Quantitative empirical treatment of 13C NMR chemical shifts of aliphatic halides

✍ Scribed by Iragavarapu Suryanarayana; Johann Gasteiger

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 604 KB
• Volume: 29
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260291002

✦ Synopsis

Abstract

The ^13^C NMR chemical shifts of the α, β, γ and δ carbons of aliphatic fluorides, chlorides, bromides and iodides can be reproduced by a four‐parameter equation; the charge Q on the carbon atom, the number of hydrogen atoms three bonds away, N~3H~, the interactions of the polarizabilities of the halogen atoms one bond away with the hydrogens present in the first sphere, as represented by P~X~N~1H~, and the polarizabilities of halogens in the second sphere, P~X~(2). A regression coefficient of 0.9714 and a standard deviation of 4.85 ppm are obtained for all aliphatic halides in which the R skeleton includes alkyl, acyclic and bicyclic rings. For alkyl compounds only the correlation is of the order of R = 0.997 and the standard deviation is less than 2 ppm. Here the influence of C, H, F, Cl, Br and I are reproduced quantitatively.