Synthesis, Crystal Structure, Hirshfeld Surface Analysis, and Computational Study of a Novel Organic Salt Obtained from Benzylamine and an Acidic Component

Abstract

A novel Schiff base compound named as phenylmethanaminium (E)-4-((benzylimino)methyl)benzoate C₇H₁₀N⁺. C₁₅H₁₂NO₂ ^- (A) is synthesized by the chemical reaction of benzylamine and 4-carboxybenzaldehyde in ethanol, and the structure of the titled compound is verified using the single-crystal X-ray diffraction technique. Structural investigation inferred that the crystal packing is mainly stabilized by N-H···O and comparatively weak C-H···O bonding between the cation and anion and further stabilized by weak C-H···π and C-O···π interactions. Hirshfeld surface analysis is employed to explore the noncovalent interactions that are responsible for crystal packing quantitatively. Furthermore, we have used state-of-the-art quantum chemical calculations to get comprehensive insights into the structure-optoelectronic property relationship for the entitled compound. The molecular geometry of compound A is optimized at the M06/6-311G* level of theory. The linear polarizability, third-order nonlinear optical (NLO) polarizability, total and partial density of states, and UV-visible spectrum are calculated through quantum chemical calculations. We believe that compound A is not only a new addition to crystallographic data but also possesses good optical and NLO properties for its potential use in lasers and frequency-converting applications.

Figure 1

ORTEP diagram of the title compound drawn at a probability level of 30%. The H atoms are shown by small circles of arbitrary radii. Only the major portion of the disordered benzyl group (C9A–C15A) is shown for clarity.

Figure 2

Packing diagram of compound A showing that the cation and anion are connected through N–H···O and C–H···O interactions. Only selected H atoms and the major part of the disordered moiety are shown for clarity.

Figure 3

Graphical representation of C–H···π and C–O···π interactions for Schiff base compound A. Selected H atoms are shown for clarity. The distances are measured in Å.

Figure 4

HS plotted over (a) d_norm and (b) shape index for compound A.

Figure 5

2D FP plot for (a) overall interactions and (b–h) individual interactions in crystal packing of A.

Figure 6

(a) Percentage contributions of the interaction of all the atoms present inside the HS to an atom outside the HS. (b) Percentage contributions of the interaction of an atom present inside the HS to all the atoms present in the surrounding of the HS.

Figure 7

Optimized geometry of compound A at the B3LYP/6-31G* level of theory.

Figure 8

Graphical representation of the TDOS and PDOS determined using the M06/6-31G* method.

Figure 9

UV–visible spectrum of compound A as calculated using the TD-M06/6-31G* methodology.

Scheme 1. Synthetic Scheme of Schiff Base A