Synthesis, Crystal Structures, and Magnetic Properties of a Cobalt Complex With Nitronyl Nitroxide Radical

Abstract

A cobalt complex with nitronyl nitroxide, Co(hfac)₂(NITPh-p-Br)₂ (hfac = hexafluoroacetylacetonate; NITPh-p-Br = 2-(4′- bromophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), was synthesized. The complex has been investigated by X-ray crystal diffraction and magnetic susceptibility measurements. The crystal structure consists of Radical-Co-Radical tri-spin units, in which the central Co(II) ion is coordinated by four oxygen atoms from two hfac and two oxygen atoms from the NITPh-p-Br. Furthermore, dimmer structure [Co(hfac)₂(NITPh-p-Br)₂]₂ is formed through hydrogen bond interaction between the hydrogen atom of C-H group from the hfac ligand and the fluorine atom of the C-F group from another hafc ligand. Magnetic susceptibility measurements indicate that the Co(II) ions interact antiferromagnetically with the directly bonding nitroxide group of the radicals.

Keywords:

• crystal structure
• hydrogen bond
• magnetic property
• nitronyl nitroxide

Acknowledgments

This work was supported by the National Natural Science Foundation of China (No. 20771081).