A polyoxoniobate based on dimeric hexanionbate: [Cu(en)₂]₄{[Nb₆O₁₉H₂]K(H₂O)₅}₂ · (H₂en) · 17H₂O

Abstract

A polyoxoniobate, [Cu(en)₂]₄{[Nb₆O₁₉H₂]K(H₂O)₅}₂ ⋅ (H₂en) ⋅ 17H₂O (en = ethylenediamine) (1), has been synthesized and characterized by elemental analysis, IR, XPS, TGA, and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P 1, with a = 12.3533(16) Å, b = 12.7188(16) Å, c = 29.626(4) Å, α = 93.235(2)°, β = 96.094(1)°, γ = 106.098(2)°, V = 4429.0(10) ų, Z = 2. The polyoxoanion is composed of a Lindqvist-type [Nb₆O₁₉H₂]⁶⁻ dimer bi-bridged via two K⁺. K⁺ is 10-coordinate with 10 oxygens, three from one [Nb₆O₁₉H₂]⁶⁻, one from a terminal oxygen of another [Nb₆O₁₉H₂]⁶⁻ moiety, and the other six from water molecule. Adjacent dimeric polyoxoanions are linked to form an infinite 1-D chain via O–H ··· O hydrogen-bonding interactions which exist between the two water trimers and the dimeric polyoxoanions.

Keywords:

• Polyoxoniobate
• Lindqvist type
• Dimer
• Trimer

Acknowledgments

This work was supported by the Natural Science Fund Council of China (NSFC, Nos. 20671011, 20731002, 20801004, 10876002, 20801005), Program of Cooperation of the Beijing Education Commission (20091739006), Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP, No. 200800070015), Open Fund of State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology (No. ZDKT08-01, 1020020450802).