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

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

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

Polymers ◽

10.3390/polym13050829 ◽

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.

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Characterization of Process Induced Contamination and Residues on Semiconductor Components Via FTIR and Raman Microanalysis

Microscopy and Microanalysis ◽

10.1017/s1431927600026830 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 152-153

Author(s):

H. Gotts

Keyword(s):

Molecular Structure ◽

Yield Enhancement ◽

Spectroscopic Techniques ◽

Bulk Materials ◽

Scanning Calorimetry ◽

Vis Spectroscopy ◽

Classical Technique ◽

Raman Microprobe ◽

Scanning Electron

FTIR and Raman microanalysis may be used as a powerful combination to determine the identity, and hence infer the source, of contaminant particles which diminish yields of semiconductor components and devices. The complimentarity of these techniques arises from the underlying spectroscopic selection rules.Vibrational spectroscopic techniques are commonly used to characterize the molecular structure of bulk organic materials. These bulk materials typically represent purified fractions of components which may be further investigated with various classical instrumental techniques such as Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) spectroscopy, UV-Vis spectroscopy. However, these classical technique may have limited value for the interrogation of small impure particles or materials of limited quantity(ng.).Elemental techniques such as Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy are enhanced by the specificity of FTIR Microprobe Spectroscopy and Raman Microprobe Spectroscopy which are now used in process laboratories to characterize and identify particulate and thin film residues with the intent of device yield enhancement.

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

Crystals ◽

10.3390/cryst9120637 ◽

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.

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