Über Orceinfarbstoffe, XI. Die Konstitution der Amino‐orceimine

Musso, Hans; Matthies, Hans‐Georg; Kramer, Horst E. A.; Hocks, P.

doi:10.1002/cber.19600930814

Cited by 13 publications

(2 citation statements)

References 15 publications

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“…Protonation of Ox + in the S 1 state causes luminescence quenching. The different pK a values at room temperature are: pK a1 = 11.3, [106] pK a2 = À1.2, [107] pK a2 * = 1.2, [108] whereas the pH of hydrated potassium ZL is about 3.4 at which exclusively Ox + is present. [10,58,62] If, however, the pH of the ZL becomes more acidic or more basic, fluorescence properties and photostability of the Ox + -ZL can be heavily affected.…”

Section: Ox + -Zlmentioning

confidence: 98%

Designing Dye–Nanochannel Antenna Hybrid Materials for Light Harvesting, Transport and Trapping

et al. 2011

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We discuss artificial photonic antenna systems that are built by incorporating chromophores into one-dimensional nanochannel materials and by organizing the latter in specific ways. Zeolite L (ZL) is an excellent host for the supramolecular organization of different kinds of molecules and complexes. The range of possibilities for filling its one-dimensional channels with suitable guests has been shown to be much larger than one might expect. Geometrical constraints imposed by the host structure lead to supramolecular organization of the guests in the channels. The arrangement of dyes inside the ZL channels is what we call the first stage of organization. It allows light harvesting within the volume of a dye-loaded ZL crystal and also the radiationless transport of energy to either the channel ends or center. One-dimensional FRET transport can be realized in these guest-host materials. The second stage of organization is realized by coupling either an external acceptor or donor stopcock fluorophore at the ends of the ZL channels, which can then trap or inject electronic excitation energy. The third stage of organization is obtained by interfacing the material to an external device via a stopcock intermediate. A possibility to achieve higher levels of organization is by controlled assembly of the host into ordered structures and preparation of monodirectional materials. The usually strong light scattering of ZL can be suppressed by refractive-index matching and avoidance of microphase separation in hybrid polymer/dye-ZL materials. The concepts are illustrated and discussed in detail on a bidirectional dye antenna system. Experimental results of two materials with a donor-to-acceptor ratio of 33:1 and 52:1, respectively, and a three-dye system illustrate the validity and challenges of this approach for synthesizing dye-nanochannel hybrid materials for light harvesting, transport, and trapping.

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Section: Ox + -Zlmentioning

confidence: 98%

Designing Dye–Nanochannel Antenna Hybrid Materials for Light Harvesting, Transport and Trapping

et al. 2011

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“…Ground‐ and excited‐state pK a values measured in H 2 O (thionine, oxonine, Dsm + , and Resorufin) and in DMSO (JCG65 and Hostasol Red). Thionine (ThH + ): pK a1 =11.0,22 pK a2 =−0.33,23 ${pK{{{\ast}\hfill \atop {\rm a2}\hfill}}}$ (S 1 )=3.1, ${pK{{{\ast}\hfill \atop {\rm a2}\hfill}}}$ (T)=6.3;23 oxonine (OxH + ): pK a2 =−1.2, pK a1 =11.27,24, 25 ${pK{{{\ast}\hfill \atop {\rm a2}\hfill}}}$ (S 1 )=1.2;25 Dsm + : pK a1 =3.726; Hostasol Red (HR): ${pK{{{\ast}\hfill \atop {\rm a1}\hfill}}}$ (S 1 )=1–2; JCG65: pK a1 =8–9; Resorufin (ResH): pK a1 =5.5,27 ${pK{{{\ast}\hfill \atop {\rm a1}\hfill}}}$ (S 1 )=−1.328; For Pyronine the second protonation, which occurs at the carbon atom, breaks the long π system of the dye and causes PyH 2+ solutions to be colorless. …”

Section: Introductionmentioning

confidence: 99%

Proton Activity Inside the Channels of Zeolite L

Albuquerque

Calzaferri

2007

Chemistry A European J

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The proton activity inside the channels of zeolite L has been studied by investigating dye-loaded zeolite L crystals under different conditions, such as water content, nature of the counterions, and nature of the solvent. The discussion is made within the frame of three types of dye-loaded zeolite L systems, classified according to their ability to exchange matter (dyes, cations, solvent, and other small molecules) with the environment. The classification refers to dye-loaded zeolites. The term "closed" and "semi-open" characterize different possibilities of the channels to exchange small molecules, cations, and solvent molecules with the environment, but not dyes. The "open" systems also allow for dye exchange. UV-visible and fluorescence spectroscopy have been used to observe the proton activity inside the zeolite L channels. The influence of the proton activity on the luminescence of encapsulated dyes is discussed, special attention being given to luminescence quenching by excited-state protonation. Partially proton-exchanged zeolite L can be a superacid, whereas for the M-exchanged form (M: K(+), Li(+), Cs(+), Mg(2+), Ca(2+)) the pH ranges from about 2.5 to 3.5. For these last forms, the differences in pH are due to the acid-base reactions of the respective metal cations with water inside the zeolite. Finally, we describe an easy experimental procedure that can be used to tune the proton activity inside the zeolite L to a considerable extent.

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The 1,4‐Oxazines

McKee¹

1962

Chemistry of Heterocyclic Compounds: A Series of Monographs

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Über Orceinfarbstoffe, XI. Die Konstitution der Amino‐orceimine

Cited by 13 publications

References 15 publications

Designing Dye–Nanochannel Antenna Hybrid Materials for Light Harvesting, Transport and Trapping

Designing Dye–Nanochannel Antenna Hybrid Materials for Light Harvesting, Transport and Trapping

Proton Activity Inside the Channels of Zeolite L

The 1,4‐Oxazines

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