pH-dependent assembly of two polyoxometalate-based coordination polymers: structures and electrocatalytic properties

Abstract

Two new polyoxometalate-based coordination polymers have been synthesized at different pHs under identical hydrothermal conditions, (Hbib)[Cu₂(bib)₂(PMo₁₂O₄₀)] (1) and (Hbib)₂[Cu(bib) (PMo₁₂O₄₀)]·2H₂O (2) (bib = 4-bis(imidazol-1-yl) benzene). Their structures were determined by single crystal X-ray diffraction analyses and characterized by routine methods. When the pH was adjusted to 2.0 − 2.5, 1 was obtained, which exhibits a 1-D rail-like chain. Compound 2 was obtained at pH of 2.5 − 3.2 and exhibits a 2-D layer with (4⁴) sql net. The pH of the reaction plays a key role in the assembly of the polyoxometalate-based coordination polymer. The electrochemical experiments indicate that 2-based carbon paste electrode possesses high catalytic efficiency and high stability towards reduction of iodate and oxidation of ascorbic acid.

Keywords:

• Polyoxometalates
• coordination polymer
• pH-dependent
• electrocatalytic property

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Science Foundation of China (21603113), the National Science Foundation of Heilongjiang Province (QC2016014), the Foundation of Education Committee of Heilongjiang (Qiqihar University Research Project 135209302 and 135109212), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2017158), and Undergraduate Training Programs for Innovation and Entrepreneurship of Qiqihar University (no. 201810232023).