Nanometer-sized and stable thiolate-protected cobalt clusters were synthesized by a wet chemical method, leading to a pink solution with well-defined optical activity (UV-Vis) and photoluminescence (PL). The cobalt cluster core of ~1.3 nm size was metallic (as indicated by STEM, STM, XPS, HAADF-EELS) and was surrounded by a specific configuration of thiolate staples (according to Raman, FTIR, XAFS, MALDI) that is similar to that of corresponding gold clusters.
