CuII acetate complexes involving N,N,O donor Schiff base ligands: Mono-atomic oxygen bridged dimers and alternating chains of the dimers and Cu2(OAc)4

Abstract Two tridentate N,N,O donor Schiff bases, HL 1 (4-(2-ethylamino-ethylimino)-pentan-2-one) and HL 2 (3-(2-amino-propylimino)-1-phenyl-butan-1-one) on reaction with Cu II acetate in presence of triethyl amine yielded two basal-apical, mono-atomic acetate oxygen-bridging dimeric copper(II) complexes, [Cu 2 L 1 2 (OAc) 2 ] ( 1 ), [Cu 2 L 2 2 (OAc) 2 ] ( 2 ). Whereas two other similar tridentate ligands HL 3 (4-(2-amino-propylimino)-pentane-2-one) and HL 4 (3-(2-amino-ethylimino)-1-phenyl-butan-1-one) under the same conditions produced a mixture of the corresponding dimers and a one-dimensional alternating chain of the dimer and copper acetate moiety, [Cu 4 L 3 2 (OAc) 6 ] n ( 3 ) and [Cu 4 L 4 2 (OAc) 6 ] n ( 4 ), formed by a very rare μ 3 bridging mode of the acetate ion. All four complexes ( 1 – 4 ) have been characterized by X-ray crystallography. The isotropic Hamiltonian, H  = − JS 1 S 2 has been used to interpret the magnetic data. Magnetic measurements of 1 and 2 in the temperature range 2–300 K reveal a very weak antiferromagnetic coupling for both complexes ( J  = −0.56 and −1.19 cm −1 for 1 and 2 , respectively).