Iron and Chromium Complexes Containing Tridentate Chelates Based on Nacnac and Imino- and Methyl-Pyridine Components: Triggering C鈥擷 Bond Formation

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• 作者：Wesley D. Morris ; Peter T. Wolczanski ; J枚rg Sutter ; Karsten Meyer ; Thomas R. Cundari ; Emil B. Lobkovsky
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：July 21, 2014
• 年：2014
• 卷：53
• 期：14
• 页码：7467-7484
• 全文大小：1033K
• ISSN：1520-510X

文摘

Nacnac-based tridentate ligands containing a pyridyl-methyl and a 2,6-dialkyl-phenylamine (i.e., (2,6-R₂-C₆H₃N鈺怌(Me)CH鈺怌(Me)NH(CH₂py); R = Et, {Et(nn)PM}H; R = ⁱPr, {ⁱPr(nn)PM}H) were synthesized by condensation routes. Treatment of M{N(TMS)₂}THF_n (M = Cr, n = 2; M = Fe, Co, n = 1; TMS = trimethylsilane; THF = tetrahydrofuran) with {ⁱPr(nn)PM}H) afforded {ⁱPr(nn)PM}MN(TMS)₂ (1-M^iPr; M = Cr, Fe); {Et(nn)PM}MN(TMS)₂ (1-M^Et; M = Fe, Co) was similarly obtained. {R(nn)PM}FeBr (R = ⁱPr, Et; 2-Fe^R) were prepared from FeBr₂ and {R(nn)PM}Li, and alkylated to generate {R(nn)PM}Fe^neoPe (R = ⁱPr, Et; 3-Fe^R). Carbonylation of 3-Fe^R provided {ⁱPr(nn)PM}Fe(CO^neoPe)CO (4-Fe^iPr), and carbonylations of 1-Fe^R (R = Et, ⁱPr) and 1-Cr^iPr induced deamination to afford {R(nn)PI}Fe(CO)₂ (R = ⁱPr, 5-Fe^iPr; Et, 5-Fe^Et), where PI is pyridine-imine, and {魏²-N,N-pyrim-pyr}Cr(CO)₄ (6-Cr^iPr), in which the aryl-amide side of the nacnac attacked the incipient PI group. Carbon鈥揷arbon bonds were formed at the imine carbon of the {R(nn)PI} ligand. Addition of [{ⁱPr(nn)PI}^{2鈥?/sup>](K+(THF)_x)₂ to FeCl₃ generated {iPr(nn)CHpy}₂Fe₂Cl₂ (7-FeiPr), and TMSN₃ induced the deamination of 1-FeEt, but with disproportionation to provide {[Et(nn)CHpy]₂}Fe (8-FeEt). Ph₂CN₂ induced C鈥揅 bond formation with 1-FeiPr via its thermal degradation to ultimately afford {iPr(nn)CHpy}₂(FeN鈺怌Ph₂)₂ (9-FeiPr). The compounds were examined by X-ray crystallography (1-MiPr, M = Cr, Fe; 1-CoEt; 2-FeiPr; 4-FeiPr; 5-FeiPr; 6-CriPr; 7-FeiPr; 8-FeEt; 9-FeiPr), M枚ssbauer spectroscopy, and NMR spectroscopy. Structural parameters assessing redox noninnocence are discussed, as are structural and mechanistic consequences of the various electronic environments.}