In Situ Ligand-Transformation-Assisted Assembly of a Polyoxometalate and Silver-Phosphine Oxide Cluster for Colorimetric Detection of Phenol Contaminants.

In situ ligand transformation strategies represent an efficient pathway for constructing function-oriented polyoxometalate (POM)-based crystalline materials. Herein, three POM-based hybrid networks were synthesized through in situ transformation of the phosphine ligand, formulated as [Ag(dppeo) 6 ][H 2 PMo 12 O 40 ]·5H 2 O ( 1 ), [Ag(dedpo)] 4 [SiW 12 O 40 ]·6H 2 O ( 2 ), and [Ag(dppeo)] 3 [PW 12 O 40 ]·3H 2 O ( 3 ) (dedpo = (2-(diphenylphosphaneyl)ethyl)diphenylphosphine oxide; dppeo = ethane-1,2-diylbis(diphenylphosphine oxide)). During the synthesis of these compounds, the 1,2-diphenylphosphine ethane molecule underwent in situ oxidation, transforming into dppeo and dedpo ligands, respectively. Compound 1 features a supramolecular architecture assembled from [Ag(dppeo) 3 ] + /[Ag 2 (dppeo) 6 ] 2+ cationic clusters with disordered Ag centers and protonated [H 2 PMo 12 O 40 ] - anions. Compound 2 presents a 3-D POM-supported metal-organic framework consisting of binuclear [Ag(dedpo)] 2 2+ units, {-dedpo-Ag-dedpo-} chains, and [SiW 12 O 40 ] 4- polyoxoanions. Compound 3 displays a 2-D layered structure formed by {-dppeo-Ag 3 -dppeo-} chains and [PW 12 O 40 ] 3- clusters. Pronounced argentophilic interactions are observed in compounds 1 and 3 . The three compounds demonstrate satisfactory heterogeneous catalytic activity in the colorimetric detection reactions toward phenol pollutants with detection limits of 1.73, 1.92, and 4.6 μM, respectively. Additionally, compounds 1 - 3 show high anti-interference capabilities and high sensitivity in differentiating phenol from its halogenated derivatives. This work presents some guidance for designing specific function-oriented POM-based materials via an in situ ligand transformation strategy.