Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, CxP. 26077, São Paulo, 05508-000, Brazil.
BIOSCOPE Group, UCIBIO-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Caparica, Universidade Nova de Lisboa, 2829-516 Portugal.
Photochem Photobiol Sci. 2017 Jul 1;16(7):1174-1181. doi: 10.1039/c7pp00036g. Epub 2017 Jun 12.
A new selenium containing coumarin (compound 7) was designed and synthesized from the amide linkage between coumarin-519 (6) and 2-(butylselanyl)ethanamine (5). The molecular structure of 7 was accurately characterized, and its photophysical properties in acetonitrile, ethanol and chloroform solutions were studied by absorption, stationary and time-resolved fluorescence spectroscopies. Changes in the solvent polarity affected the Stokes shift, quantum yields and lifetime of the excited states. The spectroscopic behavior of compound 7 was evaluated in the presence of different monovalent, divalent and trivalent metallic cations (Na, K, Ca, Co, Ni, Cu, Zn, Cd, Pb, Hg, Hg, Ag, Al, Fe, Ga and Cr) in acetonitrile solution. Among the tested cations, 7 exhibited high selective interaction with Cu, which was evidenced by the not expected absorption hypsocromic shift (usually coumarin-519 gives red-shifted complexes) and intense chelation-enhanced fluorescence quenching (CHEQ). We performed spectrophotometric and spectrofluorimetric titrations of 7 upon addition of Cu. From these data, the minimal detectable and quantifiable amounts were calculated and found to be 0.2 and 0.4 μmol L by absorption and 0.6 and 1.0 μmol L by emission, respectively. The 7-Cu compound presented the 1 : 1 stoichiometry and the stability constant values of absorption and emission were found to be log β = 5.78 and log β = 6.32 respectively. Taking into account the high selectivity of the 7-Cu compound in organic solvent systems, and considering the role of copper in organic transformations, it can be regarded as a promising fluorescent sensor for studies concerning the determination of oxidation-dependent transient entities in organic reactions like those involving cuprates. Additionally, it can be used for the detection and quantification of this metal cation in vitro in aprotic biological systems.
一种新的含硒香豆素（化合物 7）通过香豆素-519（6）和 2-（丁基硒基）乙胺（5）之间的酰胺键设计和合成。准确地描述了 7 的分子结构，并通过吸收、固定和时间分辨荧光光谱研究了其在乙腈、乙醇和氯仿溶液中的光物理性质。溶剂极性的变化影响了激发态的斯托克斯位移、量子产率和寿命。在乙腈溶液中研究了化合物 7 在不同单价、二价和三价金属阳离子（Na、K、Ca、Co、Ni、Cu、Zn、Cd、Pb、Hg、Hg、Ag、Al、Fe、Ga 和 Cr）存在下的光谱行为。在所测试的阳离子中，7 与 Cu 表现出高度选择性相互作用，这一点从意想不到的吸收蓝移（通常香豆素-519 给出红移配合物）和强烈的螯合增强荧光猝灭（CHEQ）得到证实。我们对 7 与 Cu 的加合进行了分光光度法和分光荧光法滴定。根据这些数据，计算出最小可检测和可量化的量分别为 0.2 和 0.4 μmol L 通过吸收和 0.6 和 1.0 μmol L 通过发射。7-Cu 化合物具有 1:1 的化学计量比，吸收和发射的稳定常数值分别为 logβ=5.78 和 logβ=6.32。考虑到 7-Cu 化合物在有机溶剂体系中的高选择性，以及铜在有机转化中的作用，它可以被视为一种有前途的荧光传感器，用于研究涉及铜盐的有机反应中氧化依赖的瞬态实体的测定，如涉及 cuprates 的反应。此外，它可以用于在非质子生物体系中体外检测和定量这种金属阳离子。
