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

Abstract

Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H(4)eda3p and H(4)eddadp (H(4)eda3p = ethylenediamine-N-acetic-N,N',N'-tri-3-propionic acid; H(4)eddadp = ethylenediamine-N,N'-diacetic-N,N'-di-3-propionic acid) have been prepared. An octahedral trans(O(6)) geometry (two propionate ligands coordinated in axial positions) has been established crystallographically for the Ba[Cu(eda3p)]·8H(2)O compound, while Ba[Cu(eddadp)]·8H(2)O is proposed to adopt a trans(O(5)) geometry (two axial acetates) on the basis of density functional theory calculations and comparisons of IR and UV-vis spectral data. Experimental and computed structural data correlating similar copper(II) chelate complexes have been used to better understand the isomerism and departure from regular octahedral geometry within the series. The in-plane O-Cu-N chelate angles show the smallest deviation from the ideal octahedral value of 90°, and hence the lowest strain, for the eddadp complex with two equatorial β-propionate rings. A linear dependence between tetragonality and the number of five-membered rings has been established. A natural bonding orbital analysis of the series of complexes is also presented.

Five novel dicyanidoaurate(i)-based complexes exhibiting significant biological activities: synthesis, characterization and three crystal structures

“…The and ϕ 2 , relate to the deviations of the atoms from the mean plane of the ring, should be compared to the ideal values of q2>0 and ϕ 2 =0 for the envelope conformation versus q 2 >0 and ϕ 2 =90 for the twisted conformation 51. The basal plane occupied by the four N atoms from the hydeten ligand.…”

Di-µ-oxidovanadium(V) Complex with N'-[(Z)-Phenyl(pyridin-2-yl)methylidene]pyridine-4-carbohydrazide: Synthesis, Structural Characterization and in vitro Antidiabetic Inhibition Study

“…The behaviour of Jahn-Teller effect is decided by the calculated T values of vanadyl complex. This parameter indicates static (T < 0.9) and dynamic (T = 1) distortions in molecular geometry [26,27]. For the present vanadyl complex, T value (1.063) showing a dynamic Jahn-Teller effect.…”

Molecular modeling for Cu(II)‐aminopolycarboxylate complexes: Structures, conformational energies, and ligand binding affinities

“…To be of greater utility, it should also reproduce relative energies. In our previous study, we asserted on the basis of DFT calculations and spectroscopic comparisons that [Cu(eddadp)] 2− should have a trans (O 5 ) geometry with trans (O 5 O 6 ) and trans (O 6 ) computed to be 0.8 and 2.3 kcal mol −1 higher in energy, respectively. The big advantage of LFMM is that a much more comprehensive conformational search can be carried out.…”

“…The archetypal ethylenediaminetetraacetic acid (H 4 edta) is commonly used as a chelating agent, whereas this and other APCs are used to remove heavy metals from soil and water, in diagnostic X‐ray and magnetic resonance imaging, and as bleaching agents in the photographic industry . Our interest spans the fundamental coordination chemistry of APCs through to their potential application for the treatment of various conditions such as Wilson's disease …”

“…Recently, we completed a combined experimental and theoretical study on a series of copper‐APC complexes based on ethylenediamine with various combinations of acetate and propionate arms . Although this work was successfully able to correlate the experimental structural and spectroscopic data with density functional theory (DFT) calculations, it was clear that screening large numbers of potential ligands, plus carrying out comprehensive conformational searches, would make the use of DFT prohibitively expensive.…”