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Ramsey terms for two-, three-, and four-bond coupling involving 15 N and 17 O in hydrogen-bonded and nonhydrogen-bonded systems: are coupling constants sensitive to RAHBs?
| Content Provider | Scilit |
|---|---|
| Author | Elguero, José Alkorta, Ibon Bene, Janet E. Del |
| Copyright Year | 2013 |
| Description | Ab initio EOM-CCSD/(qzp,qz2p) calculations have been performed on complexes with intermolecular hydrogen bonds involving$ ^{15}$N and$ ^{17}$O, and molecules with and without intramolecular hydrogen bonds involving these nuclei. Coupling constants across intermolecular hydrogen bonds are well approximated by the Fermi-contact (FC) term. In general,$ ^{2h}$J(X–Y) for intramolecular coupling across $X–H^{…}$Y hydrogen bonds are not sensitive to the presence of resonance-assisted hydrogen bonds (RAHBs). However,$ ^{2h}$J(O–O) for coupling across the intramolecular hydrogen bond in malonaldehyde is greater than$ ^{2h}$J(O–O) for its saturated counterpart, so that$ ^{2h}$J(O–O) is sensitive to the presence of the RAHB. This is also the case for the sulphur analogues of malonaldehyde. For these unsaturated hydrogen-bonded molecules, molecules with carboxyl groups, and trans-glyoxal, J is dominated by the paramagnetic spin orbit (PSO) term. For these systems, the primary mode of coupling transmission is through the conjugated chain. For complexes with intermolecular hydrogen bonds, saturated molecules with intramolecular hydrogen bonds, unsaturated and saturated molecules in which the hydrogen bond has been broken, and unsaturated molecules with intramolecular $N–H^{…}$N or $O–H^{…}$N hydrogen bonds, J is dominated by the FC term. FC domination in hydrogen-bonded systems indicates that the primary transmission mode is across the hydrogen bond. |
| Related Links | https://digital.csic.es/bitstream/10261/89625/1/accesoRestringido.pdf |
| Ending Page | 116 |
| Page Count | 10 |
| Starting Page | 107 |
| ISSN | 00268976 |
| e-ISSN | 13623028 |
| DOI | 10.1080/00268976.2013.802820 |
| Journal | Molecular Physics |
| Issue Number | 1 |
| Volume Number | 112 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 2013-06-05 |
| Access Restriction | Open |
| Subject Keyword | Atomic, Molecular and Chemical Physics Inter- and Intramolecular Hydrogen Bonds Nmr Spin–spin Coupling Constants Eom-ccsd Calculations Relative Importance of Fc and Pso Terms Coupling Transmission Mechanisms |
| Content Type | Text |
| Resource Type | Article |
| Subject | Molecular Biology Physical and Theoretical Chemistry Biophysics Condensed Matter Physics |
