**3.2 Red-shifted of O-H bonds**

The reorganization of the O…H stretching vibration has been calculated after the system perturbation with the pollutant gases. Moreover, The IR spectrum calculation of the four stable complexes is given in **Figure 2**. In literature, Furel et al. have been studied the experimental infrared spectrum of the CX[4] molecule. In this work, we have analyzed the stretching region of the IR spectrum between 2900 and 3500 cm−1, respectively 3254 (OH), 3168(OH asymmetric), 3045(Car.H), 2951 (asym. CH2), 2916 cm−1(sym.CH2). The infrared spectrum of the CX[4]-gas have been compared to the IR spectra of the free CX[4] molecule (See **Figure 2**). In addition, to take into account the an-harmonic effect our calculated frequencies scaled by 0.956. However, we have noted that, the CX[4]-CO2 is characterized by two peaks located in the vicinity of 3177 cm−1 and 3181 cm−1respectively. The CX[4]-N2 complex have the same results. These tow peaks are specified by the O-H asymmetric stretching vibration. We have shown that the frequency band located at 3160 cm−1 is corresponding to the O-H stretching vibration of the phenol O-H groups. Concerning the CX[4]-NO2 complex, we have noted the appearance of the two peaks in the neighborhood of 3170 cm−1 and 3193 cm−1. These peaks are corresponding to the vibrations of the O-H and O-H asymmetric bonds. Finally, we have shown a burst of the OH peak in the CX[4]-NO3 gas what form four peaks located in the vicinity of 2928 cm−1 (asym.CH2), 3100 cm−1(asym.OH), 3204 cm−1(OH) and 3298 cm−1(free OH) respectively. The noted values for the comparing of the red-shifted O-H vibration between the CX[4]-gas and the free CX[4]molecule are 44 cm−1, 24 cm−1 and 9 cm−1 for CX[4]-NO3, CX[4]-NO2, CX[4]-CO2 and CX[4]-N2 successively.

### **3.3 Molecular electrostatic potential study**

In **Figure 3(a**–**d)**, we have been created the MEP map of the stable host-guests. These graphs indicate the relation between the supra-molecular structure and the physic-cal-chemical properties of the CX[4]-gas complexes. In this work, we have explained the more nucleophile or electrophile sites in these stable host-guests. The color code of the maps varying from −0.005 to 0.005 (isoval = 0.001). From **Figure 3**, we show that the electrophilic sites surrounded by N atoms and the nucleophilic sites surrounded by O atoms. In addition, these host-guests complexes are characterized by the existence of the positive charges located at the level of the phenolic branch.

**305**

**4. Conclusion**

**Figure 3.**

*Possibility of Complexation of the Calix[4]Arene Molecule with the Polluting Gases…*

This part demonstrates how the MESP can explore the region of the unravel molecular

*Molecular electrostatic potential analysis of the CX[4]-CO2 (a), CX[4]-N2 (b), CX[4]-NO2 (c)* 

**Figure 4(a)** shows the existence of a weak van der Waals (VdW) type interactions between CO2 gas and CX[4]. Concerning the CX[4]-N2 complex (**Figure 4(b)**), we show a green color between the guest and the host that indicates the existence of the weak Van der Waals interactions and the blue color at the lower edge level indicates the existence of the O-H-bonding type interactions. Also, we have shown clearly a red color located in the center of the phenol rings indicates a strong repulsion. The NCI-plots have been confirmed these results (see **Figure 4**). In addition, from CX[4]-NO2 (**Figure 4(c)**) complex, we find the existence of a red color which explain the steric effect interactions, blue color (hydrogen bonds type interactions) and a green color (week van der Waals type interactions). The type of majority bonds of the links between the NO3 gas and the CX[4] molecule is the weak VdW type interactions. The NCI-RDG analysis shows that the VdW type interactions and the hydrogen bonding interactions between the guest and the host are very necessary

The CX[4] and the CX[4]-gas complexes have been optimized using the density

functional theory (DFT). Our work has clearly explained the sensibility of the pollutant gas inside the cavity, which is very important in comparison with the gas

interactions between the CX[4] molecule and these hosts.

