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Author

Wouter Schuddeboom

Other affiliations: University of New South Wales
Bio: Wouter Schuddeboom is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Excited state & Acceptor. The author has an hindex of 16, co-authored 19 publications receiving 956 citations. Previous affiliations of Wouter Schuddeboom include University of New South Wales.

Papers
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TL;DR: In this article, the excited-state dipole moments of aminobenzonitriles have been determined in cyclohexane, benzene, and 1,4-dioxane using time-resolved microwave conductivity (TRMC) and fluorescence spectroscopy techniques.
Abstract: Singlet excited-state dipole moments of a number of aminobenzonitriles have been determined in cyclohexane, benzene, and 1,4-dioxane, using time-resolved microwave conductivity (TRMC) and fluorescence spectroscopy techniques. For the 4-(dialkylamino)benzonitriles (methyl, ethyl, propyl, and decyl) intramolecular charge transfer (ICT) occurs in the excited singlet state even in the nonpolar solvent cyclohexane

343 citations

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TL;DR: The flash-photolysis time-resolved microwave conductivity technique (FP-TRMC) has been used to investigate the nature of the relaxed S(1) state of 9,9'-bianthryl, CAA, and 10,10'-dicyano-9, 9'-bianstryl (CAAC) and conclusively demonstrate the dipolar nature of S( 1) for all three compounds in the pseudopolar solvents benzene and 1
Abstract: The flash-photolysis time-resolved microwave conductivity technique (FP-TRMC) has been used to investigate the nature of the relaxed S1 state of 9,9‘-bianthryl (AA), 10-cyano-9,9‘-bianthryl (CAA), and 10,10‘-dicyano-9,9‘-bianthryl (CAAC). Changes in both the real, Δe‘ (dielectric constant), and imaginary, Δe‘ ‘ (dielectric loss), components of the complex permittivity have been measured. The dielectric loss transients conclusively demonstrate the dipolar nature of S1 for all three compounds in the pseudopolar solvents benzene and 1,4-dioxane, and even in the nonpolar solvents n-hexane and cyclohexane. The required symmetry breaking is considered to result from density and structural fluctuations in the solvent environment. The dipole relaxation times for AA (CAAC) are ca. 2 ps for the alkanes and 7.9 (5.3) and 14 (14) ps for benzene and dioxane, respectively. The time scale of dipole relaxation for the symmetrical compounds is much shorter than that for rotational diffusion and is attributed to intramolec...

93 citations

Journal ArticleDOI
TL;DR: The potential of dimethylsilylene and isopropylidene U-spacers as bridges for photoinduced charge transfer (CT) in 4-cyano-4'-dimethylamino)- and 4-cyclo-methoxy-substituted diphenyldimethylsilanes and 2,2-diphen- ylpropanes was studied in this article.
Abstract: The potential of dimethylsilylene and isopropylidene U-spacers as bridges for photoinduced charge transfer (CT) in 4-cyano-4'-(dimethylamino)- and 4-cyano-4'-methoxy-substituted diphenyldimethylsilanes and 2,2-diphen- ylpropanes was studied. Fluorescence solvatochromism and time-resolved microwave conductivity measurements show that upon photoexcitation a charge separated state (D ¥+ UA ¥- )* is populated in all compounds. Excited state dipole moments for a given donor-acceptor combination are, irrespective of the bridge, equal. The CT states of the silanes are however lying at lower energies, implying that the presence of silicon thermodynamically facilitates the CT process. Cyclic voltammetry data of model compounds show that this is a consequence of the lowering of the acceptor reduction potential by the silicon bridge. It was however inferred from radiative decay rates that the electronic coupling between the CT and locally excited states as well as the coupling between the ground and CT state is larger for the carbon-bridged compounds. As shown by both solution and solid state electronic spectra and radiative decay rates, the photophysics of the DUA compounds are dominated by intensity borrowing of the CT transitions from transitions localized in the DU and UA chromophores.

