Comparison of an OD and an ordered structure of nickel and copper malondiamidine complexes

Schwarzenbach, D.; Schmelczer, R.

doi:10.1107/s0567740878006779

Cited by 10 publications

(2 citation statements)

References 5 publications

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“…Only one crystal structure for the homoleptic PDI complex is known. 66 The Cu−N bond (1.956 Å) in the [Cu II (PDI) 2 ] 2+ complex is slightly longer than in the BG complex (1.943 Å), which is also observed in the computed structure (1.999 Å for PDI and 1.980 Å for BG). In contrast to those of the BG complexes, the C1−C2 bond (1.501 Å) in the PDI complex is much longer than the C1−N2 bond (1.373 Å) in [Cu II (BG) 2 ] 2+ and closer to a pure single C−C bond than a double bond.…”

Section: Comparison Of X-ray Structures and Computedmentioning

confidence: 53%

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Biomolecular Mode of Action of Metformin in Relation to Its Copper Binding Properties

et al. 2014

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Metformin (Metf), the most commonly used type 2 diabetes drug, is known to affect the cellular housekeeping of copper. Recently, we discovered that the structurally closely related propanediimidamide (PDI) shows a cellular behavior different from that of Metf. Here we investigate the binding of these compounds to copper, to compare their binding strength. Furthermore, we take a closer look at the electronic properties of these compounds and their copper complexes such as molecular orbital interactions and electrostatic potential surfaces. Our results clearly show that the copper binding energies cannot alone be the cause of the biochemical differentiation between Metf and PDI. We conclude that other factors such as pKa values and hydrophilicity of the compounds play a crucial role in their cellular activity. Metf in contrast to PDI can occur as an anion in aqueous medium at moderate pH, forming much stronger complexes particularly with Cu(II) ions, suggesting that biguanides but not PDI may induce easy oxidation of Cu(I) ions extracted from proteins. The higher hydrophobicity and the lack of planarity of PDI may further differentiate it from biguanides in terms of their molecular recognition characteristics. These different properties could hold the key to metformin's mitochondrial activity because they suggest that the drug could act at least in part as a pro-oxidant of accessible protein-bound Cu(I) ions.

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Section: Comparison Of X-ray Structures and Computedmentioning

confidence: 53%

“…Only one crystal structure for the homoleptic PDI complex is known . The Cu–N bond (1.956 Å) in the [Cu II (PDI) 2 ] 2+ complex is slightly longer than in the BG complex (1.943 Å), which is also observed in the computed structure (1.999 Å for PDI and 1.980 Å for BG).…”

Section: Resultsmentioning

confidence: 83%

Biomolecular Mode of Action of Metformin in Relation to Its Copper Binding Properties

et al. 2014

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Isatin‐Schiff base copper(II) complexes—A DFT study of the metal‐ligand bonding situation

Caramori

Parreira

Ferreira

2011

Int J of Quantum Chemistry

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Herein, we report results of calculations based on density functional theory (BP86/TZVP) of a set of isatin-Schiff base copper(II) and related complexes, 1-12, that have shown significant pro-apoptotic activity toward diverse tumor cells. The interaction of the copper(II) cation with different ligands has been investigated at the same level of theory. The strength and character of the Cu(II)-L bonding was characterized by metal-ligand bond lengths, vibrational frequencies, binding energies, ligand deformation energies, and natural population analysis. The metal-ligand bonding situation was also characterized by using two complementary topological approaches, the quantum theory of atoms-in-molecules (QTAIM) and the electron localization function (ELF). The calculated electronic g-tensor and hyperfine coupling constants present significant agreement with the EPR experimental data. The calculated parameters pointed to complex 10 as the most stable among the isatin-Schiff base copper(II) species, in good agreement with experimental data that indicate this complex as the most reactive in the series.

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Crystal structure non-rigidity of central atoms for Mn(II), Fe(II), Fe(III), Co(II), Co(III), Ni(II), Cu(II) and Zn(II) complexes

Valach

Koreň

Sivý

et al. 1983

Transition Metal Complexes Structures and Spectra

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The ability of coordination polyhedra of different central atoms in the solid state to undergo distortions has often been discussed. These distortions are also correlated with the nature of the central atom. This paper deals with the conception of crystal structure non-rigidity for central atoms of some selected complexes by the using of statistical distributions of interatomic distances central atom-nearest ligand atom (M-L; M = Mn(II), Fe(II), Fe(III), Co(II), Co(Ill), Ni(II), Cu(II) and Zn(II)). Based on the vector equilibrium principle the dispersion of these empirical distributions has been introduced as a measure of non-rigidity of central atoms, decreasing in the order: Cu(II) > Fe(II)Hs > Mn(II)Hs > Ni(II)ts > Zn(II) > Fe(III)Hs ~-CO(II)Hs > Ni(II)Hs > CO(III)Ls, where LS and HS denote low-spin and high-spin states, respectively. Starting from the distribution of M-L distances for certain types of central and ligand atoms, the contribution of atoms of the inner coordination sphere to the vector equilibrium of crystal structures is discussed.The structures of complexes with all M-L bond lengths of at least one symmetrically independent central atom in the interval of maximum frequency exhibit in the appropriate set the most stable inner coordination sphere. These compounds are classified both with respect to the geometry of their inner coordination sphere fulfilling the above condition and to their crystal structure aspect. The square-planar geometry is found to be the most stable for Cu(II) and Ni(II)Ls complexes, tetragonal-pyramidal for Zn(II) complexes, while for Fe(II)Hs, Mn(II)Hs, Fe(III)Hs, Co(II)Hs, Ni(II)ns and Co(III)Ls complexes it is the regular octahedral geometry. Except for one Mn(II)Hs complex, in the discussed structures chromophores with the most stable geometry of the coordination polyhedron form part of the final relatively isolated structural unit (island) with expressively chemical bonds between atoms. These facts are illustrated by the stabilization effected by the crystal field and by the properties of the ligands.

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Comparison of an OD and an ordered structure of nickel and copper malondiamidine complexes

Cited by 10 publications

References 5 publications

Biomolecular Mode of Action of Metformin in Relation to Its Copper Binding Properties

Biomolecular Mode of Action of Metformin in Relation to Its Copper Binding Properties

Isatin‐Schiff base copper(II) complexes—A DFT study of the metal‐ligand bonding situation

Crystal structure non-rigidity of central atoms for Mn(II), Fe(II), Fe(III), Co(II), Co(III), Ni(II), Cu(II) and Zn(II) complexes

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