Journal of the American Chemical Society, Vol.118, No.17, 4133-4147, 1996
17-Electron and 19-Electron Complexes (Fe-III(Eta(5)-C(5)R(5))(S(2)Cnme(2))L)(N+) (N=1,0) - Electronic-Structure and Substitution and Redox Chemistry - Formation of (Fe-IV(Eta(5)-C(5)R(5))(Dtc)(2)) and Characterization of Both 17E and 19E States of a Transition-Metal Complex
Oxidation of [FeCp*(eta(1)-dtc)(CO)(2)], 1 (Cp* = eta(5)-C(5)Me(5), dtc = S(2)CNMe(2)), or [FeCp*(eta(2)-dtc)(CO)], 2, using [Fe(III)Cp(2)](+)X(-) (X(-) = PF6- or BF4-, Cp = eta(5)-C5H5) in THF cleanly gives [Fe(III)Cp*(eta(2)-dtc)(CO)](+)X(-), 2(+)X(-), as microcrystalline green, thermally stable, but substitution labile, salts. The substitution of CO in 2(+)PF(6)(-) by various solvents (CH2Cl2, THF, CH3COCH3, CH3CN) (visible spectroscopy) follows pseudo-first-order kinetics but shows clearly the influence of the incoming solvent ligand on the substitution rate and, hence, is in good agreement with an associative mechanism. Displacement of the labile solvent ligand in these complexes by a phosphine results in the 17-electron (17e) cations [Fe(III)Cp*(eta(2)-dtc)(L)](PF6-)-P-+, L = PPh(3) (7(+)PF(6)(-)) or eta(1)-dppe (8(+)PF(6)(-)). The same reaction in the presence of the anionic ligands CN-, SCN-, and Cl- affords the corresponding neutral 17e Fe-III complexes (respectively compounds 11, 13, and 14).
Keywords:CARBON-MONOXIDE SUBSTITUTION;IRON(III) METHYL COMPLEXES;R = H;LIGAND SUBSTITUTION;VANADIUM HEXACARBONYL;CATALYZED CHELATION;SANDWICH COMPOUNDS;CHAIN PROCESS;RADICALS;17-ELECTRON