Effect of Sulfur Oxidation on the Transmission Mechanism of (4)J(HH) NMR Coupling Constants in 1,3-Dithiane

Author(s)

Gauze, Gisele F. ^[1] ; Basso, Ernani A. ^[1] ; Contreras, Ruben H. ^{[2, 3]} ; Tormena, Claudio F. ^[4]

Affiliation

^[1] Univ Estadual Maringa, Dept Quim, BR-87020900 Maringa, Parana - Brazil

^[2] Consejo Nacl Invest Cient & Tecn, RA-1033 Buenos Aires, DF - Argentina

^[3] Univ Buenos Aires, Dept Phys, FCEyN, Buenos Aires, DF - Argentina

^[4] Univ Estadual Campinas, Inst Chem, Dept Organ Chem, BR-13084971 Campinas, SP - Brazil

• Document type: Journal article
• Source: Journal of Physical Chemistry A; v. 113, n. 11, p. 2647-2651, MAR 19 2009.
• Web of Science Citations: 11

Abstract

Long-range (4)J(HH) couplings in 1,3-dithiane derivatives are rationalized in terms of the effects of hyperconjugative interactions involving the S=O group. Theoretical and experimental studies of (4)J(HH), couplings were carried out in 1,3-dithiane-1-oxide (2), cis-1,3-dithiane-1,3-dioxide (3), 1,3-dithiane-1,1,3-trioxide (4), and 1,3-dithiane-1,1,3,3-tetraoxide (5) compounds. Hyperconjugative interactions were studied with the natural bond orbital, NBO, method. Hyperconjugative interactions involving the LP(O), oxygen lone pair and sigma{*}(C2-S1) and sigma{*}(S1-C6) antibonding orbitals yield an increase of (4)J(Hcq - Hcq) couplings. Long-range (4)J(Ha-Hax), couplings were also observed between hydrogen atoms in axial orientation, which are rationalized as originating in hyperconjugative interactions involving the bonding sigma(C6-Hax) and antibonding sigma{*}(S=O) orbitals. The symmetry for orbital interactions is possible only when the S=O group is in the axial orientation. (AU)

• FAPESP's process: 05/59649-0 - Conformational equilibria studies by nuclear magnetic resonance spectroscopy, infrared spectroscopy and theoretical calculations
• Grantee: Roberto Rittner Neto
• Support Opportunities: Research Projects - Thematic Grants