Red Organic Light-Emitting Radical Adducts of Carbazole and Tris(2,4,6-trichlorotriphenyl)methyl Radical That Exhibit High Thermal Stability and Electrochemical Amphotericity

Abstract

Synthesis and characterization of new carbazolyl derivatives with a pendant stable radical of the TTM (tris-2,4,6-trichlorophenylmethyl radical) series are reported. The EPR spectra, electrochemical properties, absorption spectra, and luminescent properties of these radical adducts have been studied. All of them show electrochemical amphotericity being reduced and oxidized to their corresponding stable charged species. The luminescence properties of them cover the red spectral band of the emission. The luminescence of the electron-rich carbazole adducts shows the donor-acceptor nature of the excited state. On the other hand, the EPR parameters of these radical adducts show an imperceptible variation with the substituents in the carbazole.

Modulated Luminescence of a Stable Open‐Shell Triarylmethyl Radical: Effects of Chemical Modification on Its Electronic Structure and Physical Properties

“…[6][7][8][9][10][11][12][13] Monoradicals with an S = 1/2 spin state (doublet state) are expected to exhibit highly efficient, longwavelength emission without extended p-conjugation in electroluminescent devices. [6][7][8][9][10][11][12][13] Monoradicals with an S = 1/2 spin state (doublet state) are expected to exhibit highly efficient, longwavelength emission without extended p-conjugation in electroluminescent devices.…”

“…This is mainly because there are few examples of luminescent radicals, and radicals are not chemically stable under ambient or photoexcited conditions. [11][12][13] We prepared the luminescent (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM;F igure 1), [14] and investigated its properties and photostability upon coordinationt oA u I or Cu II or substitution with halogen atoms. [10] Lambert et al and Juliµ et al have reported the solvent-dependent luminescent properties of donor-acceptor-types table radicals.…”

A Stable Room‐Temperature Luminescent Biphenylmethyl Radical

“…Up to now,e mission from stable radicals is ar are phenomenon, and there are only three series of roomtemperature luminescent radicals:p erchlorotriphenyl methyl (PTM) radical derivatives, [13] tris(2,4,6-trichlorophenyl)methyl (TTM) radical derivatives, [14] and pyridyl-containing triarylmethyl radicals (PyBTM) (Scheme 1). [15] Because all of them have the structure of three benzene units or benzene analogues surrounding the central radical, they are catalogued into the family of triphenylmethyl radicals.…”

Stable All‐Organic Radicals with Ambipolar Charge Transport

“…Radical adducts 1 and 2 were prepared as already reported . Radicals 3 and 4 were synthesized by coupling the corresponding 3,6‐disubstituted carbazole derivative to the TTM radical (Scheme ).…”

“…Herein, we present the charge‐transport properties of a series of radical adducts based on the ambipolar [4‐( N ‐carbazolyl)‐2,6‐dichlorophenyl]bis(2,4,6‐trichlorophenyl)methyl radical (Cbz‐TTM) (Scheme ). In this series of compounds, the electron‐donating capability of the carbazole moiety, and hence, the push–pull character of the radical adducts, has been modulated by the introduction of different electron‐donating or ‐withdrawing groups on the carbazole core ( 1 , 2 ) . In addition, the extension of the conjugated π ‐system has been also considered ( 3 , 4 ).…”