Scheme 1. Synthesis of the title compound (a = ethanol/heat).
1 13
The yield was 65%. NMR spectra ( H and C) were acquired in DMSO using a Bruker AMX 300 M Hz
1
spectrometer with tetramethylsilane (TMS) as the internal standard for H.
1
H NMR (DMSO-d ), δ, ppm: 2.10 s (3H, CH –Ar), 2.23 s (2H, –CH –CO), 3.10 s (6H, (CH ) –N–), 3.33 s (2H,
6 3 2 3 2
–CH –N–), 7.09 d (2H, J 9.0 Hz), 7.63 d (2H, J 7.0 Hz).
2
13
C NMR (DMSO-d ), δ, ppm: 21.26 (CH –Ar), 33.02 (–CH –CO), 42.12 ((CH ) N–), 51.78 (–CH CN–), 128.17-
6 3 2 3 2 2
144.23 (Aromatic carbons), 196.27 (Ar–CO).
–1
ATR-FTIR (cm ): 1673, melting point: 155-156 °C.
Single crystal X-ray diffraction analysis. The data were collected using a Bruker KAPPA APEX II single crystal
X-ray diffractometer with a 4-circle Kappa goniometer and a sensitive CCD detector. The instrument used a molybdenum
fine focus sealed X-ray tube as an X-ray source and an Oxford Cryostream 700 system for the sample temperature control.
Bruker′s APEX2 software [8] was used for the instrument control. Colourless crystals of compound I: chemical formula
C H NOCl, M = 227.72, monoclinic, a = 14.5694(10) Å, b = 6.1455(4) Å, c = 13.8072(11) Å, α = 90°, β = 90.232(3)°,
12 18
3
γ = 90°, V = 1236.24(15) Å , space group P21/c (No 14), Z = 4, d = 1.224 g/cm , μ = 0.285 mm . Intensities of 23020
3
–1
calc
reflections were measured in the angle range (2.8 ≤ θ ≤ 28.3°) by ϕ- and ω-scanning using a single crystal with the
dimensions of 0.30×0.56×0.61 mm. After completing the average intensities of equivalent reflections the working array of the
2
2
reflections measured contained 3079 independent reflections, including 2692 with F > 2σ(F ). The structure was solved
using SHELXT-2014 [9] and refined by least square procedures using SHELXL-2016 [10] with SHELXLE [11] as
a graphical interface. Data were recorded for absorption effects using the numerical method implemented in SADABS [8].
The final values of the divergence factors were as follows: R = 0.0300, R = 0.0847; GOOF = 1.06 for the observed
1
w
reflections, and R = 0.0356, R = 0.0889 for all reflections. After the refinement completion the maximum and minimum
1 w
3
3
values of the different electron density were as follows: ρ(max) 0.29 e/Å and ρ(min) –0.18 e/Å .
The molecular structure and a view along the b axis of the crystal packing of the title compound are presented in
Fig. 1a, b respectively. The bond lengths and angles fall within normal ranges [12] and are comparable with those reported in
similar compounds [13].
The C–N bond lengths are in the range 1.4864-1.4936 Å; these values are close to the literature value for the single
3
bond length (1.48 Å). The C2–C3–C4 angle is 117.97(10)° for 1, respectively, determined by the sp hybridization state of
the C3 atom. The C5–N1/C3–C4 torsion angle is 178.80(10)° while the torsion angle of C6–N1/C3–C4 is 57.05 (12)°. This
observation may be an indicator that the ligand is not planar. Also, there is one π…π ring interaction with a length of
3.8463(7) Å between the adjacent phenyl rings. No intermolecular hydrogen bond is observed from the crystal packing
except the intramolecular hydrogen bonding N1–H1…Cl1 with a length of 2.0959(15) Å in the hydrochloride part of the
ligand. Also, the ligand appears as a quaternary salt as seen from the crystal packing of the compound [14, 15].
The present paper describes the XRD analysis of the structure of novel Mannich base of 4-methylacetophenone that
is a potential candidate for biological studies and as a ligand in the synthesis of coordination compounds. The results of
studies on its various applications will be discussed in a further article. CCDC 1556977 contains the supplementary
crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallographic Data
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