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N-Heterocyclic Olefins as Electron Donors in Combination with Triarylborane Acceptors: Synthesis, Optical and Electronic Properties of D-π-A Compounds
Please always quote using this URN: urn:nbn:de:bvb:20-opus-204690
- N‐heterocyclic olefins (NHOs), relatives of N‐heterocyclic carbenes (NHCs), exhibit high nucleophilicity and soft Lewis basic character. To investigate their π‐electron donating ability, NHOs were attached to triarylborane π‐acceptors (A) giving donor (D)–π–A compounds 1–3. In addition, an enamine π‐donor analogue (4) was synthesized for comparison. UV–visible absorption studies show a larger red shift for the NHO‐containing boranes than for the enamine analogue, a relative of cyclic (alkyl)(amino) carbenes (CAACs). Solvent‐dependent emissionN‐heterocyclic olefins (NHOs), relatives of N‐heterocyclic carbenes (NHCs), exhibit high nucleophilicity and soft Lewis basic character. To investigate their π‐electron donating ability, NHOs were attached to triarylborane π‐acceptors (A) giving donor (D)–π–A compounds 1–3. In addition, an enamine π‐donor analogue (4) was synthesized for comparison. UV–visible absorption studies show a larger red shift for the NHO‐containing boranes than for the enamine analogue, a relative of cyclic (alkyl)(amino) carbenes (CAACs). Solvent‐dependent emission studies indicate that 1–4 have moderate intramolecular charge‐transfer (ICT) behavior. Electrochemical investigations reveal that the NHO‐containing boranes have extremely low reversible oxidation potentials (e.g., for 3, \(E^{ox}_{1/2}\) =−0.40 V vs. ferrocene/ferrocenium, Fc/Fc\(^+\), in THF). Time‐dependent (TD) DFT calculations show that the HOMOs of 1–3 are much more destabilized than that of the enamine‐containing 4, which confirms the stronger donating ability of NHOs.…
Author: | Jiang He, Florian Rauch, Alexandra Friedrich, Daniel Sieh, Tatjana Ribbeck, Ivo Krummenacher, Holger BraunschweigORCiD, Maik Finze, Todd B. Marder |
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URN: | urn:nbn:de:bvb:20-opus-204690 |
Document Type: | Journal article |
Faculties: | Fakultät für Chemie und Pharmazie / Institut für Anorganische Chemie |
Language: | English |
Parent Title (English): | Chemistry - A European Journal |
Year of Completion: | 2019 |
Volume: | 25 |
Pagenumber: | 13777-13784 |
Source: | Chemistry - A European Journal (2019) 25, 13777-13784. doi:10.1002/chem.201903118 |
DOI: | https://doi.org/10.1002/chem.201903118 |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 546 Anorganische Chemie |
Tag: | N-heterocyclic olefins; donor-acceptor systems; electrochemistry; photophysical prosperties; triarylboranes |
Release Date: | 2020/06/26 |
Licence (German): | CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International |