Molecular structure of the seven coordinate aqua-(N-hydroxyethyl)ethylenediaminetriacetato titanium(III) and aqua-(N-ethoxo)ethylenediaminetriacetato titanium(IV) ([TiIII(HEDTA)(H2O)]·2H2O and [TiIV(EEDTA)(H2O)]·2H2O)

The molecular structures of the title complexes, [TiIII(HEDTA)(H2O)]·2H2O (1) and [TiIV(EEDTA)(H2O)]·2H2O (2) (HEDTA3−=(N-hydroxyethyl)ethylenediaminetriacetate; EEDTA4−=(N-ethoxo)ethylenediaminetriacetate) were determined by single crystal X-ray analysis. The crystal parameters are as follows: 1, monoclinic, C2/c, a=11.6078(10), b=9.6660(10), c=14.3085(2) Å, β=110.9420(10)°, V=1499.38(3) Å3, Z=4, Dcalc=1.671 g cm−3, R=0.0558, Rw=0.1790; and 2, monoclinic, P21, a=6.7114(2), b=13.0066(2), c=8.5577(2) Å, β=93.5005(4)°, V=745.63(3) Å3, Z=2, Dcalc=1.676 g cm−3, R=0.0306, Rw=0.0741. Both complexes are seven coordinate. The geometry of complex 1 can be approximated as a monocapped trigonal prism, in which HEDTA is hexadentate, with the hydroxyl group coordinated to titanium. A water molecule caps a quadrilateral face as the seventh. Complex 2 has a pentagonal bipyradmidal, in which EEDTA is still hexadentate. Corresponding to increase in the oxidation state of the central metal ion, deprotonation of the hydroxyl group occurred to yield an ethoxo moiety, and to maintain an overall charge of zero for the complex. A water molecule is the seventh ligand, occupying one of the five basal coordination sites.