Carbene-carbanion equilibrium for tris(2-pyridylthio)methanido Fe(II) complexes.
A reaction of FeCl(2) with tris(2-pyridylthio)methane (tptmH) produced the carbanion complex [Fe(tptm)(CH(3)CN)(2)](FeCl(4)){(C(2)H(5))(3)NH}. When FeI(2) was used instead of FeCl(2), the carbene complex [FeI(pyt)(bptmd)] (pyt = 2-pyridinethiolate, bptmd = bis(2-pyridylthio)methylidene) was isolated. The carbene forms [FeX(pyt)(bptmd)](n+) (n = 1 for X = CH(3)CN, n = 0 for X = I) were observed for [Fe(tptm)(CH(3)CN)(2)](FeCl(4)){(C(2)H(5))(3)NH} and [FeI(pyt)(bptmd)] in chloroform, whereas the carbene-carbanion equilibrium was observed in acetonitrile by NMR measurements. The thermodynamic parameters were evaluated by variable temperature (1)H NMR measurements using the diamagnetic salt [Fe(tptm)(CH(3)CN)(2)]PF(6) for [Fe(tptm)(CH(3)CN)(2)](+)⇆ [Fe(pyt)(bptmd)(CH(3)CN)](+) + CH(3)CN (ΔH = 23 kJ mol(-1), ΔS = 55 J mol(-1) K(-1)).
Kuwamura
Naoto
N
Department of Material Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan.
Kato
Ryo
R
Kitano
Ken'ichi
K
Hirotsu
Masakazu
M
Nishioka
Takanori
T
Hashimoto
Hideki
H
Kinoshita
Isamu
I