research communications
N-[4-(methylsulfanyl)phenyl]acetamide
Hirshfeld surface analysis and computational study of 2-chloro-aDepartment of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand, bMaterials and Textile Technology, Faculty of Science and Technology, Thammasat University, Pathum Thani, 12120, Thailand, cDepartment of Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand, and dDepartment of Materials Engineering, Faculty of Engineering, Kasetsart University Bangkok, 10900, Thailand
*Correspondence e-mail: fscibnw@ku.ac.th
In the title compound, C9H10ClNOS, the amide –C(=O)NH– adopts a trans conformation with the four atoms nearly coplanar. This conformation promotes the formation of a C(4) hydrogen-bonded chain propagating along the [010] direction. The central part of the molecule, including the six-membered ring, the S and N atoms, is fairly planar (r.m.s. deviation of 0.014). The terminal methyl group and the C(=O)CH2 group are slightly deviating out-of-plane while the terminal Cl atom is almost in-plane. Hirshfeld surface analysis of the title compound suggests that the most significant contacts in the crystal are H⋯H, H⋯Cl/Cl⋯H, H⋯C/C⋯H, H⋯O/O⋯H and H⋯S/S⋯H. π–π interactions between inversion-related molecules also contribute to the crystal packing. DFT calculations have been performed to optimize the structure of the title compound using the CAM-B3LYP functional and the 6–311 G(d,p) basis set. The theoretical of the title compound was calculated using the TD–DFT method. The analysis of revealed that the π–π* electronic transition was the major contributor to the absorption peak in the electronic spectrum.
Keywords: 4-methylthioaniline; chloroacetyl chloride; hydrogen bonds; π–π interactions; crystal structure.
CCDC reference: 1987798
1. Chemical context
Methylthioanilines are a class of S- and N- et al., 2012; Martin et al., 2016; Das et al., 2017; Cross et al., 2018). Metal–methylthioaniline complexes have also been utilized in many applications including as homogeneous catalysts, organic semiconductors, antibacterial and antifungal drugs (Chen et al., 2019; Kumar et al., 2017; Mandal et al., 2018; Wang et al., 2009). In this research, we report the synthesis and the solid state structure of 2-chloro-N-[4-(methylsulfanyl)phenyl]acetamide, a methylthioaniline derivative. Hirshfeld surface analysis was used to investigate the interactions within the and DFT calculations were performed to study the frontier molecular orbitals of the title compound and also its electronic properties.
that are widely used in antimicrobial applications (Chatterjee2. Structural commentary
The ). The central part of the molecule, including the six-membered ring, the S and N atoms, is fairly planar (r.m.s. deviation of 0.0142 for the eight fitted non-hydrogen atoms). The terminal methyl group deviates from this plane, atom C9 being displaced by −0.498 (4) Å to the mean plane. On the other side of the benzene ring, the C(=O)CH2 group also deviates slightly from the central plane in the opposite direction [deviations of 0.246 (3), 0.324 (3) and 0.489 (4) Å for atoms C2, O1 and C1, respectively] while the terminal Cl atom is almost in-plane [−0.007 (3) Å] as a result of the N1—C2—C1—Cl1 torsion angle of −150.97 (18)°. The amide adopts a trans conformation with the four atoms nearly coplanar as shown by the O1—C2—N1—H1 torsion angle of −176.5 (19)°. An intramolecular C—H⋯O contact is observed (Table 1).
of the title compound contains one molecule (Fig. 13. Supramolecular features
The main feature of the crystal packing is the presence of an N—H⋯O hydrogen-bonded chain along the a-axis direction (Table 1) with graph set C(4). A view along the a axis showing the unit-cell packing is shown in Fig. 2a while the hydrogen-bonded chain is illustrated in Fig. 2b. Apart from the hydrogen-bonding interactions, π-π stacking is observed between inversion-related molecules. The distance between the ring centroids is 3.8890 (14) Å while the distance between the mean planes is 3.3922 (10) Å (slippage 1.904 Å).
