Akademik Veri Yönetim Sistemi
Journal of Physical Organic Chemistry, cilt.39, sa.5, 2026 (SCI-Expanded, Scopus)
Alkyl nitrenes are highly reactive intermediates that are particularly challenging to study experimentally. Here, we report the first investigation of the simplest triplet alkyl nitrene bearing a pyridine-N-oxide moiety. Direct irradiation (λ > 350 nm) of 4-azidomethyl-pyridine-N-oxide in an Ar matrix (15 K) generated the target triplet 4-nitrenemethyl-pyridine-N-oxide 32, along with E and Z isomers of 4-iminomethyl-pyridine-N-oxide 3. Results from subsequent irradiations (λ > 325 nm) enabled the discrimination of the IR spectroscopic signatures of these species, allowing their unequivocal identification with support from DFT-B3LYP computations. Triplet nitrene 32 was found to be stable in dark Ar matrices, demonstrating that quantum tunneling 1,2-H shift to imine 3 is not operative on the experimental timescale. Computations show that this reaction is thermodynamically favorable on the triplet surface but involves a high-energy barrier (~36 kcal mol−1), explaining the absence of H-tunneling. As the pyridine-N-oxide moiety can act as an anchoring site for complexation with calix[4]pyrrole derivatives, our findings open new perspectives for investigating alkyl nitrene reactivity and tunneling phenomena under supramolecular confinement conditions.