The Crystal and Molecular Structure of sym- fac -(1,4,7-Triazaheptane)-( S )-aspartatocobalt(III) Diperchlorate Dihydrate

The crystal and molecular structure of s- fac -[Co(( S )-Asp)(dien)]ClO 4 . HClO 4 .2 H 2 O (dien = 1,4,7-triazaheptane) was solved by the heavy atom method. The position parameters of the non-hydrogen atoms and their anisotropic temperature parameters were refined based on 1 726 observed reflections with a final value of R = 0.073. The substance crystallizes in the orthorhombic system in the space group P2 1 2 1 2 1 , Z = 4, a = 8.506(1), b = 17.171(2), c = 13.277(1) A. The structure involves hydrogen bonds between the O2, O4 and HN2 atoms of aspartic acid and the two molecules of water. The five-membered dien chelate rings take the asymmetric envelope conformations. The five-membered ring of ( S )-aspartic acid possesses the symmetric envelope conformation whereas the six-membered ring exhibits the skew boat conformation.