scholarly journals Photochromism of indolino-benzopyrans studied by NMR and UV-visible spectroscopy

2006 ◽  
Vol 2006 ◽  
pp. 1-7 ◽  
Author(s):  
S. Delbaere ◽  
J. Berthet ◽  
M. A. Salvador ◽  
G. Vermeersch ◽  
M. M. Oliveira
Keyword(s):  
Nmr Spectroscopy ◽  
Rate Constant ◽  
Colored Form ◽  
Visible Spectroscopy ◽  
Uv Visible

The synthesis of photochromic 3,3-di(4′-fluorophenyl)-3H-benzopyrans fused to an indole moiety is described. The structures of photomerocyanines elucidated by NMR spectroscopy and spectrokinetic data (λmax⁡of colored form, colorability, and rate constant of bleaching) obtained by UV-visible spectroscopy are reported.

Synthesis of perialkynylated tetrapyrazinoporphyrazines and its Optical Properties

2009 ◽  
Vol 2009 (5) ◽  
pp. 312-316 ◽  
Author(s):  
Chun Keun Jang ◽  
Jae Yun Jaung
Keyword(s):  
Optical Properties ◽  
Nmr Spectroscopy ◽  
Laser Desorption ◽  
Diels Alder ◽  
Visible Spectroscopy ◽  
H Nmr ◽  
Uv Visible ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Some phthalocyanines soluble in organic solvents have been developed by peripheral introduction of substituent groups. We report a new method for preparation of the polyphenyl-substituted dicyanopyrazines based on the [2 + 4] Diels-Alder cycloaddition of the tetraphenylcyclopentadienone to an ethynyl compound. The synthesised tetrapyrazinoporphyrazinato metal complexes were characterised by UV-visible spectroscopy, MALDI-TOF-Ms (matrix-assisted laser desorption ionisation time-of-flight mass) spectroscopy, and 1H NMR spectroscopy.

A Highly Selective Chemosensor for Naked-Eye Detection of Fluoride and Aluminium(III) Ions Based on a New Schiff Base Derivative

2016 ◽  
Vol 69 (8) ◽  
pp. 911 ◽  
Author(s):  
Masoumeh Orojloo ◽  
Saeid Amani
Keyword(s):  
Nmr Spectroscopy ◽  
Low Cost ◽  
Anion Recognition ◽  
Visible Spectroscopy ◽  
Elemental Analyses ◽  
Base Derivative ◽  
Anions And Cations ◽  
Uv Visible ◽  
Job's Method ◽  
Naked Eye Detection

A new chromogenic receptor, 4-((2,4-dichlorophenyl)diazenyl)-2-(3-hydroxypropylimino)methyl)phenol, has been designed and synthesized for quantitative and low-cost detection of various biological anions and cations. The dye was characterized by elemental analyses, infrared, UV-visible spectroscopy, and NMR spectroscopy. The chemosensor showed visual changes towards anions, such as F– and H2PO4–, in DMSO and towards cations, such as Al3+, Cu2+, Fe3+, and Cr3+, in DMSO/water (9 : 1). The anion recognition property of the receptor via proton transfer was monitored by UV-visible titration and 1H NMR spectroscopy. The binding constant (Ka) and stoichiometry of the host–guest complexes formed were determined by the Benesi–Hildebrand (B–H) plot and Job's method, respectively.

Activated Carbon as Heterogeneous Catalyst of Catalytic Ozonation Activity for Improvement RB 49 Dye Degradation

2016 ◽  
Vol 860 ◽  
pp. 105-110 ◽  
Author(s):  
Suntree Sangjan ◽  
Montri Sratongin ◽  
Atit Kawpakpor ◽  
Pornrung Ampha ◽  
Laksika Jamtanom ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Heterogeneous Catalyst ◽  
Rate Constant ◽  
Dye Degradation ◽  
Degradation Kinetics ◽  
Order Rate Constant ◽  
Catalytic Ozonation ◽  
Catalyst Loading ◽  
Visible Spectroscopy ◽  
Uv Visible

Activated carbon (AC) catalyst was successfully improved activity for the degradation of Reactive blue 49 dye (RB 49) in catalytic ozonation system. The degradation of the RB 49 dye was visualized by UV-Visible spectroscopy. As the RB 49 degradation kinetics were investigated by different initial parameters, initial RB 49 concentrations, AC catalyst loading, H2O2 dosage and additives. The degradation efficiency of AC catalytic ozonation towards RB 49 was found to be 95% when compared to 45% using pure ozone. The concentration of AC catalyst ranged from 0, 0.01, 0.05 and 0.1 g/L. We found that the maximum pseudo first and second order rate constant were 0.186 min-1 and 1.416 L.mg-1min-1 for 0.05 g/L AC. The results showed that the optimum of AC concentration in system was 0.05 g/L. In addition, this research studied the effect of auxiliary chemicals such as NaCl, Na2CO3, Na2SO4 and H2O2 upon dye degradation in AC catalytic ozonation system.

