Data on GC/MS elution profile, 1H and 13C NMR spectra of 1-, 3-, and 6-Nitrobenzo[a]pyrenes

The data presented in this article is related to the research article entitled, “13C NMR Chemical Shift Assignments of Nitrated Benzo[a]pyrenes based on Two-dimensional Techniques and DFT/GIAO Calculations”, Kefa K. Onchoke, J. Chem. Sci. (2020) [1]. The NMR spectral profiles of nitrated benzo[a]pyrenes is presented. Further, the article describes elution profiles of 1-, 3- and 6-NBaP, the acquisition of 1H and 13C NMR data and the J-Coupling constants (which are useful for the assignment of peaks via 2D HMQC and HMBC techniques). The data presented is useful for developing structure-activity relationships for other nitrated polycyclic aromatic hydrocarbons (NPAHs).


1
H and 13 C NMR J-coupling constants Elution profile GC/MS 1-NBaP 3-NBaP 6-NBaP a b s t r a c t The data presented in this article is related to the research article entitled, " 13 C NMR Chemical Shift Assignments of Nitrated Benzo [a]pyrenes based on Two-dimensional Techniques and DFT/GIAO Calculations", Kefa K. Onchoke, J. Chem. Sci. (2020) [1]. The NMR spectral profiles of nitrated benzo[a]pyrenes is presented. Further, the article describes elution profiles of 1-, 3-and 6-NBaP, the acquisition of 1 H and 13 C NMR data and the J-Coupling constants (which are useful for the assignment of peaks via 2D HMQC and HMBC techniques). The data presented is useful for developing structure-activity relationships for other nitrated polycyclic aromatic hydrocarbons (NPAHs).

Data
The dataset contains raw TLC and GC elution profiles (Figs. 1e3) and the MS fragmentation patterns (Fig. 4) of benzo[a]pyrene and its mononitrated derivatives (BaP, 1-, 3-, and 6-NBaP, Scheme 1). In addition, the 1 H and 13 C NMR data of BaP, 1-, 3-, and 6-NBaP are presented in Figs. 5e11, respectively. The actual raw data files are included in this article.
The synthesis of 1-, 3-, and 6-NBaP and 1 H acquisition is first presented prior to 13 C NMR spectra (Figs. 5e11). Further information on the 1 H chemical shifts and J-coupling constants of 1-, 3-, and 6nitrobenzo[a]pyrene acquired in 500.1 MHz is presented in Table 1.

Experimental design, materials, and methods
The experimental methods and procedures that allowed the data here presented are described in Ref. [1]. Here, only the protocol for NMR acquisition for 1 H and 13 C NMR are provided usually omitted in research articles due to the words limit.

GC/MS analysis
Benzo[a]pyrene and mononitro-BaPs were analyzed by Finnigan Ultra Trace GC-Mass DSQ spectrometer (or Electron impact mass, 70 ev MASPEC II system) in the positive ion chemical ionization mode. The analytical columns were 15-m and/or 30-m X 0.25-mm i. d. TR-5MS (Thermo Electron Corp., Specifications Table   Subject area Environmental Chemistry More specific subject area Nitrated polycyclic aromatic compounds Type of data Value of the Data The data provides important information for identification of nitrated benzo[a]pyrenes (BaP) derivatives in environmental samples [6]. The nitrated benzo[a]pyrenes derivatives are ubiquitous in environmental matrices such as soils, wastewater samples, drinking water resources, and air particulates. The chromatographic elution profiles are important for identification and distinguishing of nitrated BaPs. This data can also be used for rationalizing structure-mutagenicity relationships in toxicological studies. The data serves as a benchmark for other researchers analyzing mononitrated benzo[a]pyrene isomers generated from high temperature emissions. The 13 C NMR spectra is useful for referencing and identification of NPAHs prevalent in biosolids/wastewater sludge [7].
CA) and XTI-5 (0.25 mm id, 0.25 mm df, Reseek Corp., PA) fused silica capillary columns containing a 5% phenyl polysilylphenylenesiloxane phase with a 0.25 mm film thickness. The initial oven temperature was held at 40 C for 2 min, then increased at 20 C/min to 280 C and held for 10 min. The carrier gas, helium, was held at a constant flow of 1 mL min À1 . All injections were 1.0 mL on column. The transfer line was maintained at 300 C. A splitless mode of effluent from the analytical column was let into the mass ion source. For all GC/MS analyses, the total ion chromatograms (Figs. 2e3) and selected ion monitoring (SIM) was used for assessing fragmentation patterns of the ions of interest (Fig. 4aed). The molecular ion peak for BaP m/z 251 (M þ ) and nitro-BaPs m/z 297 (1-, 3-, and 6-NBaP, M þ ) (Fig. 4) were monitored.

