Influence of Spatial Restrictions on Equilibrium Reactions:  A Case Study about the Excimer Formation of Pyrene

Thomas, Arne; Polarz, Sebastian; Antonietti, Markus

doi:10.1021/jp026587g

Cited by 53 publications

(31 citation statements)

References 35 publications

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“…The structures of the G1, G2, G3-pyrene-CH 2 OH dendrons (3, 5, 7), their precursors G1, G2, G3-pyrene-COOMe (2, 4, 6), G1, G2, G3 dendrimers (10,11,12), and model compound (13), were confirmed by FTIR, 1 H NMR, MALDI-TOF MS spectra and elemental analyses. Figure 1 shows the representative FTIR spectrum of benzyl ether dendrimer with pyrene end groups.…”

Section: Characterizationmentioning

confidence: 88%

“…Purification of the crude compound by column chromatography eluting with CH 2 Cl 2 /hexane/ THF ¼ 80:10:1 gave (6) Synthesis of G1 Dendrimer (10) This was prepared from pyrene-G1-CH 2 OH (3) and compound (9). Purification of the crude compound by column chromatography eluting with CH 2 Cl 2 /hexane/THF ¼ 60:35:5 gave G1-dendrimer (10) …”

Section: Synthesis Of Pyrene G3-coome Dendron (6)mentioning

confidence: 99%

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Synthesis, Characterization and Photophysical Properties of DCM‐Based Light‐Harvesting Dendrimers

Vanjinathan

Lin

Nasar

2011

Macro Chemistry & Physics

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A series of highly soluble light‐harvesting dendrimers up to third generation were synthesized using a DCM‐based core and Frechet‐type benzyl ether dendrons containing pyrene end groups. All dendrimers and intermediates were characterized by FTIR, 1H NMR, MALDI‐TOF MS, UV‐Vis, and PL spectra and EA, GPC, and TGA techniques. The dendrimers emit strong red PL around 570 nm. The excitation of the terminal chromophores results in core emission alone, as the donor emission is seriously quenched due to FRET to the core. The dendrimers showed enhanced luminescence properties of the core, and its efficiency was dependent on the generation number of the dendrimers. The above results reveal that these dendrimers are suitable candidates for red emissive materials in OLEDs. magnified image

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Section: Characterizationmentioning

confidence: 88%

Section: Synthesis Of Pyrene G3-coome Dendron (6)mentioning

confidence: 99%

Synthesis, Characterization and Photophysical Properties of DCM‐Based Light‐Harvesting Dendrimers

Vanjinathan

Lin

Nasar

2011

Macro Chemistry & Physics

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“…The observed confinement effect is in agreement with findings we have acquired before on various alternative systems in siliceous mesoporous materials. [28][29][30][31] The significant stability of the C 6 H 3 BrSi 2 O 3 (UKON1) (composition supported by elemental analysis) under oxidative conditions allows the template to be removed at T ¼ 300 8C without destruction of the organosilica matrix. The thermal stability of the phenyl-containing organosilica materials is in good agreement with the literature.…”

Section: A Mesoporous Organosilica Materials With Bridgingmentioning

confidence: 99%

Organosilica Materials with Bridging Phenyl Derivatives Incorporated into the Surfaces of Mesoporous Solids

Kuschel

Polarz

2008

Adv Funct Materials

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An interesting class of materials is mesoporous organosilica materials containing a bridging, organic group along the pore‐surface. Such materials are prepared from silsesquioxane precursors of the type (R′O)3Si‐R‐Si(OR′)3 where R is the bridging organic group of interest, in combination with a lyotropic phase as a template for the generation of the pores. A new silsesquioxane precursor, 1,3‐bis‐(trialkoxysilyl)‐5‐bromobenzene, and the related mesoporous organosilica material containing bromobenzene groups located at the pore walls are presented in the current publication. The latter precursor allows access to the derivatization reactions known for halogenated aromatic compounds. Materials containing phenyl derivatives can be obtained either by chemical modifications starting from the mentioned precursor on the molecular scale, or the modifications can be performed directly at the surfaces of the porous material. Materials with surfaces containing benzoic acid, styrene, and phenylphosphonic acid are described.

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“…Since the temperature dependence of the monomer-excimer equilibrium can provide information on the steric or electronic environment of the pyrene moiety, [3,27] the temperature-dependent fluorescence spectra of polyphenylenedendronized pyrenes 10 and 11 a were recorded (excitation at 390 nm, Figure 3b). [28] At room temperature (300 K), a 10 À2 m solution of 10 in tetrachloroethane displayed a broad emission spectrum with a maximum at 470 nm, which indicates aggregation.…”

mentioning

confidence: 99%

Pyrene as Chromophore and Electrophore: Encapsulation in a Rigid Polyphenylene Shell

Bernhardt

Kastler

Enkelmann

et al. 2006

Chemistry A European J

144

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Starting from the fourfold ethynyl-substituted chromophore 1,3,6,8-tetraethynylpyrene as core, a series of polyphenylene dendrimers was prepared in high yield by combining divergent and convergent growth methods. The fluorescence quantum yields (Q(f)>0.92) of the encapsulated pyrene chromophore were independent of the size of the polyphenylene shell. Fluorescence quenching studies and temperature-dependent fluorescence spectroscopy were performed to investigate the site isolation of the core. They indicate that a second-generation dendrimer layer is needed to efficiently shield the encapsulated pyrene and prevent aggregate formation. Alkali-metal reduction of the encapsulated pyrene core was carried out to afford the corresponding pyrene radical anions, for which hampered electron transfer to the core was observed with increasing dendrimer generation, which is further proof of the site isolation due to the polyphenylene shell. To improve film formation and solubility of the material, solubilizing alkyl chains were introduced on the periphery of the spherical particles. Furthermore, highly transparent films obtained by a simple drop-casting method showed blue emission mainly from the unaggregated species. The materials presented herein combine high quantum efficiency, good solubility, and improved film-forming properties, which make them possible candidates for several applications in electronic devices.

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Influence of Spatial Restrictions on Equilibrium Reactions: A Case Study about the Excimer Formation of Pyrene

Cited by 53 publications

References 35 publications

Synthesis, Characterization and Photophysical Properties of DCM‐Based Light‐Harvesting Dendrimers

Synthesis, Characterization and Photophysical Properties of DCM‐Based Light‐Harvesting Dendrimers

Organosilica Materials with Bridging Phenyl Derivatives Incorporated into the Surfaces of Mesoporous Solids

Pyrene as Chromophore and Electrophore: Encapsulation in a Rigid Polyphenylene Shell

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