SYNTHESIS, CRYSTAL STRUCTURES AND MAGNETIC PROPERTIES OF TWO METHOXO-BRIDGED DIMERIC COPPER(II) COMPLEXES [Cu_2(APMD)_4((mu)_2-OMe)_2]X_2 (APMD = 2-aminopyrimidine; X = BF_4~- or CIO_4~-)

摘要

Two bis-methoxo-bridged dimeric copper(II) complexes, [Cu_2(OMe)_2(APMD)_4](BF_4)_2 1 and [Cu_2(OMe)_2(APMD)_4](ClO_4)_2 2, were prepared and characterized by x-ray single-crystal structure analysis and magnetic susceptibility. Complexes 1 and 2 are isomorphous, being composed of discrete [Cu_2((mu)_2-OMe)_2(APMD)_4]~(2+) cations and anions with each Cu(II) atom ligated by two pyrimidine nitrogen atoms (Cu-N approx= 20.1 A) from two APMD ligands and two oxygen atoms (Cu-O approx= 1.92 A) from the (mu)_2-methoxo groups in a distorted square-planar geometry. The intramolecular metal-metal separations in the two complexes are ca. 2.95 A. the intermediate antiferromagnetic exchanges (J approx= -270 cm~(-1)) for the two complexes indicate a good overlap between the electronic orbitals of the square-planar copper(II) center via bridging oxygen atoms.