Synthesis and Characterization of Hexadentate Cobalt (III) Complexes with new edta-Type Ligands Part 5.~# Structure and Absolute Configuration of the trans(O_5)(-)_(546)-Isomer of Lithium (Ethylenediamine-N,N,N'-triacetato-N'-3-propionato)cobaltate (

摘要

The preparation and resolution of the two hexadentate Co(III) complexes containing unsymmetrical data-type ligands, [Co(ed3ap)]~- (A) and [Co(u-eddadp)]~- (B) (ed3ap = ethylenediamine-N,N,N'-triacetate-N'-3-propionate ion; u-eddadp = ethylenediamine-N-diacetate-N'-di-3-propionate ion) have been reexamined. The X-ray data are reported for the Λ-(-)_(546)-trans(O)_5-Li[Co(ed3ap)]·H_2O for which the same (Λ) absolute configuration was predicted from the CD sign pattern of the lowest energy band. The complex crystallize in the space group P2_1 (#4) of the monoclinic crystal system with a = 6.523(4), b = 15.025(7) c = 7.464(3), A, β = 105.40(4)°, and Z = 2. The conformations of the chelate rings are found to be envelope for the glycinates and skew-boat (half-chair) for the β-alaninate ring. Structural parameters and strain analysis of [Co(edta-type)]~- chelates are discussed in relation to the structure of the ligand and octahedral distortion of complexes. The CD and IR (carboxylate region) spectra of complexes A and B are also discussed.