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Whole-mol­ecule disorder of the Schiff base compound 4-chloro-N-(4-nitro­benzyl­­idene)aniline: crystal structure and Hirshfeld surface analysis

aDepartment of Physics, Ethiraj College for Women, Chennai - 600 008, Tamilnadu, India, bCrystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli - 620 024, India, cPG and Research Department of Physics, Srimad Andavan Arts and Science College, Tiruchirappalli - 620 005, India, dLight and Matter Physics Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanaga, Bangalore - 560 080, India, eDepartment of Bio-Medical Engineering, Aarupadai Veedu Institute of Technology, Vinayaga Mission's Research Foundation, Vinayaga Nagar, Paiyanoor, 603 104, Tamil Nadu, India, and fInstitute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
*Correspondence e-mail: leelabeena@gmail.com, helen.stoeckli-evans@unine.ch

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 10 January 2020; accepted 17 February 2020; online 18 February 2020)

In the crystal of the title Schiff base compound, C13H9ClN2O2, [CNBA; systematic name: (E)-N-(4-chloro­phen­yl)-1-(4-nitro­phen­yl)methanimine], the CNBA mol­ecule shows whole-mol­ecule disorder (occupancy ratio 0.65:0.35), with the disorder components related by a twofold rotation about the shorter axis of the mol­ecule. The aromatic rings are inclined to each other by 39.3 (5)° in the major component and by 35.7 (9)° in the minor component. In the crystal, C—H⋯O hydrogen bonds predominate in linking the major components, while weak C—H⋯Cl inter­actions predominate in linking the minor components. The result is the formation of corrugated layers lying parallel to the ac plane. The crystal packing was analysed using Hirshfeld surface analysis and compared with related structures.

1. Chemical context

A number of benzyl­ideneaniline derivatives crystallize in non-centrosymmetric space groups and are therefore of inter­est for their non-linear optical properties (Bar & Bernstein, 1977[Bar, I. & Bernstein, J. (1977). Acta Cryst. B33, 1738-1744.]; Batra et al., 2004[Batra, A. K., Gebre, T., Bhat, K., Aggarwal, M. D., Peterson, B., Sarkisov, S. & Lal, R. B. (2004). Proc. SPIE, 5351, 57-68.]). In 1970, Bürgi & Dunitz (1970[Bürgi, H.-B. & Dunitz, J. (1970). Helv. Chim. Acta, 53, 1747-1764.]) analysed a number of N-benzyl­anilines and found that they were twisted about the N=C bond unlike trans-stilbenes (see for example: Behrnd et al., 2010[Behrnd, N.-R., Labat, G., Venugopalan, P., Hulliger, J. & Bürgi, H.-B. (2010). Cryst. Growth Des. 10, 52-59.]; De Borger et al., 2005[De Borger, R., Vande Velde, C. M. L. & Blockhuys, F. (2005). Acta Cryst. E61, o819-o821.]) or trans-azo­benzenes (see for example: Huang et al., 2002[Huang, X.-J., Kuhn, G. H., Nesterov, V. N., Averkiev, B. B., Penn, B., Antipin, M. Yu. & Timofeeva, T. V. (2002). Acta Cryst. C58, o624-o628.]; Bushuyev et al., 2016[Bushuyev, O. S., Friščić, T. & Barrett, C. J. (2016). Cryst. Growth Des. 16, 541-545.]), which are almost planar.

[Scheme 1]

Benzyl­ideneaniline derivatives are known to exhibit disorder and Bernstein and collaborators (Bar & Bernstein, 1983[Bar, I. & Bernstein, J. (1983). Acta Cryst. B39, 266-272.]; Kluge et al., 2003[Kluge, S., Dohnke, I., Budde, F. & Hulliger, J. (2003). CrystEngComm, 5, 67-69.]) have defined the different types of orientational disorder of these compounds, where the mol­ecules may be oriented in different ways but in the two or more dispositions each atom is essentially superimposed on another at any one crystallographic site. Static disorder around the C=N bond is also responsible for the apparent shortening of the C=N bond at room temperature (Bar & Bernstein, 1984[Bar, I. & Bernstein, J. (1984). J. Phys. Chem. 88, 243-248.]). This phenomenon has also been studied by Harada et al. (2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]), who, by means of a variable temperature study, concluded that the shortening depends on temperature and is due to a torsional vibration of the C–phenyl and N–phenyl bonds in the crystals.

The crystal structures of a number of disordered benzyl­ideneaniline compounds have been reported on and various forms of the disorder have been analysed (Bar & Bernstein, 1977[Bar, I. & Bernstein, J. (1977). Acta Cryst. B33, 1738-1744.], 1984[Bar, I. & Bernstein, J. (1984). J. Phys. Chem. 88, 243-248.]; Harada et al., 2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.],b[Harada, J., Harakawa, M. & Ogawa, K. (2004b). Acta Cryst. B60, 589-597.]). The disorder appears to fall into three categories (Fig. 1[link]): D1 – twofold rotation about the longer axis of the mol­ecule, D2 – the mol­ecule is located about a crystallographic center of symmetry, and D3 – twofold rotation about the shorter axis of the mol­ecule.

[Figure 1]
Figure 1
Disorder types in benzyl­ideneanilines.

