|
|||||
|
|
The Effects of Ring Strain on Cyclic Tetraaryl[5]cumulenes |
|
| Authors: | Dr. Bozheng Sun Dr. Meagan S. Oakley Dr. Kota Yoshida Yanwen Yang Prof. Matteo Tommasini Dr. Chiara Zanchi Dr. Andrea Lucotti Dr. Michael J. Ferguson Dr. Frank Hampel Prof. Mariusz Klobukowski Prof. Rik R. Tykwinski |
| Affiliation: | 1. Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada;2. Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan;3. Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;4. Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), University of Erlangen-Nuremberg, Nikolaus-Fiebiger Str. 10, 91058 Erlangen, Germany |
| Abstract: | Cyclic tetraaryl[5]cumulenes ( 1 a–f ) have been synthesized and studied as a function of increasing ring strain. The magnitude of ring strain is approximated by the extent of bending of the cumulenic core as assessed by a combination of X-ray crystallographic analysis and DFT calculations. Trends are observed in 13C NMR, UV-vis, and Raman spectra associated with ring strain, but the effects are small. In particular, the experimental HOMO-LUMO gap is not appreciably affected by bending of the [5]cumulene framework from ca. 174° (λmax=504 nm) in 1 a to ca. 178° (λmax=494 nm) in 1 f . |
| Keywords: | cumulenes macrocycles Raman spectroscopy ring strain X-ray crystallography |