4. Hirshfeld analysis
The intermolecular interactions in the crystal of the title compound were investigated by performing a Hirshfeld surface (HS) analysis (Hirshfeld, 1977; Spackman & Jayatilaka, 2009) using Crystal Explorer 17.5 (Turner et al., 2017). The HS is plotted over the dnorm range −0.5588 to 1.0138 a.u. (Fig. 3). The faint red spots on the Hirshfeld surface near atoms O1 and H1 confirm the hydrogen bonding described above. The presence of adjacent orange and blue triangular regions in the shape-index HS (Fig. 4) confirm that π–π interactions also occur in the crystal. Fig. 5 shows the full two-dimensional fingerprint plot (McKinnon et al., 2007) and those delineated into H⋯H (35.5%), H⋯Cl/Cl⋯H (19.2%), H⋯C/C⋯H (11.8%), H⋯O/O⋯H (11.6%) and H⋯S/S⋯H (9.7%) contacts. The H⋯H contacts are characterized by a single spike at de + di ≃ 2.2 Å, while the H⋯O/O⋯H contacts are viewed as a pair of spikes at de + di ≃ 1.8 Å. Two pairs of beak-shaped tips at de + di ≃ 2.8 and 3.1 Å represent H⋯Cl/Cl⋯H and H⋯S/S⋯H contacts, respectively. The H⋯C/C⋯H contacts are seen as forcep-like tips at de + di ≃ 2.7 Å. Other contacts with smaller contributions to the HS have a less significant effect on the crystal packing: C⋯Cl/Cl⋯C (2.9%), C⋯S/S⋯C (2.1%), H⋯N/N⋯H (2.1%) and C⋯C (2.8%).
5. Computational Methods
DFT calculations were carried out to optimize the structure of the title compound using the CAM-B3LYP method and the 6-311G(d,p) basis set in an ethanol solvent within the Gaussian09 program package (Frisch et al., 2010). DFT was chosen because it is a good compromise between the computational time and the description of the electronic correlation and has been found to be the best method to obtain accuracy for molecular geometry and electronic transition energies for organic molecules (Perdew et al., 2005; Niskanen et al., 2014; Arı et al., 2017; Miengmern et al., 2019). Time-dependent density functional theory (TD–DFT) (Jacquemin et al., 2009) was also used for the calculation of the electronic transitions of the title compound in conjunction with the polarized continuum model (PCM) for computation of the solvent effect (Scalmani et al., 2010). The theoretical of the optimized structure of the titled compound in ethanol solvent was obtained using the TD–DFT method. The electronic properties such as EHOMO, ELUMO, and the energy gap between HOMO and LUMO of the optimized structure were also determined and the electronic structure of the title compound was visualized in order to understand the hyperconjugative interactions and charge delocalization.
6. Computational study
The DFT structure optimization of the compound was performed starting from the X-ray geometry at the CAM-B3LYP/6-311G(d,p) level of theory in an ethanol solvent. The experimental and calculated geometrical parameters such as bond lengths and angles show good agreement although most of the calculated bond lengths are slightly longer than X-ray values (about 0.01 Å) because experimental values are for interacting molecules in the
whereas the computational method deals with an isolated molecule in the solvent phase.We used the TD-CAM-B3LYP/6-311G(d,p) method to predict the λmax) of the title compound was obtained using this method. As seen in Table 2, the strong absorption at λmax = 250 nm and the oscillator strength f = 0.7144 are due to the S0→S2 electronic transition with a wave function of two configurations [(HOMO→LUMO) and (HOMO→L+4)]. The transition from HOMO to LUMO is mainly responsible for the formation of the maximum wavelength at 250 nm (Table 3). Fig. 6 shows the shape of molecular orbitals participating in the absorption at λmax = 250 nm. The electron density of the HOMO is mainly focused on the –C=C– group in the phenyl ring, the sulfur atom, S–CH3, –NH=C and –C=O groups, whereas the LUMO is mainly focused on the =C—C= group in the phenyl ring. Therefore, the electronic transition from HOMO to LUMO mainly corresponds to the π–π* electron. The other excited states of the title compound have a very small intensity that is nearly forbidden by considerations.
