Optical activity of cobalt(III), chromium(III) and rhodium(III) complexes with aminopolycarboxylate EDTA-type and related ligands

Synthetic, Crystallographic, and Computational Study of Copper(II) Complexes of Ethylenediaminetetracarboxylate Ligands

“…With respect to the carboxylate donors, the three possible isomers are shown in Figure 1, where the nomenclature trans(O 5 ) and trans(O 6 ) refers to axial acetato and propionate groups, respectively. 9,10 The sixmembered carboxylate rings of ethylenediamine-N,N′-diacetato-N,N′-dipropionato ion ([eddadp] 4− ) serve better for the formation of less-strained G rings favoring the trans(O 5 ) isomer of [M(eddadp)] n− complexes when M = Co III , 23,24 Cr III , 25,26 and Rh III or Ni II . 11,27,28 It is worth noting that, for Co III and Rh III , the less stable trans(O 5 O 6 ) isomer is also found and characterized.…”

“…The optically active S,S-edds ligand (S,S-ethylenediamine-N,N′disuccinate ion) produces only the trans(O 5 ) isomer but does so stereospecifically with the Λ configuration. 9 The unsymmetrical ed3ap (ethylenediamine-N,N,N′-triacetate-N′-3-propionate ion) and eda3p (ethylenediamine-N-acetate-N,N′,N′-tri-3-propionate ion) ligands can yield two geometrical isomers differing in the position of the six-and five-membered rings, respectively: trans(O 5 ) or trans(O 6 ) and trans(O 5 O 6 ) ( Figure 1). For M = Co III , 29,30 Cr III , 31,32 or Cu II , 33 the favored lessstrained trans(O 5 ) isomer of [M(ed3ap)] n− was isolated and characterized.…”

Cobalt(II) complexes with aminopolycarboxylate 1,3-pdta-type ligands: synthesis and characterization of trans(O6)-[Mg(H2O)6][CoII(1,3-pddadp)]·H2O

“…In recent years many aminopolycarboxylate ligands, structurally related to edta (ethylenediaminetetraacetate ion), have been prepared and used to form hexadentate complexes with transition metal ions [1,2]. In relation to edta these structurally related ligands have changes in the diamine chain (1,3-propanediminetetraacetate ion, 1,3-pdta [3][4][5][6][7][8][9][10][11]) or in the carboxylate arms (ethylenediamine-N,N¢-diacetate-N,N¢-di-3-propionate ion, eddadp [2,[12][13][14][15][16][17][18][19][20][21][22]), but most of them have longer diamine chains as well as longer single or more carboxylate arms (1,3propane-diamine-N,N¢-diacetate-N,N¢-di-3-propionate ion, 1,3-pddadp [23][24][25][26][27][28]).…”

“…The coordination chemistry of these edta-type ligands is very interesting because they can form hexadentate complexes with rather large metal ions and under their hexadentate coordination more geometrical isomers can be obtained. In the second half of the last century the broad chemistry research of transition metal complexes with different edta-type ligands was carried out [1,2], but only a few hexadentate cobalt(II) complexes with these ligands were described [11,29].…”

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