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The two-dimensional (2D) graphitic carbon nitride currently has attracted attention for his electronic structure and optical properties. It is a good candidate for photocatalytic applications. The graphitic carbon nitride has been successfully synthesis and characterized by XRD, FTIR and UV–Vis Spectroscopy. The influence of acids treatment on structural and optical properties of g-C3N4 has been examined. It was found that the treatment of g-C3N4 bulk by different acids shows a disorder in the structure of samples which affect the optical performance of material. For the determination of the contributions of each orbital to the valence band maximum and the minimum conduction band the electronic structure of g-C3N4 has been investigated by density functional theory. The theoretical investigation reveals that the lone pair state and the π bonding play an important role in the electronic structure of graphitic carbon nitride and favorites the absorption of the g-C3N4 in the visible light. The optical properties such as the extinction coefficient (k), the refractive index (n), the optical conductivity ( σ opt ), and the dielectric function (εr, εi) have been explored by DFT calculation and confirmed by the experimental results. [ABSTRACT FROM AUTHOR]

To enhance the photogeneration and separation of charge carriers, ZnO/MnO2 nanocomposites were efficiently synthesized using a simple hydrothermal process and tested as photocatalyst for dye degradation. The samples of ZnO, MnO2, and ZnO/MnO2 nanocomposites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflection spectroscopy, and photoluminescence spectra (PL). The photocatalytic activity of the ZnO/MnO2 prepared using 10 mg was significantly higher than that of ZnO or MnO2, as demonstrated by optical and photoluminescence measurements. In fact, the degradation efficiency of methyl orange (MO) with ZnO/MnO2 (10 mg) reaching to 98% after 2 h of sunlight irradiation. The enhanced degradation of MO compared with pure ZnO and MnO2 can be attributed to the high surface area, efficient sunlight absorption, and excellent charge carrier separation of the ZnO/MnO2 photocatalyst. Density functional theory (DFT) simulations of ZnO and MnO2 further revealed the electronic origins of the structural properties, showing that the photocatalytic activity is due to the electron transitions between the valence and conduction bands of materials. [ABSTRACT FROM AUTHOR]

Abstract A novel organic-inorganic hybrid material 2-carboxyanilinium hypophosphite was synthesized by slow evaporation. The crystal structure was determined by X-ray at room temperature in the centrosymmetric triclinic space group P-1 with the following parameters: a = 4.812 (7), b = 9.527 (16), c = 9.789 (14), α = 106.21 (13), β = 102.11 (12), γ = 90.69 (13), and Z = 2. The X-ray crystal structure of the title compound (C 7 H 8 NO 2 +. H 2 PO 2 −) show extensive stacking interactions, the anions and cations were associated via hydrogen bonding giving a one-dimensional network structure. In the former crystal, the cations, anions molecules are linked into layers by two types of hydrogen bonds: N H⋯O and O H⋯O. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compound were theoretically examined by the DFT/B3LYP method with the 6-31G (d,p) and 6-311G (d,p) basis sets. The FT-Raman and FT-IR spectra of the compound were determined and compared to the theoretical spectra. The results revealed that the deviation of the theoretical wavenumbers from the experimental values was very small. Graphical abstract Image Highlights • A new organic-inorganic hybrid material C 7 H 8 NO 2 +.H 2 PO 2 −, was synthesized by slow evaporation. • The crystal X-ray structure has been determined. • N H⋯O and O H⋯O bonds are formed between the cation and the anion. • The FT-IR and Raman spectra were recorded and analyzed using DFT calculations. [ABSTRACT FROM AUTHOR]

The crystal structure of (H-phen) 2 [Fe 2 (μ-O)(H 2 O) 6 (phen) 2 ](NO 3 ) 6 has been determined using single-crystal X-ray crystallography at low and room temperature. Complex 1 crystallizes in the monoclinic C 2/ c space group. This compound contained two iron(III) centers which are bridged by one oxygen atom to form dinuclear units. This binuclear complex exhibits strong antiferromagnetic coupling between the two iron(III) centers with g = 2, S = 5/2 and J = −223 cm − 1 . An investigation of the magnetic order was performed using spin projected broken symmetry via density functional theory. This approach of broken symmetry (BS) has provided a good numerical estimation of the J value ( J = −198 cm − 1 ), which is in agreement with the experimental magnetic susceptibility measurements. By means of DFT and TD-DFT methods, the electronic absorption and infrared spectra of the title compound were predicted with good agreement with the experimental data. Natural bond orbital (NBO) analysis has been used to explain the formation of a hydrogen bond and the most possible interaction. In addition, the chemical reactivity of the complex has been obtained by mapping electron density with molecular electrostatic potential (MEP) and the electrical, optical and chemical properties have been investigated through the energies of the frontier molecular orbitals (FMO). [ABSTRACT FROM AUTHOR]