2116-62-3Relevant articles and documents
Photochemistry of chromium arene tricarbonyl complexes with tethered pyridinyl and propenyl groups: Investigations of the effect of ring size on chelate formation, structure, and linkage isomerization
Duke, Charles B.,Letterman, Roger G.,Johnson, Jermaine O.,Barr, James W.,Hu, Songnan,Ross, Charles R.,Webster, Charles Edwin,Burkey, Theodore J.
, p. 485 - 497 (2014)
Chromium arene tricarbonyl complexes with tethered pyridinyl groups [Cr{η6-C6H5(CH2) n(2-Py)}(CO)3] (4-6) (2-Py = 2-pyridinyl, n = 1-3, respectively) were synthesized and irradiated to form the chelates [Cr{η6-C6H5(CH2) n(2-Py)-κN}(CO)2] (7-9). Studies examined the effect of ring size and structure on chromophore λmax, stability, and photosensitivity, which are factors important for photochromes based on linkage isomerization of tethered functional groups. The studies also include [Cr{η6-C6H5CH(2-Py)CH2CH=CH 2}(CO)3] (3), which has a bifunctional tether of propenyl and pyridinyl groups, and irradiation produces the linkage isomers [Cr{η6-C6H5(CH(2-Py)CH2CH= CH2)-κN}(CO)2] (1) and [Cr{η6-C 6H5(CH(2-Py)CH2CH=CH2) (η2-CH=CH2)}(CO)2] (2). X-ray crystal structures for 7-9 show that the dihedral angle between the coordinated pyridinyl groups and the phenyl-chromium centroid increases from 1 to 73 (n = 1-3, respectively). The experimental and TDDFT computed optical changes accompanying an increase in the dihedral angle are modest and not monotonic for 7-9 due to structural changes inherent in the chelate rings. An increase in Cr-N bond lengths and decrease in their bond energies were observed experimentally and computationally for the series of 7-9. The quantum yields for formation of the five-, six-, and seven-membered chelate rings during the conversion of 4-6 to 7-9, respectively, were within experimental error for that observed for conversion of 10 [Cr{η6-C6H6}(CO) 3] with free pyridine to 11 [Cr{η6-C6H 6}(C5H5N-κN)(CO)2], indicating that the product-determining step precedes chelation. The enthalpies for chelation of 4-6 to 7-9 were determined independently by photoacoustic calorimetry and DFT computations. The computationally derived mechanism for thermal isomerization of 1 to 2 indicates that the transition state is a dissociative interchange with a free energy of activation of 27.9 kcal mol -1 (1 → 2), a result consistent with an experimentally bistable photochrome. The results indicate which tether properties are important for optimizing photochrome performance.
An improved method for aromatic hydroxylation with heteroaromatic oxides
Serra-Errante, Guido,Sammes, Peter G.
, p. 573 - 574 (1975)
Photolysis of the boron trifluoride complex of pyridine-N-oxide in benzene gives a higher yield of phenol than photolysis of pyridine-N-oxide alone; with some intramolecular models, intramolecular hydroxylation can be achieved.
Reduction of Electron-Deficient Alkenes Enabled by a Photoinduced Hydrogen Atom Transfer
Larionova, Natalia A.,Ondozabal, Jun Miyatake,Cambeiro, Xacobe C.
supporting information, p. 558 - 564 (2020/12/07)
Direct hydrogen atom transfer from a photoredox-generated Hantzsch ester radical cation to electron-deficient alkenes has enabled the development of an efficient formal hydrogenation under mild, operationally simple conditions. The HAT-driven mechanism is supported by experimental and computational studies. The reaction is applied to a variety of cinnamate derivatives and related structures, irrespective of the presence of electron-donating or electron-withdrawing substituents in the aromatic ring and with good functional group compatibility. (Figure presented.).
Compound containing carbon-silicon bond and application thereof
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Paragraph 0402-0405, (2020/09/08)
The invention discloses a compound containing a carbon-silicon bond and application of the compound in construction of the carbon-carbon bond. The invention provides an application of a compound containing the carbon-silicon bond as shown in a formula I or a formula I' in a chemical reaction for constructing the carbon-carbon bond, wherein one carbon in the carbon-carbon bond is from carbon connected with silicon in the compound containing the carbon-silicon bond. According to the preparation method, the compound containing the carbon-silicon bond is used for providing a carbon free radical, and the carbon free radical can directly react with carbon provided in another molecule under a mild condition to construct the carbon-carbon bond; the preparation method is wider in substrate application range, is suitable for functional group activated C and carbon free radical substrates, and is also suitable for unactivated C-H bond substrates.
Iron-catalysed alkylation of 2-methyl and 4-methyl azaarenes with alcoholsviaC-H bond activation
Banerjee, Debasis,Bera, Sourajit,Kabadwal, Lalit Mohan
supporting information, p. 4777 - 4780 (2020/05/13)
The first Fe-catalysed alkylation of 2-methyl and 4-methyl-azaarenes with a series of alkyl and hetero-aryl alcohols is reported (>39 examples and up to 95% yield). Multi-functionalisation of pyrazines and synthesis of anti-malarial drug (±) Angustureine significantly broaden the scope of this methodology. Preliminary mechanistic investigation, deuterium labeling and kinetic experiments including trapping of the enamine intermediate1a'are of special importance.
