Linear and T-Shaped Iron(I) Complexes Supported by N-Heterocyclic Carbene Ligands: Synthesis and Structure Characterization.
The use of the N-heterocyclic carbene (NHC) ligands 1,3-bis(2',6'-diethylphenyl)-4,5-(CH2)4-imidazol-2-ylidene (cyIDep), 1,3-bis(2',6'-diethylphenyl)-imidazolin-2-ylidene (sIDep), and its N-mesityl analogue sIMes enables the preparation of the two-coordinate homoleptic iron(I)-NHC complexes [(cyIDep)2Fe][BAr(F)4] (3, Ar(F) denoted for 3,5-di(trifluoromethyl)phenyl) and [(sIDep)2Fe][BAr(F)4] (4) and the T-shaped iron(I)-NHC complex [(sIMes)2Fe(THF)][BPh4] (5, THF = tetrahydrofuran). Complexes 3-5 were prepared via the sequential protocol of control reduction of iron(II) dihalides by KC8 in the presence of the corresponding NHC ligands followed by halide-abstraction with NaBAr4. Spectroscopic characterization, including single-crystal X-ray diffraction studies and (57)Fe Mössbauer spectroscopy, in combination with density functional theory calculations, suggest their high-spin nature. Solution property study (absorption spectroscopy and cyclic voltammetry) indicates that 3 and 5 keep their corresponding two- and three-coordinate nature in THF solution, and 4 might reversibly coordinate a THF molecule to form, presumably, the T-shaped species [(sIDep)2Fe(THF)][BAr(F)4]. The isolation of 3 and 4 demonstrates the accessibility of homoleptic two-coordinate iron(I)-NHC complexes.
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Zhenwu
Z
Ouyang
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Jingzhen
J
Du
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Lei
L
Wang
Department of Chemistry, University of Rochester , New York 14627, United States.
Jared L
JL
Kneebone
Department of Chemistry, University of Rochester , New York 14627, United States.
Michael L
ML
Neidig
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Liang
L
Deng
D006571:Heterocyclic Compounds / Q000737:chemistry*; D058085:Iron Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D008024:Ligands; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation
D006571:Heterocyclic Compounds; D058085:Iron Compounds; D008024:Ligands; C030011:carbene; D008697:Methane