One-bond and long-range coupling constants of substituted 2-cyanopyridines. GIAO/DFT calculations of proton and carbon chemical shifts and coupling constants

• Published in: Journal of molecular structure Vol. 783; no. 1; pp. 191 - 203
• Main Authors: Katritzky, Alan R., Akhmedov, Novruz G., Güven, Alâattin, Scriven, Eric F.V., Majumder, Suman, Akhmedova, Rena G., Hall, C. Dennis
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 06-02-2006
• Subjects: 2-Cyanopyridines; GIAO; Long-range coupling constants; Proton-coupled 13C NMR spectra; GIAO; Proton-coupled 13C NMR spectra; Long-range coupling constants; 2-Cyanopyridines
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2005.07.003

The magnitude of one bond and long-range coupling constants (
n
J
HH and
n
J
CH) in isomeric cyanopyridines-(
1,
2,
3), methyl-(
4,
5,
6,
7), 3-ethyl-(
8), chloro-(
9), 3-bromo-(
10), acetyl-(
11,
12), 5-ethoxycarbonyl-(
13) and 4-(4′-pyridyl)-(
14) derivatives of 2-cyanopyridines were determined in CDCl
3. The Density Functional Theory/Gauge Including Atomic Orbitals (GIAO/DFT) calculation was employed for the estimation of proton or carbon chemical shifts and coupling constants (
n
J
HH and
n
J
CH) and the calculated NMR data compared with the experimental NMR data. The experimental values of
n
J
HH and
n
J
CH in derivatives of 2-cyanopyridines
1–
14 are discussed with respect to the corresponding data in previously reported compounds and compared with values obtained from GIAO/DFT calculations and iterative simulation using gNMR software. Assignments of proton and carbon chemical shifts were achieved using one- and two-dimensional NMR techniques, such as 1D NOE difference, COSY, long-range COSY, gHMBC and gHMQC.