Synthesis of 4-Amino- N-[2 (diethylamino)Ethyl]Benzamide Tetraphenylborate Ion-Associate Complex: Characterization, Antibacterial and Computational Study

Abstract

The 4-amino-N-[2 (diethylamino) ethyl] benzamide (procainamide)-tetraphenylborate complex was synthesized by reacting sodium tetraphenyl borate with 4-amino-N-[2 (diethylamino) ethyl] benzamide, chloride salt, and procainamide in deionized water at room temperature through an ion-associate reaction (green chemistry) at room temperature, and characterized by several physicochemical methods. The formation of ion-associate complex between bio-active molecules and/or organic molecules is crucial to comprehending the relationships between bioactive molecules and receptor interactions. The solid complex was characterized by infrared spectra, NMR, elemental analysis, and mass spectrometry, indicating the formation of ion-associate or ion-pair complex. The complex under study was examined for antibacterial activity. The ground state electronic characteristics of the S1 and S2 complex configurations were computed using the density functional theory (DFT) approach, using B3LYP level 6-311 G(d,p) basis sets. R² = 0.9765 and 0.9556, respectively, indicate a strong correlation between the observed and theoretical ¹H-NMR, and the relative error of vibrational frequencies for both configurations was acceptable, as well. HOMO and LUMO frontier molecular orbitals and molecular electrostatics using the optimized were used to obtain a potential map of the chemical. The n → π* UV absorption peak of the UV cutoff edge was detected for both configurations of the complex. Spectroscopic methods were structures used to characterize the structure (FT-IR and 1HNMR). In the ground state, DFT/B3LYP/6-311G(d,p) basis sets were used to determine the electrical and geometric properties of the S1 and S2 configurations of the title complex. Comparing the observed and calculated values for the S1 and S2 forms, the HOMO-LUMO energy gap of compounds was 3182 and 3231 eV, respectively. The small energy gap between HOMO and LUMO indicated that the compound was stable. In addition, the MEP reveals that positive potential sites were around the PR molecule, whereas negative potential sites were surrounding the TPB site of atoms. The UV absorption of both arrangements is comparable to the experimental UV spectrum.

Keywords: antibacterial activity; characterization; computational study; ion-associate complex; procainamide; tetraphenyl borate.

Scheme 1

The synthetic pathway of the tetraphenylborate salt of procainamide.

Figure 1

Absorption spectra of procainamide, sodium tetraphenyl borate, and procainamide-tetraphenyl borate (0.0001M, each).

Figure 2

B3LYP/6-311G(d,p) optimized geometries of the molecules: (A) procainamide cation, (B) tetraphenylborate anion, (C,D) procainamide cation, and tetraphenylborate anion salt.

Figure 3

(A–C) TD-DFT calculated absorption spectra in the gas phase and water solvent for complexes conformation S1 (A,C) and S2 (B,D), respectively. (E) Experimental absorption spectrum of the title complex in water solvents at room temperature.

Figure 4

Electronic absorption in the gas phase is facilitated by band gaps (ΔE) and frontier molecular orbitals in both (A) complex S1 and (B) complex S2 (E).

Figure 5

Correlation studies between observed and calculated (A,B) ¹H-NMR of conformation S1 and S2 of complex, respectively.

Figure 6

Standard NCI index representations and RDG scatter plots (A,B) at the B3LYP/6-311G level. The RDG cut-off is sign(λ₂)ρ = 0.5 a.u, and the color scale is -0.030 to 0.02 a.u, (blue, green, and red surfaces imply attracting, van der Waals, and repulsive interactions, respectively) for both S1 and S2 configurations, and (C,D) isosurface maps for both S1 and S2 configurations, respectively.

Figure 7

Topological atoms in molecules (AIM) graph of both PR-TPB complexes, configuration for: (A) complex S1 and (B) complex S2.

Figure 8

Electrophilic site study by MESP for: (A) procainamide cation, (B) tetraphenylborate anion, (C) S1 configuration, and (D) S1 configuration of complex of procainamide with tetraphenylborate, superimposed on the structure’s isodensity surface (isovalue = 0.002), which was calculated at the B3LYP/6311 G (d, p) level.