The synthesis and crystal structure of (E)-2-{[(4-methoxynaphthalen-1-yl)methylidene]amino}-4-methylphenol: Hirshfeld surface analysis, DFT calculations and anticorrosion studies.

The title Schiff base compound, (E)-2-{[(4-methoxynaphthalen-1-yl)methylidene]amino}-4-methylphenol, C19H17NO2 (I), was synthesized via the reaction of 2-amino-4-methylphenol with 4-methoxynaphthalene-1-carbaldehyde. The structure of I was characterized by NMR, IR and UV-Vis spectroscopies in different solvents. The interatomic contacts in the crystal structure were explored using Hirshfeld surface analysis, which, together with the two-dimensional fingerprint plots, confirm the predominance of dispersion forces in the crystal structure. The molecule of I has a twisted conformation, with the mean plane of the naphthalene ring system being inclined to the plane of the phenol ring by 33.41 (4)°. In the crystal, molecules are linked by C-H...O hydrogen bonds to form inversion dimers. There are parallel-displaced π-π interactions present, together with C-H...π interactions, resulting in the formation of a three-dimensional structure. The anticorrosion potential of I was also investigated using density functional theory (DFT) in the gas phase and in various solvents. The compound was shown to exhibit significant anticorrosion properties for iron and copper. The molecular structure of I was determined by DFT calculations at the M062X/6-311+g(d) level of theory and compared with the crystallographically determined structure. Local and global reactivity descriptors were computed to predict the reactivity of I. Excellent agreement was observed between the calculated results and the experimental data.

Correlation between Second Ionization Potential and Nonlinear Optical Properties of Bivalent Transition-Metal Complexes: A Quantum Chemical Study.

Discovering new materials with excellent nonlinear optical responses has recently become a very interesting research topic in the different domains of materials science. Currently, density functional theory (DFT) has been shown to be a powerful tool in the explanation and prediction of the performance of novel nonlinear optical (NLO) materials. Quantum chemical calculations using DFT/TD-DFT with the B3LYP exchange-correlation functional are reported to study the NLO properties of 26 bivalent transition-metal (TM) complexed by six acyclic hexadentate ligands providing pyridyl/pyrazine-amide-thioether/ether coordination and differing by the nature of the methylene dichalcogenate spacer between the rings. However, the geometry parameters and the theoretically predicted UV-vis absorption spectra of the optimized compounds M(II)Li are in excellent agreement with the experiment, when available, the trends among the nature of the TM, the importance of the ligand spacer, and of the substituents of the pyridine/pyrazine amide ligand are discussed. To the best of our knowledge, our work evidences for the first time that the hyper-polarizability, second harmonic generation, and hyper-Rayleigh scattering response of TM coordination complexes can be correlated to the second ionization potential of metal and spin state of complexes.

A quantum chemistry investigation on the structure of lanthanide triflates Ln(OTf)3 where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu.

Density functional theory has been used to probe the electronic structure, coordination number, optical properties and the vibration spectra of monolanthanide trifluoromethane sulfonate Ln(OTf)(3) complexes where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu. The study reveals that the OTf group is bonded to Ln as a bidentate ligand. TDDFT calculations show that, for La(OTf)(3), MLTC and HOMO-LUMO transitions in the UV-vis are strongly bathochromically shifted compared to those of Lu(OTf)(3.).