Methylene imino radical H2CN center dot: matrix isolation ESR and density functional theory study

Methylene imino radical H2CN, and its C-13 isotopic isomer were generated i n argon matrices and their ESR spectra were observed. The g tensor and the proton, C-13, and N-14 hyperfine coupling (hfc) tensors of the radical were determined. The experimentally determined g tensor and the hfc tensors wer e initially analysed in terms of the singly occupied molecular orbital (SOM O) as predicted by semi-empirical INDO calculations. Finally the hfc tensor s were calculated by gradient corrected density functional theory (DFT), us ing both the INDO and DFT optimized geometries, as well as a model of H2CN embedded in 6 argon atoms (fully optimized). The calculated isotropic compo nent of the hydrogen hfc tensor and the anisotropic components of all the t ensors are in very nice agreement with the observed data whereas the isotro pic components for the nitrogen and carbon show larger deviation, as previo usly noted. The effects of the Ar matrix are minor.