Engineering of silver nanoparticle fabricated poly (N-isopropylacrylamide-co-acrylic acid) microgels for rapid catalytic reduction of nitrobenzene

2016 ◽  
Vol 36 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Zahoor H. Farooqi ◽  
Khalida Naseem ◽  
Aysha Ijaz ◽  
Robina Begum
Keyword(s):  
Acrylic Acid ◽  
Rate Constant ◽  
Apparent Rate Constant ◽  
Reduction Method ◽  
Catalytic Reduction ◽  
Visible Spectroscopy ◽  
Uv Visible ◽  
Polymerization Method ◽  
Hybrid Microgels

Abstract Three different poly(N-isopropylacrylamide-co-acrylic acid) [p(NIPAM-AA)] microgel samples were prepared using a precipitation polymerization method by varying the concentration of NIPAM and AA in aqueous medium. The microgels were used as microreactors to fabricate Ag nanoparticles (NPs) by in situ a reduction method. Fourier transform infrared (FTIR) and UV-visible spectroscopy were used to characterize the pure and hybrid microgels. The hybrid microgels with different AA content were used as catalysts for reduction of nitrobenzene (NB) into aniline. The progress of the reaction was monitored by a UV-visible spectrophotometer. The results show that the value of the apparent rate constant for catalytic reduction of NB decreases from 0.431 min-1 to 0.227 min-1 by increasing AA content from 3 mol% to 7 mol%, respectively. Decrease in apparent rate constant with increase of AA content can be attributed to an increase in hydrophilicity with increase of AA contents of the microgels. The increase in induction period with increase of AA contents indicates that diffusion of NB towards the catalytic surface becomes difficult due to an increase of hydrophilicity.

Synthesis and optical properties of tetrapyrazino-porphyrazines containing camphorquinone group

2009 ◽  
Vol 13 (07) ◽  
pp. 794-797 ◽  
Author(s):  
Chun Keun Jang ◽  
Seung Hwan Byun ◽  
Song Hak Kim ◽  
Do Kyung Lee ◽  
Jae Yun Jaung
Keyword(s):  
Optical Properties ◽  
Nmr Spectroscopy ◽  
Fluorescence Spectroscopy ◽  
Elemental Analysis ◽  
Infrared Radiation ◽  
Condensation Reaction ◽  
Visible Spectroscopy ◽  
H Nmr ◽  
Uv Visible ◽  
Tof Ms

2,3-dicyanopyrazine and metallophthalocyanines were synthesized with magnesium containing (±)camphorquinone substituent. 2,3-dicyanopyrazine was prepared by condensation reaction of diaminomaleonitrile (DAMN) with 1,7,7-trimethylbicyclo[2.2.1]heptane-2,3-dione (1). The tetrapyrazinoporphyrazine was characterized by a combination of UV-visible spectroscopy, fluorescence spectroscopy, infrared radiation, elemental analysis, MALDI-TOF-MS and 1H NMR spectroscopy.

scholarly journals Formation of Carbon-Silicon Bond and Effect of Silicon on Organic Reactions

2020 ◽  
Vol 11 (1) ◽  
pp. 101-105
Author(s):  
Ashis K Sarker
Keyword(s):  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Bond Formation ◽  
Research Work ◽  
Engineering Science ◽  
Proton Nmr Spectroscopy ◽  
Visible Spectroscopy ◽  
Ft Ir ◽  
Uv Visible ◽  
Ft Ir Spectroscopy

In this work, we report carbon-silicon bond formation in thiophene, assisted with alkylated silylchloride. The formylation reaction of silylated thiophene has been discussed and achieved 61% overall yield of reactions. The compounds obtained are characterized quantitatively and qualitatively by using elemental analysis, FT-IR spectroscopy, UV/Visible spectroscopy, and proton NMR spectroscopy. This research work will boost chemists to make the carbon-silicon bond and utilize them in various applications. Journal of Engineering Science 11(1), 2020, 101-105

Biocompatibility of Silver Nano Bio-conjugates from Vitis vinifera Seeds and its Major Component Resveratrol

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
R. Preethi ◽  
P. Padma
Keyword(s):  
Zeta Potential ◽  
Vitis Vinifera ◽  
Silver Ions ◽  
Seed Extract ◽  
Polydispersity Index ◽  
Potential Range ◽  
Visible Spectroscopy ◽  
Grape Seeds ◽  
X Ray ◽  
Uv Visible

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.

