Wannipurage Duleeka C, Yang Eric S, Chivington Austin D, Fletcher Jess, Ray Debanik, Yamamoto Nobuyuki, Pink Maren, Goicoechea Jose M, Smith Jeremy M
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
J Am Chem Soc. 2024 Oct 2;146(39):27173-27178. doi: 10.1021/jacs.4c10704. Epub 2024 Sep 17.
Despite their potential relevance as molecular models for industrial and biological catalysis, well-defined mononuclear iron carbide complexes are unknown, in part due to the limited number of appropriate C synthons. Here, we show the ability of the cyaphide anion (C≡P) to serve as a C source. The high spin ( = 2) cyaphide complex PhB(BuIm)Fe-C≡P (PhB(BuIm) = phenyl(tris(3--butylimidazol-2-ylidene)borate) is readily accessed using the new cyaphide transfer reagent [Mg(NacNac)(CP)] (NacNac = CH{C(CH)N(Dipp)} and Dipp = 2,6-di(iso-propyl)phenyl). Phosphorus atom abstraction is effected by the three-coordinate Mo(III) complex Mo(NBuAr) (Ar = 3,5-MeCH), which produces the known phosphide (BuArN)Mo≡P along with a transient iron carbide complex PhB(BuIm)Fe≡C. Electronic structure calculations reveal that PhB(BuIm)Fe≡C adopts a doublet ground state with nonzero spin density on the carbide ligand. While isolation of this complex is thwarted by rapid dimerization to afford the corresponding diiron ethynediyl complex, the carbide can be intercepted by styrene to provide an iron alkylidene.
尽管作为工业和生物催化的分子模型具有潜在相关性，但结构明确的单核碳化铁配合物却并不为人所知，部分原因是合适的碳合成子数量有限。在此，我们展示了氰磷化物阴离子（C≡P）作为碳源的能力。利用新型氰磷化物转移试剂[Mg(NacNac)(CP)]（NacNac = CH{C(CH)N(Dipp)}，Dipp = 2,6 - 二（异丙基）苯基），可轻松得到高自旋（S = 2）的氰磷化物配合物PhB(BuIm)Fe - C≡P（PhB(BuIm) = 苯基（三（3 - 叔丁基咪唑 - 2 - 亚基）硼酸酯）。通过三配位的Mo(III)配合物Mo(NBuAr)（Ar = 3,5 - MeCH）实现磷原子的夺取，生成已知的磷化物（BuArN）Mo≡P以及瞬态碳化铁配合物PhB(BuIm)Fe≡C。电子结构计算表明，PhB(BuIm)Fe≡C采用双重态基态，在碳化物配体上具有非零自旋密度。虽然该配合物因快速二聚生成相应的二铁乙炔二基配合物而无法分离，但碳化物可被苯乙烯捕获，生成铁亚烷基配合物。
