A robust Ag/Ti nanocluster as an efficient heterogeneous Lewis Acid-Base catalyst for C–C bond formation

• Published in: Journal of catalysis 2023-08, Vol.424, p.189-196
• Main Authors: Wang, Ran, Sheng, Kai, Huang, Xian-Qiang, Azam, Mohammad, Tung, Chen-Ho, Sun, Di
• Format: Article
• Language: English
• Subjects: C–C bond formation; Heterometallic Ag/Ti cluster; Lewis acid-base catalyst; Synergistic catalysis
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2023.05.013

[Display omitted] •A novel Ag7Ti4 heterometallic cluster featuring an hourglass-shaped Ag7 cluster surrounded by a quasi-plane {Ti4} metalloligand has been developed.•The multiple surface-exposed silver atoms are potential Lewis acidic sites and the uncoordinated O atoms on Ti based metalloligands are potential Lewis basic sites.•The cluster acting as Lewis acid-base bifunctional catalyst exhibits excellent catalytic activity and stability as well as reusability for C−C bond formation reactions including Knoevenagel condensation and cyanosilylation. In heterogeneous catalysis, the quest for atom-precise heterometallic nanoclusters bearing bifunctional Lewis acid-base sites to achieve both heterometallic synergism and metal–ligand cooperation is a significant but challenging task. In this regard, a novel Ag/Ti heterometallic cluster featuring an hourglass-shaped Ag7 cluster surrounded by a quasi-plane {Ti4} metalloligand has been developed through facial one-pot solvothermal strategy. Although the Ag7 cluster is further stabilized by phenylacetylide, it is not entirely obstructed by outer ligands, allowing multiple silver active sites to be exposed on the surface. Moreover, the cluster manifests excellent Lewis acid-base activity and recyclability towards C−C bond formation reactions, involving the Knoevenagel condensation and the cyanosilylation.