STRUCTURALLY DIVERSE COPPER(II) HERBICIDE COMPLEXES - MONONUCLEAR ANDBINUCLEAR NEUTRAL OR CATIONIC COMPLEXES

Copper complexes with the commercial auxin herbicides 2,3-dichlorophen oxyacetic acid and 2-(2,4-dichlorophenoxy)propanoic acid and 2,2'-bipy ridine (bipy) were prepared and characterized: [Cu-2(Cl2C6H3OCH2CO2)(4 )(MeOH)(2)] 1, [Cu{Cl2C6H3OCH(Me)CO2}(2)(bipy)(H2O)] 2 and [Cu{Cl2C6H3 OCH(Me)CO2)(bipy)(2)]Cl 3. The available evidence supports a dimeric s tructure for complex 1 while the presence of bipy leads to monomeric f orms. In dimethylformamide solution the binuclear complex is converted into a monomeric complex upon addition of a > 1:2 ratio of bipy. The ESR powder spectrum of compound 2 exhibits features characteristic of the presence of a S = 1 triplet state which may be assigned to a hydro gen-bond network. The crystal structures of the three complexes have b een determined.