Structure, Spectral and Magnetic Properties of 3-(p-Pyridyl)-1,5-diphenylverdazyl (p-PyV) and the Binuclear Copper(II) Radical Complex [Cu2(OCOCH3)4(p-PyV)2]

3‐(p‐Pyridyl)‐1,5‐diphenylverdazyl (p‐PyV) and its binuclear copper(II) complex [Cu2(OCOCH3)4(p‐PyV)2] have been synthesized and structurally characterized. The magnetic behavior of a single crystal of p‐PyV and [Cu2(OCOCH3)4(p‐PyV)2] have been studied by magnetic susceptibility measurements in the temperature range 2–300 K and by ESR spectroscopy. Data fitting for p‐PyV using the singlet‐triplet equilibrium model revealed the existence of antiferromagnetic interactions in the radical crystal lattice. The exchange interactions between the copper(II) ion and p‐PyV in Cu2(OCOCH3)4(p‐PyV)2 were found to be negligibly small compared to the strong intramolecular copper–copper antiferromagnetic interaction. Intermolecular antiferromagnetic coupling between p‐PyV molecules was detected in the crystal lattice of complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) Pyridyl‐substituted verdazyl (p‐PyV) and the binuclear copper complex [Cu2(OCOCH3)4(p‐PyV)2] are synthesized and structurally characterized. Their magneticproperties are studied by ESR spectroscopy and by measuring their temperature‐dependent magnetic susceptibility.