76-83-5Relevant articles and documents
-
Halford
, p. 105,110 (1931)
-
Red and green chemiluminescence of Na, Mg, and lanthanide triphenylmethyl derivatives during oxidation by dioxygen and cerium(IV)
Bulgakov,Kuleshov,Valiullina,Mustafin
, p. 1091 - 1094 (1999)
Chemiluminescence (CL) of triphenylmethyl organometallics (TPM), Ph3CNa, Ph3CMgCl, and Ph3CLnCl2 (Ln = Cd, Eu, and Dy), in THF and toluene during oxidation by O2 and the (NH4)2Ce(NO3)6 complex was found. The first CL is caused by the luminescence of two emitters: (Ph3C.)*, emitting in the green spectral region (λmax = 524, 550 nm), and an unstable product of substitution of the hydrogen atom in the phenyl ring of the Ph3C. radical, emitting in the red region (λmax = 580±20 nm). The emitter of the second CL, Ph3C. *, is generated in the elementary electron transfer from the Ph3C- anion to CeIV, reducing the latter to CeIII.
Halogen Transfer to Carbon Radicals by High-Valent Iron Chloride and Iron Fluoride Corroles
Farley, Geoffrey W.,Siegler, Maxime A.,Goldberg, David P.
, p. 17288 - 17302 (2021/11/17)
High-valent iron halide corroles were examined to determine their reactivity with carbon radicals and their ability to undergo radical rebound-like processes. Beginning with Fe(Cl)(ttppc) (1) (ttppc = 5,10,15-tris(2,4,6-triphenylphenyl)corrolato3-), the new iron corroles Fe(OTf)(ttppc) (2), Fe(OTf)(ttppc)(AgOTf) (3), and Fe(F)(ttppc) (4) were synthesized. Complexes 3 and 4 are the first iron triflate and iron fluoride corroles to be structurally characterized by single crystal X-ray diffraction. The structure of 3 reveals an AgI-pyrrole (η2-π) interaction. The Fe(Cl)(ttppc) and Fe(F)(ttppc) complexes undergo halogen transfer to triarylmethyl radicals, and kinetic analysis of the reaction between (p-OMe-C6H4)3C?and 1 gave k = 1.34(3) × 103 M-1 s-1 at 23 °C and 2.2(2) M-1 s-1 at -60 °C, ΔHL = +9.8(3) kcal mol-1, and ΔSL = -14(1) cal mol-1 K-1 through an Eyring analysis. Complex 4 is significantly more reactive, giving k = 1.16(6) × 105 M-1 s-1 at 23 °C. The data point to a concerted mechanism and show the trend X = F- > Cl- > OH- for Fe(X)(ttppc). This study provides mechanistic insights into halogen rebound for an iron porphyrinoid complex.
C(sp3)-H Fluorination with a Copper(II)/(III) Redox Couple
Bower, Jamey K.,Cypcar, Andrew D.,Henriquez, Brenda,Stieber, S. Chantal E.,Zhang, Shiyu
supporting information, p. 8514 - 8521 (2020/05/28)
Despite the growing interest in the synthesis of fluorinated organic compounds, few reactions are able to incorporate fluoride ions directly into alkyl C-H bonds. Here, we report the C(sp3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogues, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized with single-crystal X-ray diffraction, X-ray absorption spectroscopy, UV-vis spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Quantum chemical calculations reveal significant halide radical character for all complexes, suggesting their ability to initiate and terminate a C(sp3)-H halogenation sequence by sequential hydrogen atom abstraction (HAA) and radical capture. The capability of HAA by the formally copper(III) halide complexes was explored with 9,10-dihydroanthracene, revealing that LCuF exhibits rates 2 orders of magnitude higher than LCuCl and LCuBr. In contrast, all three complexes efficiently capture carbon radicals to afford C(sp3)-halogen bonds. Mechanistic investigation of radical capture with a triphenylmethyl radical revealed that LCuF proceeds through a concerted mechanism, while LCuCl and LCuBr follow a stepwise electron transfer-halide transfer pathway. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.
