Linear conjuncted porphyrin trimer synthesis via "click" reaction

2014 ◽  
Vol 18 (01n02) ◽  
pp. 20-34 ◽  
Author(s):  
Yulia P. Polevaya ◽  
Vladimir S. Tyurin ◽  
Irina P. Beletskaya

Two isomers of porphyrin trimer with 1,4-diaryltriazole linkers have been synthesized using "click" methodology and characterized by MS, NMR and UV-vis spectroscopy. The porphyrin compounds were shown to exhibit photostability and high solubility. Photophysical data were compared with corresponding ones of synthesized triazole-bridged dimer with the same electronic surrounding and known linear dimer and trimer with diarylethyne linkers. Obtained data revealed weak inter-chromophore electronic communication in the ground state but significant exciton coupling whereas the properties of the individual chromophores are mainly retained for triazole-bridged dimer and trimers.

1979 ◽  
Vol 34 (12) ◽  
pp. 1507-1511
Author(s):  
Werner Urland

Abstract The magnetic behaviour of Cs2MYbF6 (M = Na, K, Rb) and Cs2NaYbBr6 has been studied in the temperature range between 3.5 and 251.3 K. The magnetic data are interpreted by means of a previously developed model in which the influence of the crystal field is theoretically described by the angular overlap model. The obtained values of the angular overlap parameter eσ(R) for the individual compounds are discussed and compared with each other. The energy values of the crystal-field levels of the 2F7/2 ground state are calculated.


1977 ◽  
Vol 55 (21) ◽  
pp. 3712-3716 ◽  
Author(s):  
Kim Doan Truong ◽  
André D. Bandrauk

Two new solid TCNQ complexes have been isolated, coronene–TCNQ 1:1 and 3:1. The infrared and electronic absorption spectra are presented for the two different stoichiometries. From these spectra we infer that the complexes are covalent in the ground state with a charge transfer band appearing at 730 nm. The out of plane vibrations of the individual molecules are noticeably perturbed upon complexation.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1498
Author(s):  
Miroslawa Prochon ◽  
Anna Marzec ◽  
Oleksandra Dzeikala

Buffing Dust Collagen (BDC) is a hazardous waste product of chromium tanning bovine hides. The aim of this study was to investigate whether BDC has the desirable properties required of modern fillers. The microstructural properties of BDC were characterized by elemental analysis (N, Cr2O3) of dry residue and scanning electron microscopy (SEM). The BDC was applied (5 to 30 parts by weight) to styrene butadiene rubber (SBR), obtaining SBR-BDC composites. The physicochemical properties of the SBR-BDC composites were examined by Fourier transform infrared analysis, SEM, UV–Vis spectroscopy, swelling tests, mechanical tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The biodegradability of the SBR-BDC composites and their thermo-oxidative aging were also investigated. The filler contributed to increase the cross-link density in the elastomer structure, as evidenced by enhanced mechanical strength. The introduction of a filler into the elastomer structure resulted in an increase in the efficiency of polymer bonding, which was manifested by more favorable rheological and mechanical parameters. It also influenced the formation of stable interfacial bonds between the individual components in the polymer matrix, which in turn reduced the release of compact chromium in the BDC filler. This was shown by the absorption bands for polar groups in the infrared analysis and by imaging of the vulcanization process.


1990 ◽  
Vol 186 ◽  
Author(s):  
W. A. Shelton ◽  
F. J. Pinski ◽  
D. D. Johnson ◽  
D. M. Nicholson ◽  
G. M. Stocks

AbstractWe have performed calculations of the electronic structure of the random substitutional bcc Fe1-xCrx alloys, using the spin-polarized, self-consistent Korringa, Kohn and Rostoker coherent potential approximation (KKR-CPA) method. This is a first principles method based on a local spin density approximation for electron exchange and correlation energy. For the iron-rich alloys, we find that the average moment decreases linearly with Cr concentration, although the individual moments show a different concentration dependence and the Cr moment is anti-parallel to the Fe moment. This system is similar to Fe1-xVx system, although some details are different.


2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
M. Z. H. Khan ◽  
M. A. Rahman ◽  
P. Yasmin ◽  
F. K. Tareq ◽  
N. Yuta ◽  
...  

In this study, we present a new approach for the formation and deposition of Cu nanocube-decorated reduced graphene oxide (rGO-CuNCs) nanosheet on indium tin oxide (ITO) electrode using very simple method. Cubic Cu nanocrystals have been successfully fabricated on rGO by a chemical reduction method at low temperature. The morphologies of the synthesized materials were characterized by ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The as-formed CuNCs were found to be homogeneously and uniformly decorated on rGO nanosheets. We demonstrated that the individual rGO sheets can be readily reduced and decorated with CuNCs under a mild condition using L-ascorbic acid (L-AA). Such novel ITO/rGO-CuNCs represent promising platform for future device fabrication and electrocatalytic applications.