Type D1 disorder has been observed for one of the two independent mol­ecules in the crystal of N-(4-nitro­benzyl­idene)aniline at 300 and 200 K, but the disorder is not present at 90 K (Harada et al., 2004b[Harada, J., Harakawa, M. & Ogawa, K. (2004b). Acta Cryst. B60, 589-597.]). Orientational disorder about a center of symmetry (type D2) was found in N-(p-chloro­benzyl­idene)-p-chloro­aniline (Bar & Bernstein, 1982[Bar, I. & Bernstein, J. (1982). Acta Cryst. B38, 121-125.]; Bernstein & Schmidt, 1972[Bernstein, J. & Schmidt, G. M. (1972). J. Chem. Soc. Perkin Trans. 2, pp. 951-955.]). Type D3 disorder has been observed for N-benzyl­ideneaniline (Bernstein & Izak, 1976[Bernstein, J. & Izak, I. (1976). J. Chem. Soc. Perkin Trans. 2, pp. 429-434.]; Harada et al., 2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]) and for 4-methyl-4′-meth­oxy­benzyl­ideneaniline (Harada et al., 2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]).

Three forms of p-methyl-N-(p-methyl­benzyl­idene)aniline (Bernstein, Bar & Christensen, 1976[Bernstein, J., Bar, I. & Christensen, A. (1976). Acta Cryst. B32, 1609-1611.]; Bar & Bernstein, 1982[Bar, I. & Bernstein, J. (1982). Acta Cryst. B38, 121-125.]; Bar & Bernstein, 1977[Bar, I. & Bernstein, J. (1977). Acta Cryst. B33, 1738-1744.]) have been shown to exist: Form I (Bar & Bernstein, 1982[Bar, I. & Bernstein, J. (1982). Acta Cryst. B38, 121-125.]), crystallizes in space group P21/c and the C=N bond of the mol­ecule is located about a center of symmetry, hence the mol­ecule has type D2 disorder; form II (Bar & Bernstein, 1977[Bar, I. & Bernstein, J. (1977). Acta Cryst. B33, 1738-1744.]) crystallizes in space group P21 and the mol­ecule is not disordered; form III (Bar & Bernstein, 1977[Bar, I. & Bernstein, J. (1977). Acta Cryst. B33, 1738-1744.]; Harada et al., 2004b[Harada, J., Harakawa, M. & Ogawa, K. (2004b). Acta Cryst. B60, 589-597.]), has a fourfold disorder with the mol­ecule being located about a center of symmetry and has a twofold rotation about the longer axis of the mol­ecule (D1 + D2).

In the past few years some benzyl­ideneaniline compounds have been synthesized using p-nitro­benzaldehyde as one of the reactants; for example, 4-nitro-benzyl­ideneaniline (HNBA; Harada et al., 2004b[Harada, J., Harakawa, M. & Ogawa, K. (2004b). Acta Cryst. B60, 589-597.]), 4-fluoro-4′-nitro-benzyl­idene­aniline (FNBA; Subashini et al., 2013b[Subashini, A., Ramamurthi, K. & Stoeckli-Evans, H. (2013b). Private Communication (refcode CCDC 940430). CCDC, Cambridge, England.]), 4-bromo-4′-nitro-benzyl­ideneaniline (BNBA; Subashini et al., 2013a[Subashini, A., Leela, S., Ramamurthi, K., Arakcheeva, A., Stoeckli-Evans, H. V., Petříček, V., Chapuis, G., Pattison, P. & Reji, P. (2013a). CrystEngComm, 15, 2474-2481.]) and 4-hy­droxy-4′-nitro-benzyl­ideneaniline [systematic name: 4-[(E)-(4-nitro­benzyl­idene)amino]­phenol] (HONBA; Atioğlu et al., 2015[Atioğlu, Z., Akkurt, M., Jarrahpour, A., Ebrahimi, E. & Büyükgüngör, O. (2015). Acta Cryst. E71, o113-o114.]).

To continue the series of 4-halogen species, we report herein on the crystal structure of 4-chloro-4′-nitro-benzyl­ideneaniline (CNBA). It was previously synthesized by Batra et al. (2004[Batra, A. K., Gebre, T., Bhat, K., Aggarwal, M. D., Peterson, B., Sarkisov, S. & Lal, R. B. (2004). Proc. SPIE, 5351, 57-68.]), who found that the crystals they obtained showed good second harmonic generation (SHG) of 1.064 micron wavelength radiation. The crystal structure analysis carried out for CNBA in this work shows that it crystallizes in the centrosymmetric space group P21/c, and that the mol­ecule has positional disorder (type D3), hence no SHG properties are expected for this particular sample. It is inter­esting to note that the structure of 4-bromo-4′-nitro­benzyl­ideneaniline (BNBA) crystallizes in a non-centrosymmetric space group (A2), while the title compound and 4-fluoro-4′-nitro­benzyl­idene aniline (FNBA; Subashini et al., 2013b[Subashini, A., Ramamurthi, K. & Stoeckli-Evans, H. (2013b). Private Communication (refcode CCDC 940430). CCDC, Cambridge, England.]) both crystallize in space group P21/c.

2. Structural commentary

The mol­ecular structure of CNBA is shown in Fig. 2[link]. It crystallizes in the centrosymmetric monoclinic space group P21/c, and is disordered with a twofold rotation about the shorter axis of the mol­ecule – type D3. The twofold axis almost bis­ects the central C=N bond, so that the two component mol­ecules are superimposed head-to-tail, as shown clearly in a difference-Fourier map (Fig. 3[link]). They have an occupancy ratio that, after initial refinement, was fixed at 0.649:0.351. As mentioned above, this type of disorder (D3) has been observed previously for related phases.

