Preparation of a discotic 2,4,7,9‐tetraaryl‐6H‐dibenzo[c,e][1,2]thiazine and generation of a persistent Radical 1

Abstract

6H‐Dibenzo[d,e][1,2]thiazine substituted with four 3,4‐dioctyloxyphenyl groups forms a room temperature discotic phase with a clearing temperature of 104°C. Oxidation of the thiazine 2b with either metal oxides (PbO₂ or AgO) or SO₂Cl₂ gave a moderately stable radical 1b (a _N = 0.95 mT, g = 2.0045). Full conversion of 2b to 1b was observed with AgO in a toluene/MeCN mixture or with SO₂Cl₂. The radical 1b was isolated in the neat form with the latter oxidant. It shows sensitivity to molecular oxygen, which hampered its purification and subsequent thermal and magnetic studies.

Acknowledgements

This project was supported by NSF grants (CHE‐9528029 and CHE‐0096827).