Design of a new palladium(ii) halide complex as a bio-active material: synthesis, physico-chemical studies, DFT-computations and evaluation of anti-inflammatory, antioxidant and anti-gastric damage activities.

Colorless single crystals of the zero-dimensional hybrid compound, (C6H10N2)2[PdCl6]·2H2O were acquired through the slow evaporation technique. The crystal structure was explored using SC-XRD, which demonstrates that the material crystallizes in the centrosymmetric space group P1̄ of the triclinic system. The density functional theory method at the B3LYP/Lan2mb basis set level was employed to establish the optimized geometry and vibrational frequencies of the title compound. An acceptable correspondence was observed between the results obtained through calculation and the experimental data, including the structure, and IR spectra. The optical characteristics revealed a direct band gap energy of 2.35 eV, validating the semiconductor characteristics of this new material. The results suggest strong agreement with the experimental data and validate the involvement of metal orbitals in defining the HOMO-LUMO boundary. Simultaneous TGA-DTA shows that this material remains solid up to 210 °C. Beyond these temperatures, a gradual decomposition process occurs, extending up to 440 °C and unfolding in several steps. This process entails the liberation of diverse compounds, encompassing organic molecules, and the evaporation of chlorine ions, ultimately leading to the formation of palladium oxide (PdO) as the final product. When given to rats with gastric ulcers at a dose of 100 mg kg-1, these compounds inhibit the key enzyme responsible for neutrophil infiltration as myeloperoxidase (MPO) by 38.7%. The compound also alleviates cellular damage induced by free radicals, demonstrated by a notable 48.3% decrease in thiobarbituric acid reactive substance rates (TBARS) compared to untreated rats. Additionally, these compounds bring about a substantial 30.6% reduction in the surface area of ulcers.

Synthesis of a new potassium-substituted lead fluorapatite and its structural characterization.

Prismatic crystals of partially potassium substituted lead fluorapatite Pb5.09Ca3.78K1.13(PO4)6F0.87 were grown through a solid-state reaction. The structural study conducted by single-crystal X-ray diffraction revealed that the compound crystallizes in the hexagonal P63/m space group, with unit cell parameters a = b = 9.7190(5) Å, c = 7.1700(6) Å and V = 587.37(7) Å3(Z = 1), as well as final values amounting to R and wR of 0.0309 and 0.0546, respectively. The structural refinement demonstrated that Pb occupies both the (6h) and (4f) structural sites of hexagonal fluorapatite, K occupies the (6h) site, and Ca is placed on the (4f) site. Powder X-ray diffraction study indicated the absence of additional phases or impurities. Chemical analysis using atomic absorption spectrometry and energy-dispersive X-ray spectroscopy confirmed the expected chemical formula. The electrical conductivity measured over a wide temperature range was found to be governed by the ion mobility mechanism in the tunnel along the c axis (probably attributed to the fluorine ion located there). We, therefore, could infer from the analysis of the complex impedance spectra that the electrical conductivity of our apatite depends essentially on the temperature and frequency, which produces a relaxation phenomenon and semiconductor-like behavior. Moreover, the strong absorption in the UV-Visible region was substantiated through studies of the optical properties of the developed sample. Fluorescence spectra exhibited emissions in the orange regions when excited at 375 nm. The findings of the phenomena resulting from the emission and conduction of the apatite in question suggest its potential for application in various technological fields such as photovoltaic cells, optoelectronics, photonics, LED applications, catalysis and batteries.

Crystal structure and vibrational spectral studies of a new organic-inorganic crystal: 4-Benzylpiperidinium trioxonitrate.

Single crystals of a new organic-inorganic crystal, 4-benzylpiperidinium trioxonitrate (4-BPPN) were grown by slow evaporation at room temperature and were characterized by X-ray diffraction, DTA-TG measurement, FT-IR and FT-Raman spectroscopies. The title compound crystallizes in the monoclinic system P21/c at room temperature with the following parameters: a=12.787(8)Å, b=9.007(5)Å, c=11.120(5)Å, ß=95.974(2)° and Z=4. Its crystal structure is packing of alternated inorganic and organic layers parallel to (a, c) planes. The different components are connected by a bi-dimensional network of N-H⋯O hydrogen bonds. The ability of ions to form spontaneous three-dimensional structure through N-H⋯O hydrogen bond is fully utilized. These hydrogen bonds give notable vibrational effects. The optimized molecular structure and the vibrational spectra were calculated by the Density Functional Theory (DFT) method using the B3LYP function with the 6-31G(d) basis set. All observed vibrational bands have been discussed and assigned to normal mode or to combinations on the basis of our DFT calculations as a primary source of attribution and also by comparison with the previous results for similar compounds. Good consistency is found between the calculated results and the experimental structure, IR, and Raman spectra.

Vibrational spectroscopic study, charge transfer interaction and nonlinear optical properties of L-asparaginium picrate: a density functional theoretical approach.

Single crystals of L-asparaginium picrate (LASP) were grown by slow evaporation technique at room temperature and were the subject of an X-ray powder diffraction study to confirm the crystalline nature of the synthesized compound. FT-IR and Raman spectra were recorded and analyzed with the aid of the density functional theory (DFT) calculations in order to make a suitable assignment of the observed bands. The optimum molecular geometry, normal mode wavenumbers, infrared and Raman intensities and the first hyperpolarizability were investigated with the help of B3LYP method using 6-31G(d) basis set. The theoretical FT-IR and Raman spectra of LASP were simulated and compared with the experimental data. A good agreement was shown and a reliable vibrational assignment was made. Natural bond orbital (NBO) analysis was carried out to demonstrate the various inter and intramolecular interactions that are responsible for the stabilization of the title compound leading to high NLO activity. A study on the electronic properties was performed by time-dependent DFT (TD-DFT) approach. The lowering in the HOMO and LUMO energy gap explains the eventual charge transfer interactions that take place within the molecules.

Vibrational spectra, optical properties, NBO and HOMO-LUMO analysis of L-Phenylalanine L-Phenylalaninium Perchlorate: DFT calculations.

In this work, we report a combined experimental and theoretical study of a nonlinear optical material, L-Phenylalanine L-Phenylalaninium Perchlorate. Single crystals of the title compound have been grown by slow evaporation of an aqueous solution at room temperature. Theoretical calculations were preceded by redetermination of the crystal X-ray structure. The compound crystallizes in the non-centro symmetric space group P2(1)2(1)2(1) of the orthorhombic system. The FT-IR and Raman spectra of the crystal were recorded and analyzed. The density functional theory (DFT) computations have been performed at B3LYP/6-31G(d) level to derive equilibrium geometry, vibrational wavenumbers, intensity and NLO properties. All observed vibrational bands have been discussed and assigned to normal mode or to combinations on the basis of our DFT calculations as a primary source of attribution and also by comparison with the previous results for similar compounds. Natural bond orbital analysis was carried out to demonstrate the various inter-and intramolecular interaction that are responsible of the stabilization of the compound. The lowering of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap appears to be the cause of its enhanced charge transfer interaction leading to high NLO activity.