[Figure 2]
Figure 2
Mol­ecular structure of CNBA, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level. The major component is shown with solids bonds, while the minor component is shown with dashed bonds.
[Figure 3]
Figure 3
A difference electron-density map showing the density peaks related to the minor disordered component.

The configuration about the C=N bond is E in both components. The dihedral angle between the benzene rings of the major component CNBA_1 (C1–C6 and C8–C13) is 38.6 (2)°, and that between rings C21–C26 and C28–C33 of the minor component (CNBA_2) is 36.5 (4)°. In CNBA_1 the N1=C7 bond length is 1.291 (6) Å, while for CNBA_2 the equivalent N21=C27 bond length is 1.234 (12) Å. The NO2 group, N2/O1/O2, in CNBA_1 is inclined to benzene ring C8–C13 by 2.2 (7)°, and atom Cl1 is displaced by 0.016 (3) Å from benzene ring C1–C6. In component CNBA_2, the NO2 group, N22/O21/O22, is inclined to benzene ring C28–C33 by 9.0 (15)°, while atom Cl2 lies in the plane of the benzene ring C21–C26 [deviation 0.002 (5) Å].

3. Supra­molecular features

A view along the a axis of the crystal packing of CNBA is presented in Fig. 4[link], and details of the hydrogen bonding are given in Table 1[link]. The crystal packing of the individual components, CBNA_1 and CBNA_2, are given in Fig. 5[link]a and 5b, respectively. In Fig. 5[link]a it can be seen that the mol­ecular packing for CNBA_1 is influenced by two C—H⋯O inter­actions: namely, C5—H5⋯O2 and C13—H13⋯O1. The first of these links the mol­ecules into C(11) chains and the second generates C(6) chains. In Fig. 5[link]b, it can be seen that for CNBA_2 the mol­ecular packing features weak C—H⋯Cl inter­actions (Table 1[link]). As a result of these inter­actions, corrugated layers are formed, lying parallel to the ac plane.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C5—H5⋯O2i 0.95 2.55 3.489 (7) 172
C13—H13⋯O1ii 0.95 2.57 3.426 (5) 151
C27—H27⋯Cl2i 0.95 2.78 3.661 (11) 155
Symmetry codes: (i) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (ii) [x+1, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].
[Figure 4]
Figure 4
A view along the a axis of the crystal packing of CNBA. The hydrogen bonds (see Table 1[link]) are shown as dashed lines.
[Figure 5]
Figure 5
A view along the a axis of the crystal packing of (a) the major disorder component and (b) the minor component. The hydrogen bonds (see Table 1[link]) are shown as dashed lines.

4. Database survey

A search of the Cambridge Structural Database (Version 5.41, last update November 2019; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for N,1-di­phenyl­methanimines gave 73 hits for 63 compounds, while a search for 1-(4-nitro­phen­yl)-N-phenyl­methanimines gave 25 hits for six compounds. In these searches a number of compounds have multiple reports, or have been studied at different temperatures, or concern polymorphs.

The most relevant compounds that concern us here include those reported above in §1 (Chemical context), viz. N-(4-nitro­benzyl­idene)aniline (CSD refcodes QQQAIY01, QQQAIY02, QQQAIY03: Harada et al., 2004b[Harada, J., Harakawa, M. & Ogawa, K. (2004b). Acta Cryst. B60, 589-597.]), the 4-fluoro derivative (MIMDUJ: Subashini et al., 2013b[Subashini, A., Ramamurthi, K. & Stoeckli-Evans, H. (2013b). Private Communication (refcode CCDC 940430). CCDC, Cambridge, England.]), the 4-bromo derivative (FIBXIZ01: Subashini et al., 2013a[Subashini, A., Leela, S., Ramamurthi, K., Arakcheeva, A., Stoeckli-Evans, H. V., Petříček, V., Chapuis, G., Pattison, P. & Reji, P. (2013a). CrystEngComm, 15, 2474-2481.]), the 4-methyl derivative (NMBYAN: Filipenko et al., 1976[Filipenko, O. S., Ponomarev, V. I. & L.O.Atovmyan, L. O. (1976). Dokl. Akad. Nauk. SSSR, 229, 1113.]; NMBYAN22: Filipenko et al., 1977[Filipenko, O. S., Shigorin, V. D., Ponomarev, V. I., Atovmyan, L. O., Safina, Z. Sh. & Tarnopol'skii, B. L. (1977). Kristallografiya, 22, 534-.]; NMBYAN01: Cole et al., 2001[Cole, J. M., Howard, J. A. K. & McIntyre, G. J. (2001). Acta Cryst. B57, 410-414.]; NMBYAN25, NMBYAN26: Harada et al., 2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]), the 4-meth­oxy benzyl­idene derivative (NMBZYA01, NMBZYA02: Harada et al., 2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]) and the 4-hy­droxy derivative (WOTQED: Atioğlu et al., 2015[Atioğlu, Z., Akkurt, M., Jarrahpour, A., Ebrahimi, E. & Büyükgüngör, O. (2015). Acta Cryst. E71, o113-o114.]).

