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 (H3L1) and 1,5,9-tris(4-mercaptobenzoyl)-1,5,9-triazacyclododecane (H3L2) have been synthesised and characterised. On reaction with iron–sulfur clusters [Fe4S4(SR)4]2–(R = Et or But), 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 1H NMR and Mössbauer spectroscopy.