Electrophilic Attack on a Metal Alkynyl by Carbon Disulfide: Preparation and Structure of I*MeOH, a Cationic Vinylidene Complex

Article abstract of DOI:10.1021/ja00365a023

The electron-rich alkynyl complex (, I) undergoes (2 + 2) cycloaddition with carbon disulfide to form (II) containing a 2H-thiete-2-thione functional group.This CS2 adduct is subsequently alkylated by iodomethane to yield I*MeOH (III), a cationic vinylidene complex.The products were investigated by spectroscopic means and, in the case of III, by an X-ray crystal analysis: space P2₁/c, a = 11.625 (3) Angstroem, b = 20.609 (4) Angstroem, c = 15.490 ( 2) Angstroem, β = 103.25 (2) deg, V = 3612.4 Angstroem³, Z = 4, ρ(calcd) = 1.487 g*cm^-3.Refinement on 2552 reflections with F² 2) yielded the final discrepancy indices R = 0.058 and R_w = 0.070.The substituted vinylidene ligand of complex III is bounded to the iron atom by a very short Fe-C bond, 1,74 (2) Angstroem, and the Fe-Cl-C2 bond angle is nearly linear, 176 (1) deg.Spectroscopic and structural evidence suggest that 2-(dithiocarbomethoxy)propenylidene is very large strong ?-acid ligand.