Substituent-Dependent Optical and Electrochemical Properties of Triarylformazanate Boron Difluoride Complexes
Substituent-Dependent Optical and Electrochemical Properties of Triarylformazanate Boron Difluoride Complexes
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DOI：
10.1021/ic5016912
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发表时间：
2014-10-06
影响因子：
4.6
通讯作者：
Gilroy, Joe B.
中科院分区：
文献类型：
--
作者：
Barbon, Stephanie M.;Price, Jacquelyn T.;Gilroy, Joe B.
报道了9个取代的三芳基甲酸二氟化硼配合物的直接合成和详细表征。在甲氨酸酯配体骨架的两个不同位置上，研究了给电子取代基(对苯甲醚)和吸电子取代基(对苯腈)相对于苯基对光学和电化学性质的影响。通过H-1、C-13、B-11和F-19核磁共振谱、循环伏安法、红外光谱、紫外-可见吸收和发射光谱、质谱学和元素分析等手段对每个BF2配合物进行了表征。对选定的样品进行了X射线结晶学研究，揭示了固体中高度离域的结构。络合物通过两步可逆的电化学还原为自由基阴离子和双阴离子形式。化合物还表现出与取代基相关的吸收和发射性质，并伴随着显著的斯托克斯位移，其中甲酸甲酸酯主链1，5-位上的芳基取代基对这些性质的影响比3-位上的芳基取代基更大。在三种不同的配合物中打破对称性，导致发射强度相对于对称取代衍生物的发射强度略有增加。
The straightforward synthesis and detailed characterization of nine substituted triarylformazanate boron difluoride complexes is reported. The effect of electron-donating (p-anisole) and electron-withdrawing (p-benzonitrile) substituents on optical and electrochemical properties, relative to phenyl substituents, was studied at two different positions within the formazanate ligand framework. Each of the BF2 complexes was characterized by H-1, C-13, B-11, and F-19 NMR spectroscopy, cyclic voltammetry, infrared spectroscopy, UV-vis absorption and emission spectroscopy, mass spectrometry, and elemental analysis. Select examples were studied by X-ray crystallography, revealing highly delocalized structures in the solid state. The complexes were reversibly reduced in two steps electrochemically to their radical anion and dianion forms. The complexes also exhibited substituent-dependent absorption and emission properties, accompanied by significant Stokes shifts, with the aryl substituents at the 1,5-positions of the formazanate backbone having a greater influence on these properties than aryl substituents at the 3-position. Breaking the symmetry in three different complexes resulted in a modest increase in emission intensity relative to that of symmetrically substituted derivatives.