Conformational Analysis of Bis(<scp>L</scp>‐N,N‐dimethylvalinato)copper(<scp>II</scp>) and Bis(<scp>L</scp>‐N,N‐dimethylleucinato)copper(<scp>II</scp>) in Different Solvents by EPR Spectroscopy and a Molecular Mechanics Study

Mirosavljević, Krunoslav; Sabolović, Jasmina; Noethig-Laslo, Vesna

doi:10.1002/ejic.200300781

Cited by 9 publications

(4 citation statements)

References 47 publications

(60 reference statements)

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“…to the side with the higher value of overlapping volume, V*, as defined by the algorithm presented in this paper. This quite unexpected result could be connected with the finding that bulky substituents prevent hydrogen bonding of an apically situated ligand with solvent molecules (Noethig-Laslo & Paulić, 1999;Mirosavljević et al, 2004), stabilizing in such a way the apical Cu-O bond in the crystal structure. Also, the structure could possibly be stabilized by weak C-HÁ Á ÁO hydrogen bonding (Steiner, 1996) between the apical ligand and the amino acid side chain(s).…”

Section: Discussionmentioning

confidence: 92%

Theoretical analysis of apical bonding in copper(II) chelates with amino acids

Miličević

Raos

2009

J Appl Cryst

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The interdependence between the side of apical coordination (H2O, >C=O, dimethyl sulfoxide and Cl−) and steric crowding at the apical positions was investigated for a set of 20 copper(II) bis complexes with naturally occurring amino acids. As a measure of steric crowding the overlapping volumes, V*, were used, calculated by the modified overlapping spheres method. It was found that the apically coordinated side of a complex is more hindered by the side‐chain atoms. In addition, if both sides are apically coordinated, the apical bond is shorter at the more crowded side. The interdependence between the length of the apical bond and distortion of the coordination polyhedron was also studied. The apical bond length shows sigmoidal dependence on the magnitude of distortion, and is also dependent on the kind of distortion (square‐pyramidal or tetrahedral).

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Section: Discussionmentioning

confidence: 92%

Theoretical analysis of apical bonding in copper(II) chelates with amino acids

Miličević

Raos

2009

J Appl Cryst

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“…The coordination environment provided by our DFT calculations for [Cu 2 (L T ) 2 ] 12− is very similar to that observed for such complexes with amino acids, 31,32 which also provides EPR parameters close to those determined for the Cu(II) complex of L T . 33…”

Section: Dft Studiesmentioning

confidence: 99%

Tetraphosphonated thiophene ligand: mixing the soft and the hard

et al. 2014

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The synthesis of ligand L(T)H8, based on a thiophene framework containing two bis(aminomethyldiphosphonate) functions in the ortho position to the central sulfur atom, is described, together with the characterization of the intermediate compounds. The physico-chemical properties of the ligand were first studied by means of potentiometry and UV-Vis absorption spectrophotometric titrations to determine its pK values. Six successive equilibrium constants were determined in aqueous solutions. The same means were then used to quantify the interactions of the ligand with Ni(II), Cu(II) and Zn(II). Following the conventional Irving-Williams trend, L(T) was shown to have the highest affinity towards Cu(II) (log K(CuL(T)) = 16.11(3)), while Zn(II) and Ni(II) showed similar values (log K(ML(T)) = 10.81(8) and 10.9(1), respectively), revealing a large selectivity of L(T) toward Cu(II). Based on a combination of UV-Vis absorption spectroscopy and EPR measurements as a function of pH, along with DFT calculations, the coordination behavior of the hard phosphonate, medium amino and soft thiophene entities are questioned regarding their coordination to the Cu atom.

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“…Most spectroscopic and electrochemical methods allow identification of the prevailing complexes and their stability constants in solutions, but they provide no structural information. 3,[8][9][10][11][12][13][14][15][16][17][18][19] For instance, trans and cis isomers for a number of bis(amino acidato)copper(II) complexes were confirmed to exist in aqueous solution by the 14 N superhyperfine structure in electron paramagnetic resonance (EPR) spectra without details on their geometry. [16][17][18][19] Some structural data only for bis(glycinato)copper(II), Cu(Gly) 2 , in aqueous solution were obtained by X-ray absorption spectroscopy, 20 whereas for other copper(II) chelates with aliphatic R-amino acids and their N-alkyl derivatives, the only experimentally available structures are those determined by X-ray and neutron diffraction studies.…”

Section: Introductionmentioning

confidence: 99%

Structure Prediction of Bis(amino acidato)copper(II) Complexes with a New Force Field for Molecular Modeling

Sabolović

Gomzi

2009

J. Chem. Theory Comput.

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This article presents a new force field whose parameterization was based on experimental crystal data and quantum chemically obtained vacuum structures of a series of copper(II) complexes with aliphatic α-amino acids and their N-alkyl derivatives, along with the SPC/E water model. The ability of the new force field to reproduce and predict the structural properties of the copper(II) complexes in the gas phase, in simulated crystalline surroundings, and solvated in water is examined. Molecular dynamics (MD) simulations with the new force field yielded time-average structural coordinates of bis(glycinato)copper(II) [the only one of 25 modeled bis(amino acidato)copper(II) systems with published experimental structural data in aqueous solution at room temperature] within the experimental error values. The study of the cis-trans isomerization of bis(glycinato)copper(II) in aqueous medium at 300 K using the quantum chemical polarized continuum model revealed a small energy difference (5 kJ mol(-1)) between the solvated cis and trans minima, in line with the MD energy estimations. The new force field proved promising in predicting the association of the complexes in aqueous solution and formation of a nucleus of crystallization.

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Conformational Analysis of Bis(L‐N,N‐dimethylvalinato)copper(II) and Bis(L‐N,N‐dimethylleucinato)copper(II) in Different Solvents by EPR Spectroscopy and a Molecular Mechanics Study

Cited by 9 publications

References 47 publications

Theoretical analysis of apical bonding in copper(II) chelates with amino acids

Theoretical analysis of apical bonding in copper(II) chelates with amino acids

Tetraphosphonated thiophene ligand: mixing the soft and the hard

Structure Prediction of Bis(amino acidato)copper(II) Complexes with a New Force Field for Molecular Modeling

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