Hexadentate rhodium(III) complexes of 1,3-propanediamine-N,N′-diacetic-N,N′-di-3-propionic acid. Crystal structures of trans-(O5)-Na[Rh(1,3-pddadp)]·H2O and (+)589-trans-(O5O6)-Na[Rh(1,3-pddadp)]·3H2O and CD spectra correlation. Octahedral distortion of [

Structural data are given for two earlier reported hexadentate Rh(III) complexes: trans-(O5)-Na[Rh(1,3-pddadp)]·H2O (1) and trans-(O5O6)-Na[Rh(1,3-pddadp)]·3H2O (2) (1,3-pddadp=1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate ion). Both complexes have been resolved. The absolute configuration around the Rh(III) ion for the (+)589 optical isomer in the crystal 2 has been determined to be the Λ (ΛΔΛ). The complexes crystallize in monoclinic P21/c (1) and orthorhombic P212121 (2) space groups. Based on a low-temperature measurements (150 K), both crystal structures have been refined to a final R value of 0.029. The conformations of the glycinate rings in 2 are common (R relatively flat and G with a significant deviation) while the two R rings of 1 (in an envelope and twist conformations) show unusually large total deviation (of −6°av.). The six-membered β-alaninate (R, G) and the diamine (T) rings adopt in both compounds distorted boat (twist-boat) conformations. Octahedral distortion of [Rh(edta-type)]− chelates is discussed in relation to the structure of the ligand and the geometry of the complex. The CD spectra of the Λ-(−)589-trans-(O5)-Rh[(1,3-pddadp)]− (1) and Λ-(+)589-trans-(O5O6)-[Rh(1,3-pddadp)]− (2) and the other Λ-[Rh(edta-type)]− complexes have been correlated and discussed. The lowest energy CD component is positive for the Λ-isomers of 1 and 2, but negative for the other Λ-[Rh(edta-type)]− complexes that is forced to reverse the assignments of the CD peaks.