The importance of specific solvent–solute interactions for studying UV–vis spectra of light-responsive molecular switches

Computational study of the intermolecular interactions and their effect on the UV-visible spectra of the ternary liquid mixture of benzene, ethanol and propylene glycol

Quantum chemical calculations are well-equipped to provide answers to the questions regarding the different aspects of intermolecular interactions. We investigate the benzene, ethanol and 1,2 propanediol ternary mixture with theoretical as well as experimental UV-Vis spectroscopy. An extensive theoretical study on the molecular structure and UV-Vis spectral analysis was undertaken using density functional theory (DFT) method. Structural parameter analysis and the HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) energy gap help to describe the possible interaction between molecules in dimer and in combination. Interaction energy has been calculated from topological study. Time-dependent density functional theory (TDDFT) calculations on dimer/cluster in gas phase help to understand the effect of the molecular interaction on the overall spectral shift and related intensity variation. Our results show that in the ternary mixture, the interaction energies of the interactions are π-π interaction: 0.52-2.57 kcal/mol, Hp-π interaction: 1.15 kcal/mol and H-bonding: 2.49 to 4.46 kcal/mol. The π-π interaction and H-bonding cause red shift in absorption spectra while Hp-π interaction causes blue shift. In the ternary mixture, the strength of different kinds of interaction depends on the concentration, and as each interaction has its own effect on spectral shift, the overall experimental spectra get broader and distorted from the Gaussian shape.

CoFe2O4 Nanomaterials: Effect of Annealing Temperature on Characterization, Magnetic, Photocatalytic, and Photo-Fenton Properties

In this research, structural, magnetic properties and photocatalytic activity of cobalt ferrite spinel (CoFe2O4) nanoparticles were studied. The samples were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), transmission electronic microscopy (TEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), and UV-visible diffused reflectance spectroscopy (DRS) analysis. The XRD analysis revealed the formation of the single-phase CoFe2O4 with a cubic structure that is annealed at 500–700 °C in 3 h. The optical band gap energy for CoFe2O4 was determined to be in the range of 1.57–2.03 eV. The effect on the magnetic properties of cobalt ferrites was analyzed by using a vibrating sample magnetometer (VSM). The particle size and the saturation magnetization of cobalt ferrite nanoparticles increased with increasing annealing temperature. The photocatalytic activity of CoFe2O4 nanoparticles was investigated by using rhodamine B dye under visible light. The decomposition of rhodamine B reached 90.6% after 270 min lighting with the presence of H2O2 and CF500 sample.