Interestingly, when the same reaction conditions were employed with 98% pure TBBTH (FUJIFILM Wako Pure Chemical Corporation) as the exchanging ligand (Scheme S2), 2 was produced instead of 3. This finding indicated that HSCH2SCH2SH (TDTH2) was present as an impurity in 97% TBBTH. To provide further evidence, we conducted a thiolate-exchange reaction of 1 using a mixture of two commercially available thiols, 98% pure TBBTH and 1,3-propanedithiol (PDTH2) (Schemes 1c and S5), a structural homologue of TDTH2. The UV-vis spectrum of the crude reaction mixture was similar to that of 3, suggesting that a structural homologue of 3 was obtained. Subsequent purification of the main product via PTLC (Figure ), followed by an ESI-MS analysis (Figure ), confirmed that this material comprised [Au24Pt(TBBT)12(PDT)3] 0 (4; Table ).