Mr. Sundberg et al., CRYSTAL-STRUCTURE AND MOLECULAR-STRUCTURE OF O)BIS(1,3-DIAMINO-2-HYDROXYPROPANE-N,N')COPPER(II) AT 193-K AND 296-K, Acta chemica Scandinavica, 50(5), 1996, pp. 405-410
The structure of the title compound was determined by single-crystal X
-ray methods. -O)bis(1,3-diamino-2-hydroxypropane-N,N)copper(II) cryst
allises in the monoclinic crystal system, space group P2(1)/c, no. 14,
Z = 2. At 193 K a = 6.507(9), b = 7.182(7), c = 24.300(8) Angstrom, b
eta = 95.02(7)degrees and V = 1131(2) Angstrom(3); at 296 K a = 6.519(
2), b = 7.205(2), c = 24.445(5) Angstrom, beta = 95.12(2)degrees and V
= 1144(1) Angstrom(3). The copper(II) displays elongated pseudo-octah
edral coordination polyhedron with the site symmetry Ci. The 1,3-diami
no-2-hydroxypropane forms a six-membered chelate ring displaying a cha
ir conformation in the equatorial direction. The non-coordinated hydro
xyl group in the chelate ring forms a hydrogen bond to a neighbouring
coordinated oxygen atom of the carboxylate group. The axially situated
carboxylate group is twisted about 82 degrees with respect to the ana
logous compound, where the equatorial ligand is 1,3-diaminopropane wit
hout a hydroxyl group. The non-coordinated oxygen is now projected in
between the two chelate rings. The only significant difference upon co
oling is seen in the compression of the axial Cu-O bond length from 2.
479(3) to 2.459(2) Angstrom. Based upon EHMO calculations, the amount
of d-s mixing as a rationale for the axial elongation is about 6%.