Molecular structure and exchange interactions in trans-bis(L-2-aminobutyrato)copper(II) and trans-bis(DL-2-aminobutyrato)copper(II)

Levstein, Patricia R.; Calvo, Rafael; Castellano, E. E.; Piro, Oscar E.; Rivero, B. E.

doi:10.1021/ic00345a003

Cited by 26 publications

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“…Other magnetic or specific heat measurements in copper complexes of amino acids and peptides have been reported by Newman et al [66] for Cu(L-isoleucine) 2, by Calvo et al [45] and Rapp et al [67] for Cu(L-alanine)z and by Siqueira et al [68] for Cu(L-but) 2 and Cu(D,L-but)2 (but stands for 2-aminobuty¡ acid). In the analysis of the information it has to be considered that interactions connecting copper ions with identical positions in the lattice do not contribute to the EPR results.…”

Section: Comparison Of Epr Results With Values Obtained From Nonresonmentioning

confidence: 81%

“…However, they may be the leading factors in the magnetic properties (see, for example, refs. 45,47,50,55,63,67,68). In other cases the thermodynamic measurements allow measuring interactions with magnitudes larger than those that can be observed by EPR [50,63].…”

Section: Comparison Of Epr Results With Values Obtained From Nonresonmentioning

confidence: 99%

“…The exchange interactions produce a spin dynamics with a characteristic frequency oex that averages out the splitting of the lines. Cases where x > 1 allow simple implementations of the exchange narrowing process to evaluate exchange interactions [38,[43][44][45][46][47][48][49][50][51][52][53][54].…”

Section: Collapsed-resonance Regimementioning

confidence: 99%

“…It is similar to what is obtained with the simpler Anderson theory (Eq. (8)) and has been used in several works to calculate exchange interactions from line width data [28,[38][39][40][42][43][44][45][46][47][48][49][50][51][52][53][54][55].…”

Section: Collapsed-resonance Regimementioning

confidence: 99%

“…(9) on co02 allows the separation of contributions to the width arising from the exchange narrowing process from those arising from dipolar and other interactions that are frequency independent (see for example, refs. 28,[42][43][44][45][46][47][48][49]. The molecular g-tensors gA and g~ corresponding to individual metal sites can be evaluated under simple assumptions [56,57] from the crystal g-tensor obtained from the observed resonance positions and the value of CO~x is calculated by Eq.…”

Section: Collapsed-resonance Regimementioning

confidence: 99%

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EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

Calvo

2007

Appl. Magn. Reson.

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I review electron paramagnetic resonance (EPR) measurements performed to evaluate very weak exchange interactions (defined as rYr -J,jS,$j, with 10 -3 cm-t< IJ,~l < I cm-') between unpaired spins, transmitted through long and weak chemical pathways typical of protein structures. They are performed in appropriate model compounds, mainly copper derivatives of amino acids and peptides, making use of the phenomenon of exchange narrowing and collapse of the resonances. I describe the theoretical basis and the implementations of the method to different situations, including selected experimental values of the exchange couplings J between metal centers, and briefly discuss correlations between J and the structure of the paths. Results obtained in relatively simple EPR experiments performed at room temperature in single-crystal samples are compared with those obtained from thermodynamic magnetic measurements having higher experimental difficulties. The experimental information allows describing the role of molecular segments typieal of biomolecules (H bonds, aromatic ring stacking, cation-Ÿ contacts, etc.) in the transmission of the exchange interaction. The values of J obtained in some model compounds are compared with those obtained in proteins to conclude that the magnitudes of the exchange interactions are useful to characterize long and weak biologically relevant chemical pathways. One observes that these exchange couplings are weakly dependent on the nature of the unpaired spins and strongly dependent on the chemical pathway. Thus, measurements of exchange couplings in model compounds may provide usefui information about biological function, particularly about electron transfer in proteins.

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Section: Comparison Of Epr Results With Values Obtained From Nonresonmentioning

confidence: 81%

Section: Comparison Of Epr Results With Values Obtained From Nonresonmentioning

confidence: 99%

Section: Collapsed-resonance Regimementioning

confidence: 99%

Section: Collapsed-resonance Regimementioning

confidence: 99%

Section: Collapsed-resonance Regimementioning

confidence: 99%

See 3 more Smart Citations

EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

Calvo

2007

Appl. Magn. Reson.

