Some 1,2-diarylimidoyl radicals were generated in the gas-phase by intramolecular radical translocation from ortho-imino-aryloxyl radicals, in turn generated under flash vacuum pyrolysis (FVP) conditions. The imidoyls reacted with XR ortho'-substituents in the N-aryl group to give (in most cases) modest yields of cyclisation products. Depending on the nature of the bridging atom (X), the formation of these products was initiated either by a further hydrogen atom translocation (X = CH(2)), or by ipso-attack onto the aryl group (R = Ph), or by direct substitution at the heteroatom (X = S). With XR = N(Me)Ph, the major reaction product was probably the result of a competing pathway not involving the corresponding imidoyl.
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http://dx.doi.org/10.1039/c1ob06228j | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry and Research Center for Chemical Biology and Omics Analysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
ConspectusThe advancement of synthetic methodologies is fundamentally driven by a deeper understanding of the structure-reactivity relationships of reactive key intermediates. Carbyne anions are compounds featuring a monovalent anionic carbon possessing four nonbonding valence electrons, which were historically confined to theoretical constructs or observed solely within the environment of gas-phase studies. These species possess potential for applications across diverse domains of synthetic chemistry and ancillary fields.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
There has been a significant recent surge in the number of studies interrogating chiral molecules in the gas phase using photoelectron circular dichroism (PECD) and related techniques. These investigations have revealed new fundamental insights into the structure and dynamics of chiral species and, furthermore, have the potential to revolutionize the field of chiral analysis for more practical and industrial applications. As it has been just over 20 years since the first PECD imaging experiments were demonstrated - and 10 years since the last dedicated general perspective article on the topic - a new overview now seems extremely timely.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Via G. Amendola 165/a, 70126 Bari, Italy.
Coenzyme Q (CoQ) and closely related compounds with varying isoprenoid tail lengths (CoQ, = 6-9) are biochemical cofactors involved in many physiological processes, playing important roles in cellular respiration and energy production. Liquid chromatography (LC) coupled with single or tandem mass spectrometry (MS) using electrospray (ESI) or atmospheric pressure chemical ionization (APCI) is considered the gold standard for the identification and quantification of CoQ in food and biological samples. However, the characteristic fragmentation exhibited by the CoQ radical anion ([M], / 862.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Istituto di Biostrutture e Bioimmagini-CNR (IBB-CNR), Via De Amicis 95, I-80145 Napoli, Italy.
We here simulate in the gas phase the population dynamics of guanine/cytosine (GC) and cytosine/guanine (CG) stacked dimers in B-DNA and A-DNA arrangement, following excitation in the lowest-energy band, and considering the four lowest-energy ππ* bright excited states, the three lowest-energy π* states, and the G → C charge-transfer (CT) state. We resort to a generalized Linear Vibronic Coupling (LVC) model parametrized with time-dependent density functional theory (TD-DFT) computations, exploiting a fragment-based diabatization and we run nonadiabatic quantum dynamical simulations with the multilayer version of the Multiconfigurational Time-Dependent Hartree (ML-MCTDH) approach. G → C CT results in a major decay process for GC in B-DNA but less in A-DNA arrangement, where also the population transfer to the lowest-energy excited state localized on C is an important intermonomer process.
View Article and Find Full Text PDFWater Res
January 2025
Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Current published models for nitrous oxide (NO) emission in membrane aerated biofilm reactors (MABR) have several simplifications that are not representative of full-scale systems. This study developed an improved MABR NO model that captured commonly overlooked phenomena such as back diffusion of generated NO into MABR lumen gas and the recirculation of the NO laden lumen gas for tank mixing and biofilm thickness control. The improved model was validated with measured NO concentrations in the lumen gas phase and bulk mixed liquor in a full-scale hybrid MABR facility.
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