75-10-5 Infrared Multiphoton Dissociation of Pentafluoroethane: Two-Channel Dissociation Process and Secondary Photolysis of Radical Products

The dissociation yield and branching ratio in CO2 laser-induced multiphoton dissociation (MPD) of C2HF5 were investigated.In order to distinguish the two primary dissociation pathways (C2HF5 -> C2F4 + HF, Ea=71.6 kcal/mol; C2HF5 -> CF3 + CHF2, Ea=93.5 kcal/mol), Br2 was employed as an excellent scavenger of radicals and C2F4.The scavenged products were CBrF3, CHBrF2, CBr2F2, and C2Br2F4.The yield of C2Br2F4 originating from HF elimination was much smaller than those of CBrF3 and CHBrF2 from C-C bond rupture.The pulse energy dependence of the product distribution demonstrates that the primarily produced radicals were further photolyzed within the laser pulse (CF3 + nhν -> CF2 + F, and CHF2 + n'hν -> CF2 + H) to yield CBr2F2.The secondary photolysis of the radicals was also confirmed by real-time monitoring of infrared emission from HF* and DF* generated in the MPD of C2DF5 in the presence of H2 as an F atom scavenger.In the MPD of neat C2HF5, the formation of C2F4 was unexpectedly enhanced with increasing pulse energy; this was explained by assuming that C2F4 was mainly formed via recombination of CF2 radicals originating from the secondary photolysis of primarily produced radicals. https://www.lookchem.com/CASDataBase_75-10-5.htm

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726-18-1 Electrophilic alkylations in neutral aqueous or alcoholic solutions

Acid-free Friedel-Crafts chemistry: A paradox? Nucleophilicity scales, based on reactions with benzhydrylium ions, show that many π systems are more nucleophilic than aqueous or alcoholic solutions that are generally employed as solvents for S N 1 reactions. Solvolytically generated carbocations can, therefore, be trapped by donor-substituted arenes and alkenes to form products of Friedel-Crafts-type reactions in neutral aqueous solutions (see scheme). https://www.lookchem.com/CASDataBase_726-18-1.htm
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102-82-9 Selective Synthesis of Secondary and Tertiary Amines by Reductive N-Alkylation of Nitriles and N-Alkylation of Amines and Ammonium Formate Catalyzed by Ruthenium Complex

A new ruthenium catalytic system for the syntheses of secondary and tertiary amines via reductive N-alkylation of nitriles and N-alkylation of primary amines is proposed. Isomeric complexes 8 catalyze transfer hydrogenation and N-alkylation of nitriles in ethanol to give secondary amines. Unsymmetrical secondary amines can be produced by N-alkylation of primary amines with alcohols via the borrowing hydrogen methodology. Aliphatic amines were obtained with excellent yields, while only moderate conversions were observed for anilines. Based on kinetic and mechanistic studies, it is suggested that the rate determining step is the hydrogenation of intermediate imine to amine. Finally, ammonium formate was applied as the amination reagent for alcohols in the presence of ruthenium catalyst 8. Secondary amines were obtained from primary alcohols within 24 hours at 100 °C, and tertiary amines can be produced after prolonged heating. Secondary alcohols can only be converted to secondary amines
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1023-17-2 Syntheses, structures, and catalytic activity in Friedel–Crafts acylations of substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes

Reactions of the substituted tetramethylcyclopentadienes [C 5 HMe 4 R] [R?=? t Bu, Ph, CH 2 CH 2 C(CH 3 ) 3 ] with Mo(CO) 3 (CH 3 CN) 3 in refluxing xylene gave a series of dinuclear molybdenum carbonyl complexes [(η 5 -C 5 Me 4 R)Mo(CO) 3 ] 2 [R?=? t Bu (1), Ph (2), CH 2 CH 2 C(CH 3 ) 3 (3)], [(η 5 -C 5 Me t Bu)Mo(μ-CO) 2 ] 2 (4)], and [(η 5 -C 5 Me 4 ) t Bu] 2 Mo 2 O 4 (μ-O) (5)], respectively. Complexes 1–5 were characterized by elemental analysis, IR, 1 H NMR, and 13 C NMR spectroscopy. In addition, their crystal structures were determined by X-ray crystal diffraction analysis. The catalytic activities of complexes 1–3 in Friedel–Crafts acylation in the presence of o-chloranil has also been investigated; the reactions were achieved under mild conditions to give the corresponding products in moderate yields. https://www.lookchem.com/CASDataBase_1023-17-2.htm
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