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Lippert, Hans-Dieter; Kern, Bernd-Rüdiger

doi:10.1007/978-3-642-78388-3_7

Cited by 35 publications

(43 citation statements)

References 4 publications

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“…Similar observations were previously reported for other heteroleptic Ir(III) complexes. 138,139 The strong charge-transfer (CT) character of the phen ligand phosphorescence was identified by positive solvatochromism revealed in the Lippert-Mataga plot 140,141 (SI, Figure S2). We previously observed similar solvatochromic and rigidochromic phosphorescence for a series of Ir(III) complexes exhibiting interligand energy transfer.…”

Section: Resultsmentioning

confidence: 99%

Phosphorescent Sensor for Biological Mobile Zinc

You

Lee²,

Kim³

et al. 2011

J. Am. Chem. Soc.

223

128

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A new phosphorescent zinc sensor (ZIrF) was constructed based on an Ir(III) complex bearing two 2-(2,4-difluorophenyl)pyridine (dfppy) cyclometalating ligands and a neutral 1,10-phenanthroline (phen) ligand. A zinc-specific di(2-picolyl)amino (DPA) receptor was introduced at the 4-position of the phen ligand via a methylene linker. The cationic Ir(III) complex exhibited dual phosphorescence bands in CH3CN solutions originating from blue and yellow emission of the dfppy and phen ligands, respectively. Zinc coordination selectively enhanced the latter, affording a phosphorescence ratiometric response. Electrochemical techniques, quantum chemical calculations, and steady-state and femtosecond spectroscopy were employed to establish a photophysical mechanism for this phosphorescence response. The studies revealed that zinc coordination perturbs nonemissive processes of photoinduced electron transfer (PeT) and intraligand charge transfer (ILCT) transition occurring between DPA and phen. ZIrF can detect zinc ions in a reversible and selective manner in buffered solution (pH 7.0, 25 mM PIPES) with Kd = 11 nM and pKa = 4.16. Enhanced signal-to-noise ratios were achieved by time-gated acquisition of long-lived phosphorescence signals. The sensor was applied to image biological free zinc ions in live A549 cells by confocal laser scanning microscopy. A fluorescence lifetime imaging microscope (FLIM) detected an increase in photoluminescence lifetime for zinc-treated A549 cells as compared to controls. ZIrF is the first successful phosphorescent sensor that detects zinc ions in biological samples.

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Section: Resultsmentioning

confidence: 99%

Phosphorescent Sensor for Biological Mobile Zinc

You

Lee²,

Kim³

et al. 2011

J. Am. Chem. Soc.

223

128

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“…The values of ${\nu _{\rm{A}}^{\max } }$ , ${\nu _{\rm{F}}^{\max } }$ , and parameters describing the solvent properties are listed in Table 1. Figure 4 shows the dependence of ${\nu _{\rm{A}}^{\max } }$ and ${\nu _{\rm{F}}^{\max } }$ on the Lippert–Mataga solvent polarity function, f ( ε , n )=[( ε −1)/(2 ε +1)]−[( n 2 −1)/(2 n 2 +1)],16, 17 where ε is the dielectric constant and n the refractive index. The bathochromic shift of ${\nu _{\rm{A}}^{\max } }$ and ${\nu _{\rm{F}}^{\max } }$ can be caused by non‐specific and specific interactions between the solute and solvent molecules.…”

Section: Resultsmentioning

confidence: 99%

Spectral and Photophysical Properties of Thioxanthone in Protic and Aprotic Solvents: The Role of Hydrogen Bonds in S₁‐Thioxanthone Deactivation

Krystkowiak¹,

Maciejewski²,

Kubicki³

2006

ChemPhysChem

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Spectral and photophysical properties of thioxanthone (9H-thioxanthen-9-one, TX) were determined in a few protic solvents (H2O, D2O, hexafluoro-2-propanol) and compared with those in aprotic solvents. On the basis of the time-resolved and steady-state emission measurements and available literature data, it has been shown that the dominant S1-TX deactivation process in protic solvents is the formation of the S1-complex. The important modes of deactivation of the S1-complex are fluorescence (phiF approximately 0.4-0.5) and intersystem crossing to the T1 state. The S1-complex-->S0 internal conversion plays, at most, an insignificant role in S1-complex deactivation, which is evidenced by the absence of an isotope effect of protic solvents on the lifetime and quantum yield of fluorescence.

