ELECTRON COUPLING OF NUCLEAR SPINS. 6. RELATIVE SIGNS OF J SUPER HH SUB GEM, J SUPER HH SUB G, AND J SUPER HH SUB T IN (2.2) METACYCLOPHANE
Abstract
This analysis is concerned with the comparison between experiment and valence-bond calculations of the -electron contribution to the protonproton coupling constants of CH2 and HCCH groups in high resolution nmr spectra. Such calculations predicted the geminal coupling JHHgem to be +12.5 cps in methane, and subsequent, more approximate, calculations for the coupling of vicinal protons in the HCCH ethanic fragment with tetrahedral HCC bond angles gave the trans coupling JHHt to be about +9.2 cps and the gauche JHHg, + 1.7 cps. The magnitudes of these valuesAGREE WELL WITH EXPERIMENT EXCEPT THAT THE TRANS VICINAL CONSTANTS OBSERVED FOR ETHANIC GROUPS (and also both the cis and trans constants for ethylene) are often about 50% larger than predicted.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 14, 1962
- Accession Number
- AD0273771
Entities
People
- Cynthia Juan
- Herbert S. Gutowsky
Organizations
- University of Illinois Urbana–Champaign