Photophysical Properties of Squaraine Derivatives:  Evidence for Charge Separation

1997 ◽  
Vol 101 (50) ◽  
pp. 9673-9677 ◽  
Author(s):  
Claudia Cornelissen-Gude ◽  
Wolfgang Rettig ◽  
René Lapouyade
Keyword(s):  
Charge Separation ◽  
Photophysical Properties

scholarly journals Charge separation and energy transfer in multicomponent porphyrinic arrays

2001 ◽  
Vol 73 (3) ◽  
pp. 421-424 ◽  
Author(s):  
Lucia Flamigni
Keyword(s):  
Energy Transfer ◽  
Charge Separation ◽  
Photophysical Properties ◽  
Photoinduced Charge Separation ◽  
Recent Activity ◽  
Photoinduced Charge

An overview of the recent activity of the laboratory in the determination of the photophysical properties of porphyrinic arrays, with emphasis on the theme of photoinduced charge separation, is presented.

scholarly journals Photophysical Properties of Donor-Acceptor Stenhouse Adducts and Their Inclusion Complexes with Cyclodextrins and Cucurbit[7]uril

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4928
Author(s):  
Liam Payne ◽  
Jason D. Josephson ◽  
R. Scott Murphy ◽  
Brian D. Wagner
Keyword(s):  
Aqueous Solution ◽  
Fluorescence Spectroscopy ◽  
Inclusion Complex ◽  
Charge Separation ◽  
Photophysical Properties ◽  
Protic Solvents ◽  
Mechanistic Insight ◽  
Donor Acceptor ◽  
Strong Inclusion ◽  
Supramolecular Complexation

Donor-acceptor Stenhouse adducts (DASAs) are a novel class of solvatochromic photoswitches with increasing importance in photochemistry. Known for their reversibility between open triene and closed cyclized states, these push-pull molecules are applicable in a suite of light-controlled applications. Recent works have sought to understand the DASA photoswitching mechanism and reactive state, as DASAs are vulnerable to irreversible “dark switching” in polar protic solvents. Despite the utility of fluorescence spectroscopy for providing information regarding the electronic structure of organic compounds and gaining mechanistic insight, there have been few studies of DASA fluorescence. Herein, we characterize various photophysical properties of two common DASAs based on Meldrum’s acid and dimethylbarbituric acid by fluorescence spectroscopy. This approach is applied in tandem with complexation by cyclodextrins and cucurbiturils to reveal the zwitterionic charge separation of these photoswitches in aqueous solution and the protective nature of supramolecular complexation against degradative dark switching. DASA-M, for example, was found to form a weak host-guest inclusion complex with (2-hydroxypropyl)-γ-cyclodextrin, with a binding constant K = 60 M−1, but a very strong inclusion complex with cucurbit[7]uril, with K = 27,000 M−1. This complexation within the host cavity was found to increase the half-life of both DASAs in aqueous solution, indicating the significant and potentially useful stabilization of these DASAs by host encapsulation.

Synthesis and comparative charge transfer studies in porphyrin–fullerene dyads: mode of attachment effect

2017 ◽  
Vol 41 (22) ◽  
pp. 13276-13286 ◽  
Author(s):  
Neha Gupta ◽  
Chhavi Sharma ◽  
Mahesh Kumar ◽  
Rachana Kumar
Keyword(s):  
Electrical Conductivity ◽  
Charge Transfer ◽  
Charge Separation ◽  
Photophysical Properties ◽  
Electronic Devices ◽  
Potential Candidate ◽  
Organic Electronic Devices ◽  
Organic Electronic ◽  
Thermally Activated ◽  
Mode Of Attachment

Two types of dyads having different modes of attachment i.e. cyclopropanation vs. pyrrolidine type in porphyrin–fullerene linked systems are compared for their photophysical properties. Dyad II with pyrrolidine type of linkage shows faster charge separation and generation of long lived charge separated states. It also shows a new property of thermally activated electrical conductivity which makes it potential candidate for organic electronic devices.

Synthesis and Photophysical Properties of Two Dual Oligothiophene-Fullerene Linkage Molecules as Photoinduced Long-Distance Charge Separation Systems

2006 ◽  
Vol 71 (5) ◽  
pp. 1761-1768 ◽  
Author(s):  
Masashi Narutaki ◽  
Kazuo Takimiya ◽  
Tetsuo Otsubo ◽  
Yutaka Harima ◽  
Huimin Zhang ◽  
...  
Keyword(s):  
Charge Separation ◽  
Photophysical Properties ◽  
Long Distance ◽  
Separation Systems

Photodecomposition of H2S to H2 over Cu2+ Doped Cd0.3In2S4-Zn0.7In2S4 Composite Photocatalysts

