Chiral transtion metal complexs containing the ligand (S,S)-2,7-Diisopropyl-3,6-diazaoctanedioic acid

Abstract

Complexes of the ligand (S,S)-2,7-diisopropyl-3,6-diazaoctanedioic acid [(S,S)-ebv] with cobalt(111), nickel(11), palladium(11) and copper(11) are reported and structural assignments are made on the basis of spectroscopic data. The complex [Co{(S,S)-ebv}(en)]⁺ has been isolated as the trans(O) isomer with a Δ absolute configuration, as indicated by the c.d. spectrum. The Ni[(S,S)-ebv] complex appears to have an octahedral structure which is attributed to the bidentate character of the carboxylate groups. The Pd[(S,S)-ebv] complex contains an uncoordinated carboxylate group having the fourth coordination site of a square-planar structure occupied by either a bidentate carboxylate group or a water molecule. The c.d. spectrum of Cu[(S,S)-ebv] conforms to the general pattern of copper-amino acidato complexes by having a negative dominant c.d. band-the collective vicinal effect of the asymmetric nitrogen donor atoms does not oppose the remaining symmetric influences in the molecule.