Ligand versus Complex: C-F and C-H Bond Activation of Polyfluoroaromatics at a Cyclic (Alkyl)(Amino)Carbene was written by Paul, Ursula S. D.;Radius, Udo. And the article was included in Chemistry – A European Journal in 2017.Computed Properties of C5F5N The following contents are mentioned in the article:
C-F and C-H bond activation reactions of polyfluoroaroms. at the cyclic (alkyl)(amino)carbene (cAAC) cAACmethyl (1) are reported. Studies on the C-F bond activation using the cAAC-stabilized nickel(0) complex [Ni(cAACmethyl)2] (2) have shown that 2 does not react with fluorinated arenes. However, these investigations led to the observation of C-F bond cleavage of perfluorinated arenes by the carbene ligand cAACmethyl (1) itself. The reaction of 1 with C6F6, C6F5-C6F5, C6F5-CF3, and C5F5N afforded the insertion products of cAAC into one of the C-F bonds of the substrate, i.e., the C-F bond activation products (cAACmethyl)F(Arf) (Arf=C6F5 4 a, C6F4-C6F5 4 b, C6F4-CF3 4 c, C5F4N 4 d). These products decompose readily upon heating to 80 °C within a few hours in solution with formation of ionic iminium salts [(cAACmethyl)(Arf)][X] 6 a-d or neutral alkenyl perfluoroaryl imine compounds 7 a-d. The compounds (cAACmethyl)F(Arf) 4 a-d readily transfer fluoride, which has been exemplified by the fluoride transfer of all compounds using BF3 etherate as fluoride acceptor. Fluoride transfer has also been achieved starting from (cAACmethyl)F(C6F4-CF3) (4 c) or (cAACmethyl)F(C5F4N) (4 d) to other selected substrates such as trimethylchlorosilane, benzoyl chloride and tosyl chloride. Instead of C-F bond activation, insertion of the cAAC into the C-H bond was observed if 1 was treated with the partially fluorinated arenes C6F5H, 1,2,4,5-C6F4H2, 1,3,5-C6F3H3, and 1,3-C6F2H4. The compounds (cAACmethyl)H(Arf) (Arf=C6F5 12 e, 2,3,5,6-C6F4H 12 f, 2,4,6-C6F3H2 12 g and 2,6-C6F2H3 12 h) have been isolated in good yields and have been characterized including X-ray anal. Fluorobenzene C6FH5 (pKa ≈37), the least C-H acidic fluoroarene used in this study, does not react. In order to investigate the scope and limitations of this type of cAAC C-H bond activation reaction, cAACmethyl (1) was treated with several other reagents of different C-H acidity such as imidazolium salts, imidazoles, esters, and trimethylphosphine. These investigations led to the isolation and characterization of the compounds [(cAACmethyl)H(R2ImMe2)]X (13 a,b), (cAACmethyl)H(ImR2) (14 a-c), (cAACmethyl)H(CH(COOCH3)2) (15 b) and (cAACmethyl)H(CH2-PMe2) (16). Deprotonation of [(cAACmethyl)H(Me2ImMe2)][BF4] (13 a) at the cAAC carbon atom using KHMDS as a base led to isolation and structural characterization of the cAACmethyl-NHC heterodimer (17). This study involved multiple reactions and reactants, such as 2,3,4,5,6-Perfluoropyridine (cas: 700-16-3Computed Properties of C5F5N).
2,3,4,5,6-Perfluoropyridine (cas: 700-16-3) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. Reduced pyridines, namely tetrahydropyridines, dihydropyridines and piperidines, are found in numerous natural and synthetic compounds. The synthesis and reactivity of these compounds have often been driven by the fact many of these compounds have interesting and unique pharmacological properties. Computed Properties of C5F5N