2012 ◽  
Vol 486 ◽  
pp. 174-180
Author(s):  
Xue Feng Bai ◽  
Wen Yan Shan
Keyword(s):  
Crystal Structure ◽  
Photocatalytic Activity ◽  
Charge Separation ◽  
Separation Efficiency ◽  
Photophysical Properties ◽  
H2 Evolution ◽  
Composite Photocatalyst ◽  
Long Wavelength ◽  
Composite Photocatalysts ◽  
Charge Separation Efficiency

The Cd0.3In2S4-Zn0.7In2S4 composite photocatalyst doped with transition metal Cu2+ has been synthesized by hydrothermal method. The physical and photophysical properties of the above-prepared photocatalysts were characterized by XRD, UV-Vis, SPS, SEM and XPS. The XRD peaks of Cu2+ doped Cd0.3In2S4-Zn0.7In2S4 were almost the same as the crystal structure of Cd0.3In2S4-Zn0.7In2S4. The UV-Vis absorption edge of Cu2+ doped Cd0.3In2S4-Zn0.7In2S4 shifted monotonically to long wavelength. The photocatalytic activity of Cu2+ doped photocatalysts had been improved as a result of the enhancement of the charge separation efficiency. The results indicated that the photocatalyst of Cu2+(2wt %)-Cd0.3In2S4/Zn0.7In2S4 exhibited the highest photocatalytic activity with the rate of H2 evolution to be 1141 μmol/(h·g) under visible light irradiation.

Photoinduced electron transfer processes in three component rotaxanes with porphyrins, [60]fullerene and triphenylamine

2006 ◽  
Vol 10 (12) ◽  
pp. 1346-1359 ◽  
Author(s):  
Hisahiro Sasabe ◽  
Yoshio Furusho ◽  
Atula S.D. Sandanayaka ◽  
Yasuyuki Araki ◽  
Nobuhiro Kihara ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Time Resolved ◽  
Transfer Processes ◽  
Back Electron Transfer ◽  
Electron Transfer Processes ◽  
Absorption Measurements

Electron transfer processes occurring through-space and through-bond were studied for novel mechanically linked triad [2]rotaxanes, which contain a porphyrin (MP) unit as a pendant and [60]fullerene ( C 60) and triphenylamine ( TPA ) moieties as stopper groups at the axle ends (abbreviated as ( MP ; C 60- TPA ) rot+ with MP = H 2 P or ZnP . The photophysical properties were investigated by means of time-resolved fluorescence and transient absorption measurements with changing solvent polarity. The charge separation took place mainly via(1 MP *; C 60- TPA ) rot+ and ( MP ;1 C 60*- TPA ) rot + in polar solvents. Within the charge-separated states of triads ( MP ; C 60- TPA ) rot +, hole-shift and/or back electron transfer took place competitively. The lifetime of the charge separation state of ( ZnP ; C 60- TPA ) rot+ was similar to that of dyad ( C 60- TPA ) rot+ (140 ns in dimethylformamide), whereas that of ( H 2 P ; C 60- TPA ) rot + was as long as 230 ns, suggesting two final charge separation states such as ( MP ; C 60•-- TPA •+) rot + and ( MP •+; C 60•-- TPA ) rot+ depending on the kind of porphyrin.

Structure, Physical and Photophysical Properties, and Charge Separation Studies of Re(bpm)(CO)3Ln+ Complexes (L = CH3CN, py, MeQ+, py-PTZ)

1995 ◽  
Vol 34 (22) ◽  
pp. 5446-5454 ◽  
Author(s):  
Randy J. Shaver ◽  
Marc W. Perkovic ◽  
D. Paul Rillema ◽  
Clifton Woods
Keyword(s):  
Charge Separation ◽  
Photophysical Properties

Long-lived photoinduced charge transfer state of synthetically affable porphyrin-fullerene dyads

2003 ◽  
Vol 07 (10) ◽  
pp. 651-666 ◽  
Author(s):  
Franz-Peter Montforts ◽  
Ivan Vlassiouk ◽  
Sergei Smirnov ◽  
Michael Wedel
Keyword(s):  
Charge Transfer ◽  
Charge Separation ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Charge Transfer State ◽  
Displacement Current ◽  
Intramolecular Electron Transfer ◽  
High Yields ◽  
Photoinduced Charge ◽  
Transfer State

Bislactone linked porphyrin-fullerene dyads show promising photophysical properties for mimicking photosynthesis. Optical and transient displacement current investigations of the dyads demonstrate efficient intramolecular electron transfer from porphyrin to fullerene with the lifetime of the charge transfer state on the order of a few nanoseconds in low polarity solvents. Solvent polarity effect on the yield of charge separation and conformations in the charge transfer state are investigated in detail. The facile synthesis could readily be applied to constructing extended compounds with high yields of photoinduced charge separation.

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