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.

本文报道了硫代配位金(I)配合物的高产率合成方法，目标产物为双(吡啶-2-硫代)氯化金(I)（1）与双(吡啶-4-硫代)氯化金(I)（2）。通过固态结构表征可知，尽管两类吡啶硫代配体中氮(N)与硫(S)原子的相对位置存在差异，但两种配合物均展现出Au(I)的直线型配位模式、配体的共平面排布特征，且均存在两处弱γ-agostic相互作用（γ-agostic interaction）。针对配合物1和2开展的密度泛函理论（DFT）计算，可复现实验观测到的X射线晶体结构。计算结果显示，尽管Au(I)与两个吡啶基团间的C−H···Au相互作用相对较弱（配合物1中键长分别为2.83 Å、2.88 Å，配合物2中为2.86 Å），但该类相互作用可进一步稳定配体的配位状态与空间取向。在配合物1中，最短Au···Au间距为3.50 Å，表明固态下存在弱的亲金相互作用（aurophilic interaction）；而配合物2中则未出现此类相互作用。