Syntheses, crystal structures, and magnetism of two phenylacetate imidazolate copper(II) complexes

The influence of pH for the reaction system involving CuCl2 · 2H2O, imidazole (Him) and phenylacetic acid (HL) at room temperature was investigated. Cu2(Him)4L4 · 2H2O (1) and Cu3(Him)2(im)2L4 (2) were synthesized at pH 6.5 and 7.5, respectively. In 1, the Cu is coordinated by two nitrogen atoms of two Him and three oxygen atoms from three phenylacetates to form a square pyramid CuN2O3. Adjacent square pyramids share edges to form Cu2N4O4 dimers, which are assembled by hydrogen bonds into a 2-D layer parallel to the (001) plane. In 2, copper atoms are interlinked by im− and L− to form a 2-D layer parallel to (100). The resulting layers have C–H···O hydrogen bonds leading to a 3-D supramolecular architecture. Variable temperature magnetism of 1 and 2 suggests a weak ferromagnetic or antiferromagnetic coupling exchange (J = 0.58 cm−1 for 1, J = −10.24 cm−1 for 2).