κ2-N,N'-Sulfurdiimide and κ1-O-Sulfinylamine Complexes of Tin(IV) Chloride.

A series of Sn(IV) chloride complexes with sulfur diimide (SDI, R-NSN-R) ligands are presented, including structural characterization of first-in-class complexes of bidentate diaryl-SDIs, [SnCl₄{κ²-N,N'-S(NAr)₂}] (Ar = 4-X-C₆H₄-), and an oxygen-coordinated sulfinylamine, [SnCl₄{κ¹-O-OSNPh}₂]. As part of the comprehensive experimental and DFT computational investigation, ¹¹⁹Sn NMR analysis revealed a dynamic exchange equilibrium in acetonitrile between SDI ligands and solvent, providing insight into their complicated solution-state chemical and electrochemical behavior. Voltammetric experiments show that, despite this dynamic equilibrium, the SDI ligands appear to suppress typical Sn(IV) reduction pathways. While tentative due to the complex behavior, this suggests that SDIs are functioning as redox-active (RA) ligands. In conjunction with our previous systematic characterization of diaryl-SDIs, these findings highlight their potential as an easily derivatized and highly redox-tunable category of RA ligand and emphatically warrant further investigation.