*and CX[4]-NO3 (d) complexes calculated by B3LYP-D3/6–31 + G(d) level.*

**3.4 Non covalent interactions analysis**

for the stability of the encapsulated complexes.

*DOI: http://dx.doi.org/10.5772/intechopen.93838*

**Figure 2.** *Infrared spectrum of the stable host-guests complexations (H-bonding region (the unit is cm−1)).*

*Possibility of Complexation of the Calix[4]Arene Molecule with the Polluting Gases… DOI: http://dx.doi.org/10.5772/intechopen.93838*

**Figure 3.**

*Environmental Issues and Sustainable Development*

**3.2 Red-shifted of O-H bonds**

complex is higher than that of CX[4]-CO2(exo/endo). Therefore, The CX[4]-NO2(endo) complex is more stable than others, which is explained by the lowest dipole moment.

The reorganization of the O…H stretching vibration has been calculated after the system perturbation with the pollutant gases. Moreover, The IR spectrum calculation of the four stable complexes is given in **Figure 2**. In literature, Furel et al. have been studied the experimental infrared spectrum of the CX[4] molecule. In this work, we have analyzed the stretching region of the IR spectrum between 2900 and 3500 cm−1, respectively 3254 (OH), 3168(OH asymmetric), 3045(Car.H), 2951 (asym. CH2), 2916 cm−1(sym.CH2). The infrared spectrum of the CX[4]-gas have been compared to the IR spectra of the free CX[4] molecule (See **Figure 2**). In addition, to take into account the an-harmonic effect our calculated frequencies scaled by 0.956. However, we have noted that, the CX[4]-CO2 is characterized by two peaks located in the vicinity of 3177 cm−1 and 3181 cm−1respectively. The CX[4]-N2 complex have the same results. These tow peaks are specified by the O-H asymmetric stretching vibration. We have shown that the frequency band located at 3160 cm−1 is corresponding to the O-H stretching vibration of the phenol O-H groups. Concerning the CX[4]-NO2 complex, we have noted the appearance of the two peaks in the neighborhood of 3170 cm−1 and 3193 cm−1. These peaks are corresponding to the vibrations of the O-H and O-H asymmetric bonds. Finally, we have shown a burst of the OH peak in the CX[4]-NO3 gas what form four peaks located in the vicinity of 2928 cm−1 (asym.CH2), 3100 cm−1(asym.OH), 3204 cm−1(OH) and 3298 cm−1(free OH) respectively. The noted values for the comparing of the red-shifted O-H vibration between the CX[4]-gas and the free CX[4]molecule are 44 cm−1, 24 cm−1 and

9 cm−1 for CX[4]-NO3, CX[4]-NO2, CX[4]-CO2 and CX[4]-N2 successively.

*Infrared spectrum of the stable host-guests complexations (H-bonding region (the unit is cm−1)).*

In **Figure 3(a**–**d)**, we have been created the MEP map of the stable host-guests. These graphs indicate the relation between the supra-molecular structure and the physic-cal-chemical properties of the CX[4]-gas complexes. In this work, we have explained the more nucleophile or electrophile sites in these stable host-guests. The color code of the maps varying from −0.005 to 0.005 (isoval = 0.001). From **Figure 3**, we show that the electrophilic sites surrounded by N atoms and the nucleophilic sites surrounded by O atoms. In addition, these host-guests complexes are characterized by the existence of the positive charges located at the level of the phenolic branch.

**3.3 Molecular electrostatic potential study**

**304**

**Figure 2.**

*Molecular electrostatic potential analysis of the CX[4]-CO2 (a), CX[4]-N2 (b), CX[4]-NO2 (c) and CX[4]-NO3 (d) complexes calculated by B3LYP-D3/6–31 + G(d) level.*

This part demonstrates how the MESP can explore the region of the unravel molecular interactions between the CX[4] molecule and these hosts.