of the title compound in ethanol, also considering the excited states in the calculation. The maximum absorption wavelength (
|
7. Database survey
A search of the Cambridge Structural Database (CSD version 5.41, November 2019 update; Groom et al., 2016) for the 2-chloro-N-phenylacetamide core shows that most of the structures were reported by Gowda and Co-workers, for example, the compound 2-chloro-N-phenylacetamide (I) (RIYWIG; Gowda et al., 2008a) reported in the Cc Other structures with substituent(s) on the benzene ring include 2-chloro-N-(2,3-dichlorophenyl)acetamide (II) (GISWEL; Gowda et al., 2008b) in the P21/n 2-chloro-N-(3,5-dichlorophenyl)acetamide (III) (GISWIP; Gowda et al., 2008c) also in P21/n, and 2-chloro-N-(2,4-dimethylphenyl)acetamide (IV) (YIRJAL; Gowda et al., 2008d) in P. The title compound and compounds (I)–(IV) crystallized in different space groups so it can be concluded that the substituent(s) play a vital role in the crystallization of 2-chloro-N-phenylacetamide derivatives. It is worth noting that the structures all of the above 2-chloro-N-phenylacetamide derivatives feature a C(4) hydrogen-bond chain involving the primary amide This feature was also observed in the crystal structures of 2,2-chloro-N-phenylacetamide derivatives, viz. 2,2-dichloro-N-(2,3-dimethylphenyl)acetamide (V) (space group C2/c; XISROH; Gowda et al., 2008e) and 2,2-dichloro-N-(3,5-dimethylphenyl)acetamide (VI) (P21/n; GISGUL; Gowda et al., 2008f) and the of the derivative with no substituent on the 2nd position, [N-(3-chlorophenyl)acetamide] (VII) (P212121; GISPOO; Gowda et al., 2008g). This suggests that the substituents on both the benzene ring and at the 2-position did not affect the hydrogen-bonded framework in the N-phenylacetamide crystal structures. However, the derivatives with an N,N-disubstituted acetamide moiety cannot form hydrogen bonds in the same fashion as the N-monosubstituted acetamide derivatives because of the lack of a hydrogen-bond donor on the amide nitrogen atom. The supramolecular packing of N,N-disubstituted acetamide derivatives instead features weak intermolecular C—H⋯O interactions (Zhi et al., 2011).
8. Synthesis and crystallization
The title compound was prepared by combining 4-(methylthio)aniline (5.0 g), chloroacetylchloride (4.30 mL) and triethylamine (7.50 mL) in dichloromethane (10 mL) at a controlled temperature using an ice bath. After stirring under an N2 atmosphere for 24 h, the reaction mixture was poured into water and extracted with 30 mL CH2Cl2 (3 times). The organic layer was dried with anhydrous Na2SO4. The mixture product was purified by using 9:1 CH2Cl2/EtOAc as an affording a light-brown solid, yield 42%. Light-brown crystals were grown by evaporating a solution of the title compound in a mixture of dichloromethane and hexane (1:1) at room temperature. 1H NMR (CHCl3-d; 400 MHz): δ 8.23 (1H, s, NH), 7.51 (2H, d, ArH), 7.29 (2H, d, ArH), 4.20 (2H, s, CH2), 2.50 (3H, s, SCH3). Analysis calculated: C9H10ClNOS: C, 50.11; H, 4.67; N, 6.49 Found: C, 50.44; H, 4.69; N, 6.50
9. Refinement
Crystal data, data collection and structure . All C-bound H atoms were positioned geometrically and refined using a riding model with d(C—H) = 0.95 Å and Uiso(H) = 1.2Ueq(C) for aromatic and d(C—H) = 0.98 Å, Uiso(H) = 1.5Ueq(C) for methyl H atoms. The N-bound H atom (H1) was located in a difference-Fourier map and freely refined.