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“…The increase in the molecular dipole moment from the ground state to the excited state can be estimated by following the Lippert equation [Eqs. (1) and (2)]:19, Δ f =[( ε −1)/(2 ε +1)]−[( n 2 −1)/(2 n 2 +1)] …”

Section: Resultsmentioning

confidence: 99%

Trivalent Boron as an Acceptor in Donor–π–Acceptor‐Type Compounds for Single‐ and Two‐Photon Excited Fluorescence

Liu

Fang

Wang

et al. 2003

Chemistry A European J

195

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The synthesis, structure, and fluorescence properties of a series of new donor-pi-acceptor (D-pi-A) type compounds, with a trivalent boron, protected by two mesityl groups, as acceptor, and with various typical donors and different pi-conjugated bridges, are reported. All these stable organoboron compounds show intense single-photon excited fluorescence (SPEF) and two-photon excited fluorescence (TPEF) in a wide spectral range from blue to green, with the spectral peak position of the SPEF being basically the same as that of the TPEF. The remarkably strong Cbond;B(mesityl)(2) bonding, and the well-conjugated pi-system, shown in X-ray crystal structures of two compounds, indicate some charge transfer features of the ground state. Meanwhile, spectral data indicate that the charge transfer from donor to acceptor is greatly enhanced in the excited states. Based on typical structural data and comprehensive spectral data, the following structure-property relationships can be drawn: 1) the moderate arylamino donor can more effectively enhance the SPEF and TPEF intensities than can the strong alkylamino donor; 2) stilbene is a better pi-bridge than styrylthiophene for its capability of enhancing and blue-shifting the SPEF and TPEF of the corresponding D-pi-A compounds; and 3) when compared to its boron-free precursors and other analogues, -B(mesityl)(2) invariably and consistently acts as an effective SPEF and TPEF fluorophore in all this series of organoboron compounds, which may result from its strong pi-electron-withdrawing and charge transfer-inducing nature in the ground-state and, more dominantly, in the excited-state. Combining all the above positive structure factors, trans-4'-N,N-diphenylamino-4-dimesitylborylstilbene (compound 3) stands out as the optimized green SPEF and TPEF emitter. This compound exhibits an SPEF quantum yield Phi of 0.91 at 522 nm in THF, a TPEF cross-section sigma' that is an order of magnitude larger than that of its boron-free precursor upon excitation by 800 nm femto-second laser pulses, and a two-photon absorption section sigma of 3.0 x 10(-48) cm(4) s. In the blue light region, trans-4'-N-carbazolyl-4-dimesitylboryl-stilbene (compound 4) shows significant SPEF and TPEF properties, with Phi=0.79 at 464 nm in THF and a large sigma' value, which is five times that of fluorescein upon excitation by 740 nm femto-second laser pulses.

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H

Cited by 35 publications

References 4 publications

Phosphorescent Sensor for Biological Mobile Zinc

Phosphorescent Sensor for Biological Mobile Zinc

Spectral and Photophysical Properties of Thioxanthone in Protic and Aprotic Solvents: The Role of Hydrogen Bonds in S₁‐Thioxanthone Deactivation

Trivalent Boron as an Acceptor in Donor–π–Acceptor‐Type Compounds for Single‐ and Two‐Photon Excited Fluorescence

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H

Cited by 35 publications

References 4 publications

Phosphorescent Sensor for Biological Mobile Zinc

Phosphorescent Sensor for Biological Mobile Zinc

Spectral and Photophysical Properties of Thioxanthone in Protic and Aprotic Solvents: The Role of Hydrogen Bonds in S1‐Thioxanthone Deactivation

Trivalent Boron as an Acceptor in Donor–π–Acceptor‐Type Compounds for Single‐ and Two‐Photon Excited Fluorescence

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Product

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Spectral and Photophysical Properties of Thioxanthone in Protic and Aprotic Solvents: The Role of Hydrogen Bonds in S₁‐Thioxanthone Deactivation