A new rhodamine derivative, N-(3-carboxy)acryloyl rhodamine B hydrazide (CARB), has been synthesized, and its unusual spectroscopic reaction with Cu2+ has been investigated. The derivative exhibits a rapid and reversible non-fluorescent absorption upon coordination to Cu2+, which is a rather unusual phenomenon for rhodamine B derivatives. Stoichiometric measurements using the Job’s method and the molar ratio method reveal that one CARB molecule combines two Cu2+ ions, and the two Cu2+ ions play different roles: one opens the spirocyclic structure and the other quenches the fluorescence of the xanthene moiety. This reaction mechanism is supported by a comparative study on the model compound N-acryloyl rhodamine B hydrazide as well as by the density functional theory calculations. Furthermore, the absorption response of CARB is highly selective for Cu2+ over other common ions, which implies that CARB may be used as a colorimetric probe for the rapid visual detection of Cu2+.
我们合成了一种新的
罗丹明衍
生物--N-(3-羧基)
丙烯酰
罗丹明 B 肼(CARB),并研究了它与 Cu2+ 的不寻常光谱反应。该衍
生物在与 Cu2+ 配位后表现出快速、可逆的非荧光吸收,这在
罗丹明 B 衍
生物中是一种相当不寻常的现象。利用约伯法和摩尔比法进行的
化学计量学测量显示,一个 CARB 分子结合了两个 Cu2+ 离子,而这两个 Cu2+ 离子起着不同的作用:一个打开螺环结构,另一个熄灭呫吨分子的荧光。对模型化合物 N-
丙烯酰基
罗丹明 B 肼的比较研究以及密度泛函理论计算均支持这一反应机理。此外,CARB 的吸收响应对 Cu2+ 而非其他常见离子具有高度选择性,这意味着 CARB 可用作快速目测 Cu2+ 的比色探针。