Steric effects on excimer formation in 2‐amino‐1,3‐di(2‐naphtyl)propane luminiscent markers covalently bonded to poly [N‐(2‐hydroxypropyl)methacrylamide]
Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Steric effects on excimer formation in 2‐amino‐1,3‐di(2‐naphtyl)propane luminiscent markers covalently bonded to poly [N‐(2‐hydroxypropyl)methacrylamide]
Beteiligte:
Burešová, Marie;
Koñák, Čestmír;
Labský, Jiří
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The fluorescence spectra of poly[N‐(2‐hydroxypropyl)methacrylamide] (poly[1‐(2‐hydroxypropylaminocarbonyl)‐1‐methylethylene]) with covalently bonded luminiscent markers (2‐amino‐1, 3‐di(2‐naphthyl)propane (ADNP)) dissolved in methanol were measured over the temperature range 190–290 K. The effect of the spacer length on intramolecular excimer formation in ADNP was investigated. The ratio of the fluorescence intensities of the dimer <jats:italic>I</jats:italic><jats:sub>D</jats:sub> and the monomer <jats:italic>I</jats:italic><jats:sub>M</jats:sub> follows an Arrhenius temperature dependence in the temperature range 190–250 K with an activation energy independent of the spacer length. The numerical value of <jats:italic>I</jats:italic><jats:sub>D</jats:sub>/<jats:italic>I</jats:italic><jats:sub>M</jats:sub> at constant temperature increased with increasing spacer length reaching quickly a limiting value. The effect is explained by increasing hindrance to intramolecular excimer formation which is due—particularly for the shortest spacers—to increased steric interactions of the marker with the polymer chain.</jats:p>