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首页> 外文期刊>Chemistry: A European journal >Luminescence properties of C-diazaborolyl-ortho-carboranes as donor-acceptor systems
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Luminescence properties of C-diazaborolyl-ortho-carboranes as donor-acceptor systems

机译：C-二氮杂硼烯丙基-邻氨基甲酸酯作为供体-受体系统的发光特性

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Seven derivatives of 1,2-dicarbadodecaborane (ortho-carborane, 1,2-C _2B _(10)H _(12)) with a 1,3-diethyl- or 1,3-diphenyl-1,3,2-benzodiazaborolyl group on one cage carbon atom were synthesized and structurally characterized. Six of these compounds showed remarkable low-energy fluorescence emissions with large Stokes shifts of 15100-20260 cm ~(-1) and quantum yields (φ _F) of up to 65 % in the solid state. The low-energy fluorescence emission, which was assigned to a charge-transfer (CT) transition between the cage and the heterocyclic unit, depended on the orientation (torsion angle, ψ) of the diazaborolyl group with respect to the cage C-C bond. In cyclohexane, two compounds exhibited very weak dual fluorescence emissions with Stokes shifts of 15660-18090 cm ~(-1) for the CT bands and 1960-5540 cm ~(-1) for the high-energy bands, which were assigned to local transitions within the benzodiazaborole units (local excitation, LE), whereas four compounds showed only CT bands with φ _F values between 8-32 %. Two distinct excited singlet-state (S _1) geometries, denoted S _1(LE) and S _1(CT), were observed computationally for the benzodiazaborolyl-ortho-carboranes, the population of which depended on their orientation (ψ). TD-DFT calculations on these excited state geometries were in accord with their CT and LE emissions. These C-diazaborolyl-ortho-carboranes were viewed as donor-acceptor systems with the diazaborolyl group as the donor and the ortho-carboranyl group as the acceptor. Official D-A business: Visible low-energy fluorescence emissions with large Stokes shifts were observed for a series of C-benzodiazaborolyl-ortho- carboranes owing to relaxation by cage C-C bond-lengthening. Experimental and computational data showed that these emissions were due to a charge transfer (CT) that involved the cluster and the borolyl group.
机译：1,2-二卡巴多癸硼烷的七种衍生物（邻-甲硼烷，1,2-C _2B _（10）H _（12））与1,3-二乙基-或1,3-二苯基-1,3,2-合成了一个笼状碳原子上的苯并二氮杂硼烯丙基，并对其结构进行了表征。这些化合物中的六个显示出显着的低能量荧光发射，固态的斯托克斯位移为15100-20260 cm〜（-1），量子产率（φ_F）高达65％。低能荧光发射被分配给笼和杂环单元之间的电荷转移（CT）过渡，取决于二氮杂硼烯丙基相对于笼C-C键的方向（扭转角，ψ）。在环己烷中，两种化合物表现出非常弱的双重荧光发射，CT谱带的斯托克斯位移为15660-18090 cm〜（-1），高能谱带的斯托克斯位移为1960-5540 cm〜（-1），这被分配给局部苯并二氮杂硼烷单元内的跃迁（局部激发，LE），而四种化合物仅显示出Φ_F值在8-32％之间的CT谱带。通过计算观察到苯并二氮杂硼烯丙基-邻位碳二烯的两个不同的激发单重态（S _1）几何形状，分别表示为S _1（LE）和S _1（CT），其种群取决于它们的取向（ψ）。在这些激发态几何上的TD-DFT计算与它们的CT和LE发射一致。这些C-二氮杂硼烯丙基-原碳硼烷被认为是供体-受体体系，其中二氮杂硼烯丙基为供体，邻碳硼烷基为受体。 D-A官方业务：由于笼型C-C键加长而松弛，因此观察到一系列C-苯并二氮杂硼烯丙基-邻甲硼烷的可见光，低能量荧光和大的斯托克斯位移。实验和计算数据表明，这些排放是由于涉及团簇和硼烯丙基的电荷转移（CT）所致。

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