Direct Detection of a Persistent Carbonyloxyl Radical in the Gas Phase

Abstract

Long lived: Carbonyloxyl radicals (RCO2.) are reactive intermediates that play key roles in initiating polymerization reactions. This reactivity also makes their direct observation difficult. For the first time a persistent organic RCO2. radical is detected in the gas phase, its extraordinary longevity is attributed to the high barrier towards fragmentation owing to the endothermicity of the decarboxylation products.

Helical frontier orbitals of conjugated linear molecules

“…9,19 Some studies do correctly suggest that ECOs demonstrate non-planar geometries: the terminating functional motifs rotate out of plane if they partake in the p conjugation of the alkyne. 20,21 This geometry is similar to that observed in the allene family, with one fundamental difference: ECOs have even numbers of carbon in the chain.…”

A lipidomic workflow capable of resolving sn- and CC location isomers of phosphatidylcholines

“…The process is followed by homolytic cleavage of the C-N bond leading to a neutral loss of (CH 3 ) 2 N-CH 2 c. These two losses (120 Da) collectively lead to the formation of an ethyl radical on the remaining lipid anion (C 39 (ref. 43) and forms a double bond between C2 and C3 on the glycerol backbone. Given that this radical fragmentation channel is not observed from CID of formate or acetate adduct anions of PCs, we hypothesize that the -OH group in bicarbonate may form a relatively strong hydrogen bond with phosphate oxygen in PC molecules (possible interaction is indicated in Scheme 1).…”

Site‐Specific C(sp3)–H Aminations of Imidates and Amidines Enabled by Covalently Tethered Distonic Radical Anions

“…As we can see, the O À IBDEs for distonic radical anions F and I manifest in 12-13 kcal mol À1 decrease as compared with the protonated (E and H)ornonsubstituted forms (D and G), which confirms the temporal regulation brought by tethered carboxylate anion. Apart from the improved stabilities,the dicarboxylate radical anions in our studies also display that the singly occupied molecular orbital (SOMO) of the unpaired electron of the radical lies at alower energy than the doubly occupied molecular orbital (HOMO) of the lone pair electrons of the anion [10] (Figure 1d,F igure S2, S3, and Table S4), which seems to represent av iolation of the aufbau or building-up principle.Itsworth noting that the SOMO-HOMO converted distonic radical anions are all too infrequently applied in practical organic synthesis.…”

“…Awide range of trichloroacetimidates bearing sterically and electronically diverse functional groups smoothly underwent the intramolecular aminations and the subsequent hydrolysis to generate b amino alcohols. Ortho-, meta-, and para-substitutions of either electronically rich or deficient groups were tolerated (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Additionally,naphthalenes (18 and 19)and heteroarenes such as thiophene (20)w ere also tolerant with good yields (> 81 %), but indole-derived b amino alcohol 22 was isolated with al ow yield probably due to the undesirable overoxidation.…”