13C NMR Chemical Shift Assignments of Nitrated Benzo[a]pyrenes Based on Two-dimensional Techniques and DFT/GIAO Calculations

Authors

Kefa Karimu Onchoke, Stephen f. Austin state univetsityFollow

Document Type

Article

Publication Date

Spring 1-6-2021

Publication Title

Results in Chemistry

Abstract

Nitrated benzo[a]pyrenes are known to be mutagenic, carcinogenic and teratogenic to bacterial and animal cells. For differentiation of isomers and environmental analytical trace studies, spectroscopic information is necessary. The present studies report the ¹³C NMR spectra of 1‐,3‐and 6‐nitrobenzo[a]pyrene measured in CDCl₃. Complete ¹³C NMR assignments based on 2D NMR spectroscopy (HMQC and HMBC) were carried out. Further, the computation of fifty ¹³C chemical shifts of 1‐, 3‐, and 6‐nitrobenzo[a]pyrenes by using GIAO B3LYP/6‐311+G(d,p)//B3LYP/6‐31+G(d), 6‐31+G(d,p), 6‐311+G(d), 6‐311+G(d,p), 6‐311G(d,p) levels of theory was investigated. For 1‐,3‐ and 6‐NBaP the calculated chemical shifts δ_calc versus δ_expt plots of chemical shifts fall on a linear correlation line with r²> 0.90. The GIAO B3LYP/6‐311+G(d,p)//B3LYP/6‐311G(d,p) level of theory was found to yield chemical shifts in good agreement with experiment with r²> 0.90. The most expensive method (larger basis set) has provided the best agreement with the experiment. It is therefore important to continue to seek computational methods that can predict precise chemical shifts in nitrated or related compounds.

Volume

3

DOI

https://doi.org/10.1016/j.rechem.2021.100099

ISSN

2211-7156

Comments

Simulated ¹³C NMR chemical shifts were calculated using DFT method with Pople-type basis sets and correlated with experimental peaks.

Repository Citation

Onchoke, Kefa Karimu, "13C NMR Chemical Shift Assignments of Nitrated Benzo[a]pyrenes Based on Two-dimensional Techniques and DFT/GIAO Calculations" (2021). Faculty Publications. 95.
https://scholarworks.sfasu.edu/chemistry_facultypubs/95