Coordination of Pyridinethiols in Gold(I) Complexes

High-yield synthesis of gold(I) thionato complexes, bis(pyridine-2-thionato)gold(I) chloride (1) and bis(pyridine-4-thionato)gold(I) chloride (2), are described. According to their solid-state structures, a linear coordination of Au(I), equiplanar coordination of the ligands and two weak γ-agostic interactions are found in both of these complexes despite of different relative positions of N and S atoms in the pyridinethionato ligands. Density functional theory calculations on 1 and 2 reproduce the observed X-ray structures. Even though the C−H···Au interactions of Au(I) and two pyridine moieties (2.83 and 2.88 Å in 1 and 2.86 Å in 2) are relatively weak, according to calculations they seem to provide further stabilization for the coordination and orientation of the ligands. In 1 the shortest Au···Au distances of 3.50 Å indicate that aurophilic interactions, even though weak, are present in the solid state, whereas in 2 these interactions are absent.