Synthesis, Electronic Structure, and Reactivities of Two‐Sulfur‐Stabilized Carbones Exhibiting Four‐Electron Donor Ability

Bis(sulfane)carbon(0) (BSC; Ph2S→C←SPh2 (1)) is successfully synthesized by deprotonation of the corresponding protonated salt 1·HTfO. The diprotonated salt 1·(HTfO)2 as the starting material can be also easily accessed by the deimination of iminosulfane(sulfane)carbon(0) (iSSC)·HBF4. Density functional theory calculations revealed the peculiar electronic structure of 1 having two lone pairs of electrons at the central carbon atom. The largest proton affinities (PA(1): 297.5 kcal mol−1; PA(2) 183.7 kcal mol−1) and the highest energy levels of the HOMOs (HOMO: −4.89 eV; HOMO−1: −5.02 eV) for 1 among the two-sulfur-stabilized carbones clearly indicate the strong donor ability of carbon center stabilized by two SII ligands. The donating ability of these lone pairs of electrons is demonstrated by the C-diaurated and C-proton-aurated complexes, which provide the first experimental evidence for two-sulfur-stabilized carbones behaving as four-electron donors. Furthermore, the syntheses and application of AgI carbone complexes as carbone transfer agents are also reported.