Synthesis, single crystal X-ray analysis, and TEM for a single-sized Au11 cluster stabilized by SR ligands: The interface between molecules and particles

An SR-modified Au cluster with a sub-nanometer size, Au11(S-4-NC5H4)3(PPh3)7 (1), has been synthesized by NaBH4 reduction of Au(S-py)(PPh3) or by reacting [Au9(PPh3)8](NO3)3 with HS-4-py in good yield. Its molecular structure has been elucidated by single crystal X-ray diffraction, and TEM observation has been achieved for the first time for this size of SR-modified Au clusters. The core structure is best described in terms of an incomplete icosahedron. CV measurements in CH2Cl2 have suggested that the cluster does not coagulate in solution with significant concentration.