MULTINUCLEATING 2,2'/6',2''-TERPYRIDINE LIGANDS AS SUPRAMOLECULAR BUILDING-BLOCKS - HETEROTRINUCLEAR COMPLEXES AND THE CRYSTAL AND MOLECULAR-STRUCTURE OF 6',6''-BIS(2-PYRIDYL)-2,2'/4',4''/2'',2'''-QUATERPYRIDINE (BTPY)

The crystal structure of the dinucleating 2,2':6',2''-terpyridine ligand 6',6''-bis(2-pyridyl)-2,2':4',4'':2'',2'''-quaterpyridine (btpy) has been determined and the two metal-binding tpy domains shown to be essentially planar and co-planar (P1BAR, a = 6.304(2), b = 8.208(2), c = 11.535(3) angstrom, alpha = 97.42(2), beta = 104.25(2), gamma = 96.23(2)-degrees, Z = 1, d(c) = 1.36 g cm-3, 2214 unique observed reflections with I > 1.5sigma (I), R = 0.0583); a methodology involving sequential reaction with non-labile and labile metal centres allows the specific assembly of heterometallic supramolecular oligomers such as [(Xtpy)Ru(btpy)M(btpy)Ru(Ytpy)]n+ (M = cobalt(II), cobalt(III) or iron).