298230-47-4Relevant academic research and scientific papers
Synthesis and Photophysical Properties of Aza[n]helicenes
Upadhyay, Gourav M.,Talele, Harish R.,Bedekar, Ashutosh V.
, p. 7751 - 7759 (2016/09/09)
Synthesis and study of aza[7]helicene and aza[9]helicene is presented in this paper. Photo-dehydrocyclization of the 3,6-bis-styryl derivative of carbazole leading to sterically less demanding aza[7]helicene resulted in smooth reaction, and only the desired angular-angular product was detected. However, in the case of aza[9]helicene, along with the expected angular-angular cyclization, three other products involving linear mode of cyclization were also isolated and characterized. In this case, the helical compound aza[9]helicene was predominantly formed at lower concentration while the other isomers were obtained at higher concentration. All of the compounds formed by angular-angular, angular-linear, and linear-linear modes of cyclization were fully characterized, and their photophysical properties were investigated.
Experimental and theoretical studies on the one-photon and two-photon properties of a series of carbazole derivatives containing styrene
Li, Liang,Wu, Yiqun,Zhou, Qinling,He, Chunying
, p. 362 - 372 (2012/07/28)
Symmetric-type carbazole derivatives show great potential for application in two-photon absorption (TPA) materials and organic light-emitting diodes. The absorption spectra and fluorescence emission spectra of three different N-alkyl symmetric-type carbazole derivatives were investigated. The density functional theory (DFT) time-dependent-DFT//Becke, three-parameter, Lee-Yang-Parr/6- 31G* method has been used to theoretically study one-photon absorption properties. The computational results are in good agreement with the available experimental values. The two-photon excited fluorescence of the compounds was surveyed by 120fs pulse at 790nm Ti: sapphire laser operating at 1kHz repetition rate. Two-photon excited fluorescence was obtained in the range of 380-600nm, and TPA cross-sections were calculated. The TPA properties of the series of compounds were investigated by the ZINDO/single and double electronic excitation configuration interaction method. The influence of the chemical structure of the compounds on two-photon optical properties was discussed. The results show how the different changes in one-photon absorption and TPA properties on the basis of lengthening the conjugated bridge and the different carbazole N-alkyl substituents are attributed to the transition dipole moment in the excited process. Copyright
