Abstract
The magnitude of one bond and long-range coupling constants in 3-nitropyridine
1 and its derivatives
2–
16 were determined from the proton-coupled
13C NMR spectra in CDCl
3. The GIAO/DFT (Density Functional Theory/Gauge Including Atomic Orbitals) calculations on B3LYP/6-31+G(d,p)//6-31G(d) and B3LYP/6-311++G(d,p)//6-31G(d) optimized structures of
1–
16 were employed for the determination of proton and carbon chemical shifts and coupling constants (
J
HH
n
and
J
CH
n
) and the calculated data compared with the experimental NMR data. The GIAO/DFT calculations, in conjugation with iterative simulations of the proton-coupled
13C NMR spectra using gNMR software, provide reliable values of
J
C
NO2,H
n
couplings, which could not be obtained from the proton-coupled
13C NMR spectra of
1–
16 due to line broadening associated with quadruple relaxation involving the
14N nuclei and non-zero
13C–
14N couplings.