Gas-phase 13C chemical shifts in the zero-pressure limit: refinements to the absolute shielding scale for 13C
✍ Scribed by A.Keith Jameson; Cynthia J. Jameson
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 501 KB
- Volume
- 134
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
C chemical shifts have been measured relative to ')CO in the zero-pressure limit for over twenty molecules for which theoretical calculations of "C nuclear shielding have recently been reported. Rovibrational averaging effects on the spin-rotation constant in '3C'6O have been used to find a,("C in 13C60) =3.0? 1.2 ppm and aa( *'C in 'aC'60)= l.O+ 1.2 ppm. With the latter, the u,, values for the 13C nuclei in this work have been determined absolutely and compared with calculated values. Agreement is generally good in most cases except where low-lying n-r%* transitions contribute significantly to the paramagnetic shielding.