For N-(4-nitro­benzyl­idene)aniline measured at 300 K (QQQAIY01), one of the two independent mol­ecules in the asymmetric unit has type D1 disorder. At 200 K (QQQAIY02) a difference-Fourier map indicated only a few weak residual density peaks corresponding to the minor component, while at 90 K (QQQAIY03) no disorder was observed. For the 4-fluoro derivative measured at 173 K (MIMDUJ) no disorder was observed. For the 4-bromo derivative (FIBXIZ01), the crystals were incommensurate and twinned and the structure was refined in space group A2. A triclinic polymorph of the 4-methyl derivative (NMBYAN) with two independent mol­ecules in the asymmetric unit was reported on by Filipenko et al. (1976[Filipenko, O. S., Ponomarev, V. I. & L.O.Atovmyan, L. O. (1976). Dokl. Akad. Nauk. SSSR, 229, 1113.]). A monoclinic polymorph, with one mol­ecule in the asymmetric unit, was reported on first by Filipenko et al. (1976[Filipenko, O. S., Ponomarev, V. I. & L.O.Atovmyan, L. O. (1976). Dokl. Akad. Nauk. SSSR, 229, 1113.]) for NMBYAN22, and later a neutron diffraction study at 20 K was carried out by Cole et al. (2001[Cole, J. M., Howard, J. A. K. & McIntyre, G. J. (2001). Acta Cryst. B57, 410-414.]) for NMBYAN01. The triclinic polymorph was also studied by Harada et al. (2004a[Harada, J., Harakawa, M. & Ogawa, K. (2004a). Acta Cryst. B60, 578-588.]), at 300 K (NMBYAN25) and at 90 K (NMBYAN26) and showed only disorder of the methyl hydrogen atoms at both temperatures. The 4-meth­oxy benzyl­idene derivative, measured at 300 K (NMBZYA01) and 90 K (NMBZYA02), showed no disorder at either temperature. Finally, the 4-hy­droxy derivative, WOTQED, crystallizes with four independent mol­ecules in the asymmetric unit, and one of the mol­ecules has type D1 disorder.

The N=C bond lengths vary from as short as ca.1.187 Å, in one of the four independent mol­ecules of WOTQED, to ca 1.281 Å in NMBZYA02. In the title compound, the N1=C7 bond length in the major component is 1.291 (6) Å, while for the minor component the N21=C27 bond length is 1.234 (12) Å. In the above-mentioned compounds, the benzene rings are inclined to each other by dihedral angles varying from ca 2.24° in one of the independent mol­ecules of WOTQED to ca 55.76° in one of the two independent mol­ecules in NMBYAN26; thus the dihedral angles for the disorder components of the title compound fall roughly in the middle of this range.

5. Hirshfeld surface analysis and two-dimensional fingerprint plots

The Hirshfeld surface analysis (Spackman & Jayatilaka, 2009[Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19-32.]) and the associated two-dimensional fingerprint plots (McKinnon et al., 2007[McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. pp. 3814-3816.]) were performed with CrystalExplorer17 (Turner et al., 2017[Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). CrystalExplorer17. University of Western Australia. http://hirshfeldsurface.net]) following the protocol of Tiekink and collaborators (Tan et al., 2019[Tan, S. L., Jotani, M. M. & Tiekink, E. R. T. (2019). Acta Cryst. E75, 308-318.]).

The Hirshfeld surface of CNBA mapped over dnorm is given in Fig. 6[link]a, where short inter­atomic contacts are indicated by the red spots. The Hirshfeld surfaces of the individual components, CNBA_1 and CNBA_2, mapped over dnorm are given in Fig. 6[link]b and 6c, respectively.

[Figure 6]
Figure 6
(a) The Hirshfeld surface of CNBA mapped over dnorm, in the colour range −0.15 to 1.13 a.u., (b) the Hirshfeld surface of CNBA_1 mapped over dnorm, in the colour range −0.14 to 1.32 a.u., (c) the Hirshfeld surface of CNBA_2 mapped over dnorm, in the colour range −0.15 to 1.29 a.u.

The full two-dimensional fingerprint plots for CNBA and for the individual components, CNBA_1 and CNBA_2, are given in Fig. 7[link]a, 7b and 7c, respectively. The relative percentage contributions of close contacts to the Hirshfeld surface for CNBA and for the individual components are compared in Table 2[link]. For CNBA the principal inter­molecular inter­actions are delineated into O⋯H/H⋯O at 37.3%, H⋯H at 25.5%, C⋯H/H⋯C and C⋯C both at 10.2%, followed by Cl⋯H/H⋯Cl and N⋯H/H⋯N contacts both at 3.5%. For CNBA_1 and CMBA_2 the order is somewhat different with H⋯H contributions being superior or almost equal to the contributions of the O⋯H/H⋯O contacts, the latter contributions being 22.3 and 24.4%, respectively, compared to 37.3% for CNBA. In contrast, the Cl⋯H/H⋯Cl contacts contribute 14.5% and 14.8% for CNBA_1 and CNBA_2, respectively, compared to only 3.5% for CNBA. This situation reflects the details of the hydrogen bonding in the crystal structure (see Fig. 5[link]a and 5b, and Table 1[link]).