73 citations

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TL;DR: In this paper, preliminary fluorescence and time-resolved microwave conductivity (TRMC) measurements are reported for the novel triad, DMA[4]DMN[8]DCV, in which the three chromophores, N, N-dimethylaniline, DMN (dimethoxynaphthalene), and DCV (dicyanovinyl), are connected via bridges comprising linearly fused norbornyl and bicyclo[2.2]hexyl units, four and eight bonds in length.
Abstract: Preliminary fluorescence and time-resolved microwave conductivity (TRMC) measurements are reported for the novel triad, DMA[4]DMN[8]DCV, in which the three chromophores, DMA (N,N-dimethylaniline), DMN (dimethoxynaphthalene), and DCV (dicyanovinyl), are connected via bridges comprising linearly fused norbornyl and bicyclo[2.2.0]hexyl units, four and eight bonds in length. The triad, DMA[4]DMN[8]DCV, exists in two noninterconvertible syn and anti diastereomeric forms, the former having a U-shaped geometry and the latter having an S-shaped geometry. Samples of the two stereoisomers, labeled H and L, were obtained, but the actual stereochemistry, syn or anti, of each isomer is presently unknown

66 citations

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TL;DR: In this article, a minimum dipole moment of ca. 7.5 D for the individual Z[sub [+-]] states is found, on a timescale of several picoseconds, which provides direct evidence for the dipolar or [open quotes]zwitterionic nature of the [sup 1]p* phantom state formed from S[sub 1] by rotation around the central carbon-carbon bond.
Abstract: Photoexcitation of the symmetrical molecules tetraphenylethylene and tetra-p-methoxyphenylethylene dissolved in saturated hydrocarbon solvents results in a transient increase in the dielectric loss of the solutions as monitored using the nanosecond time-resolved microwave conductivity (TRMC) technique. This provides direct evidence for the dipolar, or [open quotes]zwitterionic,[close quotes] nature of the [sup 1]p* phantom state formed from S[sub 1] by rotation around the central carbon-carbon bond. Dipole relaxation occurs mainly by charge inversion between the two energetically equivalent zwitterionic configurations. Z[sub [+-]], on a timescale of several picoseconds. A minimum dipole moment of ca. 7.5 D for the individual Z[sub [+-]] states is found. The fluorescence of TPE in alkane solvents has two decay components, one with a decay time less than 200 ps and a second with a decay time of 1.9 ns. The former ([lambda][sub max] [approx] 490 nm) is assigned to emission from the partially relaxed S[sub 1] state prior to twisting. The latter ([lambda][sub max] [approx] 540 nm) is assigned to emission from a small, ca. 1%, concentration of the relaxed S[sub 1] state in equilibrium with the [sup 1]p* state in saturated hydrocarbon solvents. 27 refs., 2 figs., 2 tabs.

62 citations


Cited by
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Journal ArticleDOI
TL;DR: The Rehybridization of the Acceptor (RICT) and Planarization ofThe Molecule (PICT) III is presented, with a comparison of the effects on yield and radiationless deactivation processes.
Abstract: 6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

2,924 citations

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TL;DR: The main classes of fluorescent molecular sensors for cation recognition are presented: they differ by the nature of the cation-controlled photoinduced processes: photoinduced electron transfer, photoinduced charge transfer, excimer formation or disappearance as discussed by the authors.
Abstract: The main classes of fluorescent molecular sensors for cation recognition are presented: they differ by the nature of the cation-controlled photoinduced processes: photoinduced electron transfer, photoinduced charge transfer, excimer formation or disappearance. In each class, distinction is made according to the structure of the complexing moiety: chelators, podands, coronands (crown ethers), cryptands, calixarenes. The most representative examples are presented in each subclass with special attention given to selectivity.

2,128 citations

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1,365 citations

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TL;DR: PCM-TDDFT is shown to be successful in supporting the analysis of experimental data with useful insights for a better understanding of photophysical and photochemical pathways in solution.
Abstract: In this paper we present the theory and implementation of analytic derivatives of time-dependent density functional theory (TDDFT) excited states energies, both in vacuo and including solvent effects by means of the polarizable continuum model. The method is applied to two case studies: p-nitroaniline and 4-(dimethyl)aminobenzonitrile. For both molecules PCM-TDDFT is shown to be successful in supporting the analysis of experimental data with useful insights for a better understanding of photophysical and photochemical pathways in solution.

1,160 citations