| Title: |
Non-Kekulé meta -Quinodimethane Singlet Diradicals Based on Classical N-Heterocyclic Carbenes |
| Authors: |
Steffenfauseweh, H.; Rottschäfer, D.; Vishnevskiy, Y.V.; Neumann, B.; Stammler, H.-G.; de Bruin, B.; Ghadwal, R.S. |
| Source: |
Steffenfauseweh, H, Rottschäfer, D, Vishnevskiy, Y V, Neumann, B, Stammler, H-G, de Bruin, B & Ghadwal, R S 2024, 'Non-Kekulé meta -Quinodimethane Singlet Diradicals Based on Classical N-Heterocyclic Carbenes', Chemistry - A European Journal, vol. 30, no. 67, e202403029. https://doi.org/10.1002/chem.202403029 |
| Publication Year: |
2024 |
| Collection: |
Universiteit van Amsterdam: Digital Academic Repository (UvA DARE) |
| Description: |
Diradicals based on a meta-quinodimethane ( m - QDM ) scaffold generally have a triplet ground state and are rather scarce. Herein, m - QDM -based non-Kekulé diradicals [3,3′-(NHC) 2 BP] (3-NHC) (NHC = SIPr = C{N(Dipp)CH 2 } 2 ; IPr = C{N(Dipp)CH} 2 , Me-IPr = C{N(Dipp)CMe} 2 ; Dipp = 2,6-iPr 2 C 6 H 3 ; BP = 1,1′-C 6 H 4 C 6 H 4 ) featuring N-heterocyclic carbene (NHC) pendants are reported as crystalline solids. The EPR spectra of 3 -NHC show both allowed (Δm s = 1) and forbidden (Δm s = 2; ‘half-field’) transitions characteristic for triplet diradicals. Variable temperature EPR studies however reveal a singlet ground state for 3 -SIPr. Consistent with the EPR spectra, calculations predict a remarkably small singlet-triplet energy gap (ΔE ST ≤ 0.26 kcal/mol) for the 3 -NHC compounds. The calculated singlet diradical character for the ground states of the 3-NHC compounds amounts to ~99 %. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| ISSN: |
0947-6539; 1521-3765 |
| Relation: |
info:eu-repo/semantics/altIdentifier/hdl/https://hdl.handle.net/11245.1/8b25c61c-975a-4650-a3c0-8f468a247b86; info:eu-repo/semantics/altIdentifier/pissn/0947-6539; info:eu-repo/semantics/altIdentifier/eissn/1521-3765 |
| DOI: |
10.1002/chem.202403029 |
| Availability: |
https://dare.uva.nl/personal/pure/en/publications/nonkekule-metaquinodimethane-singlet-diradicals-based-on-classical-nheterocyclic-carbenes(8b25c61c-975a-4650-a3c0-8f468a247b86).html; https://doi.org/10.1002/chem.202403029; https://hdl.handle.net/11245.1/8b25c61c-975a-4650-a3c0-8f468a247b86; https://pure.uva.nl/ws/files/220817278/Non-Kekul_meta-Quinodimethane_Singlet_Diradicals.pdf; https://www.scopus.com/pages/publications/85206591144 |
| Rights: |
info:eu-repo/semantics/openAccess ; http://creativecommons.org/licenses/by-nc/4.0/ |
| Accession Number: |
edsbas.B720CC43 |
| Database: |
BASE |