The preparation and crystal structure of 8-chloro-1H-pyrrolo[2,3-b]phenazine5-oxide (1) are described. Compound 1 formed dark purple crystals from deeply colored solution in methanol. Crystal plates were in the triclinic system, P-1 space group with unit cell parameters a = 6.9514(8), b = 9.1568(10), c = 10.2067(11), α = 84.509(2), β = 82.936(2), γ = 72.357(2) and a cell volume of 613.25(12) A−3. The title compound which contains the first example of the extensively conjugated pyrrolo-phenazine N-oxide system exhibits strong light absorption in the green to cyan wavelength range which disappears upon protonation.Graphical AbstractThe synthesis, optical properties and crystal structure of the title compound is described.

中文翻译：

---

吩嗪氮氧化物的合成及晶体结构

描述了8-氯-1H-吡咯并[2,3-b]吩嗪5-氧化物(1)的制备和晶体结构。化合物 1 从深颜色的甲醇溶液中形成深紫色晶体。晶体片为三斜晶系，P-1 空间群，晶胞参数 a = 6.9514(8), b = 9.1568(10), c = 10.2067(11), α = 84.509(2), β = 82.936(2) ), γ = 72.357(2) 和 613.25(12) A−3 的单元体积。包含广泛共轭吡咯并吩嗪 N-氧化物体系的第一个例子的标题化合物在绿色到青色波长范围内表现出强烈的光吸收，在质子化时消失。图形摘要描述了标题化合物的合成、光学性质和晶体结构.