Substituent‐induced chemical shifts (SCS) by the phenyl group in sterically congested styrene derivatives | Zendy

Knorr Rudolf | Zendy; Stephenson David S. | Zendy; Böhrer Petra | Zendy; Hoang ThiPhung | Zendy

AI Assistant Blog Pricing

Home ZAIA Blog

Premium

Substituent‐induced chemical shifts (SCS) by the phenyl group in sterically congested styrene derivatives

Author(s) -

Knorr Rudolf,

Stephenson David S.,

Böhrer Petra,

Hoang ThiPhung

Publication year - 1993

Publication title -

magnetic resonance in chemistry

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.483

H-Index - 72

eISSN - 1097-458X

pISSN - 0749-1581

DOI - 10.1002/mrc.1260310415

Subject(s) - chemistry , substituent , steric effects , chemical shift , styrene , stereochemistry , proton nmr , medicinal chemistry , organic chemistry , copolymer , polymer

The two 13 C NMR methyl signals of the sterically congested 9‐benzylidene‐1,8‐dimethylfluorene (1a) have the surprisingly small separation of only 0.37 ppm; for 9‐benzylidene‐2,7‐dimethylfluorene the corresponding methyl separation is 0.04 ppm. An alternative analysis of 1a with respect to 1,8‐dimethylfluorene shows that the perturbing syn ‐phenyl substituent has caused a downfield ( + 0.47 ppm) 13 C shift but an upfield 1 H shift ( − 0.97 ppm) of the compressed 1‐CH 3 group. For further comparisons, NMR assignments were also made for 2,7‐dimethylfluorene, 1,8‐dimethylfluoren‐9‐one and 2‐(1,1‐dimethylethyl)‐3,3‐dimethyl‐1‐phenylbut‐1‐ene.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here

Accelerating Research