Department of Chemistry and Biochemistry, The University of Texas at Arlington , Arlington, Texas 76019, United States.
Department of Chemistry, Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas , Denton, Texas 76203, United States.
J Am Chem Soc. 2017 Oct 11;139(40):14292-14301. doi: 10.1021/jacs.7b08595. Epub 2017 Sep 28.
Iron(0) pentacarbonyl is an organometallic compound with a long history. It undergoes carbonyl displacement chemistry with various donors (L), leading to molecules of the type Fe(CO)(L). The work reported here illustrates that Fe(CO) can also act as a ligand. The reaction between Fe(CO) with the silver salts AgSbF and Ag[B{3,5-(CF)CH}] under appropriate conditions resulted in the formation of [(μ-HO)AgFe(CO)][SbF] and [B{3,5-(CF)CH}]AgFe(CO), respectively, featuring heterobimetallic {Ag-Fe(CO)} fragments. The treatment of [B{3,5-(CF)CH}]AgFe(CO) with 4,4'-dimethyl-2,2'-bipyridine (MeBipy) and Fe(CO) afforded a heterobimetallic [(MeBipy)AgFe(CO)][B{3,5-(CF)CH}] species with a Ag-Fe(CO) bond and a heterotrimetallic [{Fe(CO)}(μ-Ag)][B{3,5-(CF)CH}] with a (CO)Fe-Ag-Fe(CO) core, respectively, illustrating that it is possible to manipulate the coordination sphere at silver while keeping the Ag-Fe bond intact. The chemistry of [B{3,5-(CF)CH}]AgFe(CO) with EtO and PMes (Mes = 2,4,6-trimethylphenyl) has also been investigated, which led to [(EtO)Ag][B{3,5-(CF)CH}] and [(MesP)Ag][B{3,5-(CF)CH}] with the displacement of the Fe(CO) ligand. X-ray structural and spectroscopic data of new molecules as well as results of computational analyses are presented. The Fe-Ag bond distances of these metal-only Lewis pairs range from 2.5833(4) to 2.6219(5) Å. These Ag-Fe bonds are of primarily an ionic/electrostatic nature with a modest amount of charge transfer between Ag and Fe(CO). The ν̅(CO) bands of the molecules with Ag-Fe(CO) bonds show a notable blue shift relative to those observed for free Fe(CO), indicating a significant reduction in Fe→CO back-bonding upon its coordination to silver(I).
五羰基合铁是一种具有悠久历史的有机金属化合物。它与各种给体（L）经历羰基取代化学，生成 Fe(CO)(L)型分子。这里报道的工作表明，Fe(CO)也可以作为配体。在适当的条件下，Fe(CO)与银盐 AgSbF 和 Ag[B{3,5-(CF)CH}]反应，分别生成 [(μ-HO)AgFe(CO)][SbF] 和 [B{3,5-(CF)CH}]AgFe(CO)，它们都具有异双核 {Ag-Fe(CO)} 片段。用 4,4'-二甲基-2,2'-联吡啶（MeBipy）和 Fe(CO)处理 [B{3,5-(CF)CH}]AgFe(CO)，得到具有 Ag-Fe(CO)键的异双核 [(MeBipy)AgFe(CO)][B{3,5-(CF)CH}]物种和具有 (CO)Fe-Ag-Fe(CO)核的杂三核 [{Fe(CO)}(μ-Ag)][B{3,5-(CF)CH}]，分别说明有可能在保持 Ag-Fe 键完整的情况下操纵银的配位场。还研究了 [B{3,5-(CF)CH}]AgFe(CO)与 EtO 和 PMes（Mes = 2,4,6-三甲基苯基）的化学性质，导致 Fe(CO)配体被取代，生成 [(EtO)Ag][B{3,5-(CF)CH}]和 [(MesP)Ag][B{3,5-(CF)CH}]。给出了新分子的 X 射线结构和光谱数据以及计算分析的结果。这些金属单路易斯对的 Fe-Ag 键距离范围为 2.5833(4)至 2.6219(5) Å。这些 Ag-Fe 键主要具有离子/静电性质，在 Ag 和 Fe(CO) 之间有少量电荷转移。具有 Ag-Fe(CO)键的分子的 ν̅(CO) 带与游离 Fe(CO)相比有明显的蓝移，表明其配位到银（I）后，Fe→CO 反键作用显著降低。