Table 2
Percentage contributions of inter­atomic contacts to the Hirshfeld surface for CNBA, and for the individual disordered components, CNBA_1 and CNBA_2

Contact Percentage contributions
  CNBA CNBA_1 CNBA_2
H⋯H 25.5 26.2 24.7
O⋯H/H⋯O 37.3 22.3 24.4
Cl⋯H/H⋯Cl 3.5 14.5 14.8
C⋯H/H⋯C 10.2 12.0 12.6
C⋯C 10.2 11.0 11.1
N⋯H/H⋯N 3.5 4.2 3.4
C⋯N 3.2 2.4 2.4
O⋯O 2.3 0.3 0.6
C⋯O 1.6 1.9 0.7
O⋯Cl 0.8 2.0 1.4
C⋯Cl 0.4 1.0 1.9
[Figure 7]
Figure 7
(a) The full two-dimensional fingerprint plot for CNBA, and fingerprint plots delineated into H⋯H, O⋯H/H⋯O, C⋯H/H⋯C, C⋯C and Cl⋯H/H⋯Cl contacts, (b) the full two-dimensional fingerprint plot for CNBA_1, and fingerprint plots delineated into H⋯H, O⋯H/H⋯O, C⋯H/H⋯C, C⋯C and Cl⋯H/H⋯Cl contacts, (c) the full two-dimensional fingerprint plot for CNBA_2, and fingerprint plots delineated into H⋯H, O⋯H/H⋯O, C⋯H/H⋯C, C⋯C and Cl⋯H/H⋯Cl contacts.

6. Synthesis and crystallization

The commercially available organic compounds p-nitro­benzaldehyde and p-chloro­aniline were used without further purification and the title compound was synthesized following reported procedures (Batra et al., 2004[Batra, A. K., Gebre, T., Bhat, K., Aggarwal, M. D., Peterson, B., Sarkisov, S. & Lal, R. B. (2004). Proc. SPIE, 5351, 57-68.]; Subashini et al., 2013a[Subashini, A., Leela, S., Ramamurthi, K., Arakcheeva, A., Stoeckli-Evans, H. V., Petříček, V., Chapuis, G., Pattison, P. & Reji, P. (2013a). CrystEngComm, 15, 2474-2481.]): the two reactants were taken in equimolar ratio and refluxed in ethanol for 6 h. On cooling, the synthesized compound was deposited at room temperature as a deep-yellow microcrystalline powder. The material was purified by repeated recrystallization using ethanol at room temperature and the purity of the sample was confirmed by thin layer chromatography. A saturated solution of CNBA was prepared using mixed solvents of ethanol and ethyl­acetate (1:1, v:v) and single crystals were obtained as yellow rods by slow evaporation of the solvents at room temperature over a period of 18 days. The 1H NMR spectrum of CNBA recorded in CDCl3 is shown in the supporting information, Fig. 1S, and the FTIR and FT Raman spectra are shown in Fig. 2S.

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. The C-bound H atoms were included in calculated positions and refined as riding: C—H = 0.95 Å with Uiso(H) = 1.2Ueq(C). The mol­ecule is disordered with an occupancy ratio that after refinement was fixed at 0.649: 0.351. The benzene rings in the two components were refined as rigid bodies and the anisotropic displacement parameters of corresponding C atoms were made equal.

Table 3
Experimental details

Crystal data
Chemical formula C13H9ClN2O2
Mr 260.67
Crystal system, space group Monoclinic, P21/c
Temperature (K) 173
a, b, c (Å) 3.8195 (5), 22.826 (4), 13.6381 (19)
β (°) 92.829 (11)
V3) 1187.6 (3)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.32
Crystal size (mm) 0.34 × 0.17 × 0.09
 
Data collection
Diffractometer STOE IPDS2
Absorption correction Multi-scan (MULABS; Spek, 2020[Spek, A. L. (2020). Acta Cryst. E76, 1-11.])
Tmin, Tmax 0.923, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 9572, 2256, 1498
Rint 0.046
(sin θ/λ)max−1) 0.610
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.121, 0.98
No. of reflections 2256
No. of parameters 206
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.30, −0.19
Computer programs: X-AREA and X-RED32 (Stoe & Cie, 2006[Stoe & Cie. (2006). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2018 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), PLATON (Spek, 2020[Spek, A. L. (2020). Acta Cryst. E76, 1-11.]), Mercury (Macrae et al., 2020[Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226-235.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: X-AREA (Stoe & Cie, 2006); cell refinement: X-AREA (Stoe & Cie, 2006); data reduction: X-RED32 (Stoe & Cie, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2020) and Mercury (Macrae et al., 2020); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015), PLATON (Spek, 2020) and publCIF (Westrip, 2010).

