Metal-cinnamic acids interactions. Part IV. Synthesis, study and antimicrobial activity of copper(II) complexes of 3,4-dimethoxyhydrocinnamic acid

Compounds [Cu(DPP)2] (1), [Cu(DPP)2H2O]MeOH (2) (DPPH=3,4-dimethoxyhydrocinnamic acid), were synthesized and investigated by means of electronic, i.r. and room and low temperature e.s.r. spectroscopy. Compound (2) shows an e.s.r. spectrum characteristic of axially symmetric carboxylate dimers with S=1, whereas the anhydrous compound (1) shows e.s.r. features that can be interpreted if the triplet state, depending on the temperature, is able to migrate through the crystal lattice. The results for the copper(II) compounds obtained with DPPH are compared with those obtained with 3,4- and 3,5-DMCH (3,4-, and 3,5-DMCH=3,4- and 3,5-dimethoxycinnamic acid). The ligands and their complexes have been tested for antimicrobial activity. © 1989 Chapman and Hall Ltd.