메뉴 건너뛰기




Volumn 127, Issue 21, 2005, Pages 7857-7870

Synthesis and reactivity of low-coordinate iron(II) fluoride complexes and their use in the catalytic hydrodefluorination of fluorocarbons

Author keywords

[No Author keywords available]

Indexed keywords

ACTIVATION ENERGY; ADDITION REACTIONS; CATALYSIS; CATALYSTS; COMPLEXATION; CRYSTALLOGRAPHY; FLUOROCARBONS; OXIDATION; REACTION KINETICS; SYNTHESIS (CHEMICAL);

EID: 19744376115     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja042672l     Document Type: Article
Times cited : (293)

References (138)
  • 7
    • 0034665598 scopus 로고    scopus 로고
    • Representative examples of intramolecular C-F activation: (a) Richmond, T. G. Angew. Chem., Int. Ed. 2000, 39, 3241-3244.
    • (2000) Angew. Chem., Int. Ed. , vol.39 , pp. 3241-3244
    • Richmond, T.G.1
  • 30
    • 19744366693 scopus 로고    scopus 로고
    • (a) Jones, W. D. Dalton 2003, 3991-3995.
    • (2003) Dalton , pp. 3991-3995
    • Jones, W.D.1
  • 35
    • 0000721702 scopus 로고    scopus 로고
    • Metal reagents for activation and functionalization of carbon-fluorine bonds
    • Murai, S., Ed.; Springer: Berlin
    • (f) Richmond, T. G. Metal Reagents for Activation and Functionalization of Carbon-Fluorine Bonds. In Activation of Unreactive Bonds in Organic Synthesis; Murai, S., Ed.; Springer: Berlin, 1999; pp 243-269.
    • (1999) Activation of Unreactive Bonds in Organic Synthesis , pp. 243-269
    • Richmond, T.G.1
  • 48
    • 0027997310 scopus 로고
    • Homogeneous catalytic C-F activation with transition metal complexes: (a) Aizenberg, M.; Milstein, D. Science 1994, 265, 359-361.
    • (1994) Science , vol.265 , pp. 359-361
    • Aizenberg, M.1    Milstein, D.2
  • 54
    • 0033533949 scopus 로고    scopus 로고
    • Catalytic C-F activation through cross-metathesis reactions: (a) Widdowson, D. A.; Wilhelm, R. Chem. Commun. 1999, 2211-2212.
    • (1999) Chem. Commun. , pp. 2211-2212
    • Widdowson, D.A.1    Wilhelm, R.2
  • 71
    • 0001752768 scopus 로고    scopus 로고
    • Cambridge Structural Database. ConQuest version 1.7, November 2004 release. (a) Allen, F. H. Acta Crystallogr. 2002, B58, 380-388.
    • (2002) Acta Crystallogr. , vol.B58 , pp. 380-388
    • Allen, F.H.1
  • 82
    • 19744370180 scopus 로고    scopus 로고
    • note
    • An alternative assignment is a halide-to-metal LMCT.
  • 90
    • 0001607410 scopus 로고    scopus 로고
    • (f) Gu, X. Organometallics 1998, 17, 5920-5923.
    • (1998) Organometallics , vol.17 , pp. 5920-5923
    • Gu, X.1
  • 91
    • 0000714026 scopus 로고    scopus 로고
    • (a) Poli, R. Chem. Rev. 1996, 96, 2135-2204.
    • (1996) Chem. Rev. , vol.96 , pp. 2135-2204
    • Poli, R.1
  • 100
    • 19744369577 scopus 로고    scopus 로고
    • note
    • In the absence of iron fluoride or hydride there was no sign of reaction (= 1%) between any of the substrates and trisubstituted silanes.
  • 106
    • 19744362019 scopus 로고    scopus 로고
    • note
    • The HDF reaction does not take place in more polar solvents such as DMF or HMPA. This may be due to reaction between the iron(II) hydride complex and these solvents.
  • 109
    • 19744375162 scopus 로고    scopus 로고
    • note
    • Another possibility is that the active species is a silyl complex. Unfortunately, our several attempts to isolate a diketiminate iron(II) silyl complex independently have so far failed. The intermediacy of silyl cations (cf. ref 13) or silyl radicals is inconsistent with the regioselectivity of C-F activation and with the first-order dependence of the initial rate on iron concentration.
  • 110
    • 19744378711 scopus 로고    scopus 로고
    • note
    • 3CH, 0.47 molar equiv) is used as the radical trap (48% conversion under the same conditions).
  • 111
    • 19744377723 scopus 로고    scopus 로고
    • note
    • 18a
  • 115
    • 19744370965 scopus 로고    scopus 로고
    • note
    • 2-complexes of perfluoronaphthalene and perfluoropyridine (see ref 7b). In these nickel systems, C-F activation of perfluoropyridine occurred at C2 rather than at C4 as observed in the iron-catalyzed process demonstrated here. In our system, electronic absorption spectra show no substantial coordination of perfluorocarbons to the iron(II) diketiminate complex (see text and Figure 4).
  • 116
    • 19744365964 scopus 로고    scopus 로고
    • note
    • 41
  • 120
    • 19744375777 scopus 로고    scopus 로고
    • note
    • There is a large disparity between the ability of perfluoroarenes to be reduced in the gas and solution phases. For example, the gas phase electron affinities of hexafluorobenzene and octafluorotoluene are favorable with values of 0.52(1) and 0.94(1) eV, respectively, but both have highly negative irreversible reduction potentials in THF solution (-3.0 and -2.95 V vs ferrocene; see refs 48 and 4b). In our mechanistic analysis, we use the solution values and assume that the overpotentials are not excessive (more than a few hundred millivolts).
  • 121
    • 19744364055 scopus 로고    scopus 로고
    • note
    • A similar hydride insertion/β-fluoride elimination mechanism is unlikely to operate in the HDF of perfluoroarenes. Such a mechanism would involve breaking the aromaticity of the substrate and therefore is expected to increase the activation barrier relative to olefinic C-F activation. This is inconsistent with HDF of perfluoroarenes occurring at lower temperatures than for olefinic substrates.
  • 122
    • 19744380318 scopus 로고    scopus 로고
    • note
    • 2 does not react with 1-hexene: we conclude that hydride formation must occur before catalysis proceeds.
  • 137
    • 84977289324 scopus 로고
    • The SADABS program is based on the method of Blessing; see Blessing, R. H. Acta Crystallogr. A 1995, 51, 33-38.
    • (1995) Acta Crystallogr. A , vol.51 , pp. 33-38
    • Blessing, R.H.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.