Proton NMR Spectroscopy and Magnetic Properties of a Solution-Stable Dicopper(II) Complex Bearing a Single μ-Hydroxo Bridge

The reaction of copper(II) perchlorate with the macrocyclic ligand [22]py4pz in the presence of base leads to
formation of a dinuclear complex [Cu2([22]py4pz)(μ-OH)](ClO4)3·H2O, in which two copper ions are bridged by a
single μ-hydroxo bridge. Each copper ion is further surrounded by four nitrogen atoms of the ligand. The μ-hydroxo
bridge mediates a strong antiferromagnetic coupling (2J = −691(35) cm-1) between the metal centers, leading to
relatively sharp and well-resolved resonances in the 1H NMR spectrum of the complex in solution. We herein
report the crystal structure, the magnetic properties, and the full assignment of the hyperfine-shifted resonances in
the NMR spectrum of the complex, as well as the determination of the exchange coupling constant in solution
through temperature-dependent NMR studies.