Carbon−Fluorine Bond Cleavages and Organoiron Ring Transformations: Reaction of a Perfluorosulfanylvinyldiiron(I) Complex with Amines

The reaction of the perfluorosulfanylvinyldiiron(I) complex [{Fe(CO)3}2{μ-C(SMe)(CF3)Cβ(CαF2)}] (1) with secondary mono- and diamines (L = Me2NH, (CH2)4NH, HN(CH2)4NH)
in a 1:1 ratio in dichloromethane at room temperature led in a multistep reaction to the
new monoaminocycloferrathiapentadiene compounds [{Fe(CO)3}2{μ-S(Me)C(CF3)CFCX}] (Χ
= NMe2 (2), N(CH2)4 (3), N(CH2)4NH (4)) and [[{Fe(CO)3}2{μ-S(Me)C(CF3)CFC]2{μ-N(CH2)4N}] (5). However, when the reaction of 1 was conducted in THF with a large excess
of amine, the diaminocycloferrathiabutene complexes [{Fe(CO)3}2{μ-S(Me)C(CF3)C(CX2)}]
(X = NMe2 (6), N(CH2)4 (7)) and [{Fe(CO)3}2{μ-S(Me)C(CF3)C(CX)}] (X = MeN(CH2)2NMe
(8), HN(CH2)2 NH (9)) were formed. It is suggested that these compounds form via initial
nucleophilic attack at Cα to give the common zwitterionic intermediate [{Fe(CO)3}2{μ-S(Me)C(CF3)C(CFNX2)] (C). Thermally induced C−F bond activation is a feature of these reactions.
Thermolysis of diaminocycloferrathiabutene compounds (6−9) in tetrahydrofuran gave the
amidinium-substituted μ∥-alkyne derivatives [{Fe(CO)3}2(μ-SMe){μ-(CF3)CC(CX2)}] (X =
NMe2 (10), N(CH2)4 (11)) and [{Fe(CO)3}2(μ-SMe){μ-(CF3)CC(CX)}] (X = MeN(CH2)2 NMe
(12), NH(CH2)2NH (13)), in quantitative yields via C−S bond scission. The molecular
structures of 6, 8, and 10 have been established by X-ray diffraction studies.