Evaluation of Antibacterial and Antidiabetic Potential of Silver Nanoparticles using Eugenia Uniflora L. Seed Extract

2020 ◽  
Vol 13 (6) ◽  
pp. 5217-5225
Author(s):  
Guru Kumar Dugganaboyana ◽  
Chethankumar Mukunda ◽  
Suresh Darshini Inakanally
Keyword(s):  
Biomedical Applications ◽  
Pathogenic Bacteria ◽  
Seed Extract ◽  
Drug Formulation ◽  
Visible Spectroscopy ◽  
Plant Materials ◽  
X Ray ◽  
Eugenia Uniflora ◽  
Uv Visible

In recent years, green nanotechnology-based approaches using plant materials have been accepted as an environmentally friendly and cost-effective approach with various biomedical applications. In the current study, AgNPs were synthesized using the seed extract of the Eugenia uniflora L. (E.uniflora). Characterization was done using UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The formation of AgNPs has confirmed through UV-Visible spectroscopy (at 466 nm) by the change of color owing to surface Plasmon resonance. Based on the XRD pattern, the crystalline property of AgNPs was established. The functional group existing in seed of E.uniflora extract accountable for the reduction of Ag+ ion and the stabilization of AgNPs was investigated. The morphological structures and elemental composition was determined by SEM and EDX analysis. With the growing application of AgNPs in biomedical perspectives, the biosynthesized AgNPs were evaluated for their antibacterial and along with their antidiabetic potential. The results showed that AgNPs are extremely effective with potent antidiabetic potential at a very low concentration. It also exhibited potential antibacterial activity against the three tested human pathogenic bacteria. Overall, the results highlight the effectiveness and potential applications of AgNPs in biomedical fields such as in the treatment of acute illnesses as well as in drug formulation for treating various diseases such as cancer and diabetes. It could be concluded that E. uniflora seed extract AgNPs can be used efficiently for in vitro evaluation of their antibacterial and antidiabetic effects with potent biomedical applications.

scholarly journals Polymer Composites with 0.98 Transparencies and Small Optical Energy Band Gap Using a Promising Green Methodology: Structural and Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1648
Author(s):  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Jihad M. Hadi ◽  
Wrya O. Karim ◽  
Elham M. A. Dannoun ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Polymer Composites ◽  
Amorphous Phase ◽  
Absorption Edge ◽  
Complex Form ◽  
Bandgap Energy ◽  
Optical Parameters ◽  
Visible Spectroscopy ◽  
Uv Visible

In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.

scholarly journals Green synthesis of silk sericin-embedded silver nanoparticles and their antibacterial application against multidrug-resistant pathogens

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Md. Abdullah Al Masud ◽  
Hamid Shaikh ◽  
Md. Shamsul Alam ◽  
M. Minnatul Karim ◽  
M. Abdul Momin ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Bombyx Mori ◽  
Multidrug Resistant ◽  
Visible Spectroscopy ◽  
Silk Sericin ◽  
X Ray ◽  
Synthesis Strategy ◽  
Uv Visible ◽  
Multidrug Resistant Pathogens

Abstract Background The green synthesis strategy of metallic nanoparticles (NPs) has become popular due to being environmentally friendly. Stable silver nanoparticles (AgNPs) have been synthesized by natural products such as starch, soy protein, various extract of leaves, barks, and roots functioning both as reducing and stabilizing agents. Likewise, silk sericin (SS) is a globular protein discarded in the silk factory might be used for NP synthesis. In this research, we focus on the green synthesis and stabilization of AgNPs by SS as well as assessment of their antibacterial activities against some drug-resistant pathogen. Results SS was extracted from Bombyx mori silkworm cocoons in an aqueous medium. 17 w/w% of dry sericin powder with respect to the cocoon’s weight was obtained by freeze-drying. Furthermore, AgNPs conjugated to sericin, i.e., SS-capped silver nanoparticles (SS-AgNPs) were synthesized by easy, cost-effective, and environment-friendly methods. The synthesized SS-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction measurement. It has been found from the absorbance of UV-visible spectroscopy that a higher percent of SS-AgNPs was obtained at a higher concentration of silver nitrate solution. FTIR-ATR spectra showed that the carboxylate groups obtained from silk sericin act as a reducing agent for the synthesis of silver nanoparticles, while NH2+ and COO− act as a stabilizer of AgNPs. The X-ray diffractogram of SS-AgNPs was quite different from AgNO3 and sericin due to a change in the crystal structure. The diameter of AgNPs was around 20–70 nm observed using TEM. The synthesized SS-AgNPs exhibited strong antibacterial activity against multidrug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 20μg/mL. Conclusions This study encourages the use of Bombyx mori for the ecofriendly synthesis of SS-AgNPs to control multidrug-resistant microorganisms.

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