Triazacyclane-based trithiols and their use in the preparation of site-differentiated iron–sulfur clusters

Abstract

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 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 ¹H NMR and Mössbauer spectroscopy.