AMINO-ACID COMPLEXES OF [CO(III)(TRIEN)](+3)

Seven beta(2)-[Co(trien)(amino acid)](+n) complexes have been investig ated and the structural parameters compared with literature values and molecular mechanics calculations. All beta(2) compounds exhibit the ( S,S,lambda lambda delta) or (R,R,delta delta lambda) configuration. Th ree of the beta(2), complexes have monocoordinated amino acids or amin o acid esters while the amino acid is chelated in the others. The Co-N bond trans to the amino acid oxygen or a Cl- varies significantly in length due to the trans-effect. The chelate rings are twisted to minim ize torsional interactions and the changes in conformation in the vari ous structures can be modeled by molecular mechanics. In one complex t he carbonyl groups of enantiomeric complexes are bridged by silver ion s. In beta(2)-[Co(trien)(C-formylglycine)]Cl-2.H2O the carbonyl oxygen of the chelated amino acid is protonated and the formyl group exists in the enol form.