7-Azaindolyl- and indolyl-functionalized starburst molecules with a 1,3,5-triazine or a benzene core — Syntheses and luminescence

Abstract

The syntheses of several new 7-azaindolyl-, indolyl-, and 3-methylindolyl-functionalized starburst molecules that contain either a 1,3,5-triazine, a benzene, a 2,4,6-triphenyl-2,4,6-triazine, a 1,3,5-triphenylbenzene, a 2,4,6-tris(biphenyl)-1,3,5-triazine, or a 1,3,5-tris(biphenyl)benzene core have been achieved. The synthetic methods used for these new compounds involve mostly Ullmann condensation and Suzuki coupling reactions. The thermal properties of the new molecules have been found to be highly dependent on the molecular weight and the central core. Glass transition temperatures greater than 150 °C were observed for the large starburst molecules based on the 2,4,6-tris(biphenyl)-1,3,5-triazine or the 1,3,5-tris(biphenyl)benzene core. The new starburst molecules are luminescent in the violet-blue region in solution and in the solid state. The emission energy and the quantum efficiency were found to be highly dependent on the central core and the functional group. In general, the triazine-based molecules were found to have a smaller HOMO–LUMO energy gap than the benzene-based analogues. The triphenyltriazine- or triphenylbenzene-based molecules were found to display a higher emission quantum efficiency than the large tris(biphenyl)triazine- or tris(biphenyl)benzene-based molecules.Key words: 7-azaindolyl, indolyl derivative, triazine and benzene cores, starburst molecule, blue luminescence.

Star-Shaped Conjugated Systems

“…98h is a suitable substrate for three-fold copper-catalyzed N -arylations, e.g., with 7-azaindole [ 288 ]. Ullmann reaction with di-2-pyridylamine gave a star 98l with triarylamine branches in 60% yield.…”

“…Wang described a 2,4,6-tris-biphenyltriazine star 98t with six N -indolyl groups on the 3,5-positions of the terminal rings [ 288 ]. The key step for the synthesis is a Suzuki coupling of the 3,5-bis( N -indolyl)benzeneboronic acid 100i with 98h (61%).…”

Structure–Activity Relationships of Small Molecule Autotaxin Inhibitors with a Discrete Binding Mode

“…Prepared according to a modified version of a literature procedure for an Ullmann coupling. 38 To a microwave vial was added 1,10-phenanthroline (56 mg, 0.311 mmol, 1 equiv. ), CuI (30 mg, 0.156 mmol, 0.5 equiv.…”

Luminescence and reactivity of 7-azaindole derivatives and complexes

“…43 One notable difference between the triazine and the benzene analogues is that the emission energy of the triazine derivatives is consistently lower than their benzene analogues. 44 DFT calculations indicate that the lowest electronic transition in the benzene derivatives involves typical pp* transitions delocalized on the entire molecule while in the triazine derivatives it involves charge transfer from the 7-azaindolyl substituent to the central core. 45 This compound is also a rare phosphorescent Pd(II) complex with l em = 575 nm.…”