TY - JOUR
T1 - Synthesis, Structure, and Hydrogenolysis of Pyridine Dicarbene Iron Dialkyl Complexes
AU - Rummelt, Stephan M.
AU - Darmon, Jonathan M.
AU - Yu, Renyuan Pony
AU - Viereck, Peter
AU - Pabst, Tyler P.
AU - Turner, Zoë R.
AU - Margulieux, Grant W.
AU - Gu, Shunlin
AU - Chirik, Paul J.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/8/26
Y1 - 2019/8/26
N2 - Two methods for the synthesis of bis(imidazol-2-ylidene)pyridine iron dialkyl complexes, (CNC)Fe(CH2SiMe3)2, have been developed. The first route consists of addition of 2 equiv of LiCH2SiMe3 to the iron dihalide complex (CNC)FeBr2, while the second relies on addition of the free CNC ligand to the readily prepared (py)2Fe(CH2SiMe3)2 (py = pyridine). With aryl-substituted CNC ligands, octahedral complexes of the type (ArCNC)Fe(CH2SiMe3)2(N2) (ArCNC = bis(arylimidazol-2-ylidene)pyridine) were isolated, where the dinitrogen ligand occupies the site trans to the pyridine of the CNC chelate. In contrast, the alkyl-substituted variant (tBuACNC)Fe(CH2SiMe3)2 (tBuACNC = 2,6-(tBu-imidazol-2-ylidene)2pyridine) was isolated as the five-coordinate compound lacking dinitrogen. Exposure of the (ArCNC)Fe(CH2SiMe3)2(N2) derivatives to an H2 atmosphere resulted in formation of the corresponding iron hydride complexes (ArCNC)FeH4. These compounds catalyzed hydrogen isotope exchange between the deuterated benzene solvent and H2, generating isotopologues and isotopomers of (ArCNC)Fe(Hn)(D4-n) (n = 0-4). When (3,5-Me2 MesCNC)Fe(CH2SiMe3)2(N2) (3,5-Me2 MesCNC = 2,6-(2,4,6-Me3-C6H2-imidazol-2-ylidene)2-3,5-Me2-pyridine) was treated successively with H2 and then N2, the corresponding reduced dinitrogen complex (3,5-Me2 MesCNC)Fe(N2)2 was isolated. The same product was also obtained following addition of pinacolborane to (3,5-Me2 MesCNC)Fe(CH2SiMe3)2(N2).
AB - Two methods for the synthesis of bis(imidazol-2-ylidene)pyridine iron dialkyl complexes, (CNC)Fe(CH2SiMe3)2, have been developed. The first route consists of addition of 2 equiv of LiCH2SiMe3 to the iron dihalide complex (CNC)FeBr2, while the second relies on addition of the free CNC ligand to the readily prepared (py)2Fe(CH2SiMe3)2 (py = pyridine). With aryl-substituted CNC ligands, octahedral complexes of the type (ArCNC)Fe(CH2SiMe3)2(N2) (ArCNC = bis(arylimidazol-2-ylidene)pyridine) were isolated, where the dinitrogen ligand occupies the site trans to the pyridine of the CNC chelate. In contrast, the alkyl-substituted variant (tBuACNC)Fe(CH2SiMe3)2 (tBuACNC = 2,6-(tBu-imidazol-2-ylidene)2pyridine) was isolated as the five-coordinate compound lacking dinitrogen. Exposure of the (ArCNC)Fe(CH2SiMe3)2(N2) derivatives to an H2 atmosphere resulted in formation of the corresponding iron hydride complexes (ArCNC)FeH4. These compounds catalyzed hydrogen isotope exchange between the deuterated benzene solvent and H2, generating isotopologues and isotopomers of (ArCNC)Fe(Hn)(D4-n) (n = 0-4). When (3,5-Me2 MesCNC)Fe(CH2SiMe3)2(N2) (3,5-Me2 MesCNC = 2,6-(2,4,6-Me3-C6H2-imidazol-2-ylidene)2-3,5-Me2-pyridine) was treated successively with H2 and then N2, the corresponding reduced dinitrogen complex (3,5-Me2 MesCNC)Fe(N2)2 was isolated. The same product was also obtained following addition of pinacolborane to (3,5-Me2 MesCNC)Fe(CH2SiMe3)2(N2).
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U2 - 10.1021/acs.organomet.9b00382
DO - 10.1021/acs.organomet.9b00382
M3 - Article
C2 - 31481822
AN - SCOPUS:85071419494
SN - 0276-7333
VL - 38
SP - 3159
EP - 3168
JO - Organometallics
JF - Organometallics
IS - 16
ER -