Studies on Nucleation and Growth Kinetics, Molecular Structure, Spectral Characterization and Antibacterial activity of DL-Methioninium Maleate Compound for Biological Applications

Abstract

Single crystals of DL-methioninium maleate (abbreviated as DLMM) were synthesized by slow evaporation technique from aqueous solution at room temperature. Before growing the crystal, the nucleation kinetics was analysed to estimate the critical supersaturation required for the growth of good quality crystal. The classical theory was employed to analyse the growth kinetics of the crystal. Using single crystal X-ray diffraction analysis, the lattice dimensions of the title compound were found to be a = 11.07 Å, b = 5.74 Å, and c = 19.69 Å. The crystallized compound belongs to monoclinic system (space group P21/c). From the powder X-ray diffraction study the different planes of the reflections have been distinguished and the results were confirmed. The molecular structure of the grown crystal DLMM was also analysed by using SHELXT-2014/7 program. The results indicate that the cationic form of the DL-methioninium molecule consists of a protonated amino group and an uncharged carboxylic acid group. The maleic acid molecule exists in its mono-ionized state. By observing the UV-Visible absorbance spectrum, the range and percentage of absorption and the material band gap were evaluated for the grown material. The absorption coefficient, complex refractive index and the optical transparency of the compound depend upon the optical band gap of the material. From the value of band gap (3.96eV) of the material, the absorption coefficient can be assessed. The absorption coefficient is an additional factor to elucidate the antibacterial behaviour of the material. Fourier transform infrared (FTIR) spectra have been used to determine the vibrational frequency of several DL-methioninium maleate functional groups. Using proton and carbon nuclear magnetic resonance (NMR) spectra, the presence of hydrogen and carbon in the formed crystal was verified. The presence of sulphur component in the grown material is one of the prime factors of the bioactive material. By using the Agar disc diffusion method, the antibacterial properties of the grown compound were also examined. The anti-bacterial activities of DLMM compound suggest that it can be employed to treat a number of bacterial infections in the field of pharmaceutical science.