Vibrational studies of polar aprotic molecule in aromatic chemical and isotropic solvents: experimental and quantum chemical investigations

Abstract

Raman spectroscopic technique has been used to study the intermolecular interactions and dynamics of S¼O, C-H and CSC stretching modes of dimethyl sulfoxide (DMSO) in binary mixtures using methyl benzene (MBN) and deuterated methyl benzene (MBNd) aromatic solvents. The Raman band of S¼O stretching mode has been deconvoluted into four distinct bands for neat DMSO as well as in binary mixtures. Deconvoluted bands in neat DMSO were assigned as monomer, cyclic out-of-phase, cyclic in-phase and chain dimers having peak wavenumbers 1069.10, 1056.60, 1041.50 and 1027.30 cm À1 respectively. Peak wavenumber of S¼O stretching mode shows red shift, while peak wavenumbers of C-H and CSC stretching modes show blue shift with the increase in solvent concentration. The vibrational relaxation phenomena for all the stretching modes have been studied as a function of solvent concentration. Quantum-chemical calculations have been carried out to gain more insight into the self-association of DMSO and in interacting environment with the solvents using ab initio and density functional theory method. The ab initio basis set is HF/6-31 + G (d, p) for the interacting system. The hydrogen bond complexes of DMSO with MBN and MBNd using IEF-PCM model have been calculated using B3LYP functional and 6-31 + G(d,p) basis sets. Theoretical calculations have been compared with the experimental findings and we obtained good coherence of the results.

Raman signatures of strong and weak hydrogen bonds in binary mixtures of phenol with acetonitrile, benzene and orthodichlorobenzene

“…Concentration-dependent Raman study gives clear idea of hydrogen bonding patterns in organic as well as aqueous solutions and helps to understand their solute-solvent interaction behavior. [28][29][30][31][32][33][34][35][36][37][38][39] In some recent studies by our group, strong hydrogen bonding has been observed in aqueous solutions such as pyridine-water, pyrimidine-water and many other systems. [29,31,33] In pyridines/pyrimidine + H 2 O mixtures, at higher water concentration the original reference peak of solute completely vanishes.…”

Quantum chemical study on the structural mechanism, π-π* interactions and hydrogen bonding network of 2, 6-diamine-7H-purine molecule: using molecular modeling

“…Hence, the mulliken population analysis of DAP was also obtained by the DFT method in order to explain the atomic charges. These atomic charge techniques play a vital role in the chemical application of calculations in computational chemistry, including vibrational spectroscopy, electronic structure, non-linear optical, and a lot of properties of molecular structures [19,20]. From Supplementary Table S2, it can be seen that the atomic charge distribution of the N1, N3, N5, N7 and N11 atoms for DAP ligand, which indicates that the intermolecular charge transfer from the purine rings.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part X

“…carried out vibrational studies of polar aprotic molecules in aromatic chemical and isotropic solvents as a combined experimental and quantum chemical investigation. Theoretical calculations were compared with the experimental findings and good agreement of the results were obtained …”

“…Theoretical calculations were compared with the experimental findings and good agreement of the results were obtained. [147] Pharmaceutical, food, and forensic applications Pharmaceutical and forensic applications of Raman spectroscopy are finding use as instrumentation and chemometric methods increase in sophistication and ease of use. Raman spectroscopy has evolved into an important fast, direct and nondestructive technique in pharmaceutical, biopharmaceutical and food analyses and in forensics.…”