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Synthesis, Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)₂(H₂O)].NaNO₃

Köse

Toprak

Avcı

et al. 2014

J Chinese Chemical Soc

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Transition metal complexes of arginine (using Co(II), Ni(II), Cu(II) and Zn(II) cations separately) were synthesized and characterized by FTIR, TG/DTA-DrTG, UV-Vis spectroscopy and elemental analysis methods. Cu(II)-Arg complex crystals was found suitable for x-ray diffraction studies. It was contained, one mole Cu II and Na + ions, two arginate ligands, one coordinated aqua ligand and one solvent NO 3 group in the asymmetric unit. The principle coordination sites of metal atom have been occupied by two N atoms of arginate ligands, two carboxylate O atoms, while the apical site was occupied by one O atom for Cu II cation and two O atoms for Co II , Ni II , Zn II atoms of aqua ligands. Although Cu II ion adopts a square pyramidal geometry of the structure. Co II , Ni II , Zn II cations have octahedral due to coordination number of these metals. Neighbouring chains were linked together to form a three-dimensional network via hydrogen-bonding between coordinated water molecule, amino atoms and O atoms of the bridging carboxylate groups. Cu II complex was crystallized in the monoclinic space group P2 1 , a = 8.4407(5) Å, b = 12.0976(5) Å, c = 10.2448(6) Å, V = 1041.03(10) Å 3 , Z = 2. Structures of the other metal complexes were similar to Cu II complex, because of their spectroscopic studies have in agreement with each other. Copper complex has shown DNA like helix chain structure. Lastly, anti-bacterial, anti-microbial and anti-fungal biological activities of complexes were investigated.

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Bonding properties and electronic structures of glycylglycinato copper(II) complexes. Molecular structure of acetylhistaminegly-cylglycinatocopper(II) dihydrate

Chiu

Wang

et al. 1994

Transition Met Chem

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Mixed ligand diglycinatocopper(II) complexes of the Cu(giygly)L-nH20 type, where glygly stands for [NH 2-CHzCONCHzCO2] 2-and L for imidazole (n= 1.5), N-methylimidazole (n = 1), 2-methylimidazole (n = 2), 4-methylimidazole (n = 2), 4-phenylimidazole (n = 2), Nacetylhistamine (n = 2) and NH3 (n = 2), were prepared and characterized by elemental analyses, i.r., vis. and e.p.r. spectroscopic measurements. The molecular structure of [Cu(glygly)(achmH)]-2H20 (achmH = acetylhistamine) was determined using three dimensional XRD data. The structure consists of distorted square planar [Cu(glygly)-(achmH)] units interconnected via the peptide oxygen at the apex to complete a square pyramidal structure, Cu--O-(peptide) 2.477(2)A. The H20 molecules, not binding directly to the copper ion, involve in intermolecular hydrogen bonding with the copper units. The dianionic glygly ligand and the imidazole ring bind strongly to the central copper ion with Cu--N(amino) 2.045(6) ~, Cu--N-(peptide) 1.891(5)~, Cu--O(carboxylate) 2.001(4)~ and Cu--N(imidazole) 1.956(5)~. The dihedral angle between the imidazole nucleus and the CuN30 xy plane is 6.0 ~ Similar structures with a CuN30 coordination plane are proposed for the imidazole complexes, based on spectroscopic data. The bonding properties of the glygly ligand and the unidentate imidazole ligands are elucidated and discussed with reference to the electronic structures of the complexes deduced from Gaussian analyses.

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Molecular structure and exchange interactions in trans-bis(L-2-aminobutyrato)copper(II) and trans-bis(DL-2-aminobutyrato)copper(II)

Cited by 26 publications

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EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

Synthesis, Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)₂(H₂O)].NaNO₃

Bonding properties and electronic structures of glycylglycinato copper(II) complexes. Molecular structure of acetylhistaminegly-cylglycinatocopper(II) dihydrate

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Molecular structure and exchange interactions in trans-bis(L-2-aminobutyrato)copper(II) and trans-bis(DL-2-aminobutyrato)copper(II)

Cited by 26 publications

References 0 publications

EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

EPR measurements of weak exchange interactions coupling unpaired spins in model compounds

Synthesis, Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)2(H2O)].NaNO3

Bonding properties and electronic structures of glycylglycinato copper(II) complexes. Molecular structure of acetylhistaminegly-cylglycinatocopper(II) dihydrate

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Synthesis, Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)₂(H₂O)].NaNO₃