Coordination chemistry of azamacrocycles functionalised with N-pendant pyridyl, bipyridyl and terpyridyl arms
This thesis describes the synthesis and characterisation of a series of new azamacrocyclic ligands (L1-L3, L1O, L11, L14, L16-Ll9), which have been N-functionalised with pendant pyridylmethyl- (pyCH2-), bipyridylmethyl(bipyCH2-) and terpyridylmethyl- (terpyCH2-) arms. Some of the coordination chemistry of these ligands with transition metal ions is reported. A sexidentate tris(2,2'-bipyridyl) chelating ligand, 1,4, 7-tris(2,2'-bipyridyl-5'-ylmethyl)-1,4,7-triazacyclononane (Ll) has been developed, and the crystal structures of the mononuclear complexes [M(L1H)]3+ (M = Ru, Cu) are reported. In [M(L1H)]3+, the azamacrocyclic nitrogen atoms are non-coordinating to M, but have a high affinity for a single proton trapped in the macrocyclic cavity. An analogous nonadentate ligand (Ll7) has been developed based on 9N3 with three N-pendant terpyCH2- arms, and complexes of Ll7 with Eu(III) and La(III) are reported. The complex [Eu(L17H)](PF6)4 is found to be strongly fluorescent in acetonitrile and methanol/water solution. Ligands with potential use as fluorescent pH and transition metal ion sensors have been developed by reacting the azamacrocyclic N-pendant bipyCH2 arms of LLL3, LlO and Lll with cis-[Ru(bipYnCI2] to give macrocycles with up to four attached [Ru(bipY)3]2+ groups (LS-L7, L12, L13).