The synthesis, spectroscopic characterization, DFT/TD-DFT/PCM calculations of the molecular structure and NBO of the novel charge-transfer complexes of pyrazine Schiff base derivatives with aromatic nitro compounds

Abstract

Novel charge-transfer complexes of pyrazine Schiff bases derived from 2-aminopyrazine with benzaldehyde and N-4-dimethylaminobenzaldehyde with some aromatic nitro compounds have been synthesized and characterizes experimentally and confirmed theoretically.

Spectroscopic (UV and fluorescence), biological, DFT and molecular docking studies of 3,5‐diethyl‐2r,6c‐di(4‐fluorophenyl)piperidin‐4‐one picrate

“…The first order hyperpolarizability value (β0) of the title compound is 4.02087×10 -30 esu, which is ~21 times greater than that of standard value of urea (β0 = 0.194710 -30 esu). [29][30][31][32][33] This results shows that the title molecule belongs to good NLO property.…”

Synthesis, characterization, theoretical study and biological activity studies of the mercury (II) complexes of 5‐methyl‐5‐(4‐nitrophenyl)‐hydantoin

“…On the other, the stretching frequency of N-H groups shifted to the higher frequencies at 3411; 3258; and 3276 cm À1 for complexes (1), (2), and (3), respectively, which indicates the ligand is not Nbonded. [7,12,[29][30][31][32][33][34][35] Also, the broadband of N-H groups for all complexes in the spectra, compared with two sharp stretching bands for (L) [21] indicates resonance that occurred through the free electron pair of nitrogen atoms in the ring. [7,12,[29][30][31][32][33][34][35] 2.1.2 | NMR spectra 13 C NMR and 1 H NMR data of the prepared complexes (1-3) are inserted in Tables 2 and 3.…”

“…[7,12,[29][30][31][32][33][34][35] Also, the broadband of N-H groups for all complexes in the spectra, compared with two sharp stretching bands for (L) [21] indicates resonance that occurred through the free electron pair of nitrogen atoms in the ring. [7,12,[29][30][31][32][33][34][35] 2.1.2 | NMR spectra 13 C NMR and 1 H NMR data of the prepared complexes (1-3) are inserted in Tables 2 and 3. These data verified the coordination of the ligand to the mercury atom from the oxygen atom in all complexes.…”

“…Again, the 1 H NMR data indicated the differences in electronegativity in the halogens connected to mercury. [31][32][33] Thus, H[N 1 ] protons are more shielded in the complexes than in the (L). The shielding in the complexes is from the hydrogen bonds and also from the positive charge in the ring.…”

“…The shielding in the complexes is from the hydrogen bonds and also from the positive charge in the ring. [31][32][33] These data indicated that the electron transfers between N-H and C═O groups occurred via resonance in the ring. [21,[37][38][39] T A B L E 1 The IR data (L) and complexes…”