4-Chloro-N-(4-nitrobenzylidene)aniline top
Crystal data top
C13H9ClN2O2F(000) = 536
Mr = 260.67Dx = 1.458 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 3.8195 (5) ÅCell parameters from 3565 reflections
b = 22.826 (4) Åθ = 1.7–26.0°
c = 13.6381 (19) ŵ = 0.32 mm1
β = 92.829 (11)°T = 173 K
V = 1187.6 (3) Å3Rod, yellow
Z = 40.34 × 0.17 × 0.09 mm
Data collection top
STOE IPDS-2
diffractometer
2256 independent reflections
Radiation source: fine-focus sealed tube1498 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
phi & ω scansθmax = 25.7°, θmin = 1.7°
Absorption correction: multi-scan
(MULABS; Spek, 2020)
h = 44
Tmin = 0.923, Tmax = 1.000k = 2727
9572 measured reflectionsl = 1616
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.049H-atom parameters constrained
wR(F2) = 0.121 w = 1/[σ2(Fo2) + (0.0668P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.98(Δ/σ)max < 0.001
2256 reflectionsΔρmax = 0.30 e Å3
206 parametersΔρmin = 0.19 e Å3
0 restraintsExtinction correction: (SHELXL2018; Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.036 (4)
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cl11.0727 (7)0.60002 (12)0.0780 (3)0.0575 (7)0.649
O10.0813 (9)0.23891 (13)0.7308 (2)0.0628 (8)0.649
O20.212 (2)0.1651 (2)0.6402 (7)0.069 (2)0.649
N10.7162 (7)0.42998 (14)0.3862 (3)0.0326 (7)0.649
N20.1963 (14)0.2188 (2)0.6565 (4)0.0444 (13)0.649
C10.9720 (11)0.54801 (15)0.16579 (17)0.0369 (11)0.649
C21.0661 (9)0.55941 (11)0.26368 (19)0.0379 (10)0.649
H21.1846260.5947460.2813490.045*0.649
C30.9869 (8)0.51912 (12)0.33572 (13)0.0334 (8)0.649
H31.0512560.5269180.4026290.040*0.649
C40.8136 (8)0.46743 (11)0.30987 (16)0.0297 (8)0.649
C50.7194 (11)0.45602 (14)0.21198 (19)0.0353 (10)0.649
H50.6009630.4206890.1943130.042*0.649
C60.7987 (12)0.49631 (18)0.13994 (13)0.0391 (11)0.649
H60.7343290.4885170.0730310.047*0.649
C70.7008 (13)0.3742 (2)0.3713 (5)0.0335 (11)0.649
H70.7741120.3588240.3108880.040*0.649
C80.5727 (10)0.33367 (11)0.44542 (19)0.0305 (10)0.649
C90.4512 (9)0.35627 (9)0.5321 (2)0.0346 (9)0.649
H90.4514470.3973910.5428160.042*0.649
C100.3292 (9)0.31870 (11)0.60298 (18)0.0337 (9)0.649
H100.2461540.3341470.6621940.040*0.649
C110.3289 (11)0.25854 (11)0.5872 (2)0.0278 (9)0.649
C120.4504 (13)0.23594 (9)0.5006 (3)0.0331 (10)0.649
H120.4501480.1948170.4898550.040*0.649
C130.5724 (12)0.27351 (12)0.4297 (2)0.0333 (10)0.649
H130.6554430.2580610.3704760.040*0.649
Cl20.1792 (12)0.1871 (2)0.6481 (4)0.0553 (12)0.351
O211.1934 (18)0.6433 (2)0.1833 (4)0.0704 (17)0.351
O221.091 (5)0.5975 (7)0.0487 (13)0.099 (8)0.351
N210.6719 (15)0.3947 (3)0.4304 (6)0.0429 (14)0.351
N221.095 (2)0.6024 (4)0.1364 (8)0.053 (2)0.351
C210.331 (3)0.2457 (2)0.5774 (7)0.0369 (11)0.351
C220.476 (3)0.2384 (3)0.4867 (7)0.0379 (10)0.351
H220.4969560.2003130.4596140.045*0.351
C230.590 (3)0.2869 (4)0.4356 (5)0.0334 (8)0.351
H230.6890790.2819740.3735530.040*0.351
C240.559 (2)0.3427 (3)0.4752 (5)0.0297 (8)0.351
C250.414 (2)0.3500 (2)0.5659 (5)0.0353 (10)0.351
H250.3934020.3880760.5929400.042*0.351
C260.300 (2)0.3015 (3)0.6170 (4)0.0391 (11)0.351
H260.2012770.3064160.6790040.047*0.351
C270.652 (2)0.3978 (5)0.3399 (7)0.039 (2)0.351
H270.5563800.3657700.3032380.047*0.351
C280.7743 (17)0.4503 (2)0.2864 (5)0.0305 (10)0.351
C290.9255 (16)0.4963 (3)0.3401 (3)0.0346 (9)0.351
H290.9535650.4936320.4095830.042*0.351
C301.0355 (18)0.5463 (2)0.2922 (5)0.0337 (9)0.351
H301.1388340.5777510.3288890.040*0.351
