A Family of Au−Tl Loosely Bound Butterfly Clusters

By treatment of the polymeric species [AuTl(C6Cl5)2]n with ketones or with acetylacetone and 4,4‘-bipyridine, the
new tetranuclear complexes [Au2Tl2(C6Cl5)4]·L (L = PhMeCO, acacH) or [Au2Tl2(C6Cl5)4(bipy)]·(acacH) have
been prepared. Their crystal structures have been determined by X-ray diffraction methods and they all present a
central Au2Tl2 core formed via one Tl···Tl and four Au···Tl unsupported interactions resulting in a loosely bound
butterfly cluster. These complexes are strongly luminescent in both the solid state and solution showing an optical
behavior in agreement with the maintenance of the Tl···Tl contact even in solution.