1330099-71-2Relevant academic research and scientific papers
Additional insights into luminescence process of polycyclic aromatic hydrocarbons with carbonyl groups: Photophysical properties of secondary N -alkyl and tertiary N, N -dialkyl carboxamides of naphthalene, anthracene, and pyrene
Niko, Yosuke,Hiroshige, Yuki,Kawauchi, Susumu,Konishi, Gen-Ichi
, p. 3986 - 3996 (2012)
Here we report the substitution effects of N-alkyl and N,N-dialkyl carboxamide groups on the fluorescence properties of polycyclic aromatic hydrocarbon chromophores, so as to control their fluorescence properties. The fluorescence properties of compounds obtained using solvents with different polarities showed very little change, indicating that the modified compounds do not form charge transfer states. TD-DFT calculations and measurements performed at low temperature (78 K) and in viscous solvents revealed that the N-alkyl and N,N-dialkyl carboxamide groups tend to reduce the contributions from intersystem crossing and increase those from internal conversion. Considering that the fluorescence mechanism of low-fluorescence carbonyl compounds such as aldehyde and ketone is dominated by intersystem crossing and that of high-luminescence carbonyl compounds such as carboxylic acid and ester is dominated by a radiative process, it can be said that the photophysical process of N-alkyl and N,N-dialkyl carboxamides is novel. In addition, the calculation results for excited states indicated that such contributions can be controlled by selecting the appropriate polycyclic aromatic hydrocarbon or amide structure, in addition to solvent viscosity and temperature.
Synthesis, luminescence properties, and theoretical insights of N-alkyl- or N,N-dialkyl-pyrene-1-carboxamide
Niko, Yosuke,Kawauchi, Susumu,Konishi, Gen-Ichi
supporting information; experimental part, p. 4843 - 4847 (2011/10/05)
We report the synthesis and photophysical properties of N-alkyl- or N,N-dialkyl-pyrene-1-carboxamide. These derivatives, as well as pyrene, exhibited blue emission. N-Alkyl-type derivatives exhibited strong fluorescence emission (Φfl = 0.61 in EtOH) in both nonpolar and polar solvents. On the other hand, N,N-dialkyl-type derivatives showed weak fluorescence emission (Φfl fl = 0.91) and N,N-dialkyl-type (Φfl = 0.082) derivatives were increased. We also investigated the fluorescence mechanism of these compounds using time-dependent density-functional theory (TD-DFT). From these results, we find that highly fluorescent pyrene-1-carboxamide derivatives can be designed by introducing an appropriate functional group at the nitrogen atom of the amide. Thus, N,N-dialkyl-type pyrene-1-carboxamide has considerable potential for use in applications such as environmental response sensors and probes.
