An Isolable, Photoswitchable N-Heterocyclic Carbene: On-Demand Reversible Ammonia Activation.
The first isolable, photoswitchable N-heterocyclic carbene was synthesized and found to undergo reversible electrocyclic isomerization upon successive exposure to UV and visible radiation. The UV-induced ring closure afforded substantial changes to the electronic structure of the dithienylethene-based NHC, as evidenced by changes in the corresponding UV/Vis absorption and (13)C NMR spectra. Likewise, molecular orbital calculations revealed diminished electron density at the carbene nucleus upon photocyclization, consistent with the enhanced electrophilicity displayed by the ring-closed form. The photoswitchable NHC was successfully switched between its ring-opened and ring-closed states with high fidelity over multiple cycles. Furthermore, the ring-closed isomer was found to undergo facile N-H bond activation, allowing for the controlled capture and release of ammonia upon cycling between its isomeric states.
Department of Chemistry, The University of Texas at Austin, 1 University Station, A1590, Austin, TX 78712 (USA).
Aaron J
AJ
Teator
Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854 (USA).
Yuan
Y
Tian
Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854 (USA).
Mu
M
Chen
Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854 (USA). jeehiun@rci.rutgers.edu.
Jeehiun K
JK
Lee
Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan 689-798 (Republic of Korea). bielawski@unist.ac.kr.|Department of Chemistry and Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Republic of Korea). bielawski@unist.ac.kr.
Christopher W
CW
Bielawski
carbenes; diarylethenes; nitrogen heterocycles; photochromism; photoswitches