TRIAZACYCLANE-BASED TRITHIOLS AND THEIR USE IN THE PREPARATION OF SITE-DIFFERENTIATED IRON SULFUR CLUSTERS

The new tripodal thiol ligands 1,4,7-tris(4-mercaptobenzoyl)-1,4,7-triazacyclononane (H-3L1) and 1,5,9-tris(4-mercaptobenzoyl)-1,5,9-triazacyclododecane (H-3L2) have been synthesised and characterised. On reaction with iron-sulfur clusters [Fe4S4(SR)4]2- (R = Et or Bu(t)), subsite-differentiated clusters, for example [Fe4S4(L1)(SEt)]2-, are formed. Site-specific reaction at the differentiated iron is demonstrated. The novel clusters have been prepared both in solution and as isolated solids, and characterised mainly by H-1 NMR and Mossbauer spectroscopy.