Three polyoxometalate-tuned copper complexes based on in situ ligand transformation: syntheses, structures, and properties

Abstract

Depending on the in situ ligand transformation of 3,5-di(1,2,4-triazol-1-yl)benzonitrile (DTCN) to 3,5-di(1,2,4-triazol-1-yl)benzoic acid (DTCA) under hydrothermal condition, three polyoxometalate-based copper complexes, [Cu^I₄Cu^II₂(OH)₂(H₂O)₄(DTCA)₄(HPMo^VI₁₀Mo^V₂O₃₉)] (1), [Cu₄(OH)₂(H₂O)₄(DTCA)₂(SiW₁₂O₄₀)]·11H₂O (2), and {Cu₂Cl(H₂O)(HDTCA)₂[CrMo₆(OH)₆O₁₈)]}·4H₂O (3), have been isolated through changing the polyoxoanions. Introducing Keggin-type polyoxoanions [PMo₁₂O₄₀]³⁻ or [SiW₁₂O₄₀]⁴⁻ to reaction systems, both 1 and 2 display 3-D framework structures containing Cu/DTCA metal-organic belts, and a kind of poly-Keggin chain derived from [PMo₁₂O₄₀]³⁻ polyoxoanions exist in 1. When the Anderson-type polyoxoanion [CrMo₆(OH)₆O₁₈)]³⁻ is utilized, a 2-D grid-like layer resulted in 3, in which the DTCA ligands are embedded, revealing that the polyoxoanions have key roles in regulating the structures of complexes. The investigations on electrochemical properties and photocatalytic activities for the degradation of organic dyes of 1–3 have been carried out.

Graphical Abstract

Keywords:

• Polyoxometalate
• in situ transformation
• electrochemical activities
• photocatalytic properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The National Natural Science Foundation of China (No. 21771025) and the General Program Fund for Education Department of Liaoning Province (LJ2019004) are gratefully acknowledged.