Mononuclear manganese and tetranuclear copper compounds and their supramolecular networks constructed from hexafluoroglutaric acid and 2,2′-bipyridine

Abstract

Mn(2,2′-bpy)₂(HFGA) (1) and [Cu₄(μ₃-OH)₂(μ₂-OH)₂(H₂O)₂(2,2′-bpy)₄] · 2HFGA · 4H₂O (2) (H₂HFGA = hexafluoroglutaric acid and 2,2′-bpy = 2,2′-bipyridine) have been synthesized and characterized by X-ray structural analyses. 1 is a monomer with six-coordinate Mn²⁺ from two oxygens of HFGA and four nitrogens of two 2,2′-bpy. Complex 2 is tetranuclear with four Cu²⁺ ions bridged by triple-bridging μ₃-OH and double-bridging μ₂-OH. There are two crystallographically independent Cu²⁺ ions in different five-coordinate environments. Cu1 is coordinated by 2,2′-bpy and three OH ligands. Cu2 is coordinated by 2,2′-bpy, two μ₃-OH ligands, and one water molecule. The mononuclear and tetranuclear molecules as building blocks are connected to construct different 3-D supramolecular architectures via noncovalent interactions. Particularly, the lone pair (lp)–π (F···π) interaction in 1 is observed. A hybrid water-anionic tape by linkage of {[(H₂O)₄(HFGA)]₂ ⁴⁻} _n fragments consisting of water dimers and HFGA anions in 2 is observed.

Keywords:

• Manganese
• Copper
• Hexafluoroglutaric acid
• Crystal structure

Acknowledgments

We are grateful to the Science and Technology Program, Beijing Municipal Education Commission (KM200910028010) and the National Natural Science Foundation of China (21071101).