Two new 2-D frameworks based on tetra-copper(II)-substituted sandwich-type polyoxotungstate anions and [Cu₂(dien)₂(OH)]³⁺ cations

Abstract

Two new organic–inorganic polyoxometalates [Cu(dien)(H₂O)]₂{[Cu₂(dien)₂(OH)]₂[Cu₄(B-α-XW₉O₃₃)₂]}·4H₂O (X = Sb, 1; X = As, 2) (dien = diethylenetriamine) were hydrothermally synthesized and characterized by elemental analysis, IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. Both compounds are constructed from one four-coordinate [Cu(dien)(H₂O)]²⁺, one {[Cu₂(dien)₂(OH)]₂[Cu₄(B-α-XW₉O₃₃)₂]} building unit, and four water molecules of crystallization. Structural analysis shows that the sandwich-like polyoxotungstate cluster anions [Cu₄(B-α-XW₉O₃₃)₂]¹⁰⁻ are linked by six adjacent dimeric cations [Cu₂(dien)₂(OH)]³⁺ into a 2-D architecture with a (6,3)-connected topology. Magnetic measurements of 1 and 2 exhibit the presence of antiferromagnetic interactions within the tetranuclear-Cu^II cluster.

Graphical Abstract

Two new organic–inorganic polyoxometalates with 2-D (6,3)-connected topology architecture [Cu(dien)(H₂O)]₂{[Cu₂(dien)₂(OH)]₂[Cu₄(B-α-XW₉O₃₃)₂]}·4H₂O (X = Sb, 1; X = As, 2) (dien = diethylenetriamine) were hydrothermally synthesized.

Keywords:

• Polyoxometalate
• Hydrothermal
• Crystal structure
• Sandwich-type

Additional information

Funding

Funding. We are grateful to the financial support by the International Technology Cooperation Project of Science and Technology Department of Henan Province of China [grant number 124300510050] and the Foundation of Education Department of Henan Province [grant number 12A150004], [grant number 14A150028].