details are summarized in Table 3Supporting information
CCDC reference: 1987798
https://doi.org/10.1107/S2056989020002960/zq2250sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020002960/zq2250Isup3.hkl
Data collection: APEX2 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: Olex2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2020); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2020).C9H10ClNOS | Dx = 1.454 Mg m−3 |
Mr = 215.69 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pbca | Cell parameters from 3435 reflections |
a = 9.6659 (7) Å | θ = 2.8–26.2° |
b = 14.0682 (11) Å | µ = 0.56 mm−1 |
c = 14.4869 (13) Å | T = 296 K |
V = 1970.0 (3) Å3 | Block, light brown |
Z = 8 | 0.12 × 0.10 × 0.08 mm |
F(000) = 896 |
Bruker APEXII CCD diffractometer | 1722 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.085 |
Absorption correction: multi-scan (SADABS; Bruker, 2016) | θmax = 28.3°, θmin = 2.8° |
Tmin = 0.686, Tmax = 0.746 | h = −12→12 |
21994 measured reflections | k = −18→17 |
2438 independent reflections | l = −19→17 |
Refinement on F2 | Primary atom site location: dual |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.047 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.127 | w = 1/[σ2(Fo2) + (0.051P)2 + 1.0616P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
2438 reflections | Δρmax = 0.51 e Å−3 |
123 parameters | Δρmin = −0.41 e Å−3 |
0 restraints |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.44778 (8) | 0.40070 (6) | 0.90711 (5) | 0.0685 (3) | |
S1 | 0.52668 (8) | 0.73979 (6) | 0.33195 (5) | 0.0612 (2) | |
O1 | 0.36226 (15) | 0.51663 (13) | 0.74128 (12) | 0.0498 (4) | |
N1 | 0.58369 (17) | 0.53698 (14) | 0.69210 (13) | 0.0364 (4) | |
H1 | 0.663 (3) | 0.5277 (17) | 0.7080 (18) | 0.044* | |
C3 | 0.56559 (19) | 0.58332 (15) | 0.60636 (15) | 0.0333 (4) | |
C7 | 0.6767 (2) | 0.66353 (17) | 0.47953 (16) | 0.0423 (5) | |
H7 | 0.757186 | 0.685406 | 0.451533 | 0.051* | |
C2 | 0.4871 (2) | 0.51212 (16) | 0.75445 (16) | 0.0370 (5) | |
C8 | 0.6844 (2) | 0.61629 (17) | 0.56270 (16) | 0.0394 (5) | |
H8 | 0.770224 | 0.606313 | 0.590012 | 0.047* | |
C6 | 0.5498 (2) | 0.67873 (16) | 0.43719 (16) | 0.0392 (5) | |
C4 | 0.4384 (2) | 0.59718 (17) | 0.56390 (17) | 0.0404 (5) | |
H4 | 0.357922 | 0.574908 | 0.591632 | 0.048* | |
C5 | 0.4319 (2) | 0.64410 (18) | 0.48042 (17) | 0.0440 (5) | |
H5 | 0.346335 | 0.652779 | 0.452346 | 0.053* | |
C1 | 0.5487 (2) | 0.4838 (2) | 0.84654 (17) | 0.0477 (6) | |
H1A | 0.559753 | 0.540211 | 0.884279 | 0.057* | |
H1B | 0.639951 | 0.457030 | 0.836228 | 0.057* | |
C9 | 0.6958 (3) | 0.7388 (2) | 0.28174 (19) | 0.0566 (7) | |
H9A | 0.691402 | 0.764360 | 0.220355 | 0.085* | |
H9B | 0.729678 | 0.674728 | 0.279361 | 0.085* | |
H9C | 0.757047 | 0.776878 | 0.318558 | 0.085* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0643 (5) | 0.0892 (6) | 0.0520 (4) | −0.0232 (4) | 0.0053 (3) | 0.0168 (4) |
S1 | 0.0566 (4) | 0.0723 (5) | 0.0548 (4) | 0.0139 (3) | −0.0006 (3) | 0.0206 (4) |
O1 | 0.0241 (7) | 0.0781 (12) | 0.0471 (10) | −0.0002 (7) | 0.0034 (6) | 0.0045 (9) |
N1 | 0.0227 (8) | 0.0513 (11) | 0.0353 (10) | −0.0003 (7) | 0.0005 (7) | −0.0016 (8) |
C3 | 0.0295 (9) | 0.0378 (11) | 0.0327 (11) | 0.0009 (8) | −0.0001 (8) | −0.0055 (9) |
