A Heterobimetallic Approach To Stabilize the Elusive Disulfur Radical Trianion (“Subsulfide”) ${{\rm S}{{{{\bullet}}3- \hfill \atop 2\hfill}}}$

A unique heterobimetallic disulfur monoradical, complex 2 , with a diamond‐shaped {NiS 2 Pt} core has been synthesized by two‐electron reduction of a supersulfido‐(nacnac)nickel(II) complex (nacnac=β‐diketiminato) with [Pt(Ph 3 P) 2 (η 2 ‐C 2 H 4 )] as a platinum(0) source and isolated in 82 % yield. Strikingly, the results of DFT calculations in accordance with spectroscopic (EPR, paramagnetic NMR) and structural features of the complex revealed that the bonding situation of the S 2 ligand is between the elusive “half‐bonded” S 2 radical trianion ( ${{\rm S}{{{{\bullet}}3- \hfill \atop 2\hfill}}}$ ) and two separated S 2− ligands. Accordingly, the Ni II center is partially oxidized, whereas the Pt II site is redox innocent. The complex can be reversibly oxidized to the corresponding Ni,Pt‐disulfido monocation, compound 3 , with a SS single bond, and reacts readily with O 2 to form the corresponding superoxonickel(II) and disulfidoplatinum(II) ( 4 ) complexes. These compounds have been isolated in crystalline form and fully characterized, including IR and multi‐nuclear NMR spectroscopy as well as ESI mass spectrometry. The molecular structures of compounds 2 – 4 have been confirmed by single‐crystal X‐ray crystallography.