Institute for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (Cenide), University of Duisburg-Essen, Universitätsstraße 5-7, D-45117, Essen, Germany.
Institute for Inorganic Chemistry and Structural Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany.
Nat Commun. 2018 Jan 8;9(1):87. doi: 10.1038/s41467-017-02581-2.
Neutral stibinyl and bismuthinyl radicals are typically short-lived, reactive species. Here we show the synthesis and solid-state structures of two stable stibinyl [L(Cl)Ga]Sb· 1 and bismuthinyl radicals [L(I)Ga]Bi· 4, which are stabilized by electropositive metal centers. Their description as predominantly metal-centered radicals is consistent with the results of NMR, EPR, SQUID, and DFT studies. The Lewis-acidic character of the Ga ligands allow for significant electron delocalization of the Sb- and Bi- unpaired radical onto the ligand. Single-electron reduction of [L(Cl)Ga]Sb· gave LGaSbGa(Cl)L 5, the first compound containing a Ga=Sb double bond. The π-bonding contribution is estimated to 9.56 kcal mol by NMR spectroscopy. The bonding situation and electronic structure is analyzed by quantum mechanical computations, revealing significant π backdonation from the Sb to the Ga atom. The formation of 5 illustrates the high-synthetic potential of 1 for the formation of new compounds with unusual electronic structures.
中性的锑基和铋基自由基通常是短寿命、反应性的物种。在这里，我们展示了两种稳定的锑基[L(Cl)Ga]Sb·1 和铋基自由基[L(I)Ga]Bi·4 的合成和固态结构，它们由正电性金属中心稳定。它们被描述为主要以金属为中心的自由基，这与 NMR、EPR、SQUID 和 DFT 研究的结果一致。Ga 配体的路易斯酸性允许 Sb-和 Bi-未成对自由基的电子显著离域到配体上。[L(Cl)Ga]Sb·的单电子还原得到 LGaSbGa(Cl)L5，这是第一个含有 Ga=Sb 双键的化合物。通过 NMR 光谱估计π键贡献为 9.56 kcal/mol。通过量子力学计算分析了成键情况和电子结构，表明 Sb 向 Ga 原子的π-backdonation 非常显著。5 的形成说明了 1 具有很高的合成潜力，可以形成具有异常电子结构的新型化合物。
