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, 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-sulfur-stabilized 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-sulfurstabilized carbones behaving as four-electron donors. Furthermore, the syntheses and application of Ag^I carbone complexes as carbone transfer agents are also reported. [ABSTRACT FROM AUTHOR]