Molecular structure, spectroscopic properties, NLO and NBO analysis of 3,4-Lutidine and [Ag(3,4-Lutidine)2NO3] complex

Abstract

The molecular structure and electronic properties of 3,4-Lutidine (34Lut) and its silver(I) complex; [Ag(34Lut)2NO3] have been reported. The geometry of the titled compounds was optimized using HF and DFT/B3LYP methods. The calculations predicted a distorted tetrahedral coordination geometry around the Ag(I) ion. The complete vibrational assignments of the 34Lut and [Ag(34Lut)2NO3] complex have been made on the basis of Total Energy Distribution (TED). The vibrational frequencies calculated using DFT/B3LYP method showed better agreement with the experimental values compared to HF method. For [Ag(34Lut)2NO3] complex, the calculations predicted the presence of intramolecular CH⋯O interactions between the oxygen of the nitrate and the neighboring hydrogen atoms of the coordinated 34Lut which is confirmed by the TED analysis of the CH stretching modes. Unexpected blue shift is predicted for the CH stretching modes involved in such interactions. A study on the electronic properties, such as HOMO and LUMO energies as well as the molecular electrostatic potential (MEP) was performed using the same level of theory. Natural charges and natural bond orbital (NBO) analyses of the studied molecules were also calculated and interpreted. The dipole moment, linear polarizability and first hyperpolarizability values were used to describe the NLO properties of the studied compounds.