UV-vis Spectroscopy and Cyclic Voltammetry Investigations of Tubular J-Aggregates of Amphiphilic Cyanine Dyes

2019 ◽  
Vol 16 (28) ◽  
pp. 77-84 ◽  
Author(s):  
Jennifer L L. Lyon ◽  
Doerthe Eisele ◽  
Stefan Kirstein ◽  
Jürgen P Rabe ◽  
David A Vanden Bout ◽  
...  
Author(s):  
Wesley Tillmann ◽  
Hussein Samha

The effect of polyvinylsulfate (PVS) on the spectroscopy of the cyanine dye, 1,1’-diethyl-2,2’-cyanine iodide (PIC), has been investigated using UV-vis spectroscopy. J-aggregates of the PIC dye were formed upon addition of PVS to the monomers of the dye in solution. The appearance of only one isosbestic point in the UV-vis spectra suggests that the dye monomers are quantitatively converted to J-aggregates and equilibrium was reached. Using Benisi-Hildebrand kinetics, aggregation number of 4 was calculated for the dye. In addition, a 1:2 mole ratio of PIC/PVS was calculated at the maximum capacity of the polymer.


2013 ◽  
Vol 66 (6) ◽  
pp. 626 ◽  
Author(s):  
Raja Azadar Hussain ◽  
Amin Badshah ◽  
Muhammad Nawaz Tahir ◽  
Bhajan Lal ◽  
Inayat Ali Khan

In this article we have presented the synthesis, chemical characterisation (by NMR and FTIR spectroscopy, atomic absorption spectrophotometry, elemental analysis, and single crystal X-ray diffraction), electrochemistry, and DNA binding studies (with cyclic voltammetry, viscometry, and UV-vis spectroscopy) of six new ferrocene incorporated selenoureas. All the six compounds interact electrostatically with DNA which was evident by a negative shift in the cyclic voltammetry peak potential of the drug–DNA adduct relative to the free drug. The drug–DNA binding constant was calculated by a decrease in peak current after the addition of DNA to the free drug. We have also reported binding site sizes and diffusion coefficients of the synthesised compounds.


2021 ◽  
Vol 12 (4) ◽  
pp. 959-963
Author(s):  
V. V. Prokhorov ◽  
S. I. Pozin ◽  
O. M. Perelygina ◽  
D. A. Lypenko ◽  
E. I. Mal’tsev
Keyword(s):  

2018 ◽  
Vol 26 (23) ◽  
pp. 30324 ◽  
Author(s):  
B. I. Shapiro ◽  
A. D. Nekrasov ◽  
V. S. Krivobok ◽  
V. S. Lebedev

Author(s):  
Juan D. Villada ◽  
Álvaro Duarte-Ruiz ◽  
Manuel N. Chaur

We report a new methodology for the synthesis of two highly symmetric equatorial malonate hexaadducts of C60 fullerene. The synthetic methodology is based on a series of protection and deprotection steps that allow the preparation of a fullerene [60] functionalized with six symmetrical positioned malonate addends without using complicated and expensive separation techniques (highperformance liquid chromatography, HPLC) or long reaction times. This methodology allowed us to prepare the carboxylic adducts 6 (equatorial octacarboxylic tetraadduct of C60) and 8 (equatorial dodecacarboxylic hexakisadduct of C60). As far as we  now, compound 6 has not yet been reported. We also studied the electronic properties of the main compounds by UV-Vis spectroscopy and cyclic voltammetry (CV). The reported fullerene adducts exhibited several reversible reduction processes whose electron transfers are controlled by diffusion. 


2021 ◽  
Vol 74 (1) ◽  
pp. 34 ◽  
Author(s):  
Jessica K. Bilyj ◽  
Jeffrey R. Harmer ◽  
Paul V. Bernhardt

Bis-thiosemicarbazones derived from the β-diketone benzoylacetone (H3banR, R=Me, Et, Ph) are potentially tetradentate N2S2 ligands whose coordination chemistry with copper is reported. In the absence of oxygen and in the presence of base they form anionic CuII complexes of the fully deprotonated ligands [CuII(banR)]–. Upon exposure to atmospheric oxygen they undergo a complex series of reactions leading to two types of products; one a ligand oxidised ketone complex [CuII(banRO)] and the other an unprecedented dimeric di-CuIII complex [(CuIII(banR))2] depending on the R substituent. Time-resolved UV-vis spectroscopy, cyclic voltammetry, spectroelectrochemistry, and electron paramagnetic resonance (EPR) spectroscopy have been used to identify intermediates on the way to stable products formed under both anaerobic and aerobic conditions. It is found that both ligand-centred and Cu-centred oxidation reactions are occurring in parallel leading to this unusually complicated mixture of products.


2002 ◽  
Vol 06 (06) ◽  
pp. 431-438 ◽  
Author(s):  
Maria Angela Castriciano ◽  
Andrea Romeo ◽  
Luigi Monsù Scolaro

The aggregation behavior of meso-tetrakis(4-sulfonatophenyl)porphyrin, [ H 2( TPPS 4)]4-, in the presence of hydrated polyethyleneimine ( PEI ) in aqueous solutions (1.6 < pH < 7.6) has been investigated. The interaction leads to the formation of a variety of pH dependent species, which have been attributed to porphyrin dimers or small oligomers under neutral conditions and J-aggregates on lowering the pH. The aggregation process follows kinetics typical of self-similar systems whose rates increase steeply on increasing the matrix concentration. This finding could be explained on the basis of an increased availability of binding sites for the growing aggregates. The charged polymer has been used to electrostatically adsorb the porphyrin onto glass substrates affording multilayered films. Our results point to the presence of fully protonated species in the solid state, which rearrange into J-aggregates as a function of pH and water content. The systems in solution and on glass surfaces have been investigated through a combination of UV-vis spectroscopy, fluorescence emission and resonance light scattering techniques.


2017 ◽  
Vol 51 (13) ◽  
pp. 1717-1723 ◽  
Author(s):  
I. V. Fedorov ◽  
A. V. Romashkin ◽  
A. V. Emelianov ◽  
V. K. Nevolin ◽  
I. I. Bobrinetskiy

1999 ◽  
Vol 77 (5-6) ◽  
pp. 903-912 ◽  
Author(s):  
James Wojtyk ◽  
Andrew McKerrow ◽  
Peter Kazmaier ◽  
Erwin Buncel

In continuing studies of the aggregation behaviour of squaraine dyes in DMSO-water mixtures, we have examined a series of symmetrical anilino-based squaraines with increasing N-alkyl chain length (n-butyl, n-octyl, and n-dodecyl). The aggregation behaviour was assessed through UV/vis spectroscopic and Dynamic Light Scattering (DLS) studies with quantitative interpretation based on exciton theory. This class of N-alkyl squaraines forms two distinct solution aggregates, Type J and Type H, depending on the composition of the DMSO-water medium. DLS measurement of the aggregates in the Type J and Type H morphologies showed that (i) the particle diameter increased with increasing hydrophobicity; (ii) DMSO has a large effect on the aggregate size; (iii) Type J aggregates are of equal dimensions with Type H aggregates. Moreover, even though as the DMSO-water solvent composition is varied the UV/vis spectra of Type H and Type J aggregates remained unchanged, the number of molecules comprising each aggregate varies widely. It is proposed that the dynamic conversion (J →> H) results from intramolecular reorganization of individual molecules within the aggregate. Quantification of aggregation through DLS has further developed the "kinetic" versus "thermodynamic" control model of dye aggregation.Key words: squaraine, dynamic light scattering, DMSO-water mixtures, self-assembly, kinetic/thermodynamic control.


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