N-Heterocyclic Carbene-Functionalized Gold Nanoclusters

最近，我们一直致力于将NHCs用于稳定金纳米团簇。在我们最初报道[Au13(NHC)9Cl3]Cl2簇的合成和分离之后，我们进一步改进了分离和纯化程序，以便将这些簇用作各种反应的催化剂。并用x射线晶体学分析证实了团簇的结构。在开发了这些簇的合成和纯化的优化程序后，我们试图测试它们在氧化催化中的活性，以及我们之前分离的nhc -膦连接簇。为此，我们选择了两个模型反应，苯甲醇氧化和光催化苯胺氧化作为测试案例。使用混合膦/NHC Au13团簇进行苯甲醇氧化，周转率适中（平均7 h-1），产生具有高选择性（平均95%）的苯甲醛。由于这些簇在催化条件下的稳定性较低，我们目前正在研究通过固体载体和/或配体修饰来提高它们的稳定性。我们还计划在未来的研究中利用我们的nhc功能化金纳米团簇家族研究其他新的催化反应。

More recently, we have been working to expand the use of NHCs to the stabilization of gold nanoclusters. Following our initial report on the synthesis and isolation of [Au13(NHC)9Cl3]Cl2 clusters, we improved the isolation and purification procedures further in order to apply these clusters as catalysts in various reactions.And structures of clusters was confirmed by X-ray crystallographic analysis. After developing optimized procedures for the synthesis and purification of these clusters, we sought to test their activity in oxidation catalysis, along with our previously isolated NHC-phosphine ligated clusters. Towards this end we chose two model reactions, benzyl alcohol oxidation and photocatalytic benzyl amine oxidation as test cases. Benzyl alcohol oxidation using mixed phosphine/NHC Au13 clusters proceeds with moderate turnover frequency (average 7 h-1), producing benzaldehyde with high selectivity (average 95%). Due to the low stability of these clusters under catalytic conditions, we are currently investigating increasing their stability via solid supports and/or ligand modifications. We plan to also investigate other novel catalytic reactions using our family of NHC-functionalized gold nanoclusters in future research.