Rethinking the X- + CH3Y [X = OH, SH, CN, NH2, PH2; Y = F, Cl, Br, I] S(N)2 reactions
Moving beyond the textbook mechanisms of bimolecular nucleophilic substitution (S(N)2) reactions, we characterize several novel stationary points and pathways for the reactions of X- [X = OH, SH, CN, NH2, PH2] nucleophiles with CH3Y [Y = F, Cl, Br, I] molecules using the high-level explicitly-correl...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
2019
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| Sorozat: | PHYSICAL CHEMISTRY CHEMICAL PHYSICS
21 No. 15 |
| doi: | 10.1039/c8cp07850e |
| mtmt: | 30934496 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/17910 |
| Tartalmi kivonat: | Moving beyond the textbook mechanisms of bimolecular nucleophilic substitution (S(N)2) reactions, we characterize several novel stationary points and pathways for the reactions of X- [X = OH, SH, CN, NH2, PH2] nucleophiles with CH3Y [Y = F, Cl, Br, I] molecules using the high-level explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ(-PP) [n = D, T, Q] basis sets. Besides the not-always-existing traditional pre- and post-reaction ion-dipole complexes, X-H3CY and XCH3Y-, and the Walden-inversion transition state, [X-CH3-Y](-), we find hydrogen-bonded X-HCH2Y (X = OH, CN, NH2; Y F) and front-side H3CYX- (Y F) complexes in the entrance and hydrogen-bonded XH2CHY- (X = SH, CN, PH2) and H3CXY- (X = OH, SH, NH2) complexes in the exit channels depending on the nucleophile and leaving group as indicated in parentheses. Retention pathways via either a high-energy front-side attack barrier, XYCH3-, or a novel double-inversion transition state, XHCH2Y-, having lower energy for X = OH, CN, and NH2 and becoming submerged (barrier-less) for X = OH and Y = I as well as X = NH2 and Y = Cl, Br, and I, are also investigated. |
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| Terjedelem/Fizikai jellemzők: | 7924-7931 |
| ISSN: | 1463-9076 |