scholarly journals New Polyporphyrin Arrays with Controlled Fluorescence Obtained by Diaxial Sn(IV)-Porphyrin Phenolates Chelation with Cu2+ Cation

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 829
Author(s):  
Galina M. Mamardashvili ◽  
Dmitriy A. Lazovskiy ◽  
Ilya A. Khodov ◽  
Artem E. Efimov ◽  
Nugzar Z. Mamardashvili
Keyword(s):  
Chemical Species ◽  
Ultra Violet ◽  
X Rays ◽  
Structure And Properties ◽  
Paramagnetic Resonance ◽  
1H Nuclear Magnetic Resonance ◽  
Infra Red ◽  
Connection Type ◽  
Chelation Reaction ◽  
Electron Paramagnetic

New coordination oligomers and polymers of Sn(IV)-tetra(4-sulfonatophenyl)porphyrin have been constructed by the chelation reaction of its diaxialphenolates with Cu2+. The structure and properties of the synthesized polyporphyrin arrays were investigated by 1H Nuclear Magnetic Resonance (1H NMR), Infra Red (IR), Ultra Violet - Visible (UV-Vis) and fluorescence spectroscopy, mass spectrometry, Powder X-Rays Diffraction (PXRD), Electron Paramagnetic Resonance (EPR), thermal gravimetric, elemental analysis, and quantum chemical calculations. The results show that the diaxial coordination of bidentate organic ligands (L-tyrazine and diaminohydroquinone) leads to the quenching of the tetrapyrrole chromophore fluorescence, while the chelation of the porphyrinate diaxial complexes with Cu2+ is accompanied by an increase in the fluorescence in the organo-inorganic hybrid polymers formed. The obtained results are of particular interest to those involved in creating new ‘chemo-responsive’ (i.e., selectively interacting with other chemical species as receptors, sensors, or photocatalysts) materials, the optoelectronic properties of which can be controlled by varying the number and connection type of monomeric fragments in the polyporphyrin arrays.

Electron Paramagnetic Resonance as a Probe for Metal Ions and Radicals in Paper

2015 ◽  
Vol 36 (4) ◽  
Author(s):  
Alfonso Zoleo ◽  
Laura Speri ◽  
Maddalena Bronzato
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Metal Ions ◽  
Chemical Species ◽  
Paramagnetic Species ◽  
Paramagnetic Resonance ◽  
Relevant Role ◽  
Historic Paper ◽  
Electron Paramagnetic ◽  
Identification And Characterization

AbstractElectron Paramagnetic Resonance (EPR) is a technique devoted to the identification and characterization of paramagnetic species, i.e. chemical species with unpaired electrons. Very common paramagnetic species which can be detected through EPR in historic paper are Fe(III), Mn(II), Cu(II) ions and radicals, where Fe(III), Cu(II) and radicals play a relevant role in paper degradation. Specifically, Fe(III) is almost ubiquitous in historic paper. Here we propose an overview of the EPR signals in historic and artificially aged paper, and in particular, we would like to show how a deep analysis of EPR signals from paper could provide useful information about the paper’s origin and unique indications of the degradation and oxidation level of the paper.

scholarly journals Influence of the Substituted Ethylenediamine Ligand on the Structure and Properties of [Cu(diamine)2Zn(NCS)4]∙Solv. Compounds

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 637
Author(s):  
Natalia Tereba ◽  
Tadeusz M. Muzioł ◽  
Robert Podgajny ◽  
Grzegorz Wrzeszcz
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Interaction ◽  
Structural Features ◽  
Molecular Formula ◽  
Structure And Properties ◽  
Magnetic Studies ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Ethylenediamine Ligand ◽  
Electron Paramagnetic

In this paper, three new heterometallic compounds were described and compared with the molecular formula [Cu(pn)2Zn(NCS)4] (1), [Cu(N,N-Me2-en)2Zn(NCS)4] (2), [Cu(N-Me-en)2Zn(NCS)4]∙½H2O (3) where pn = 1,2−diaminopropane, N,N-Me2-en = N,N‒dimethylethylenediamine and N-Me-en = N-methylethylenediamine, respectively. The compounds mentioned above were characterized by elemental analysis, infrared (IR), electronic, electron paramagnetic resonance (EPR) spectra, and magnetic studies. Crystal structures for 1 and 2 were determined by X-ray analysis. Copper(II) in these complexes adopts 4 + 2 coordination with two elongated (in 2 very long and considered as semi-coordination) Cu-S bonds. The Cu-N and Cu-S bond lengths depend on substituent position affecting steric hindrance and hence a topology of the chain. Both chains form different zigzag patterns characterized by one or two Cu-Zn distance values. Weak magnetic interaction is observed, ferromagnetic in the case of 1 and antiferromagnetic in the case of 2, due to diversity of the above structural features.