C310.994 (2)0.5502 (3)0.1906 (5)0.0278 (9)0.351
C320.843 (2)0.5042 (4)0.1369 (3)0.0331 (10)0.351
H320.8151220.5068680.0674260.040*0.351
C330.733 (2)0.4542 (3)0.1848 (5)0.0333 (10)0.351
H330.6298510.4227480.1481180.040*0.351
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0600 (10)0.0436 (10)0.070 (2)0.0011 (8)0.0144 (12)0.0180 (13)
O10.080 (2)0.070 (2)0.0402 (16)0.0056 (16)0.0215 (16)0.0067 (15)
O20.086 (4)0.044 (4)0.078 (3)0.004 (3)0.019 (3)0.017 (3)
N10.0346 (17)0.0294 (16)0.0340 (17)0.0007 (13)0.0049 (13)0.0029 (17)
N20.039 (2)0.048 (3)0.046 (2)0.005 (3)0.0023 (16)0.014 (3)
C10.038 (2)0.0319 (18)0.040 (2)0.0038 (16)0.000 (2)0.0006 (18)
C20.039 (2)0.0315 (18)0.044 (3)0.0009 (15)0.0093 (17)0.0016 (15)
C30.0362 (19)0.0280 (18)0.0363 (19)0.0026 (14)0.0043 (15)0.0024 (14)
C40.0270 (17)0.0295 (18)0.0327 (19)0.0002 (14)0.0011 (15)0.0044 (17)
C50.0339 (19)0.0328 (19)0.039 (3)0.0006 (14)0.0036 (18)0.0001 (18)
C60.036 (2)0.039 (2)0.043 (2)0.0028 (17)0.0006 (16)0.0048 (17)
C70.029 (2)0.037 (3)0.034 (3)0.005 (2)0.0000 (19)0.001 (2)
C80.0267 (16)0.035 (2)0.0289 (19)0.0004 (14)0.0039 (16)0.0050 (16)
C90.0364 (19)0.0323 (17)0.035 (2)0.0008 (14)0.0005 (17)0.0035 (15)
C100.0367 (19)0.0319 (19)0.0320 (18)0.0049 (16)0.0027 (15)0.0071 (16)
C110.0271 (19)0.029 (2)0.0267 (17)0.0014 (15)0.0009 (14)0.0031 (16)
C120.032 (2)0.0383 (19)0.030 (2)0.0029 (15)0.0022 (16)0.0033 (15)
C130.0344 (19)0.033 (2)0.0329 (18)0.0014 (17)0.0026 (15)0.0015 (15)
Cl20.0509 (15)0.057 (4)0.058 (2)0.007 (3)0.0044 (13)0.023 (3)
O210.101 (5)0.041 (3)0.069 (4)0.019 (3)0.007 (3)0.008 (3)
O220.153 (13)0.064 (7)0.079 (12)0.017 (6)0.015 (8)0.009 (6)
N210.036 (3)0.040 (4)0.053 (4)0.002 (3)0.001 (3)0.004 (4)
N220.045 (4)0.052 (5)0.063 (6)0.014 (3)0.010 (5)0.018 (5)
C210.038 (2)0.0319 (18)0.040 (2)0.0038 (16)0.000 (2)0.0006 (18)
C220.039 (2)0.0315 (18)0.044 (3)0.0009 (15)0.0093 (17)0.0016 (15)
C230.0362 (19)0.0280 (18)0.0363 (19)0.0026 (14)0.0043 (15)0.0024 (14)
C240.0270 (17)0.0295 (18)0.0327 (19)0.0002 (14)0.0011 (15)0.0044 (17)
C250.0339 (19)0.0328 (19)0.039 (3)0.0006 (14)0.0036 (18)0.0001 (18)
C260.036 (2)0.039 (2)0.043 (2)0.0028 (17)0.0006 (16)0.0048 (17)
C270.029 (4)0.041 (6)0.048 (6)0.003 (4)0.001 (4)0.010 (5)
C280.0267 (16)0.035 (2)0.0289 (19)0.0004 (14)0.0039 (16)0.0050 (16)
C290.0364 (19)0.0323 (17)0.035 (2)0.0008 (14)0.0005 (17)0.0035 (15)
C300.0367 (19)0.0319 (19)0.0320 (18)0.0049 (16)0.0027 (15)0.0071 (16)
C310.0271 (19)0.029 (2)0.0267 (17)0.0014 (15)0.0009 (14)0.0031 (16)
C320.032 (2)0.0383 (19)0.030 (2)0.0029 (15)0.0022 (16)0.0033 (15)
C330.0344 (19)0.033 (2)0.0329 (18)0.0014 (17)0.0026 (15)0.0015 (15)
Geometric parameters (Å, º) top
Cl1—C11.743 (4)Cl2—C211.763 (7)
O1—N21.214 (6)O21—N221.182 (9)
O2—N21.248 (7)O22—N221.20 (2)
N1—C71.291 (6)N21—C271.234 (12)
N1—C41.411 (4)N21—C241.412 (9)
N2—C111.420 (6)N22—C311.462 (11)
C1—C21.3900C21—C221.3900
C1—C61.3900C21—C261.3900
C2—C31.3900C22—C231.3900
C2—H20.9500C22—H220.9500
C3—C41.3900C23—C241.3900
C3—H30.9500C23—H230.9500
C4—C51.3900C24—C251.3900
C5—C61.3900C25—C261.3900
C5—H50.9500C25—H250.9500
C6—H60.9500C26—H260.9500
C7—C81.471 (6)C27—C281.488 (11)
C7—H70.9500C27—H270.9500
C8—C91.3900C28—C291.3900
C8—C131.3900C28—C331.3900
C9—C101.3900C29—C301.3900
C9—H90.9500C29—H290.9500
C10—C111.3900C30—C311.3900
C10—H100.9500C30—H300.9500
C11—C121.3900C31—C321.3900
C12—C131.3900C32—C331.3900
C12—H120.9500C32—H320.9500
C13—H130.9500C33—H330.9500
C7—N1—C4119.5 (4)C27—N21—C24118.5 (9)
