Effects of halogen atom substitution on luminescent radicals: a case study on tris(2,4,6-trichlorophenyl)methyl radical-carbazole dyads

Abstract

Series of halogen-substitute carbazole TTM radicals were synthesized. The effect of halogen substituents on radical luminescence was systematically evaluated. It was found that well-known heavy atom effect does not work...

Water-Soluble Trityl Radicals for Fluorescence Imaging

“…Both OEGylated TTM radicals 9 and 10 show weak absorption in the visible and strong absorption bands in the UV spectrum, as is typical for TTM and its derivatives (see Figure 2 ) [ 3 , 12 , 14 , 15 , 16 , 18 ]. The absorption in the visible region appears red-shifted with respect to TTM.…”

“…TTM-derived radical emitters with reported high photoluminescence efficiency typically possess CT excited states [ 3 , 14 , 15 ]. However, it is known that such polar excited states are prone to fluorescence quenching in polar solvents, as a polar medium stabilizes the CT state.…”

On the Effect of Donor Strength on the Photoluminescence Performance in Mono-substituted N-Donor Triarylmethyl Radicals

“…When we plot  against IE, we observe that the data describe a bell-shaped curve, showing poor  for weak and strong donors, and high  for medium-strength donors (see Figure 2b). [2][3][4]6,[8][9][10][11][12][13][14][15][16][17] The solid line in Figure 2 (a), approaching max of TTM (567 nm) in cyclohexane (dashed line) and the Gauss curve (black solid line in Figure 2 (b)) are guides to the eye. Data points marked by triangles are for solutions of the respective radicals in toluene.…”

“…We select a variety of TTM radicals functionalized with N-heterocyclic donorsmostly substituted carbazolesfrom the literature. [2][3][4]6,[8][9][10][11][12][13][14][15][16][17] We group the molecules into four different categories according to the structure of the donor: (i) varying carbazole ring reductions and extensions, (ii, iii) different carbazole substitutions (either 2,7-or 3,6-), and (iv) N-heterocyclic moieties other than carbazole (see Figure 1). To obtain a measure for the electron-donating quality of the respective substituents, we employ DFT calculations on the PBE0/6-31+G(d) level of theory (and, for the donors of 22 and 23, the LANL2DZ basis set because of the heavy iodide substituents).…”

“…[18][19][20][21][22] The IE is obtained as the vertical difference in total energy of the neutral and cationic species, while the geometry, optimized for the neutral compounds, is unchanged upon ionization (see Figure 1). [2][3][4]6,[8][9][10][11][12][13][14][15][16] These are computed for the individual molecules (saturated with hydrogen) at the PBE0/6-31+G(d) level (LANL2DZ basis set for the donors of 22 and 23). [18][19][20][21][22] Circles, squares, and triangles represent molecules taken from the literature; new compounds are indicated by stars.…”