C7 | 0.0332 (11) | 0.0514 (14) | 0.0423 (13) | −0.0058 (9) | 0.0034 (9) | 0.0001 (11) |
C2 | 0.0279 (10) | 0.0441 (12) | 0.0389 (12) | −0.0001 (8) | 0.0028 (8) | −0.0050 (10) |
C8 | 0.0274 (10) | 0.0517 (14) | 0.0391 (12) | −0.0021 (9) | −0.0020 (8) | −0.0020 (10) |
C6 | 0.0400 (12) | 0.0391 (12) | 0.0385 (12) | 0.0028 (9) | −0.0003 (9) | −0.0021 (10) |
C4 | 0.0266 (10) | 0.0506 (13) | 0.0440 (13) | −0.0006 (9) | 0.0008 (9) | −0.0011 (10) |
C5 | 0.0299 (10) | 0.0548 (14) | 0.0475 (14) | 0.0058 (9) | −0.0057 (9) | −0.0015 (11) |
C1 | 0.0348 (11) | 0.0638 (16) | 0.0444 (14) | −0.0040 (10) | 0.0040 (10) | 0.0069 (12) |
C9 | 0.0628 (16) | 0.0592 (17) | 0.0478 (15) | −0.0048 (12) | 0.0032 (12) | 0.0110 (12) |
Cl1—C1 | 1.757 (2) | C2—C1 | 1.515 (3) |
S1—C6 | 1.764 (2) | C8—H8 | 0.9300 |
S1—C9 | 1.789 (3) | C6—C5 | 1.388 (3) |
O1—C2 | 1.223 (2) | C4—H4 | 0.9300 |
N1—H1 | 0.82 (2) | C4—C5 | 1.379 (3) |
N1—C3 | 1.414 (3) | C5—H5 | 0.9300 |
N1—C2 | 1.345 (3) | C1—H1A | 0.9700 |
C3—C8 | 1.390 (3) | C1—H1B | 0.9700 |
C3—C4 | 1.388 (3) | C9—H9A | 0.9600 |
C7—H7 | 0.9300 | C9—H9B | 0.9600 |
C7—C8 | 1.378 (3) | C9—H9C | 0.9600 |
C7—C6 | 1.388 (3) | ||
C6—S1—C9 | 103.42 (12) | C3—C4—H4 | 120.1 |
C3—N1—H1 | 116.1 (19) | C5—C4—C3 | 119.7 (2) |
C2—N1—H1 | 115.1 (18) | C5—C4—H4 | 120.1 |
C2—N1—C3 | 128.60 (18) | C6—C5—H5 | 119.1 |
C8—C3—N1 | 116.83 (18) | C4—C5—C6 | 121.8 (2) |
C4—C3—N1 | 124.31 (18) | C4—C5—H5 | 119.1 |
C4—C3—C8 | 118.9 (2) | Cl1—C1—H1A | 108.9 |
C8—C7—H7 | 119.7 | Cl1—C1—H1B | 108.9 |
C8—C7—C6 | 120.6 (2) | C2—C1—Cl1 | 113.36 (16) |
C6—C7—H7 | 119.7 | C2—C1—H1A | 108.9 |
O1—C2—N1 | 124.5 (2) | C2—C1—H1B | 108.9 |
O1—C2—C1 | 122.62 (19) | H1A—C1—H1B | 107.7 |
N1—C2—C1 | 112.76 (18) | S1—C9—H9A | 109.5 |
C3—C8—H8 | 119.5 | S1—C9—H9B | 109.5 |
C7—C8—C3 | 120.9 (2) | S1—C9—H9C | 109.5 |
C7—C8—H8 | 119.5 | H9A—C9—H9B | 109.5 |
C7—C6—S1 | 124.67 (18) | H9A—C9—H9C | 109.5 |
C7—C6—C5 | 118.1 (2) | H9B—C9—H9C | 109.5 |
C5—C6—S1 | 117.19 (17) | ||
S1—C6—C5—C4 | −178.58 (19) | C2—N1—C3—C8 | 168.6 (2) |
O1—C2—C1—Cl1 | 32.9 (3) | C2—N1—C3—C4 | −11.7 (4) |
N1—C3—C8—C7 | −179.1 (2) | C8—C3—C4—C5 | −0.8 (3) |
N1—C3—C4—C5 | 179.4 (2) | C8—C7—C6—S1 | 178.92 (18) |
N1—C2—C1—Cl1 | −150.97 (18) | C8—C7—C6—C5 | −0.7 (4) |
C3—N1—C2—O1 | 8.9 (4) | C6—C7—C8—C3 | −0.4 (4) |
C3—N1—C2—C1 | −167.2 (2) | C4—C3—C8—C7 | 1.2 (3) |
C3—C4—C5—C6 | −0.3 (4) | C9—S1—C6—C7 | 18.0 (2) |
C7—C6—C5—C4 | 1.1 (4) | C9—S1—C6—C5 | −162.3 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.82 (2) | 2.06 (3) | 2.875 (2) | 174 (3) |
C1—H1B···O1i | 0.97 | 2.57 | 3.319 (3) | 135 |
C4—H4···O1 | 0.93 | 2.32 | 2.903 (3) | 121 |
Symmetry code: (i) x+1/2, y, −z+3/2. |
Excited states | Excitation energy | Configurations composition | ||
eV | nm | f | ||
S0→S1 | 4.80 | 258 | 0.0354 | HOMO→L+1 (84%) |
S0→S2 | 4.95 | 250 | 0.7144 | HOMO→LUMO (91%) |
S0→S3 | 5.55 | 224 | 0.0000 | HOMO→L+3 (81%) |
S0→S4 | 5.63 | 220 | 0.0005 | H-3→LUMO (69%) |
S0→S5 | 6.35 | 195 | 0.1378 | H-1→LUMO (59%) |
Acknowledgements
The authors thank the Kasetsart University Research and Development Institute, the Center of Excellence for Innovation in Chemistry (PERCH–CIC), the Ministry of Higher Education, Science, Research and Innovation, and the Department of Chemistry, Kasetsart University for financial support.
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