O1—N2—O2122.8 (8)O21—N22—O22126.8 (14)
O1—N2—C11117.9 (4)O21—N22—C31117.0 (9)
O2—N2—C11119.2 (8)O22—N22—C31115.9 (12)
C2—C1—C6120.0C22—C21—C26120.0
C2—C1—Cl1118.5 (2)C22—C21—Cl2123.6 (5)
C6—C1—Cl1121.5 (2)C26—C21—Cl2116.4 (5)
C3—C2—C1120.0C23—C22—C21120.0
C3—C2—H2120.0C23—C22—H22120.0
C1—C2—H2120.0C21—C22—H22120.0
C2—C3—C4120.0C22—C23—C24120.0
C2—C3—H3120.0C22—C23—H23120.0
C4—C3—H3120.0C24—C23—H23120.0
C5—C4—C3120.0C25—C24—C23120.0
C5—C4—N1122.0 (2)C25—C24—N21115.4 (6)
C3—C4—N1117.8 (2)C23—C24—N21124.6 (6)
C4—C5—C6120.0C24—C25—C26120.0
C4—C5—H5120.0C24—C25—H25120.0
C6—C5—H5120.0C26—C25—H25120.0
C5—C6—C1120.0C25—C26—C21120.0
C5—C6—H6120.0C25—C26—H26120.0
C1—C6—H6120.0C21—C26—H26120.0
N1—C7—C8121.7 (5)N21—C27—C28122.1 (10)
N1—C7—H7119.1N21—C27—H27118.9
C8—C7—H7119.1C28—C27—H27118.9
C9—C8—C13120.0C29—C28—C33120.0
C9—C8—C7119.2 (3)C29—C28—C27118.8 (6)
C13—C8—C7120.8 (3)C33—C28—C27121.2 (6)
C8—C9—C10120.0C28—C29—C30120.0
C8—C9—H9120.0C28—C29—H29120.0
C10—C9—H9120.0C30—C29—H29120.0
C11—C10—C9120.0C31—C30—C29120.0
C11—C10—H10120.0C31—C30—H30120.0
C9—C10—H10120.0C29—C30—H30120.0
C10—C11—C12120.0C30—C31—C32120.0
C10—C11—N2121.8 (3)C30—C31—N22122.4 (7)
C12—C11—N2118.2 (3)C32—C31—N22117.5 (7)
C13—C12—C11120.0C33—C32—C31120.0
C13—C12—H12120.0C33—C32—H32120.0
C11—C12—H12120.0C31—C32—H32120.0
C12—C13—C8120.0C32—C33—C28120.0
C12—C13—H13120.0C32—C33—H33120.0
C8—C13—H13120.0C28—C33—H33120.0
C6—C1—C2—C30.0C26—C21—C22—C230.0
Cl1—C1—C2—C3179.4 (3)Cl2—C21—C22—C23179.9 (8)
C1—C2—C3—C40.0C21—C22—C23—C240.0
C2—C3—C4—C50.0C22—C23—C24—C250.0
C2—C3—C4—N1175.4 (3)C22—C23—C24—N21178.9 (8)
C7—N1—C4—C534.9 (4)C27—N21—C24—C25147.7 (7)
C7—N1—C4—C3149.8 (4)C27—N21—C24—C2333.4 (10)
C3—C4—C5—C60.0C23—C24—C25—C260.0
N1—C4—C5—C6175.2 (3)N21—C24—C25—C26179.0 (7)
C4—C5—C6—C10.0C24—C25—C26—C210.0
C2—C1—C6—C50.0C22—C21—C26—C250.0
Cl1—C1—C6—C5179.4 (3)Cl2—C21—C26—C25179.9 (7)
C4—N1—C7—C8174.8 (3)C24—N21—C27—C28178.3 (6)
N1—C7—C8—C92.8 (6)N21—C27—C28—C292.2 (11)
N1—C7—C8—C13177.2 (4)N21—C27—C28—C33176.6 (7)
C13—C8—C9—C100.0C33—C28—C29—C300.0
C7—C8—C9—C10180.0 (4)C27—C28—C29—C30178.8 (7)
C8—C9—C10—C110.0C28—C29—C30—C310.0
C9—C10—C11—C120.0C29—C30—C31—C320.0
C9—C10—C11—N2178.0 (4)C29—C30—C31—N22178.0 (8)
O1—N2—C11—C100.1 (6)O21—N22—C31—C304.7 (12)
O2—N2—C11—C10177.9 (7)O22—N22—C31—C30170.1 (13)
O1—N2—C11—C12178.0 (4)O21—N22—C31—C32173.3 (7)
O2—N2—C11—C124.1 (9)O22—N22—C31—C3211.8 (15)
C10—C11—C12—C130.0C30—C31—C32—C330.0
N2—C11—C12—C13178.1 (4)N22—C31—C32—C33178.1 (8)
C11—C12—C13—C80.0C31—C32—C33—C280.0
C9—C8—C13—C120.0C29—C28—C33—C320.0
C7—C8—C13—C12180.0 (4)C27—C28—C33—C32178.7 (7)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O2i0.952.553.489 (7)172
C13—H13···O1ii0.952.573.426 (5)151
C27—H27···Cl2i0.952.783.661 (11)155
Symmetry codes: (i) x, y+1/2, z1/2; (ii) x+1, y+1/2, z1/2.
Percentage contributions of interatomic contacts to the Hirshfeld surface for CNBA, and for the individual disordered components, CNBA_1 and CNBA_2 top
ContactPercentage contributions
CNBACNBA_1CNBA_2
H···H25.526.224.7
O···H/H···O37.322.324.4
Cl···H/H···Cl3.514.514.8
C···H/H···C10.212.012.6
C···C10.211.011.1
N···H/H···N3.54.23.4
C···N3.22.42.4
O···O2.30.30.6
C···O1.61.90.7
O···Cl0.82.01.4
C···Cl0.41.01.9
 

Acknowledgements

HSE is grateful to the University of Neuchâtel and the Swiss National Science Foundation for their support over the years.

References

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