Synthesis and spectroscopic study of copper(II) and manganese(II) complexes with pipemidic acid

The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem) 2(H 2O)]·2H 2O, 1 and [Mn(pipem) 2(H 2O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV–vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule.