| Dokumentenart: | Artikel | ||||
|---|---|---|---|---|---|
| Titel eines Journals oder einer Zeitschrift: | Chemistry – A European Journal | ||||
| Verlag: | WILEY-BLACKWELL | ||||
| Ort der Veröffentlichung: | MALDEN | ||||
| Band: | 16 | ||||
| Nummer des Zeitschriftenheftes oder des Kapitels: | 11 | ||||
| Seitenbereich: | S. 3392-3402 | ||||
| Datum: | 2010 | ||||
| Institutionen: | Chemie und Pharmazie > Institut für Anorganische Chemie > Entpflichtete oder im Ruhestand befindliche Professoren > Arbeitskreis Prof. Dr. Rainer Winter Chemie und Pharmazie > Institut für Organische Chemie > Entpflichtete oder im Ruhestand befindliche Professoren > Arbeitskreis Prof. Dr. Hans-Achim Wagenknecht | ||||
| Identifikationsnummer: |
| ||||
| Stichwörter / Keywords: | PHOTOINDUCED ELECTRON-TRANSFER; DOUBLE-STRANDED DNA; NUCLEIC-ACIDS; CHARGE-TRANSFER; AQUEOUS-MEDIA; BIFUNCTIONAL INTERCALATORS; SACCHAROMYCES-CEREVISIAE; PHOTOAFFINITY LABELS; PROTEIN INTERACTIONS; COMPLEX-FORMATION; charge transfer; DNA; dyes/pigments; fluorescent probes; intercalations | ||||
| Dewey-Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik > 540 Chemie | ||||
| Status: | Veröffentlicht | ||||
| Begutachtet: | Ja, diese Version wurde begutachtet | ||||
| An der Universität Regensburg entstanden: | Ja | ||||
| Dokumenten-ID: | 66516 |
Web of ScienceZusammenfassung
The phenanthridinium chromophores 5-ethyl-6-phenylphenanthridinium (1), 5-ethyl-6-methylphenanthridinium (2), 3,8-diamino-5-ethyl-6-methylphenanthridinium (3), and 3,8-diamino-5-ethyl-6-(4-N,N-diethylaminophenyl)phenanthridinium (4) were characterized by their optical and redox properties. All dyes were applied in titration experiments with a random-sequence 17mer DNA duplex and their binding ...
Zusammenfassung
The phenanthridinium chromophores 5-ethyl-6-phenylphenanthridinium (1), 5-ethyl-6-methylphenanthridinium (2), 3,8-diamino-5-ethyl-6-methylphenanthridinium (3), and 3,8-diamino-5-ethyl-6-(4-N,N-diethylaminophenyl)phenanthridinium (4) were characterized by their optical and redox properties. All dyes were applied in titration experiments with a random-sequence 17mer DNA duplex and their binding affinities were determined. The results were compared to well-known ethidium bromide (E). In general, this set of data allows the influence of substituents in positions 3, 6, and 8 on the optical properties of E to be elucidated. Especially, compound 4 was used to compare the weak electron-donating character of the phenyl substituent at position 6 of E with the more electron-donating 4-N,N-diethylaminophenyl group. Analysis of all of the measurements revealed two pairs of chromophores. The first pair, consisting of 1 and 2, lacks the amino groups in positions 3 and 8, and, as a result, these dyes exhibit clearly altered optical and electrochemical properties compared with E. In the presence of DNA, a significant fluorescence quenching was observed. Their binding affinity to DNA is reduced by nearly one order of magnitude. The electronic effect of the phenyl group in position 6 on this type of dye is rather small. The properties of the second set, 3 and 4, are similar to E due to the presence of the two strongly electron-donating amino groups in positions 3 and 8. However, in contrast to 1 and 2, the electron-donating character of the substituent in position 6 of 3 and 4 is critical. The binding, as well as the fluorescence enhancement, is clearly related to the electron-donating effect of this substituent. Accordingly, compound 4 shows the strongest binding affinity and the strongest fluorescence enhancement. Quantum chemical calculations reveal a general mechanism related to the twisted intramolecular charge transfer (TICT) model. Accordingly, an increase of the twist angle between the phenyl ring in position 6 and the phenanthridinium core opens a nonradiative channel in the excited state that depends on the electron-donating character of the phenyl group. Access to this channel is hindered upon binding to DNA.
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