title: Excellent correlation between substituent constants and pyridinium N-methyl chemical shifts.
abstract: Substituents on the pyridinium ring of N-methylpyridinium derivatives, especially those on the 2- or 4-positions, have a large effect on the (1)H and (13)C NMR chemical shifts of the N-methyl group. Reasonable correlations between the chemical shift changes and the resonance substituent constants are observed. The dual substituent parameter approach provides an excellent correlation when a combination of polar and resonance substituent constants is employed.
authors.affiliation: Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132.
authors.forename: Sha
authors.initials: S
authors.lastname: Huang
authors.forename: Jesse C S
authors.initials: JC
authors.lastname: Wong
authors.forename: Adam K C
authors.initials: AK
authors.lastname: Leung
authors.forename: Yee Man
authors.initials: YM
authors.lastname: Chan
authors.forename: Lili
authors.initials: L
authors.lastname: Wong
authors.forename: Myrien R
authors.initials: MR
authors.lastname: Fernendez
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Miller
authors.forename: Weiming
authors.initials: W
authors.lastname: Wu