Interaction between tetracyanoethylene and naphthalene in reverse micelles of AOT in n-hexane. The electron-donor properties of AOT

1996 ◽  
Vol 74 (9) ◽  
pp. 1603-1608 ◽  
Author(s):  
M. A. Biasutti ◽  
Juana J. Silber
Keyword(s):  
Electron Donor ◽  
Reverse Micelles ◽  
Formation Constants ◽  
Local Concentration ◽  
Micellar Media ◽  
Visible Spectroscopy ◽  
Donor Acceptor ◽  
Uv Visible ◽  
The Stability ◽  
Homogeneous Media

The electron donor–acceptor (EDA) interaction between TCNE and naphthalene (Naph) in n-hexane and reverse micelles of AOT in n-hexane was studied by UV–visible spectroscopy with the aim of determining the influence of the micellar media on the EDA interaction. The spectra of the mixtures of TCNE–Naph in n-hexane show two typical maxima at 418 and 534 nm, assigned to the formation of a π–π EDA complex. In the micellar media a new band is observed at 398 nm. When the spectra of TCNE in n-hexane are studied in the presence of AOT two new bands at 398 and 418 nm are detected. These bands are consistent with an EDA interaction between TCNE and AOT as n-donor. The stability constants of this interaction were calculated for AOT concentrations below the CMC and in the micellar media at different W(W = [H2O]/[AOT]). The results give evidence of the tendency of AOT to interact very strongly with electron acceptors. Moreover, in the system TCNE–Naph in the micellar media it is shown that Naph and AOT compete to form a complex with TCNE. The formation constants of the complexes of AOT–Naph in the micelle system were determined at W = 0 and 5. Despite the competition of AOT for TCNE the stability constant for the complex TCNE–Naph is higher than in homogeneous media, probably due to the high local concentration of the acceptor in the micelle. Key words: reverse micelles, aerosol-OT, tetracyanoethylene, naphthalene, electron donor–acceptor complexes.

Method for determining the formation constants of intermolecular H-bonding from IR spectroscopy data

2021 ◽  
pp. 55-58
Author(s):  
N.U. Mulloev ◽  
◽  
N.L. Lavrik ◽  
J.O. Yusypova ◽  
N.A. Majidov ◽  
...  
Keyword(s):  
Optical Density ◽  
Formation Constants ◽  
Butyl Alcohol ◽  
Proton Donor ◽  
Proton Acceptor ◽  
Ir Absorption ◽  
Visible Spectroscopy ◽  
Absorption Bands ◽  
Intermolecular Hydrogen Bonds ◽  
Uv Visible

An experimental method is proposed for determining the efficiency of the formation of intermolecular hydrogen bonds by determining the formation constant of the H-complex (K). The essence of the experiment to determine the value of K is that for one initial concentration of the proton donor, it is necessary to register the change in the optical density at the absorption wavelength of the monomers and the change in the optical density of the complexes of IR absorption bands at two concentrations of the proton acceptor. This approach was tested on the example of the interaction of butyl alcohol (proton donor) with 4-chloromethyl-1.3-dioxolane (proton acceptor). The obtained value of the equilibrium constant was 72.2 M-1. It is concluded that the proposed method for determining the value of K can be used not only in IR, but also in UV-visible spectroscopy.

Polarographic investigation of electron donor–acceptor complexes

1978 ◽  
Vol 56 (18) ◽  
pp. 2381-2387 ◽  
Author(s):  
Louis Ramaley ◽  
Sonia Gaul
Keyword(s):  
Electron Donor ◽  
Aromatic Hydrocarbons ◽  
Formation Constant ◽  
Reduction Potential ◽  
Charge Transfer Band ◽  
Formation Constants ◽  
Molar Absorptivity ◽  
Polar Solvents ◽  
Donor Acceptor ◽  
Computer Controlled

Using a computer-controlled precision polarograph the formation constants of electron donor–acceptor (EDA) complexes formed from aromatic hydrocarbons and nitrofluorene derivatives have been determined in acetonitrile. The EDA interactions are of the same magnitude in this solvent as in less polar solvents. The strength of the complexes is related to the reduction potential (or electron affinity) of the acceptors and the size of the π system of the donors. Spectra of the complexes were computed from spectra of mixtures of accepter and donor with the help of the polarographic data. No relationship between the molar absorptivity of the charge-transfer band and the formation constant was apparent from these spectra.

scholarly journals Study of the β-Cyclodextrin Imipramine Hydrochloride Inclusion Complex and Determination of its Stability Constant (K) by UV-Visible Spectroscopy

