Chemistry of excited complexes in copolymers containing phenanthrene and N,N-dimethylaniline moieties. Effects of chemical structure on the intramolecular exciplex formation, its emission properties, and electron transfer to dicyanobenzene

Abstract

The formation and emission properties of intramolecular exciplexes in some vinyl copolymers containing phenanthrene and 2V,IV-dimethylaniline moieties were studied. The monomers used were CK2=CK-phenanthryl (VPh), CH2=C(CH3)COOCH2-phenanthryl (PhMMA), CH2=CH-DMA (DMAS), and CH2=C(CH3)COOCH2-DMA (DMAMMA), where Ph and DMA are 9-phenanthryl and 4-(dimethylamino)phenyl groups, respectively. Poly(VPh-co-DMAS) was found to exhibit an intense intramolecular exciplex fluorescence, whereas poly (VPh-co-DMAMMA), poly (PhMMA-co-DMAS), and poly(PhMMA-co-DMAMMA) showed only a weak exciplex fluorescence. In poly(VPh-co-DMAMMA) the exciplex formation was poor, and in the PhMMA-containing copolymers, the phenanthrene monomer fluorescence was quenched effectively by the DMA chromophores, but the exciplex formed had low fluorescence quantum yields and short fluorescence lifetimes. The electron-transfer reactions in these copolymers + p-dicyanobenzene systems were also studied by flash photolysis. The amounts of p-dicyanobenzene anion radical detected in these systems decreased in the order poly(VPh-co-DMAS) > poly(VPh-co-DMAMMA) > poly(PhMMA-co-DMAS) s poly-(PhMMA-co-DMAMMA).

A Highly Efficient Luminescent Metal–Organic Framework with Strong Conjugate Unit for Sensing Small Molecules

“…And exciplexes (excited complexes) are generally formed by the interaction of an excited molecule (electron donor or acceptor) with an unexcited molecule (electron acceptor or donor). [ 55‐57 ] Therefore, the observed red shift of fluorescence emission after dripping BZ may be the formation of exciplex between JXUST‐10 and BZ. [ 58 ]…”

Multicomponent Anti-Kasha’s Rule Emission from Nanotubular Metal–Organic Frameworks for Selective Detection of Small Molecules

“…As the PNA concentration increases, the intensity of the LE band continues to increase, and a high-energy emission (HE band) shows a small blue-shift in the normalized spectra (Figure c). However, the other NAC isomers, including ONT, MNT, and PNT, cannot induce an obvious emission shift or the emergence of the LE band (Figure d) . The new emission band in the presence of the specific analyte, such as PNA, can be ascribed to two possible origins, that is, intermolecular energy transfer ( dep -H 2 L → PNA) or just the fluorescence of PNA.…”

Photoactivation of distal functional groups in polyfunctional molecules

“…Examples include copolymers containing phenanthrene and N,N-dimethylaniline units which form an exciplex [18], a polystyrene containing dimethylaniline and pyrene end groups [19], and a polypeptide chain containing excimer forming pyrene groups [20]. Smaller systems include 1-(phenylamino)-3-(9-sathryl)propanes [21], 1-(1-pyrenyl)-3-(N-skatolyl)propane [22], and 6-(2', 3'-butenyloxy)methyl-l-cyanonaphthalene (the olefin/naphthonitrile exeiplex) [23].…”