2''-terpyridine ligands 6',6''-bis(2-pyridyl)-2,2':4',4'':2'',2'''-quaterpyridine L1 and 1,4-bis(2,2;:6',2''-terpyridin-4-yl)benzene L2 give rise to a linear connectivity at the ligand, whereas 1,3,5-tris(2,2':6',2''-terpyridin-4'-yl)benzene L3 is a trinucleating species which can give rise to arrays with a connectivity of three at the ligand. The coordination oligomers [(X-terpy)RuLRu(X-terpy)]4+ (L = L1 or L2) and [{(X-terpy) Ru}3L3]6+ (X-terpy = 4'-substituted 2,2':6',2''-terpyridine) have been prepared and characterised for a variety of electron-donating and -withdrawing substituent groups X.