#### **3.4 Non covalent interactions analysis**

**Figure 4(a)** shows the existence of a weak van der Waals (VdW) type interactions between CO2 gas and CX[4]. Concerning the CX[4]-N2 complex (**Figure 4(b)**), we show a green color between the guest and the host that indicates the existence of the weak Van der Waals interactions and the blue color at the lower edge level indicates the existence of the O-H-bonding type interactions. Also, we have shown clearly a red color located in the center of the phenol rings indicates a strong repulsion. The NCI-plots have been confirmed these results (see **Figure 4**). In addition, from CX[4]-NO2 (**Figure 4(c)**) complex, we find the existence of a red color which explain the steric effect interactions, blue color (hydrogen bonds type interactions) and a green color (week van der Waals type interactions). The type of majority bonds of the links between the NO3 gas and the CX[4] molecule is the weak VdW type interactions. The NCI-RDG analysis shows that the VdW type interactions and the hydrogen bonding interactions between the guest and the host are very necessary for the stability of the encapsulated complexes.

## **4. Conclusion**

The CX[4] and the CX[4]-gas complexes have been optimized using the density functional theory (DFT). Our work has clearly explained the sensibility of the pollutant gas inside the cavity, which is very important in comparison with the gas

#### **Figure 4.**

*NCI-RDG plots of the electron density and its reduced gradient of the inclusion complexes for CX[4]-gas (CX[4]-CO2(a), CX[4]-N2(b), CX[4]-NO2(c) and CX[4]-NO3(d)). The iso-surfaces were constructed with RGD = 0.5a.u and the colors scaling from −0.01 to −0.01 a.u.*

located outside the cavity. The IR spectrum study has explained the role of the NO3 gas in the red-shifted of the O-H bonds in comparison with the other gases. The MEP results is clearly explained the charge distribution reactivity. The NCI-RDG analysis clearly shows the strong interactions of the gas NO3 and NO2 with the endo-cavity

**307**

**Author details**

(proteins).

**Acknowledgements**

CCIN2P3' at Villeurbanne, France.

and Rafik Ben Chaabane1,3

Science, Monastir, Tunisia

University, Kingdom of Saudi Arabia

Lyon, Villeurbanne Cedex, France

provided the original work is properly cited.

Bouzid Gassoumi1,3\*, Fatma Ezzahra Ben Mohamed2

1 Laboratory of Advanced Materials and Interfaces (LIMA), University of Monastir,

2 Department of Physics, Faculty of Arts and Sciences of AlMikhwah, Al-BAHA

3 University of Monastir, Quantum and Statistical Physics Laboratory, Faculty of

4 Institute of Light and Matter, UMR5306 University of Lyon 1-CNRS, University of

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Faculty of Science of Monastir, Avenue of Environment, Monastir, Tunisia

\*Address all correspondence to: gassoumibouzid2016@gmail.com

, Houcine Ghalla3

*Possibility of Complexation of the Calix[4]Arene Molecule with the Polluting Gases…*

environments of the CX[4] molecule. Finally, the non-covalent interactions analyses show that the calix[4]arene maybe useful for encapsulated the pollutant gas in the future. The sensitivity of the calix[4]arene molecule for these polluting gases opens a way to test the interaction of CX[4] with other types of biological molecules

The authors acknowledge financial support from the Tunisian's Ministry of high education and scientific research. In this work, we were granted access to the HPC resources of the FLMSN, 'Fédération Lyonnaise de Modélisation et Sciences Numériques', partner of EQUIPEX EQUIP@MESO and to the 'Centre de calcul

*DOI: http://dx.doi.org/10.5772/intechopen.93838*

*Possibility of Complexation of the Calix[4]Arene Molecule with the Polluting Gases… DOI: http://dx.doi.org/10.5772/intechopen.93838*

environments of the CX[4] molecule. Finally, the non-covalent interactions analyses show that the calix[4]arene maybe useful for encapsulated the pollutant gas in the future. The sensitivity of the calix[4]arene molecule for these polluting gases opens a way to test the interaction of CX[4] with other types of biological molecules (proteins).
