Rummelt Stephan M, Darmon Jonathan M, Yu Renyuan Pony, Viereck Peter, Pabst Tyler P, Turner Zoë R, Margulieux Grant W, Gu Shunlin, Chirik Paul J
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Organometallics. 2019 Aug 26;38(16):3159-3168. doi: 10.1021/acs.organomet.9b00382. Epub 2019 Aug 9.
Two methods for the synthesis of bis(imidazol-2-ylidene)pyridine iron dialkyl complexes, (CNC)Fe(CHSiMe), have been developed. The first route consists of addition of two equivalents of LiCHSiMe to the iron dihalide complex, (CNC)FeBr, while the second relies on addition of the free CNC ligand to readily-prepared (py)Fe(CHSiMe) (py = pyridine). With aryl-substituted CNC ligands, octahedral complexes of the type ( CNC)Fe(CHSiMe)(N) ( CNC = bis(arylimidazol-2-ylidene)pyridine) were isolated, where the dinitrogen ligand occupies the site to the pyridine of the CNC-chelate. In contrast, the alkyl-substituted variant, (ACNC)Fe(CHSiMe) (ACNC = 2,6-(Bu-imidazol-2-ylidene)pyridine) was isolated as the five-coordinate compound lacking dinitrogen. Exposure of the ( CNC)Fe(CHSiMe)(N) derivatives to an H atmosphere resulted in formation of the corresponding iron hydride complexes ( CNC)FeH. These compounds catalyzed hydrogen isotope exchange between the deuterated benzene solvent and H, generating isotopologues and isotopomers of ( CNC)Fe(H )(D ) ( = 0-4). When (3,5-Me CNC)Fe(CHSiMe)(N) (3,5-Me CNC = 2,6-(2,4,6-Me-C6H2-imidazol-2-ylidene)-3,5-Me-pyridine) was treated successively with H and then N, the corresponding reduced dinitrogen complex (3,5-Me CNC)Fe(N) was isolated. The same product was also obtained following addition of pinacolborane to (3,5-Me CNC)Fe(CHSiMe)(N).
已开发出两种合成双（咪唑-2-亚基）吡啶铁二烷基配合物（CNC）Fe（CHSiMe）的方法。第一条路线是将两当量的LiCHSiMe加入到二卤化铁配合物（CNC）FeBr中，而第二条路线则是将游离的CNC配体加入到易于制备的（py）Fe（CHSiMe）（py =吡啶）中。对于芳基取代的CNC配体，分离出了（ CNC）Fe（CHSiMe）（N）类型的八面体配合物（ CNC =双（芳基咪唑-2-亚基）吡啶），其中二氮配体占据了CNC螯合物中吡啶的 位。相比之下，烷基取代的变体（ACNC）Fe（CHSiMe）（ACNC = 2,6-（Bu-咪唑-2-亚基）吡啶）被分离为缺少二氮的五配位化合物。将（ CNC）Fe（CHSiMe）（N）衍生物暴露于H气氛中会导致形成相应的氢化铁配合物（ CNC）FeH。这些化合物催化氘代苯溶剂与H之间的氢同位素交换，生成（ CNC）Fe（H ）（D ）（ = 0-4）的同位素异构体和同位素变体。当（3,5-Me CNC）Fe（CHSiMe）（N）（3,5-Me CNC = 2,6-（2,4,6-Me-C6H2-咪唑-2-亚基）-3,5-Me-吡啶）先后用H然后用N处理时，分离出相应的还原二氮配合物（3,5-Me CNC）Fe（N）。在向（3,5-Me CNC）Fe（CHSiMe）（N）中加入频哪醇硼烷后也得到了相同的产物。
