EPR investigation of Cu(II)-complexes with nitrogen derivatives of dialdehyde starch

Łabanowska, Maria; Bidzińska, Ewa; Para, Andrzej; Kurdziel, Magdalena

doi:10.1016/j.carbpol.2011.11.034

Cited by 20 publications

(13 citation statements)

References 36 publications

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“…Further information regarding the coordination environment of copper centers in the polymer electrolytes can be obtained from the analysis of the EPR spin Hamiltonian parameters, which are greatly influenced by the ligand type and by the coordination geometry [17,19,30]. The principal values of the g-tensor are in relation g || > g ?…”

Section: Electron Paramagnetic Resonance (Epr)mentioning

confidence: 99%

“…Copper is a transition metal of importance in many catalytic and biological systems and EPR spectroscopy is particularly suitable for the study of the nature and magnetic properties of Cu 2+ doped polymer electrolytes and biomembranes [18][19][20]. Furthermore, because the host-ion combination could also lead to interesting luminescent properties, potentially useful in multifunctional devices, the photophysical characterization is justified.…”

Section: Introductionmentioning

confidence: 99%

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Ionic, paramagnetic and photophysical properties of a new biohybrid material incorporating copper perchlorate

Leones

Donoso

Magon

et al. 2015

Electrochimica Acta

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Section: Electron Paramagnetic Resonance (Epr)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ionic, paramagnetic and photophysical properties of a new biohybrid material incorporating copper perchlorate

Leones

Donoso

Magon

et al. 2015

Electrochimica Acta

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“…Some spectra showed the presence of more than one coordination complex, only the constants of the majority were calculated. The hyperfine coupling constants (A) due to the interaction of the free electron with the nuclear spin I Cu = 3/2, and the gyromagnetic constants g, and g ┴ were calculated from simulated spectra [30][31][32] and are shown in Table 1. All EPR spectra showed an axial symmetry g g ┴ g e in agreement with a d x 2 -y 2 ground state for Cu 2+ .…”

Section: Reducing and Chelating Effects On Cu 2+mentioning

confidence: 99%

Recognition of antioxidants and photosensitizers in Dyssodia pinnata by EPR spectroscopy

Arciniegas

Gómez‐Vidales

Pérez‐Castorena

et al. 2019

Phytochemical Analysis

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Introduction Previous studies report the isolation mainly of terthiophene derivatives and flavonoids from Dyssodia species. Terthiophenes are known as photosensitizers by their capacity to generate singlet oxygen (1O2), and flavonoid antioxidant activity is recognized. These opposite properties could represent interesting options in photodynamic therapy. Objective To determine the antioxidant and photosensitizer activities of extracts and isolates of Dyssodia pinnata by electron paramagnetic resonance (EPR). Methodology Extracts and isolates were evaluated as antioxidants by the interactions with copper ion (Cu2+) observed in EPR, and by the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) and the thiobarbituric reactive substances (TBARS) methods. Their abilities as 1O2 producers were also estimated by EPR. Results Terthiophenes were obtained from hexane (DPH) and acetone (DPA) extracts, and flavonoids from DPA and methanol (DPM) extracts. The interaction with Cu2+ of extracts and isolated compounds of Dyssodia pinnata showed two effects in EPR: reduction and chelation; flavonoids exhibited both effects, while terthiophenes showed only reduction. DPA, DPM, and flavonoids were active in DPPH and TBARS assays. Quercetagetin‐7‐O‐β‐glucoside showed the highest antioxidant and chelating activities, 3‐glycosidated flavonoids were less active. Upon irradiation extracts and terthiophenes induced 1O2 formation. Conclusion Flavonoid reducing activity on Cu2+ and free radical scavenging capacity were related to the number of hydroxy groups and to the conjugation between the B and C rings. All tested flavonols showed a major complex with Cu2+, with the most probable site of chelation between the 5‐hydroxy and 4‐oxo groups. Extracts and terthiophene derivatives showed photosensitizer activity. Thus, EPR is useful to evaluate free radical scavenging and pro‐oxidant properties.

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“…The simulated spectra show the values in Table 1. The tetrahedral distortion that frequently occurs for square planar copper complexes is observed by the ratio f = g ǁǁ /A ǁǁ and it is considered for the determination of the distortion and the deviation from perfect geometry depending on the coordinated ligands [26,27]. The f value in the range 110-120 is typical for signals of the copper complex with planar geometry, however, its increase to 150 indicates a small or modest distortion of the planar symmetry, and the higher values, 180-250, suggest a strong deviation from square planar geometry.…”

Section: Electron Paramagnetic Resonance (Epr) Studiesmentioning

confidence: 99%

Design and Synthesis of a Multi Cu(II)-porphyrin Array

Gómez‐Vidales¹,

Borja-Miranda²,

Cortez-Maya³

et al. 2016

CHEM

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Abstract:A new class of porphyrin array was synthesized. The Cu(II) porphyrin-PAMAM-Cu(II) porphyrin was obtained in good yields. The EPR studies showed that all porphyrins obtained have signals of a copper complex with planar geometry, and no variation in the tetrahedral distortion of the porphyrin ring was observed. The UV-vis and emission studies showed that the intensity of the signal increased due to the presence of 5 porphyrin moieties in the structure. In order to further characterize this molecule, thin films were prepared by using the thermal evaporation method. The morphology of the film showed a homogeneous structure while conductivity measurements exhibit a good conductive response.

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EPR investigation of Cu(II)-complexes with nitrogen derivatives of dialdehyde starch

Cited by 20 publications

References 36 publications

Ionic, paramagnetic and photophysical properties of a new biohybrid material incorporating copper perchlorate

Ionic, paramagnetic and photophysical properties of a new biohybrid material incorporating copper perchlorate

Recognition of antioxidants and photosensitizers in Dyssodia pinnata by EPR spectroscopy

Design and Synthesis of a Multi Cu(II)-porphyrin Array

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