Role of Photoionization on the Dynamics and Mechanism of Photoinduced Electron Transfer Reaction of Coumarin 307 in Micelles

Dhenadhayalan, Namasivayam; Selvaraju, Chellappan

doi:10.1021/jp301412c

Cited by 19 publications

(29 citation statements)

References 52 publications

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“…The observed fluorescence quenching of C-dots1 may be due to non-radiative electron transfer from the excited state of the C-dots to the d-orbital of Fe 3+ ion 18 33 . The fluorescence quenching process was analyzed by using Stern-Volmer (S-V) relation (F 0 /F = 1 + K SV [Q] = 1 + k q τ 0 [Q]) 34 . The S-V plot shows linearity in the concentration range of 0 – 100 μM, yielding K SV of 2.5 × 10 4 M −1 .…”

Section: Resultsmentioning

confidence: 99%

Chemically Induced Fluorescence Switching of Carbon-Dots and Its Multiple Logic Gate Implementation

Dhenadhayalan

Lin

2015

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Investigations were carried out on the carbon-dots (C-dots) based fluorescent off - on (Fe3 + - S2O32−) and on - off (Zn2 + - PO43−) sensors for the detection of metal ions and anions. The sensor system exhibits excellent selectivity and sensitivity towards the detection of biologically important Fe3 + , Zn2 + metal ions and S2O32−, PO43− anions. It was found that the functional group on the C-dots surface plays crucial role in metal ions and anions detection. Inspired by the sensing results, we demonstrate C-dots based molecular logic gates operation using metal ions and anions as the chemical input. Herein, YES, NOT, OR, XOR and IMPLICATION (IMP) logic gates were constructed based on the selection of metal ions and anions as inputs. This carbon-dots sensor can be utilized as various logic gates at the molecular level and it will show better applicability for the next generation of molecular logic gates. Their promising properties of C-dots may open up a new paradigm for establishing the chemical logic gates via fluorescent chemosensors.

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Section: Resultsmentioning

confidence: 99%

Chemically Induced Fluorescence Switching of Carbon-Dots and Its Multiple Logic Gate Implementation

Dhenadhayalan

Lin

2015

Sci Rep

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“…The details of this experimental setup have been given in an earlier publication. 94 Briefly, all the samples were excited using a second harmonic (400 nm) of a mode-locked Ti-sapphire laser (Tsunami, Spectra-Physics). A nonlinear crystal (1 mm BBO, θ = 25°, ϕ = 90°) was used for frequency doubling of the fundamental beam (800 nm) to generate the expected excitation source.…”

Section: Methodsmentioning

confidence: 99%

Picosecond Solvation and Rotational Dynamics: An Attempt to Reinvestigate the Mystery of Alcohol–Water Binary Mixtures

et al. 2015

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In this article, we have investigated the anomalous behavior of two alcohol-water (tert-butyl alcohol (TBA)-water and ethanol-water) binary mixtures using femtosecond fluorescence upconversion technique. Recently, Gupta and Patey (Gupta, R.; Patey, G. N. J. Chem. Phys. 2012, 137, 034509(1)-034509(12)) have used four force fields to simulate TBA-water binary mixtures. Surprisingly, two of them do not identify any aggregation of TBA molecules. We have calculated average solvation time of Coumarin 480 (C480) using two different methods. Our results indicate slowdown in solvation time in the mole fraction ranges XT = 0.09-0.15, XT = 0.40-0.46 and XE = 0.06-0.08, XE = 0.20-0.25 for TBA-water and ethanol-water binary mixtures, respectively. Additionally, we have detected another anomalous region at XT ∼ 0.03. Slow solvation responses in the ranges XT = 0.40-0.46 and XE = 0.20-0.25 are probably due to the higher shear viscosity of the medium. However, XT = 0.09-0.15 and XE = 0.06-0.08 are the manifestation of aggregation induced structural transition of alcohol molecules. Hindered rotation of C480 in the ranges XT = 0.04-0.09 and XE = 0.03-0.07 corroborates our solvation dynamics results. From temperature dependent anisotropy measurements, we have shown that aggregation of alcohol molecules increases with increase in temperature.

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“…Femtosecond fluorescence decays were collected by using the fluorescence up‐conversion technique (FOG 100, CDP, Russia). The details of this experimental setup have been given in an earlier report 63. In brief, samples were excited by using the second harmonic ( λ =405 nm) of a mode‐locked Ti‐sapphire laser (Tsunami, Spectra physics).…”

Section: Methodsmentioning

confidence: 99%

Ultrafast FRET to Study Spontaneous Micelle‐to‐Vesicle Transitions in an Aqueous Mixed Surface‐Active Ionic‐Liquid System

et al. 2014

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The spontaneous micelle-to-vesicle transition in an aqueous mixture of two surface-active ionic liquids (SAILs), namely, 1-butyl-3-methylimidazolium n-octylsulfate ([C4mim][C8SO4]) and 1-dodecyl-3-methylimidazoium chloride ([C12mim]Cl) is described. In addition to detailed structural characterization obtained by using dynamic light scattering, transmission electron microscopy (TEM), and cryogenic TEM techniques, ultrafast fluorescence resonance energy transfer (FRET) from coumarin 153 (C153) as a donor (D) to rhodamine 6G (R6G) as an acceptor (A) is also used to study micelle-vesicle transitions in the present system. Structural transitions of SAIL micelles ([C4mim][C8SO4] or [C12mim]Cl micelles) to mixed SAIL vesicles resulted in significantly increased D-A distances, and therefore, increased timescale of FRET. In [C4mim][C8SO4] micelles, FRET between C153 and R6G occurs on an ultrafast timescale of 3.3 ps, which corresponds to a D-A distance of about 15 Å. As [C4mim][C8SO4] micelles are transformed into mixed micelles upon the addition of a 0.25 molar fraction of [C12mim]Cl, the timescale of FRET increases to 300 ps, which suggests an increase in the D-A distance to 31 Å. At a 0.5 molar fraction of [C12mim]Cl, unilamellar vesicles are formed in which FRET occurs on multiple timescales of about 250 and 2100 ps, which correspond to D-A distances of 33 and 47 Å. Although in micelles and mixed micelles the obtained D-A distances are well correlated with their radius, in vesicles the obtained D-A distance is within the range of the bilayer thickness.

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Role of Photoionization on the Dynamics and Mechanism of Photoinduced Electron Transfer Reaction of Coumarin 307 in Micelles

Cited by 19 publications

References 52 publications

Chemically Induced Fluorescence Switching of Carbon-Dots and Its Multiple Logic Gate Implementation

Chemically Induced Fluorescence Switching of Carbon-Dots and Its Multiple Logic Gate Implementation

Picosecond Solvation and Rotational Dynamics: An Attempt to Reinvestigate the Mystery of Alcohol–Water Binary Mixtures

Ultrafast FRET to Study Spontaneous Micelle‐to‐Vesicle Transitions in an Aqueous Mixed Surface‐Active Ionic‐Liquid System

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