title: Influence of sodium fluoride (NaF) on the crystallization and spectral properties of L-tyrosine.
abstract: L-Tyrosine (C(9)H(11)NO(3)) is an essential amino acid in living organisms. It is also a building unit in protein, takes part in bio-synthesis of hormones, neurotransmitters, pigments and one of the organic chemical constituents of urinary stones. L-Tyrosine has been crystallized in silica gel by double diffusion technique with and without the addition of NaF. The crystals had rosette-like shape. In case of fluoride addition, two types of crystals have formed: rosette like crystallites, at the gel-solution interface and reticulate type crystallites beneath the interface. XRD results confirmed that both the products are of l-tyrosine with identical crystal structures. Crystal structure, morphology, thermal and spectral properties are analyzed using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR) and UV-vis transmittance studies. The TG-DTA results suggest that the thermal stability of L-tyrosine has markedly improved due to fluoride doping. Optical band gap energy of NaF grown l-tyrosine crystallite is estimated as 4.28eV. Second harmonic generation efficiency test indicates that L-tyrosine crystals can be used for application in nonlinear optical devices.
authors.affiliation: Department of Physics, Sri Sarada College, Salem 636016, TN, India.
authors.forename: M
authors.initials: M
authors.lastname: Thenmozhi
authors.forename: K
authors.initials: K
authors.lastname: Suguna
authors.forename: C
authors.initials: C
authors.lastname: Sekar
mesh_terms: D003460:Crystallization; D004055:Differential Thermal Analysis; D008855:Microscopy, Electron, Scanning; D011208:Powders; D012969:Sodium Fluoride / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014443:Tyrosine / Q000737:chemistry*; D014732:Vibration; D014961:X-Ray Diffraction
chemical_list: D011208:Powders; D014443:Tyrosine; D012969:Sodium Fluoride