Department of Chemistry , University of California , Berkeley , California 94720 , United States.
Department of Chemistry and Applied Biosciences , Eidgenössische Technische Hochschule Zürich , Zürich CH-8093 , Switzerland.
Inorg Chem. 2018 May 7;57(9):5213-5224. doi: 10.1021/acs.inorgchem.8b00247. Epub 2018 Apr 6.
The syntheses of high-valent niobium imido complexes [HB(Im)]Nb(N Bu)Cl (2) and [HB(Im)]Nb(N Bu)Me (3) bearing a bis(NHC)borate (NHC = N-heterocyclic carbene) supporting ligand are described. The reaction of the dimethyl complex (3) with excess CO generates an equivalent of acetone, which inserts into a B-H bond of the bis(NHC)borate ligand to form a boryl isopropoxide/niobium(III) dicarbonyl complex (4). This mode of hydroboration reactivity also occurs readily upon the treatment of either 2 or 3 with ketones, aldehydes, and isocyanates. Modification of the bis(carbene) ligand of 3 via the hydroboration of benzophenone produces the dimethylniobium complex [(OCHPh)B(Im)]Nb(N Bu)Me (12), which undergoes intramolecular η-arene coordination upon hydrogenation.
高铌亚氨基配合物[HB(Im)]Nb(N Bu)Cl（2）和[HB(Im)]Nb(N Bu)Me（3）的合成，它们都含有一个双（NHC）硼酸酯（NHC=N-杂环卡宾）配体。二甲基配合物（3）与过量的 CO 反应会生成等当量的丙酮，它插入到双（NHC）硼酸酯配体的 B-H 键中，形成一个硼酸异丙酯/铌（III）二羰基配合物（4）。这种硼氢化反应活性模式也很容易在 2 或 3 与酮、醛和异氰酸酯的处理中发生。通过苯甲酮的硼氢化反应对 3 的双（碳烯）配体进行修饰，生成二甲基铌配合物[(OCHPh)B(Im)]Nb(N Bu)Me（12），它在氢化时会发生分子内η-芳环配位。
