DppfCuBH₄: new reducing agents for the synthesis of ferrocene-functionalized metal nanoclusters

A facile synthesis of atomically precise metal nanoclusters, especially those decorated with functional groups, is the prerequisite for finding applications in special fields and studying structure-and-property relationships. The exploration of simple and efficient synthetic prototypes for introducing functional ligands (such as ferrocene) into cluster moieties is thus of high interest. In this work, a type of reducing agent of dppfCuBH(4) (dppf is 1,1'-bis(diphenyphosphino)ferrocene) is introduced for the first time to prepare ferrocene-functionalized metal nanoclusters. Two new clusters of [Ag25Cu4(dppf)(6)(3-F-PhC=C)(12)Cl-6](3+) (1) and [Ag-4(dppf)(5)Cl-2](2+) (2) have been obtained from the simple synthetic method. The two compounds have been fully characterized by advanced techniques of electrospray ionization mass spectroscopy (ESI-MS), nuclear magnetic resonance (NMR), and ultraviolet-visible spectroscopy (UV-Vis). The total structure of the clusters, as determined by X-ray single-crystal diffraction, describes the Ag-13@Ag12Cu4(dppf)(6)(3-F-PhCC)(12)Cl-6 core-shell structure of 1 and [Ag2Cl(dppf)(2)](+)-dppf-[Ag2Cl(dppf)(2)](+) polymeric structure of 2. This work opens the door to employing dppfCuBH(4) as a functional reducing agent to discover many underlying metal nanoclusters and even other nanomaterials which feature ferrocene-groups.