# $C^{13}$--NUCLEAR MAGNETIC SHIELDING IN AROMATIC COMPOUNDS

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 Title: $C^{13}$--NUCLEAR MAGNETIC SHIELDING IN AROMATIC COMPOUNDS Creators: Spiesecke, H.; Schneider, W. G. Issue Date: 1960 Publisher: Ohio State University Abstract: “The relative $C^{13}$ chemical shifts of some monosubstituted benzene derivatives have been measured. The assignments were made with the aid of the spectra of the 3,5-and 2,4,6-deuterated analogues. The most striking feature of these results is the very large shift to low field of the substituted carbon atom. Of the remaining ring atoms the para position is the most sensitive towards any change in the inductive and mesomeric character of the substituent. The results are discussed in relation to the corresponding proton chemical shifts. The nonbenzenoid five-membered ring compounds shows a steady increase in “aromaticity” from furan, pyrrole to thiophen. In contrast to chemical reactivity, the 3 and 4 positions are the most shielded. The C--H coupling constants show the expected correlation with s-character of the $C^{13}$--H bond.” Description: Author Institution: Pure Chemistry Division, National Research Council URI: http://hdl.handle.net/1811/8003 Other Identifiers: 1960-M-9