Structure and Properties of Fibrous Materials Based on Poly(-3-Hydroxybutyrate)

2020 ◽  
Vol 992 ◽  
pp. 375-379
Author(s):  
A.A. Olkhov ◽  
P.M. Tyubaeva ◽  
A.L. Iordansky
Keyword(s):  
Molecular Structure ◽  
Fibrous Materials ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Paramagnetic Resonance ◽  
Electrospinning Method ◽  
Ultrathin Fibers ◽  
Model Drug ◽  
Electron Paramagnetic ◽  
Scanning Electron

The article studies the supramolecular structure of polymer matrices for sustained isolation of drugs based on ultrathin fibers of polyhydroxybutyrate obtained by electrospinning method. Dipyridamole was chosen as a model drug. The concentration of dipyridamole in the fibers ranged from 1 to 5%. The morphology of nonwoven fibrous materials was investigated by scanning electron microscopy, differential scanning calorimetry, electron paramagnetic resonance. It was shown that the addition of the dipyridamole leads to a change in the fiber geometry. Fibers based on polyhydroxybutyrate are characterized by non-equilibrium molecular structure. In the current work, it was found that the addition of dipyridamole causes extra crystallization processes and the molecular mobility in the amorphous regions of the polymer slows down

scholarly journals Comparison of the Photocatalytic Activity of ZnO/CeO2 and ZnO/Yb2O3 Mixed Systems in the Phenol Removal from Water: A Mechanicistic Approach

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1222
Author(s):  
Erik Cerrato ◽  
Nuno Paulo Ferreira Gonçalves ◽  
Paola Calza ◽  
Maria Cristina Paganini
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Photocatalytic Activity ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Ultra Violet ◽  
Resonance Spectroscopy ◽  
Phenol Removal ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Two Samples ◽  
Electron Paramagnetic

In this paper we compare the photocatalytic activity of two semiconductors based on ZnO: ZnO/CeO2 and ZnO/Yb2O3. The two samples were prepared via hydrothermal synthesis and fully characterized by X-ray diffraction technique, diffuse reflectance Ultra Violet- Visible spectroscopy (UV-Vis), high resolution transmission electron microscopy and finally with electron paramagnetic resonance spectroscopy. The prepared materials were also tested in their photocatalytic performances both through Electron Paramagnetic Resonance (EPR) analyzing the formation of charge carriers and with the abatement of a probe molecule like phenol, in presence and in absence of scavengers.

scholarly journals Aqueous phototransformation of bisphenol S: the competitive radical-attack pathway to p-hydroxybenzenesulfonic acid

2014 ◽  
Vol 70 (3) ◽  
pp. 540-547 ◽  
Author(s):  
Xiaowen Wang ◽  
Jiahai Ma ◽  
Zhenpeng Wang ◽  
Rongrong Guo ◽  
Xuefeng Hu
Keyword(s):  
Environmental Concern ◽  
Reaction Pathway ◽  
Transformation Product ◽  
Gas Chromatography Mass Spectrometry ◽  
Bisphenol S ◽  
Paramagnetic Resonance ◽  
1H Nuclear Magnetic Resonance ◽  
Major Transformation ◽  
Radical Traps ◽  
Electron Paramagnetic

The kinetics, environmental influencing factors, products and reaction mechanism of aqueous phototransformation of bisphenol S (BPS), as an alternative to bisphenol A, which is of environmental concern, were investigated. p-Hydroxybenzenesulfonic acid, as the major transformation product was confirmed by gas chromatography – mass spectrometry, electrospray ionization, 1H nuclear magnetic resonance and fluorescence spectrum analysis. A reaction pathway was proposed based on the reactive oxygen species related results by electron paramagnetic resonance and radical traps. The competition of the excited state of BPS between transferring electron to O2 to •O2- and directly oxidizing H2O to •OH was revealed.

scholarly journals Epr Hyperfine Structure Of Radiation Defect In Oxyfluoride Glass Ceramics/ Radiācijas Defekta Epr Hipersīkstruktūra Oksifluorīdu Stikla Keramikā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 55-59
Author(s):  
D. Bērziņš ◽  
A. Fedotovs ◽  
U. Rogulis
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Structure ◽  
Radiation Defect ◽  
Glass Ceramics ◽  
Structure Characteristic ◽  
X Rays ◽  
Oxyfluoride Glass ◽  
Paramagnetic Resonance ◽  
Fluoride Crystals ◽  
Electron Paramagnetic

Abstract We have investigated the samples of thermally treated oxyfluoride glass ceramics 50SiO2-25LiO2-20YF3-3ErF3-2YbF2 by means of electron paramagnetic resonance (EPR) techniques. After irradiation of the samples with X-rays, in the EPR spectra a hyperfine structure characteristic of F-centres could be observed in different fluoride crystals. The structure of F-centre in the oxyfluoride glass ceramics containing LiYF4 crystallites is discussed.

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