Comparative X-ray Structure Analyses of Multidentate Transition Metal Complexes (2006)
AuthorsFlood, Kelly-Jayneshow all
The biological significance of macrocyclic complexes has been recognized since they were first synthesized by Neil Curtis. They have the potential to play a critical role in mimicking metalloprotein active sites. Nine Curtis macrocyclic complexes have been studied using X-ray crystallographic techniques. Their structures have been solved and comparisons of the results have been made. Biological importance is also true of the macrocyclic counterpart; side-off and end-off compartmental ligands. In some circumstances these types of ligands are more appropriate because they have extra flexibility due to their pendant arms not being fixed in place by another head-unit, like a traditional macrocycle. The synthesis of a proposed compartmental ligand; 2,2-(N,Nʼ-bis(benzimidazole-2-ylmethyl)methylamine-5,5ʼ-di-tert-butyl-3,3ʼmethanediyl-dibenzyl alcohol (Ligand 1(L1)), has been proposed and outlined. The pendant arms: bis(benzimidazole-2-ylmethyl)amine (BBIM), were successfully synthesized and characterized with 1H NMR, IR and X-ray crystallography. The head-unit: 5,5ʼ-Di-tert-butyl-2,2ʼ-dihydroxy-3,3ʼ-methanediyl-dibenzene methanol (DHTMBA), of L1 was synthesized and characterized using 1H NMR, IR and mass spectrometry. A similar head-unit; 5,5ʼ-Di-methyl-2,2ʼ-dihydroxy-3,3ʼ-methanediyl-dibenzene methanol (DHMMBA), was synthesized in an effort to shorten the synthetic time of the head-unit. This was consequently converted to the chlorine analogue; 3,3ʼ-Bis(chloromethyl)-5,5ʼ-dimethyl-2,2ʼ-methane-diyldiphenol (Cl-DHMMB), and characterized with 1H NMR, IR and X-ray crystallography. Efforts were made to synthesize Ligand 1, but due to synthetic difficulties and time restraints this proved unsuccessful. Suggestions have been made to develop this synthesis.