Thallium(I) Acetylacetonate as Building Blocks of Luminescent Supramolecular Architectures^‖

The heteropolynuclear complexes [AuTlR₂]_n (R = C₆F₅, C₆Cl₅) react with [Tl(acac)] in 1:1 or 1:2 molar ratio, leading to products of stoichiometry [AuTl₂(acac)(C₆Cl₅)₂] (2) and [AuTl₃(acac)₂(C₆F₅)₂] (3). The new complexes obtained display Tl₂(acac)₂ units acting as bridges between linear chains of [AuTl(C₆Cl₅)₂]_n in 2 or between [AuTl(C₆F₅)₂] units in 3. In both structures, in addition to the Au···Tl interactions, Tl(I)···Tl(I) contacts also appear, which are considered to be in part responsible for the luminescent behavior. The comparison of these properties in solution to that of the starting complex [Tl(acac)] allows us to propose the presence of Tl(I)···Tl(I) interactions also in solution. TD-DFT calculations show that Tl₂(acac)₂ units would be responsible for the luminescent behavior of Tl(acac) and complexes 2 and 3 in acetonitrile solution.