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Different electronic structure of phosphonyl radical adducts of N-heterocyclic carbenes, silylenes and germylenes: EPR spectroscopic study and DFT calculations
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sheberla, Dennis Tumanskii, Boris Tomasik, Adam C. Mitra, Amitabha Hill, Nicholas J. West, Robert D. Apeloig, Yitzhak |
| Copyright Year | 2010 |
| Abstract | Stable N-heterocyclic carbenes and germylenes were allowed to react with a phosphonyl radical, (i-PrO)2(O)P˙ (7), generated by photolysis of [(i-PrO)2(O)P]2Hg. The products were identified by EPR spectroscopy. An unsaturated carbene (1) and germylene (3) react with 7 at the divalent atom to give unstable radical products (τ½ = 0.2 s). A benzo-annulated carbene (4) and a saturated germylene (6) react with 7 to give more active radicals. An unsaturated (2) and a saturated silylene (5) undergo rapid reaction (in the dark) with [(i-PrO)2(O)P]2Hg to yield unusual silyl phosphites. In these cases only secondary radicals were observed. DFT (PBE0/TZVP//B3LYP/6-31+G(d)) calculations of the radical adducts of the different (C, Si, Ge) unsaturated N-heterocyclic divalent species with the phosphonyl radical show that the unpaired electron is delocalized over the five-membered ring; the spin density on the central atoms decreases in the order C, 39% > Si, 14% > Ge, 2%. These trends can be understood in terms of a zwitterionic structure of the radical adducts. The calculations of the radical adducts of 4, 5 and 6 with 7 indicate larger spin density on the central atom, 47%, 58% and 42% on C, Si, Ge, respectively. |
| Starting Page | 234 |
| Ending Page | 241 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/C0SC00143K |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/sc/c0/c0sc00143k/c0sc00143k.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/C0SC00143K |
| Volume Number | 1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
