6-Hydroxy-3-oxo-3H-xanthene-9-carboxylic acid is introduced as the first transition-metal-free carbon monoxide releasing molecule activated by visible light (photoCORM). This water-soluble fluorescein analogue releases carbon monoxide in both water and methanol upon irradiation at 500 nm. When selectively irradiated in the presence of hemoglobin (Hb) under physiological conditions, released CO is quantitatively trapped to form carboxyhemoglobin (COHb). The reaction progress can be accurately monitored by characteristic absorption and emission properties of the reactants and products.

中文翻译：

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荧光素类似物X吨9-羧酸：绿光激活的无过渡金属的CO释放分子

引入6-羟基-3-氧代-3 H-氧杂蒽-9-羧酸作为第一个由可见光（photoCORM）激活的无过渡金属的一氧化碳释放分子。该水溶性荧光素类似物在500 nm照射后会在水和甲醇中释放一氧化碳。在生理条件下在存在血红蛋白（Hb）的情况下进行选择性照射时，释放出的CO被定量捕获以形成羧基血红蛋白（COHb）。反应进程可以通过反应物和产物的特征吸收和发射特性来精确监控。