σ_w of Nuclei other than ¹H and ¹⁹ F

Abstract

We discuss these two nuclei together because the only reports on pure Van der Waals solvent effects of these nuclei are from one source (i.e. Maciel and co-workers [100, 108, 109]), where these two resonances were studied simultaneously. We also will deviate from our general rule of discussing only gas shifts or gas-to-liquid shifts, because of the paucity of such data. The first report on σ_w of ¹³C and ²⁹Si is due to Bacon, Maciel, Musker and Scholl [108], who for TMS in 20 vol % TMS, 80 vol % C₆H₁₂ reported susceptibility corrected values, relative to pure TMS, of σ_w (¹³C) = +0.12 ppm and σ_w (²⁹Si) = -0.05 ppm. In subsequent paper [109] several more of such data were given, but a full discussion of the ¹³C, ²⁹Si and ¹H solvent effects of TMS and cyclohexane by Bacon and Maciel [100] includes all previous data. In Table 41 all the relevant data (i.e. pertaining to pure σ_w effects only) is given.