Coordination chemistry of hexadentate EDTA-type ligands with M(III) ions

Nickel(II) complexes of whole set of the simple ethylenediaminetetracarboxylate ligands: DFT study of complexes invoking molecular orbital and configurational analysis

“…DFT method gave a trans(O 5 O 6 ) isomer as the most favored one the geometry that is in accordance with those already found in case of [Co III (eda3p)] complex [3]. Optimized geometry of this complex along with calculated geometry of [Ni(edtp)] 2À anion have been taken for the strain analysis.…”

“…The effects of chelating agents and drugs used clinically as antidotes to metal toxicity were reviewed in several articles [1]. Our group still continue to research in the field of M(III) and M(II) (particularly paying attention to Cu(II) and Ni(II)) complexes of EDTA-type diaminopolycarboxylate ligands in decades long tradition [2][3][4][5][6][7]. In the [M(edta)] nÀ systems the deviation of the bonding angles from the ideal values in [M = Co(III), Cu(II), Ni(II)] and other ethylenediaminetetra acetate (edta) metal complexes shows significance of the ligand strain.…”

EDTA: An Antimicrobial and Antibiofilm Agent for Use in Wound Care

“…At very low pH the fully protonated H 6 EDTA 2 + form predominates, whereas at very high pH or very basic conditions, the fully deprotonated EDTA 4 -form is prevalent. 32 EDTA has traditionally been useful as a metal chelator due to its high density of ligands and resulting affinity for metal ions with binding typically occurring through its two amines and four carboxylate groups. Figure 1 shows the conjugate base of EDTA.…”

Absolute Chiral Structures of Inorganic Compounds

“…For the present edta-type complexes, the major CD component rule for the absolute configuration results in inconsistent assignments of the absolute configurations, but are in agreement with the empirical rule that edta-type complexes take a L(LDL) configuration when the lowest frequency A(C 2 ) CD component derived from the E(D 4h ) state in the holohedralized tetragonal (D 4h ) field is positive. [165][166][167] In contrast to the high diastereospecificity found in the edta-type complexes with strained five-membered acetate rings, the edtp (ethylenediamine-N,N,N 0 ,N 0 -tetra-3-propionate) complexes with the less strained flexible six-membered propionate rings ( Figure 5.37a) displayed stereospecificity arising from the enantiomeric ethylenic gauche conformation of the propionate rings other than the diamine conformation. 168,169 The reaction of S-propylenediamine-N,N,N 0 ,N 0 -tetra-3-propionate (S-pdtp) and (1S,2S)-trans-cyclohexanediamine-N,N,N 0 ,N 0 -tetra-3-propionate (S,S-cdtp) ligands ( Figure 5.37b) with chromium(III) ion gave three isomers of [Cr(S-pdtp)] À and [Cr(S,S-cdtp)] À in comparable formation ratio.…”