E.p.r. studies of the effect of extensive conjugation of coordinated C=O and C=N in some copper(II) complexes

Abstract

E.p.r. studies indicate the delocalisation of the unpaired electron in the Cu^II complex of 2'-hydroxychalcone into the benzene ring. The 2-hydroxycrotonophenone complex has decreased covalency in the M-O σ -bond. The e.p.r. parameters of these complexes in pyridine solution show that their adducts are formed. A good correlation of magnetic properties with bonding characteristics has been obtained. The σ -bond covalency parameter shows a linear relationship with N_iso values which follow the order: ethylenediamine > N-Me > N-alkyl > N-H in the chalconeimine complexes.