2014 ◽  
Vol 69 (5) ◽  
pp. 541-553 ◽  
Author(s):  
Sarah Bay ◽  
Thomas J. J. Müller

A phenothiazinyl donor moiety can be covalently coupled to aromatic hydrocarbon acceptor units via Ugi four-component reaction in an efficient, rapid, and highly convergent fashion. These novel phenothiazine-acceptor dyads are electronically decoupled in the electronic ground state according to UV/Vis spectroscopy and cyclic voltammetry. In the excited state the inherent acceptor luminescence is substantially quenched. Calculations of the Gibbs energy of photo-induced electron transfer from readily available UV/Vis spectroscopic and cyclovoltammetric data according to the Weller approximation rationalizes the feasibility of the reductive electron transfer from phenothiazine to the aromatic hydrocarbon upon photoexcitation.


1968 ◽  
Vol 5 (1) ◽  
pp. 89-92 ◽  
Author(s):  
P. G. Manning

The optical absorption spectra of green vesuvianite crystals from Lowell County, Vermont, are reported in the energy range 12 000 cm−1 to 30 000 cm−1. The principal absorptions have been attributed to octahedrally bonded Fe3+ and the individual bands have been assigned to spin-forbidden electronic transitions from the 6A1 ground state to excited states in Fe3+. In particular, the 6A1 → 4A14E(G) transition is marked by a relatively sharp band at 21 600 cm−1.


Author(s):  
Florina Bunghez ◽  
Carmen Socaciu ◽  
Florina Zagrean ◽  
Raluca Maria Pop ◽  
Floricuta Ranga ◽  
...  

Abstract. It is known for a long time that seasoning/condimentary herbs have antioxidant activity and antibacterial properties, being good natural alternatives for disease prevention. The different efficiency of these plants is assigned to their bioactive molecules, stability and bioavailability. In the present study seven aromatic herbs (basil, thyme, oregano, rosemary, clove, cinnamon and sage) were investigated individually. A new product was developed using basil, thyme, oregano, rosemary, clove, cinnamon and sage, according to a default recipe. The characterization of each plant aimed to identify the specific “fingerprint” by its main bioactive molecules and the “traceability” of these molecules in the new product, made by mixing the selected plants according to a default recipe. In order to determine the main bioactive compounds of the individual plants composition, in comparison with the new plant-based (EPC) formula, high throughput techniques like UV-Vis spectroscopy and LC-QTOF-MS  spectrometry were used. The most important bioactive compounds determined in the studied herbs, which may exert antioxidant activity and antibacterial properties, were phenolic compounds (phenolic acids, flavonoids), quinones, clorophylls as well some polar terpenoids. The fingerprints are providing comprehensive and accurate information about the compounds that may exert antimicrobial properties. In order to assure the biological effects and the bioavailability of the polyphenols and the secondary metabolites we have to consider the antagonistic and synergistic effect that the metabolites can exert on each other.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Swati Sambita Mohanty ◽  
Arvind Kumar

AbstractThe current study investigates the decolorization of Indanthrene Blue RS dye and the optimization of process parameters needed for effective decolorization by the bacterial consortium. The pure culture of strain TS8, PMS, and NCH has been isolated from the textile wastewater sample collected from local textile processing units outlet and dye contaminated soil from Odisha, India. A bacterial consortium-BP of Bacillus flexus TS8 (BF), Proteus mirabilis PMS (PM), and Pseudomonas aeruginosa NCH (PA) were developed. The physicochemical parameters were optimized to attain maximum decolorization efficacy. Degradation of Indanthrene Blue RS and the formation of metabolites were confirmed through UV–vis spectroscopy, FT-IR, and GC–MS analysis. The developed consortium-BP showed an enhanced decolorization of Indanthrene Blue RS dye with an Average decolorization rate of 11,088 µg h−1 within 9 h compared to the individual strains under aerobic conditions. The supplementation of agricultural residual wastes showed increased decolorization efficiency of consortium-BP. Higher reduction in TOC and COD removal (≥ 80%) determined the mineralization of Indanthrene Blue RS by consortium-BP. Significant induction of various oxidoreductive enzymes in consortium-BP compared to that of Individual strains indicates their involvement in the overall decolorization and degradation process, with the higher protein concentration in the intracellular enzymes. Studies on the phytotoxicity effect revealed the non-toxic nature of the degraded products formed on mineralization of Indanthrene Blue RS by consortium-BP. This study represents a new approach for enhanced biodegradation using consortium-BP in treating textile wastewaters containing anthraquinone dyes.


Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 576
Author(s):  
Christian Lutz ◽  
Michael Breuckmann ◽  
Sven Hampel ◽  
Martin Kreyenschmidt ◽  
Xi Ke ◽  
...  

A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing Vdimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that Vdimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the Vdimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane. The Vdimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO3) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > Vdimer(IV–V) [λ = 0.039]. The results show that the Vdimer(IV–V) dimer needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.


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