Aggregation Behavior of Water Soluble Bis(benzothiazolylidene)squaraine Derivatives in Aqueous Media<sup>†</sup>

Das, Suresh; Thomas, K. George; Thomas, and K. J.; Madhavan, V.; Liu, D.; Kamat, Prashant V.; George, M. V.

doi:10.1021/jp961885x

Cited by 60 publications

(58 citation statements)

References 22 publications

(47 reference statements)

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“…Additionally, light-scattering measurements are performed for WS-TDI dodecyl (data not shown) and reveal the presence of small particles in water, typically several hundreds of nanometers in size. These observations strongly indi- cate the presence of H-aggregates for WS-TDI dodecyl in water, as already reported for WS-TDI and other fluorophores with large and rigid p-electron systems; [17][18][19][20] this phenomenon of aggregation is due to the strong inter-molecular interaction between the hydrophobic dye molecules in polar solvents such as water and is obviously not hindered by the alkyl chain in WS-TDI dodecyl.…”

Section: Absorption and Fluorescence Spectrasupporting

confidence: 85%

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

et al. 2009

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The photophysical properties of three new water-soluble terrylenediimide (WS-TDI) derivatives are investigated and their utilization in biological experiments is demonstrated. Each of these dyes can be excited in the far red region of the visible spectrum, making them good candidates for in-vivo studies. Single-molecule techniques characterize their photophysics that is, the number of emitted photons, blinking characteristics and survival times until photobleaching takes place. All three dyes exhibit bright fluorescence, as well as an extremely high resistance against photodegradation compared to other well-known fluorophores. Due to their different characteristics the three new WS-TDI derivatives are suitable for specialized biological applications. WS-TDI dodecyl forms non-fluorescent aggregates in water which can be disrupted in a hydrophobic environment leading to a monomeric fluorescent form. Due to its high lipophilicity WS-TDI dodecyl anchors efficiently in lipid bilayers with its alkyl chain and hence can be ideally used to image membranes and membrane-containing compartments in living cells. In contrast, the positively charged WS-TDI pyridoxy is a new type of chromophore in the WS-TDI family. It is fully solubilized in water forming fluorescent monomers and is successfully used to label the envelope of herpes simplex viruses. Finally, it is shown that a WS-TDI derivative functionalized with N-hydroxysuccinimide ester moiety (WS-TDI/NHS ester) provides a versatile reactive dye molecule for the specific labelling of amino groups in biomolecules such as DNA.

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Section: Absorption and Fluorescence Spectrasupporting

confidence: 85%

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

et al. 2009

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“…[4][5][6][7][8][9][10] The observed spectral changes with increasing concentration are generally interpreted in terms of the Figure 1. Structure of the studied stilbene derivative I.…”

Section: Introductionmentioning

confidence: 93%

“…When comparing the equilibrium constants from fluorescence and NMR measurements one should note that K may differ in H 2 O and D 2 O, respectively. 10 The errors of the individual fluorescence estimates are large and comparable to the scatter of the equilibrium constants obtained using different wavelengths.…”

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confidence: 96%

Dimer formation of a stilbenesulphonic acid salt in aqueous solution

Alsins

Björling

Furó

et al. 1999

J. Phys. Org. Chem.

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The steady-state and time-resolved fluorescence and 1 H NMR spectra of a stilbenesulphonic acid salt, commonly used as an optical brightening agent, was studied as a function of concentration in aqueous solution. The aggregates, formed at higher concentrations, were shown to be predominantly dimers with the central stilbene moieties of the molecules stacked plane-parallel. The equilibrium constant for the dimer formation at 25°C was obtained from both NMR and fluorescence measurements.

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“…The shift of the absorption of 12b from the NIR to the UV region caused by the addition of EtOH indicates a change of the absorbing chromophore; either the pushpull character of the donor ± acceptor ± donor system is decreased because of the interaction with the EtOH molecules or the aggregation (see, e.g., [19]) is fundamentally changed. Such a pronounced hypsochromic shift would correspond to the formation of H aggregates in which the long-wavelength absorption is forbidden.…”

mentioning

confidence: 99%

NIR Absorbing Squaraines by Extension of the Conjugation with (Aminothiazolyl)ethenyl Groups

Meier¹,

Petermann

2004

Helvetica Chimica Acta

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The bis{4-{2-[2-(dialkylamino)thiazol-5-yl]ethenyl}-2,6-dihydroxyphenyl}squaraines 12a,b were synthesized from ethyl carbonochloridate (1) in six steps (Scheme). The donor ± acceptor ± donor systems 12a,b are dark blue dyes with absorption maxima in the NIR region, unless the measurements are performed in the presence of EtOH. In the latter case, the long-wavelength band disappears, and the absorption in the UV region is strongly enhanced. The l max values in CHCl 3 and CHCl 3 /EtOH differ by more than 450 nm. The completely reversible effect can be rationalized by the reversible degradation of intramolecular H-bonds and a consequent torsion between the acceptor and the donor moieties. In contrast to 1,3-diarylsquaraines, which represent blue or blue-green pigments or dyes, we prepared some time ago 1-aryl-3-stilbenyl-and 1,3-bis(stilbenyl)squaraines, which absorb in the near infrared (NIR) [10 ± 13]. It turned out that the extension of the conjugation provokes first a strong bathochromic effect, but surprisingly further extension of the conjugation leads to a hypsochromic effect [10]. Thus, a donor ± acceptor distance as in stilbenoid moieties seems to be highly appropriate for an absorption in the NIR region, which is characterized by a strong intramolecular charge transfer (ICT). We studied in this context 2-(dialkylamino)thiazol-5-yl substituents, which are bound via ethenediylphenylene segments to the squaraine center. The heterocyclic building blocks were chosen to improve the photoconductivity induced by NIR radiation. Squaraines exhibit normally a good hole transport [1b]. The heterocyclic moieties should ameliorate the efficiency for the electron transport.

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Aggregation Behavior of Water Soluble Bis(benzothiazolylidene)squaraine Derivatives in Aqueous Media^†

Cited by 60 publications

References 22 publications

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

Dimer formation of a stilbenesulphonic acid salt in aqueous solution

NIR Absorbing Squaraines by Extension of the Conjugation with (Aminothiazolyl)ethenyl Groups

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Aggregation Behavior of Water Soluble Bis(benzothiazolylidene)squaraine Derivatives in Aqueous Media†

Cited by 60 publications

References 22 publications

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

Dimer formation of a stilbenesulphonic acid salt in aqueous solution

NIR Absorbing Squaraines by Extension of the Conjugation with (Aminothiazolyl)ethenyl Groups

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Aggregation Behavior of Water Soluble Bis(benzothiazolylidene)squaraine Derivatives in Aqueous Media^†