Intermolecular interaction and magnetic coupling mechanism of a mixed-valence Cu^IICu^I tetranuclear complex with iodide bridge

Abstract

A tetranuclear Cu^ICu^II mixed oxidation state complex, [Cu^II ₂(μ-I)₂Cu^I ₂(μ-I)₂(phenP)₂I₂] (phenPE: 2-(1H-pyrazol-1-yl)-1,10-phenanthroline), has been prepared and its crystal structure is determined by X-ray crystallography. In the complex, Cu^II is a distorted square pyramid and Cu^I is a distorted trigonal planar coordination environment; Cu^II and Cu^I are bridged by iodide. It is rare to form a Cu^II-iodide bond and for Cu^II and Cu^I to be bridged by iodide. In the crystal, there is a slipped π–π stacking between adjacent Cu^II complexes, which resulted in the formation of the 1-D chain along the c axis. The fitting for the variable-temperature magnetic susceptibility data gave magnetic coupling constant 2J = −1.16 cm⁻¹ and it may be ascribed to the intermolecular π–π magnetic coupling pathway.

Keywords:

• Crystal structure
• Magnetic coupling
• Intermolecular interaction
• Copper complex

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Grant no. 20971080), the Natural Science Foundation of Shandong Province (Grant no. ZR2010BL016), and the Project of Shandong Province Higher Educational Science and Technology Program (Grant no. J13LD53).