Novel Donor 1,4-Benzothiazino[2,3-b]phenothiazine

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation

“…We used the reduction potentials of PABI, PIC, 1 , and 2 for E red , which is the reduction potential of these imidazole moieties (acceptors), because all reduction reactions produced the imidazole anion. On the other hand, because it was difficult to measure E ox of the donor moieties of these compounds, we tentatively used the oxidation potentials of nonsubstituted triphenylimidazole, phenol, phenothiazine, and phenoxazine for E ox . − The reduction and oxidation potentials measured in different solvents (Δ solv E , acetonitrile and dichloromethane) were corrected for the benzene solution by using the Born equation, as shown below. r + and r – are the radii of the anion and cation, respectively. In the actual estimation, the r + and r – values were tentatively set to be 0.5 and 0.6 nm based on the optimized molecular structures of the DFT calculations, respectively.…”

“…In this study, we synthesized novel photochromic radical complexes composed of an imidazolyl radical and a phenothiazine or a phenoxazine radical ( 1 and 2 , respectively; Scheme b) and investigated the ultrafast bond dissociation processes of these compounds and PIC. Phenothiazine is well-known as a strong electron donor, and the highest occupied molecular orbital (HOMO) level of the nonsubstituted phenothiazine (0.32 V vs ferrocene/ferrocenium (Fc/Fc + )) is higher than those of phenol and triphenylimidazole (0.64 and 0.95 V vs Fc/Fc + , respectively). , It suggests that the phenothiazine moiety may act as the electron donor to the imidazole moiety during the bond dissociation process. Moreover, phenothiazine demonstrates a similar oxidation reaction to that of phenol, as shown in Scheme a.…”

1,4-Benzoxazino[2,3-b]phenoxazine and Its Sulfur Analogues: Synthesis, Properties, and Application to Organic Light-Emitting Diodes

“…The meta-type sulfur compounds 2 have recently been prepared by two groups: Müllen's group through nitrene-induced cyclization (Cadogan cyclization) and Sieberg's group through sulfur-bridging methods . Although fundamental studies for 2 in both the neutral and the radical cation states have been reported, their solid-state properties have not been reported. , We have more recently prepared the oxygen and sulfur analogues 1 and 2 using an intramolecular Ullmann coupling reaction as a key step . We have preliminarily shown that the benzoxazinophenoxazines 1a , b (R = H, Me) have lower oxidation potentials than those of the benzothiazinophenothiazines 2a , b (R = H, Me).…”

“…12 The study of electric conductivity for 4 and the higher analogues has been reported by Case et al 13 An oxygen analogue 3 has also been prepared by reductive acylation of 5. 14 The metatype sulfur compounds 2 have recently been prepared by two groups: Mu ¨llen's group through nitrene-induced cyclization (Cadogan cyclization) 15 and Sieberg's group through sulfurbridging methods. 16 Although fundamental studies for 2 in both the neutral and the radical cation states have been reported, their solid-state properties have not been reported.…”