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Potassium Poly(Heptazine Imide): Transition Metal‐Free Solid‐State Triplet Sensitizer in Cascade Energy Transfer and [3+2]‐cycloadditions
Author(s) -
Savateev Aleksandr,
Tarakidezda V.,
Strauss Volker,
Hussain Tanveer,
Brummelhuis Katharina,
Sánchez Vadillo José Manuel,
Markushyna Yevheniia,
Mazzanti Stefano,
Tyutyunnik Alexander P.,
Walczak Ralf,
Oschatz Martin,
Guldi Dirk M.,
Karton Amir,
Antonietti Markus
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202004747
Subject(s) - excited state , photochemistry , photocatalysis , imide , chemistry , electron transfer , intersystem crossing , singlet state , materials science , triplet state , crystallography , atomic physics , physics , catalysis , organic chemistry
Polymeric carbon nitride materials have been used in numerous light‐to‐energy conversion applications ranging from photocatalysis to optoelectronics. For a new application and modelling, we first refined the crystal structure of potassium poly(heptazine imide) (K‐PHI)—a benchmark carbon nitride material in photocatalysis—by means of X‐ray powder diffraction and transmission electron microscopy. Using the crystal structure of K‐PHI, periodic DFT calculations were performed to calculate the density‐of‐states (DOS) and localize intra band states (IBS). IBS were found to be responsible for the enhanced K‐PHI absorption in the near IR region, to serve as electron traps, and to be useful in energy transfer reactions. Once excited with visible light, carbon nitrides, in addition to the direct recombination, can also undergo singlet–triplet intersystem crossing. We utilized the K‐PHI centered triplet excited states to trigger a cascade of energy transfer reactions and, in turn, to sensitize, for example, singlet oxygen ( 1 O 2 ) as a starting point to synthesis up to 25 different N‐rich heterocycles.