Electrocatalytic reduction of carbon dioxide mediated by transition metal complexes with terdentate ligands derived from diacetylpyridine

The electrochemical characterization and electrocatalytic activity, towards the reduction of carbon dioxide, of transition metal complexes with terden tate ligands derived from diacetylpyridine are presented. We have prepared Fe, Co and Ni complexes of (i) 2,6-bis-[ 1-(phenylimino)ethyl]pyridine (DAP A), (ii) Br-DAPA, (iii) vinyl-DAPA (v-DAPA), (iv) 2,6-bis[1-(benzylimino)-e thyl]pyridine (DAPB), (v) 2,6-bis[1 -(2-methylpyridylimino)ethyl]pyridine ( DAPMP), and (vi) 2,6-bis[1-(2-ethylpyridylimino)ethyl]pyridine (DAPEP). In general, we find that all of these materials exhibit electrocatalytic behav ior towards the reduction of CO2 in non-aqueous solvent. The electrocatalyt ic activity was dependent on both the metal center and the ligand. The tren ds can be rationalized in terms of electronic effects arising from the liga nd and on whether the redox process is ligand or metal localized. (C) 2000 Elsevier Science S.A. All rights reserved.