1 H NMR assignments
The 1 H NMR spectra of BaP, 1-, 3-and 6-NBaP have been assigned previously in CDCl 3 in acetone-d 6 and DMSO [3,8e10]. Of relevance in this article are the 13 C NMR peaks.
Figs. 5e7 depict the 1 H NMR spectra of BaP, 1-, 3-, and 6-NBaP, respectively. The BaP singlet peak due to H-6 occurs at d z 8.53 ppm. The 1 H resonance peaks due to H-6 were observed at d values 8.69 and 8.64 p.m. for 1-, and 3-NBaP, respectively ( Fig. 6A and B). In contrast, the characteristic 1 H NMR spectra of 6-NBaP (shown in Fig. 7) lacks a singlet resonance peak at d z 8.53e9.00 ppm. The observed 1 H absorption peak shifts are comparable to assignments by Johansen et al. [10].  Fig. 6A) spans 7.8e9.30 ppm and reveals groups of atoms. The singlet peak at 8.69 ppm is due to H-6 whilst the multiplet peaks at 7.97e7.94 (with a J- coupling constant of 16.67 Hz) and 7.90e7.87 ppm were clearly the peaks due to H8 and H9. At lower sample concentrations the H4 doublet peaks (8.01e7.99, 9.15 Hz) were resolved as triplets exhibiting long range interactions. At higher concentrations, the proton signals due to H4 overlap with those of H9 at 7.93e9.91 ppm. Because of the neighboring nitro group, the H12 is clearly deshielded to

1 H NMR spectra of 3-Nitrobenzo(a)pyrene
The 1 H NMR spectrum (500.13 MHz, CDCl 3 , Fig. 6B) spans 7.85e9.19 ppm and reveals groups of atoms as follows. The doublet peaks at 9.19e9.18 and 9.06e9.05 ppm are assigned to H11 and H10, respectively. The singlet peak at 8.64 ppm must be due to H6 whilst the multiplet peaks at 7.95e7.92 and 7.88e7.85 ppm are due to H9 and H8, respectively. The proton spectrum at the H8 and H9 are clearly evident by the triplet splits. The proton signals due to H4, and H3 occur at 8.73e8.72 and 8.59e8.57 ppm, respectively. Because of the nitro group's electron withdrawing ability, the H12 is deshielded to 8.35e8.34 ppm. The rest of the peaks are assigned from and compared to literature [10] as follows: H1 (d, 8 H2 (d, 8.22e8.20, 8.62 Hz). The difference between 1-, and 3-NBaP, is particularly evident with H4, and the protons H2 and H5. 1-NBaP shows protons H2 and H5 occurring at a higher field compared to those in 3-NBaP. This is attributed to the extent of electronic interaction between the aromatic orbitals of the nitro group and those of the nitro group. The peri protons at H-2 and H-5 (in each 1-, and 3-NBaP) will greatly be shielded or deshielded.

1 H NMR spectra of 6-Nitrobenzo(a)pyrene
The 1 H NMR spectrum of 6-NBaP (depicted in Fig. 7) spans 7.90e9.11 ppm. Evidently, the absence of the singlet peak between 8.50 and 9.05 ppm, due to H6 in BaP, is strongly indicative of 6-NBaP. The     . The difference between 6-NBaP and 1-, and 3-NBaP is particularly evident at the H4, and the protons H2 and H5. The triplet chemical shifts due to H2 can easily be assigned vis-a-vis the H5 doublet peaks.
2.2.15. 13 C NMR assignments from HMQC/HMBC/Theory experiments While one study reports 13 C NMR assignments of 1-, and 3-NBaP in DMSO [9] none is available for 6-NBaP. The current study assigned 13 C chemical shifts of three mononitrated benzo(a)pyrenes in CDCl 3 via heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple-bond connectivity (HMBC) methods (ref # [11]). HMQC was used to assign chemical shifts based on direct C/H connectivity.
The proton-decoupled 13 C NMR (with a Waltz decoupling routine, typically more than 10, 000 scans, 125.74 MHz, CDCl 3 ) spectra corresponding to BaP, 1-, 3-, and 6-NBaP are shown in Figs. 8e11, respectively. More than 2 mg of sample were dissolved in~1 mL of CDCl 3 (99.85 atom % D). All spectra were recorded at 298 K in a 5 mm probe. In all cases HMBC experiments were optimized to detect aromatic couplings of~8 Hz. HMBC spectra were recorded with a 500.13 MHz spectrometer using states TPP1 to achieve phase sensitivity. Two hundred and fifty-six t 1 experiments of 1280 real data points (120 scans) were recorded with a relaxation delay of 0.8 s.   Fig. 11. 13 C NMR spectra of 6-NBaP, Data acquired in CDCl 3 (No calibration made, 10000 scans, Data presented are acquired).