Molecular Environment Effects That Modulate the Photophysical Properties of Novel 1,3-Phosphinoamines Based on 2,1,3-Benzothiadiazole

Radmir M. Khisamov, Alexey A. Ryadun, Sergey N. Konchenko, Taisiya S. Sukhikh

Research output: Contribution to journalArticlepeer-review

Abstract

We report synthesis, crystal structure, and photophysical properties of novel 1,3-phosphinoamines based on 4-amino-2,1,3-benzothiadiazole (NH2-btd): Ph2 PCH(Ph)NH-btd (1) and Ph2 P(E)CH(Ph)NH-btd, (E = O (2α and 2β·thf), S (3), Se (4)). Chalcogenides 2–4 exhibit bright emissions with a major band at 519–536 nm and a minor band at 840 nm. According to TD-DFT calculations, the first band is attributed to fluorescence, while the second band corresponds to phos-phorescence. In the solid state, room temperature quantum yield reaches 93% in the case of the sulphide. The compounds under study feature effects of the molecular environment on the luminescent properties, which manifest themselves in fluorosolvatochromism as well as in a luminescent response to changes in crystal packing and in contributions to aggregation effects. Specifically, trans-formation of solid 2β·thf to solvate-free 2β either by aging or by grinding causes crystal packing changes, and, as a result, a hypsochromic shift of the emission band. Polystyrene films doped with 2 reveal a bathochromic shift upon increasing the mass fraction from 0.2 to 3.3%, which is caused by molecular aggregation effects.

Original languageEnglish
Article number3857
JournalMolecules
Volume27
Issue number12
DOIs
Publication statusPublished - 1 Jun 2022

Keywords

  • aggregation effects
  • benzothiadiazole
  • luminescence
  • phosphinoamine
  • single crystal X-ray diffraction
  • TD-DFT calculations
  • Luminescence
  • Thiadiazoles/chemistry

OECD FOS+WOS

  • 1.04 CHEMICAL SCIENCES

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