scholarly journals Self Assembly of Cyanine Dye on Clay Nanoparticles

2005 ◽  
Vol 3 (4) ◽  
Author(s):  
Andrew Dixon ◽  
Clint Duncan ◽  
Hussein Samha
Keyword(s):  
Aqueous Solutions ◽  
Self Assembly ◽  
Montmorillonite Clay ◽  
Cyanine Dye ◽  
Clay Particles ◽  
Clay Nanoparticles ◽  
Charged Surfaces ◽  
Successive Addition ◽  
Vis Spectroscopy ◽  
J Aggregates

The effect of Ca-montmorillonite (clay) on the aggregation behavior of the cyanine dye, 1,1’-diethyl-2,2’-cyanine iodide (PIC), in aqueous solutions has been investigated using UV-vis spectroscopy. The absorbance of the monomeric dye in aqueous solutions is compared with the absorbance of the aggregates formed after adding the clay. The appearance of a sharp “red-shifted” band centered at 574 nm, after the addition of clay to the aqueous solutions of the dye, indicates the formation J-aggregates on the charged surfaces of the clay particles. The spontaneous and quantitative transformation of monomers into J-aggregates was controlled by the concentration of the clay in the solution. Successive addition of clay to the dye solution causes an increase in the absorbance intensity of the J-band and consequently, a decrease in the absorbance intensity of the monomer. These changes occur linearly which suggests that the dye monomers are quantitatively being converted to J-aggregates.

Aggregation of meso-tetrakis(4-sulfonatophenyl)porphyrin on polyethyleneimine in aqueous solutions and on a glass surface

2002 ◽  
Vol 06 (06) ◽  
pp. 431-438 ◽  
Author(s):  
Maria Angela Castriciano ◽  
Andrea Romeo ◽  
Luigi Monsù Scolaro
Keyword(s):  
Aqueous Solutions ◽  
Fluorescence Emission ◽  
Resonance Light Scattering ◽  
Glass Substrates ◽  
Vis Spectroscopy ◽  
The Matrix ◽  
J Aggregates ◽  
Matrix Concentration ◽  
Glass Surfaces ◽  
Neutral Conditions

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.

scholarly journals On the Aqueous Solution Behavior of C-Substituted 3,1,2-Ruthenadicarbadodecaboranes

Inorganics ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 91 ◽  
Author(s):  
Marta Gozzi ◽  
Benedikt Schwarze ◽  
Peter Coburger ◽  
Evamarie Hey-Hawkins
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Self Assembly ◽  
Self Assembling ◽  
Vis Spectroscopy ◽  
Assembly Behavior ◽  
Biological Performance ◽  
Type 3

3,1,2-Ruthenadicarbadodecaborane complexes bearing the [C2B9H11]2− (dicarbollide) ligand are robust scaffolds, with exceptional thermal and chemical stability. Our previous work has shown that these complexes possess promising anti-tumor activities in vitro, and tend to form aggregates (or self-assemblies) in aqueous solutions. Here, we report on the synthesis and characterization of four ruthenium(II) complexes of the type [3-(η6-arene)-1,2-R2-3,1,2-RuC2B9H9], bearing either non-polar (R = Me (2–4)) or polar (R = CO2Me (7)) substituents at the cluster carbon atoms. The behavior in aqueous solution of complexes 2, 7 and the parent unsubstituted [3-(η6-p-cymene)-3,1,2-RuC2B9H11] (8) was investigated via UV-Vis spectroscopy, mass spectrometry and nanoparticle tracking analysis (NTA). All complexes showed spontaneous formation of self-assemblies (108–109 particles mL−1), at low micromolar concentration, with high polydispersity. For perspective applications in medicine, there is thus a strong need for further characterization of the spontaneous self-assembly behavior in aqueous solutions for the class of neutral metallacarboranes, with the ultimate scope of finding the optimal conditions for exploiting this self-assembling behavior for improved biological performance.

scholarly journals J-Aggregates of Cyanine Dyes in Aqueous Solution of Polymers: A Quantitative Study

2004 ◽  
Vol 3 (3) ◽  
Author(s):  
Wesley Tillmann ◽  
Hussein Samha
Keyword(s):  
Aqueous Solution ◽  
Quantitative Study ◽  
Aggregation Number ◽  
Cyanine Dyes ◽  
Cyanine Dye ◽  
Isosbestic Point ◽  
Maximum Capacity ◽  
Vis Spectroscopy ◽  
J Aggregates

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.

scholarly journals Principles for Self-Assembly of Cyanine Dyes into 2-Dimensional Excitonic Aggregates Across the Visible and Near-Infrared

2020 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Austin Bailey ◽  
Leandra Forte ◽  
Xingyu Shen ◽  
Niklas Geue ◽  
...  
Keyword(s):  
Self Assembly ◽  
Near Infrared ◽  
Dynamic Equilibrium ◽  
Structural Information ◽  
Photophysical Properties ◽  
Cyanine Dyes ◽  
Cyanine Dye ◽  
Extensive Literature ◽  
Solvent Ratio ◽  
J Aggregates

