A Polyoxochromate Templated 56-Nuclei Silver Nanocluster

Most of polyoxometallates (POMs) templated silver nanoclusters recorded so far are polyoxomolybdates and polyoxotungstates; however, as congeneric polyoxochromates, they are rarely observed in silver nanoclusters. Herein, a high-nuclearity polyoxochromate, ((Cr4Cr8O36)-Cr-III-O-VI)(12-), is uncovered in a novel silver nanocluster (SD/Ag56a) as an anion template. The mixed-valent ((Cr4Cr8O36)-Cr-III-O-VI)(12-)consists of four edge-sharing (CrO6)-O-III octahedra and eight (CrO4)-O-VI tetrahedra, which are fused together by sharing one or two vertexes. The ((Cr4Cr8O36)12-)-Cr-III-O-VI is the by far highest nuclearity polyoxochromate and is trapped by outer Ag-56 bracelet-like shell coprotected by quaternary ligands including (PrS-)-Pr-i, NapCOO(-) (2-naphthalenecarboxylate), CF3COO-, and CH3CN. The antiferromagnetic property and solution behavior of SD/Ag56a are discussed in detail.