Perhalophenyl(tetrahydrothiophene)gold(I) Complexes as Lewis Bases in Acid−Base Reactions with Silver Trifluoroacetate†

Reaction of [Ag(CF3CO2)] with [Au(C6X5)(tht)] (X = halogen, tht = tetrahydrothiophene) leads to the synthesis of complexes [AgAu(C6F5)(CF3CO2)(tht)]n (1), [Ag2Au(C6Cl2F3)(CF3CO2)2(tht)]n (2), or [AgAu(C6Cl5)(CF3CO2)(tht)]n (3), confirming the capability of a neutral complex, such as a perhalophenyl(tetrahydrothiophene)gold(I), to act as electron density donor when treated with a Lewis acid substrate. All three crystal structures have been established by X-ray diffraction; all display Au···Ag and Ag···Ag interactions and polymeric 1D (2, 3) or 2D (1) networks built by means of additional Au···Au, Ag−O···Ag, or Au−S···Ag interactions. Complexes 1−3 are luminescent in the solid state at room temperature, and at 77 K or in frozen solutions they show a different luminescence in the solid state, which seems to be related to the different number and types of metal−metal interactions present in each case. DFT and TDDFT calculations on simplified model systems of 1−3 have also been carried out.