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 center dot HTfO. The diprotonated salt 1 center dot(HTfO)(2) as the starting material can be also easily accessed by the deimination of iminosulfane(sulfane) carbon(0) (iSSC)center dot HBF4. Density functional theory calculations revealed the peculiar electronic structure of 1, which has 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-sulfurstabilized carbones clearly indicate the strong donor ability of carbon center stabilized by two S-II 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 Ag-I carbone complexes as carbone transfer agents are also reported.