<div>Cyanine dyes show a remarkable tendency to form non-covalent supramolecular aggregates with diverse morphologies (dimers, sheets, tubes and bundles). Specific molecular arrangements within these H- or J-aggregates dictate the extraordinary photophysical properties, including long-range exciton delocalization, extreme redshifts, and excitonic superradiance. Despite extensive literature on cyanine dye aggregates, design principles that drive the solution self-assembly to a preferred H- or J-aggregated state are unknown. We present a general approach to tune the thermodynamics of self-assembly, selectively stabilizing H- or J-aggregates and thereby achieving supramolecular control over aggregate photophysics. A simple interplay of solvent to non-solvent ratio, ionic strength or dye concentration yields a broad range of conditions that predictably and preferentially stabilize the monomer, H- or J-aggregate species that can be easily monitored using absorption spectroscopy. Diffusion ordered spectroscopy, cryo-electron microscopy and atomic force microscopy together reveal a dynamic equilibrium between monomers, H-aggregated dimers, and extended J-aggregated 2-dimensional monolayers. This structural information informs a three-component equilibrium model that describes the observed concentration dependence of spectral signatures, showing excellent fit with experimental data and yields the Gibb’s free energies of self-assembly for dimerization and 2D aggregate assembly. We further demonstrate the universality of this approach among several sheet forming cyanine dyes including the benzothiazole and benzimidazole families with absorptions spanning visible, near and shortwave infrared wavelengths.</div>

scholarly journals Aggregation of Cyanine Dye in Bilayer Vesicles of Phospholipids

2005 ◽  
Vol 4 (3) ◽  
Author(s):  
Casey McCullough ◽  
Matthew Heywood ◽  
Hussein Samha
Keyword(s):  
Aqueous Solution ◽  
Equilibrium Constant ◽  
Room Temperature ◽  
Aggregation Number ◽  
Cyanine Dye ◽  
Molar Ratio ◽  
Isosbestic Point ◽  
Dye Molecules ◽  
Vis Spectroscopy ◽  
J Aggregates

The effect of phospholipid, 1,2-Dipalmitoyl-sn-glycero-3-Phosphocholine (DPPC) on the spectroscopy of the cyanine dye, 1-ethyl-1’-octadecyl-2,2’-cyanine iodide (PIC-18), has been investigated using UV-Vis spectroscopy. Vesicles of DPPC containing PIC-18 in the molar ratio of 1:3 (dye/phospholipids) were prepared in aqueous solution. J-aggregates of PIC-18 were detected in the bilayer wall of the vesicles. When an aqueous solution of mixed PIC-18/DPPC vesicles is treated with excess DPPC vesicles that are prepared separately, the dye molecules in the mixed vesicles underwent a rapid (aggregate)n' n(monomer) equilibrium as the appearance of only one isosbestic point in the absorbance of the dye indicates. The equilibrium constant was calculated at room temperature (Keq = 6.7x10-2). An aggregation number of 4 was calculated for the dye in the bilayer vesicles.

scholarly journals The Role of the Counterions in Self-Assembly of J-Aggregates from meso-Aryl Substituted Porphyrin Diacids in Aqueous Solutions

2015 ◽  
Vol 8 (3) ◽  
pp. 244-251 ◽  
Author(s):  
Margaret A. Gradova ◽  
Vladimir N. Kuryakov ◽  
Anton V. Lobanov
Keyword(s):  
Aqueous Solutions ◽  
Self Assembly ◽  
J Aggregates

A supramolecular probe of cyanine dye for Pb2+ detection based on the recognition of a G-quadruplex from DNA duplexes

2020 ◽  
Vol 12 (9) ◽  
pp. 1182-1185 ◽  
Author(s):  
Lijia Yu ◽  
Han Zhao ◽  
Nannan Jing ◽  
Xiaodong Shi ◽  
Yinglin Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cyanine Dye ◽  
Duplex Dna ◽  
Dna Duplexes ◽  
Vis Spectroscopy ◽  
G Quadruplex

The supramolecular self-assembly of MTC transformation between duplex DNA and G-quadruplex for the recognition of Pb2+ ions via UV-vis spectroscopy.

Inter- und intramolekularer Energietransfer und Ladungstrennung in kovalent gebundenen Cyanin-Farbstoff-Viologen-Systemen / Inter- and Intramolecular Energy Transfer and Charge Separation in Covalently Linked Cyanine Dye-Viologen Systems

1993 ◽  
Vol 48 (4) ◽  
pp. 461-470 ◽  
Author(s):  
Rupert Bauer ◽  
Christian Königstein
Keyword(s):  
Hydrogen Production ◽  
Aqueous Solutions ◽  
Charge Separation ◽  
Methyl Viologen ◽  
Cyanine Dye ◽  
Quantum Yields ◽  
Back Reaction ◽  
Dilute Aqueous Solutions ◽  
J Aggregates ◽  
Covalently Linked

