Über die Geometrie von großen organischen Molekülen in angeregten Elektronenzuständen

The synthesis of poly(2,5-dialkoxy-p-phenylene)s (PPP) by palladium-catalyzed polycondensation of 2,5-dialkoxy-4-bromophenylboronic acids is described. Number-average degrees of polymerization of ca. 30 have been reached at best. The characterization of the polymers by NMR, IR, UV-VIS and fluorescence spectra, data on the bulk structure obtained by X-ray methods, melting behavior and thermal stability are reported. PPP's with long alkoxy side chains exhibit a layered phase structure, those with short or branched alkoxy side chains, cylindrical packing. Poly(2,5-dibutoxy-p-phenylene) was prepared with chain lengths 7 5 P, I 30. The polymer with P, of 30 shows thermal transitions in the bulk phase at 182°C and 227 "C. It forms an anisotropic melt above 227 "C which only starts decomposing if heated above 300 "C. The polymers of shorter chain length show isotropic melts, with the melting point strongly depending on chain length.

show abstract

Poly(2,5‐dialkoxy‐p‐phenylene)s—synthesis and properties

Vahlenkamp

Wegner

1994

Macro Chemistry & Physics

159

112

View full text Add to dashboard Cite

show abstract

Desaktivierungsverhalten von Arenen und Heteroarenen. XXXVI. Zum Lösungsmittel‐ und Temperatureinfluß auf das Desaktivierungsverhalten von 9, 9′‐Bis(acridizinium‐yl) bei hohen Konzentrationen

et al. 1983

View full text Add to dashboard Cite

Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′‐Bis(acridizinium‐yl) at High Concentration At room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′‐bis(acridizinium‐yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1‐state emits, in the case of the solvent type B (ethanol, propanol‐(2)) the S1‐state is twisted. Both excited states have different emission spectroscopical properties. At high concentration (c ≥ 10−4 mol l−1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain S1‐state does not react.

show abstract

Vibronisches Spektralverhalten von Molekülen. VI. Theoretische Untersuchungen zur Molekülgeometrie und Spektroskopie des Perylens

Gustav

Seydenschwanz

1986

J. Prakt. Chem.

View full text Add to dashboard Cite

Vibronic Spectral Behaviour of Molecules. VI. Theoretical Investigations on the Molecular Geometry and Spectroscopy of Perylene The theoretical completely‐optimized molecular geometries of perylene are presented for the electronic states S0, S1 and T1. On this basis, the vibronic spectral behaviour in absorption and fluorescence has been calculated within the framework of the CONDON approximation. The results obtained are compared with the experimental S0‐S1 absorption and fluorescence and interpreted. The calculated geometry changes determine the significant active modes responsible for the fine structure of the corresponding spectroscopic transitions.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Über die Geometrie von großen organischen Molekülen in angeregten Elektronenzuständen

Cited by 14 publications

References 236 publications

Poly(2,5‐dialkoxy‐p‐phenylene)s—synthesis and properties

Poly(2,5‐dialkoxy‐p‐phenylene)s—synthesis and properties

Desaktivierungsverhalten von Arenen und Heteroarenen. XXXVI. Zum Lösungsmittel‐ und Temperatureinfluß auf das Desaktivierungsverhalten von 9, 9′‐Bis(acridizinium‐yl) bei hohen Konzentrationen

Vibronisches Spektralverhalten von Molekülen. VI. Theoretische Untersuchungen zur Molekülgeometrie und Spektroskopie des Perylens

Contact Info

Product

Resources

About