TY - JOUR
T1 - The effect of bulky substituents on two π-conjugated mesogenic fluorophores. Their organic polymers and zinc-bridged luminescent networks
AU - Diana, Rosita
AU - Panunzi, Barbara
AU - Concilio, Simona
AU - Marrafino, Francesco
AU - Shikler, Rafi
AU - Caruso, Tonino
AU - Caruso, Ugo
N1 - Funding Information:
This work was supported by the Italian Ministry of Education, University and Research (MIUR) (Piano Lauree Scientifiche "Scienza dei Materiali" 2016-2018).
Publisher Copyright:
© 2019 by the authors.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - From a dicyano-phenylenevinylene (PV) and an azobenzene (AB) skeleton, two new symmetrical salen dyes were obtained. Terminal bulky substituents able to reduce intermolecular interactions and flexible tails to guarantee solubility were added to the fluorogenic cores. Photochemical performances were investigated on the small molecules in solution, as neat crystals and as dopants in polymeric matrixes. High fluorescence quantum yield in the orange-red region was observed for the brightest emissive films (88% yield). The spectra of absorption and fluorescence were predicted by Density Functional Theory (DFT) calculations. The predicted energy levels of the frontier orbitals are in good agreement with voltammetry and molecular spectroscopy measures. Employing the two dyes as dopants of a nematic polymer led to remarkable orange or yellow luminescence, which dramatically decreases in on-off switch mode after liquid crystal (LC) order was lost. The fluorogenic cores were also embedded in organic polymers and self-assembly zinc coordination networks to transfer the emission properties to a macro-system. The final polymers emit from red to yellow both in solution and in the solid state and their photoluminescence (PL) performance are, in some cases, enhanced when compared to the fluorogenic cores.
AB - From a dicyano-phenylenevinylene (PV) and an azobenzene (AB) skeleton, two new symmetrical salen dyes were obtained. Terminal bulky substituents able to reduce intermolecular interactions and flexible tails to guarantee solubility were added to the fluorogenic cores. Photochemical performances were investigated on the small molecules in solution, as neat crystals and as dopants in polymeric matrixes. High fluorescence quantum yield in the orange-red region was observed for the brightest emissive films (88% yield). The spectra of absorption and fluorescence were predicted by Density Functional Theory (DFT) calculations. The predicted energy levels of the frontier orbitals are in good agreement with voltammetry and molecular spectroscopy measures. Employing the two dyes as dopants of a nematic polymer led to remarkable orange or yellow luminescence, which dramatically decreases in on-off switch mode after liquid crystal (LC) order was lost. The fluorogenic cores were also embedded in organic polymers and self-assembly zinc coordination networks to transfer the emission properties to a macro-system. The final polymers emit from red to yellow both in solution and in the solid state and their photoluminescence (PL) performance are, in some cases, enhanced when compared to the fluorogenic cores.
KW - Luminescent polymer
KW - Polymer network
KW - Salen dyes
UR - http://www.scopus.com/inward/record.url?scp=85071926099&partnerID=8YFLogxK
U2 - 10.3390/polym11091379
DO - 10.3390/polym11091379
M3 - Article
AN - SCOPUS:85071926099
SN - 2073-4360
VL - 11
JO - Polymers
JF - Polymers
IS - 9
M1 - 1379
ER -