THE FAVORED TRANS(O-6) GEOMETRY IN HEXADENTATE COPPER(II) COMPLEXES OF 3-PROPANEDIAMINE-N,N'-DIACETIC-N,N'-DI-3-PROPIONIC ACID - CRYSTAL-STRUCTURE OF [CU(1,3-PDDADP)]CENTER-DOT-NANO3-CENTER-DOT-2H(2)O - STRAINANALYSIS AND SPECTRAL ASSIGNMENTS OF COMPLEXES

The octahedral copper(II) complexes of 3-propanediamine-N,N'-diacetic- N,N'-di-3-propionic acid (H(4)1,3-pddadp) prepared in the region of pH 2 to 7 are hexadentates. Only one (trans(O-6)) of the three geometric al isomers was found to dominate. The trans(O-6)-Na-2[Cu(1,3-pddadp)] . NaNO3 . 2H(2)O complex crystallizes in the space group P2/c of the m onoclinic crystal system with a = 9.231(2), b = 11.736(14), c = 10.150 (2) Angstrom, beta = 109.33(2)degrees and Z = 2. The conformations of the chelate rings are found to be envelope for the glycinate and skew- boat for the beta-alaninate and 1,3-propanediamine rings, The complex is a tetragonally elongated octahedron (T similar to 0.8) with C-2 mol ecular symmetry. IR (carboxylate region) and electronic absorption spe ctra are assigned and discussed in relation to the structure of comple xes. For hexadentate Cu(II) edta-type complexes of known structures th e strain analysis is also discussed.