Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
J Am Chem Soc. 2012 Jan 11;134(1):165-8. doi: 10.1021/ja209808k. Epub 2011 Dec 16.
We report the observation of two transition-metal-centered nine-atom boron rings, RhⓒB(9)(-) and IrⓒB(9)(-). These two doped-boron clusters are produced in a laser-vaporization supersonic molecular beam and characterized by photoelectron spectroscopy and ab initio calculations. Large HOMO-LUMO gaps are observed in the anion photoelectron spectra, suggesting that neutral RhⓒB(9) and IrⓒB(9) are highly stable, closed shell species. Theoretical calculations show that RhⓒB(9) and IrⓒB(9) are of D(9h) symmetry. Chemical bonding analyses reveal that these complexes are doubly aromatic, each with six completely delocalized π and σ electrons, which describe the bonding between the central metal atom and the boron ring. This work establishes firmly the metal-doped B rings as a new class of novel aromatic molecular wheels.
我们报告了两个过渡金属中心的九个原子硼环 Rh ⓒ B(9)(-) 和 Ir ⓒ B(9)(-) 的观察结果。这两个掺杂硼团簇是在激光蒸发超音速分子束中产生的，并通过光电电子能谱和从头算计算进行了表征。在阴离子光电电子光谱中观察到较大的 HOMO-LUMO 能隙，表明中性 Rh ⓒ B(9) 和 Ir ⓒ B(9) 是高度稳定的、满壳层的物种。理论计算表明，Rh ⓒ B(9) 和 Ir ⓒ B(9) 具有 D(9h) 对称性。成键分析表明，这些配合物是双芳香族的，每个配合物都有六个完全离域的π和σ电子，这些电子描述了中心金属原子与硼环之间的键合。这项工作确立了金属掺杂的 B 环作为一类新型的芳香性分子轮。
