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 [Rh(edta-type)]− complexes in relation to the structure of the ligand and geometry of the complex