2007 ◽  
Vol 4 (4) ◽  
pp. 550-558 ◽  
Author(s):  
Alamdar Ashnagar ◽  
Nahid Gharib Naseri ◽  
Bita Khanaki
Keyword(s):  
Stability Constant ◽  
Inclusion Complex ◽  
Visible Spectroscopy ◽  
Constant Amount ◽  
A Value ◽  
Visible Spectra ◽  
Imipramine Hydrochloride ◽  
Uv Visible ◽  
The Stability

In this research, the interactions of imipramine hydrochloride drug with β- cyclodextrin and the stability constant (K) of the inclusion complex formed between them were investigated by using UV-visible spectroscopy. Solutions consisting of a known and constant amount of imipramine hydrochloride and varying amounts of β- cyclodextrin were prepared in 0.1 M phosphate buffer (pH 7.4). The final solutions had cyclodextrin concentrations between 0.0011 and 0.0153 M. UV-visible spectra of each solution was taken at λmax= 250 nm. The absorbances at this wavelength were recorded and plotted against cyclodextrin concentrations. From the graph, the concentrations of free and bound imipramine hydrochloride and free β-cyclodextrin were calculated using the Beer-Lambert law. From these data, the stability constant was calculated and a value of K=52.26±11.41 mol-1L was obtained. The magnitude of the stability constant is discussed in terms of the relative sizes and the chemical natures of β-cyclodextrin and imipramine hydrochloride.

scholarly journals Enhanced Thermal Conductivity and Superior Antimicrobial Activity by Cu/Ni Nanofiber Dispersed Fluids with Prolonged Stability

2019 ◽  
Vol 9 (2) ◽  
pp. 4950-4953
Keyword(s):  
Thermal Conductivity ◽  
Inhibitory Concentration ◽  
Imaging Techniques ◽  
Antibacterial Properties ◽  
Zone Of Inhibition ◽  
Visible Spectroscopy ◽  
Synthesis Parameters ◽  
Uv Visible ◽  
The Stability ◽  
Inhibition Analysis

The present study reports the synthesis, characterization and antibacterial properties of Cu/Ni nanofluids. The influence of various synthesis parameters on the stability of nano suspensions were studied and optimized. The samples were characterized using UV-Visible spectroscopy and TEM imaging techniques. The TEM images revealed the formation of nanofibers. The optimized composition of the Cu/Ni nanofluid was found to be stable for more than four months with zeta potential value of 40.4mV. The thermal conductivity studies showed 19% enhancement in comparison to the base fluid (water). The antibacterial properties of the nanosuspensions were studied by performing minimum inhibitory concentration tests (MIC) and zone of inhibition analysis.

scholarly journals Crystal Violet Partitioning in Anionic Surfactants Micellar Media: UV-Visible Spectroscopy Study

2018 ◽  
Vol 21 (3) ◽  
pp. 136-142 ◽  
Author(s):  
olaseni esan ◽  
Akeremale olaniran ◽  
Osundiya olubunmi ◽  
Aboluwoye Christopher ◽  
Orunesajo Ayorinde ◽  
...  
Keyword(s):  
Crystal Violet ◽  
Anionic Surfactants ◽  
Spectroscopy Study ◽  
Micellar Media ◽  
Visible Spectroscopy ◽  
Uv Visible

Unmodified Goldnanoparticles Used as Probes for Detection of Coralyne with poly(A40)

2013 ◽  
Vol 788 ◽  
pp. 136-140 ◽  
Author(s):  
Meng Shu Han ◽  
Ji Wei Hu ◽  
Jin Luo
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Duplex Structure ◽  
Visible Spectroscopy ◽  
Buffer Solution ◽  
Protoberberine Alkaloids ◽  
Double Stranded Dna ◽  
Uv Visible ◽  
The Stability ◽  
Induced Aggregation

Coralyne is a kind of protoberberine alkaloids with strong anticancer activity in animal models, which could induce single-stranded adenine rich nucleic acids (poly (dA)) to form a duplex structure. And poly (dA) could be absorbed on the surface of gold nanoparticles (AuNPs) to enhance the stability against NaCl induced aggregation. However, coralyne induced poly (dA) to form double-stranded DNA, which then left the AuNPs resulting in the arrgregation by NaCl. This paper investigated the conditions and effects of using poly (A40) as a probe for the coralyne detection. The detection of coralyne used 100 mM HEPES and 200 mM NaCl as the buffer solution. The poly (A40) was 250 nM in the experiment for the protection of AuNPs aggregation caused by buffer solution. UV-visible spectroscopy was employed to detect the colorimetric changes in the aggregated condition of AuNPs. From blank to 1000 nM of coralyne, a linear response was obtained with R2 = 0.862. The limit of detection was 100 nM. Results showed that the detection of coralyne with poly (A40) was achievable by using unmodified AuNPs.

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