MOLECULAR STRUCTURES OF FE(II) COMPLEXES WITH MONO- AND DIPROTONATED ETHYLENEDIAMINE-N,N,N',N'-TETRAACETATE (HEDTA AND H(2)EDTA), AS DETERMINED BY X-RAY CRYSTAL ANALYSES

摘要

The molecular structures of the title complexes [Fe(H2O)(4)][Fe(Hedta)(H2O)](2) . 4H(2)O (I) and [Fe(H(2)edta)(H2O)]. 2H(2)O (II) have been determined by single-crystal X-ray analyses. The crystal data are as follows: I: monoclinic, P2(1), a=11.794(2), b=15.990(2), c=9.206(2) Angstrom, beta=90.33(1)degrees, V=1736.1(5) Angstrom(3), Z=2 and R=0.030; II: monoclinic, C2/c, a=11.074(2), b=9.856(2), c=14.399(2) Angstrom, beta=95.86(1)degrees, V=1563.3(4) Angstrom(3), Z=4 and R=0.025. I is found to be isomorphous with the Mn-II analog reported earlier and to contain a seven-coordinate and approximately pentagonal-bipyramidal (PB) [Fe-II(Hedta) (H2O)](-) unit in which Hedta acts as a hexadentate ligand. The [Fe-II(H(2)edta)(H2O)] unit in II has also a seven-coordinate PB structure with the two protonated equatorial glycine arms both remaining coordinated, and thus bears a structural resemblance to the seven-coordinate [Co-II(H(2)edta)(H2O)] reported previously. [References: 48]