A series of POM/Ag-based hybrids: distinct forms and assembly of [AgxLy] complexes through combinational effects of POM and isomeric ligands

Abstract

Five POM/Ag-based hybrids were obtained under hydrothermal conditions: (AgL^a)₂[Ag₂L^a₂(SiW₁₂O₄₀)] (1), [(AgL^b)₂-Ag₂L^b₂][(SiW₁₂O₄₀)] (2) Na₂[AgL^a(HL^a)]₂[Ag₅L^a₄(H₂O)₂][H(P₂W₁₈O₆₂)₂] ·21.6H₂O (3), [Ag₅L^b₅][K₂(OH)P₂W₁₈O₆₂]·H₂O (4) and [Ag₂L^a₂][HPW₁₂O₄₀]·7.5H₂O (5) (L^a = 1,2-bis(imidazol-1-ylmethyl)benzene; L^b = 1,3-bis(imidazol-1-ylmethyl)benzene). It is likely that the forms and assembly of [Ag_xL_y] complexes are crucial to the eventual structures, which are quite dependent on the POM and isomeric ligands in combination. Compound 1 shows a “S”-like chain structure with [(AgL^a)₂]_n²ⁿ⁺ templates, while compound 2 features a unique 2D layer constructed by polypseudo-rotoxane motifs and infinite Ag chains. Compound 3 exhibits a 2D layer consisting of {Dawson-Ag₅} double chain and [AgL^a₂] complexes. Compound 4 possesses a 3D poly-threading framework containing {POM-K} chains and interdigitated metal–organic layers. Compound 5 is a 1D chain, formed by Keggin anions and [Ag₂L^a₂] circles. Further, the luminescent and electrochemical properties of 1–5 are also investigated.