As described by many authors, covalently linked dye-electron accepting group systems may provide a very efficient intramolecular fluorescence quenching and electron transfer. Due to the very fast thermal back reaction, no stable charge separation can be achieved. In contrast, J-aggregates of cyanine dyes (1,1′-diethyl-2,2′-cyanine iodide = 1) containing some molecules with covalently linked viologen groups (1-[3-[2-[(1-ethyl-2(1 H)-chinolinyliden)methyl]-chinolinium-l-yl]propyl]-1′-methyl-4,4′-bipyridinium triiodide = 2, 1,1′-(4,4′-bipyridinium-1,1′-diyldi-5,1 -pentandiyl)bis[2-[(1-ethyl-2(1H)-chinolinyliden)methyl]chinolinium] tetrachloride = 3) show an increase in charge separation. Hydrogen production experiments in these organized assemblies, both via inter- (with methyl viologen) and intramolecular (with 2 or 3) charge separation were successful. Hydrogen production experiments based on intramolecular charge separation gave even higher quantum yields than via intermolecular reaction steps. In contrast, hydrogen production experiments with dilute aqueous solutions (no aggregates) with 2 or 3 failed in the absence of methyl viologen (MV2+) due to the fast intramolecular back reaction. In the presence of MV2+ compounds 1-3 were able to produce H2 only when irradiated with near UV-light (λ > 280 nm). Irradiation of these solutions with visible light (λ > 400 nm) resulted in no H2 production. This is attributed to competing nonradiative desactivation processes. Dilute aqueous solutions of 1-3 gave also no visible emission (λ > 400 nm) in the absence of (additional) quenching molecules. So a further progress was achieved by using the J-aggregates: competing nonradiative desactivation processes (of the excited dye molecules) were diminished in J-aggregates.

scholarly journals Principles for Self-Assembly of Cyanine Dyes into 2-Dimensional Excitonic Aggregates Across the Visible and Near-Infrared

2020 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Austin Bailey ◽  
Leandra Forte ◽  
Xingyu Shen ◽  
Niklas Geue ◽  
...  
Keyword(s):  
Self Assembly ◽  
Near Infrared ◽  
Dynamic Equilibrium ◽  
Structural Information ◽  
Photophysical Properties ◽  
Cyanine Dyes ◽  
Cyanine Dye ◽  
Extensive Literature ◽  
Solvent Ratio ◽  
J Aggregates

<div>Cyanine dyes show a remarkable tendency to form non-covalent supramolecular aggregates with diverse morphologies (dimers, sheets, tubes and bundles). Specific molecular arrangements within these H- or J-aggregates dictate the extraordinary photophysical properties, including long-range exciton delocalization, extreme redshifts, and excitonic superradiance. Despite extensive literature on cyanine dye aggregates, design principles that drive the solution self-assembly to a preferred H- or J-aggregated state are unknown. We present a general approach to tune the thermodynamics of self-assembly, selectively stabilizing H- or J-aggregates and thereby achieving supramolecular control over aggregate photophysics. A simple interplay of solvent to non-solvent ratio, ionic strength or dye concentration yields a broad range of conditions that predictably and preferentially stabilize the monomer, H- or J-aggregate species that can be easily monitored using absorption spectroscopy. Diffusion ordered spectroscopy, cryo-electron microscopy and atomic force microscopy together reveal a dynamic equilibrium between monomers, H-aggregated dimers, and extended J-aggregated 2-dimensional monolayers. This structural information informs a three-component equilibrium model that describes the observed concentration dependence of spectral signatures, showing excellent fit with experimental data and yields the Gibb’s free energies of self-assembly for dimerization and 2D aggregate assembly. We further demonstrate the universality of this approach among several sheet forming cyanine dyes including the benzothiazole and benzimidazole families with absorptions spanning visible, near and shortwave infrared wavelengths.</div>

Green synthesis of mixed metallic nanoparticles using room temperature self-assembly

2017 ◽  
Vol 13 (2) ◽  
pp. 4671-4677 ◽  
Author(s):  
A. M. Abdelghany ◽  
A.H. Oraby ◽  
Awatif A Hindi ◽  
Doaa M El-Nagar ◽  
Fathia S Alhakami
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Bimetallic Nanoparticles ◽  
Reduction Process ◽  
Nano Particles ◽  
Nano Structure ◽  
Small Shift ◽  
Molar Ratios ◽  
Vis Spectroscopy

Bimetallic nanoparticles of silver (Ag) and gold (Au) were synthesized at room temperature using Curcumin. Reduction process of silver and gold ions with different molar ratios leads to production of different nanostructures including alloys and core-shells. Produced nanoparticles were characterized simultaneously with FTIR, UV/vis. spectroscopy, transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDAX). UV/vis. optical absorption spectra of as synthesized nanoparticles reveals presence of surface palsmon resonance (SPR) of both silver at (425 nm) and gold at (540 nm) with small shift and broadness of gold band after mixing with resucing and capping agent in natural extract which suggest presence of bimetallic nano structure (Au/Ag). FTIR and EDAX data approve the presence of bimetallic nano structure combined with curcumin extract. TEM micrographs shows that silver and gold can be synthesized separately in the form of nano particles using curcumin extract. Synthesis of gold nano particles in presence of silver effectively enhance and control formation of bi-metallic structure.

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