Bould Jonathan, Lang Kamil, Kirakci Kaplan, Cerdán Luis, Roca-Sanjuán Daniel, Francés-Monerris Antonio, Clegg William, Waddell Paul G, Fuciman Marcel, Polívka Tomáš, Londesborough Michael G S
Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež 250 68, Czech Republic.
Institute of Physical Chemistry "Rocasolano", Consejo Superior de Investigaciones Científicas (CSIC), C/Serrano 119, 28006 Madrid, Spain.
Inorg Chem. 2020 Dec 7;59(23):17058-17070. doi: 10.1021/acs.inorgchem.0c02277. Epub 2020 Nov 9.
We present the first examples of alkylated derivatives of the macropolyhedral boron hydride, -BH, which is the gain medium in the first borane laser. This new series of ten highly stable and colorless organic-inorganic hybrid clusters are capable of the conversion of UVA irradiation to blue light with fluorescence quantum yields of unity. This study gives a comprehensive description of their synthesis, isolation, and structural characterization together with a delineation of their photophysical properties using a combined theoretical and experimental approach. Treatment of -BH with RI (where R = Me or Et) in the presence of AlCl gives a series of alkylated derivatives, R--BH (where = 2 to 6), compounds -, in which the 18-vertex octadecaborane cluster architectures are preserved and yet undergo a linear "polyhedral swelling", depending on the number of cluster alkyl substituents. The use of dichloromethane solvent in the synthetic procedure leads to dichlorination of the borane cluster and increased alkylation to give Me--BHCl , Me--BHCl , and Me--BHCl . All new alkyl derivatives are highly stable, extremely efficient (Φ = 0.76-1.0) blue fluorophores (λ = 423-427 nm) and are soluble in a wide range of organic solvents and also a polystyrene matrix. The Et--BH derivative crystallizes from pentane solution in two phases with consequent multiabsorption and multiemission photophysical properties. An ultrafast transient UV-vis absorption spectroscopic study of compounds and reveals that an efficient excited-state absorption at the emission wavelength inhibits the laser performance of these otherwise remarkable luminescent molecules. All these new compounds add to the growing portfolio of octadecaborane-based luminescent species, and in an effort to broaden the perspective on their highly emissive photophysical properties, we highlight emerging patterns that successive substitutions have on the molecular size of the 18-vertex borane cluster structure and the distribution of the electron density within.
我们展示了大面体硼氢化物 -BH 的烷基化衍生物的首个实例，-BH 是首个硼烷激光器中的增益介质。这一系列新的十个高度稳定且无色的有机 - 无机杂化簇能够将紫外线 A 辐射转换为蓝光，荧光量子产率为 1。本研究使用理论与实验相结合的方法，全面描述了它们的合成、分离和结构表征，并阐述了它们的光物理性质。在 AlCl 存在的情况下，用 RI（其中 R = Me 或 Et）处理 -BH 可得到一系列烷基化衍生物 R--BH（其中 = 2 至 6），即化合物 -，其中 18 顶点的十八硼烷簇结构得以保留，但会根据簇烷基取代基的数量发生线性“多面体膨胀”。在合成过程中使用二氯甲烷溶剂会导致硼烷簇二氯化并增加烷基化程度，从而得到 Me--BHCl 、Me--BHCl 和 Me--BHCl 。所有新的烷基衍生物都是高度稳定、极其高效（Φ = 0.76 - 1.0）的蓝色荧光团（λ = 423 - 427 nm），可溶于多种有机溶剂以及聚苯乙烯基质。Et--BH 衍生物 从戊烷溶液中结晶为两个相，因此具有多吸收和多发射光物理性质。对化合物 和 的超快瞬态紫外 - 可见吸收光谱研究表明，在发射波长处的有效激发态吸收会抑制这些原本出色的发光分子的激光性能。所有这些新化合物都增加了基于十八硼烷的发光物种的不断增长的组合，并且为了拓宽对其高发射光物理性质的认识，我们强调了连续取代对 18 顶点硼烷簇结构的分子大小以及内部电子密度分布的新出现模式。
