Magnetic and Spectral Properties of 3,5-Dichloropyridine Adducts of Dimeric Copper(II) Acetate, Chloroacetate, and Dichloroacetate

Three complexes with the empirical formula of Cu(RCOO)2·L, where R=CH3, CH2Cl, or CHCl2 and L=3,5-dichloropyridine, were prepared and studied. These complexes display the antiferromagnetic behavior typical of dimeric copper(II) carboxylates. The singlet-triplet splitting energy (−2J) is 349 cm−1 for the acetate, 340 cm−1 for the monochloroacetate and 312 cm−1 for the dichloroacetate. Comparison of their magnetic and electronic spectral properties with those of the corresponding pyridine adducts indicates that both the −2J and \ ildeνmax(absorption maximum of Band I) values of the respective 3,5-dichloropyridine adducts are higher than those of the pyridine adducts. The influence of the pyridines on both the magnetic and spectral properties was discussed.