A new tiara Pd(II) thiolate complex, [Pd(SC12H25)(2)](6), has been synthesized and fully characterized by X-ray single crystal analysis, elemental analysis, MALDI, H-1 NMR, powder XRD, IR, Raman, and UV/vis. It was found that, in each complex cluster, the six palladium atoms form a nearly planar hexagonal ring and the adjacent palladium atoms are bridged by sulfur atoms from both sides. Then the complex was further used as a single-source precursor to prepare nearly monodisperse palladium sulfide (PdS) nanoparticles through the high-temperature-induced decomposition in diphenyl ether. The obtained nanoparticles are 2.87 +/- 0.51 nm in diameter and protected by a layer of thiolate species on the surface.