Mn(II) ions are incorporated in Zn(II)L-Histidine hydrochloride crystals by doping. Crystals are grown by using the technique of slow evaporation from aqueous solutions at room temperature. Thus developed crystals are characterized by powder X-Ray diffraction, EPR, FTIR, UV-VIS and Vicker's microhardness studies.

Powder XRD, EPR, optical,NLO activity and Biological activities of Fe(III)doped Mn(II)L-Histidine Hydrochloride Monohydrate (LHICl) was carried out at room temperature to ascertain the structural properties. In EPR, the angular variation of Fe(III) hyperfine lines indicated a single site, with spin Hamiltonian parameters (g) values g = 2.0292, The calculated results of the Fe(III)doped Mn(II)L-substitutes the Fe(III) ion in the host lattice, and it has orthorhombic symmetry. The EPR evaluated lattice cell parameters, a = 1.5320, b = 0.8450 and c = 0.6834 nm and V = 884.69 Å3 and optical absorption data Dq = 700, B= 610, C= 2360 [α] = 90 cm-1 were corroborated to obtain various bonding parameters, from which the nature of bonding in the complex was discussed. FT-IR and powder XRD studies were used to observe the effect of dopant on structural parameters of the host lattice.

Fe(III) ion doped Ni L-Histidine Hydrochloride monohydrate crystals (Fe(III)-NiLHICL) are grown at room temperature using slow evaporation technique.The Fe(III) doped NiLHICL crystals are characterized by spectroscopic techniques such as X-Ray diffraction studies, Electron Paramagnetic Resonance(EPR), Optical Absorption and FTIR studies.Thermal stabilities were studied by TGA/DTA analysis.The powder diffraction patterns of prepared crystals have been recorded and lattice cell parameters are evaluated as a = 1.5286, b = 0.8933, c = 0.6852 nm.From EPR studies, g and hyperfine splitting parameters for Fe(III) ion in the host crystals are determined as g = 2.0301 indicating octahedral symmetry.Crystal field and inter-electronic parameters are evaluated from the optical absorption studies in addition to obtaining the confirmation for octahedral symmetry for the ions in the host lattice.The FT-IR spectrum exhibited characteristic vibrations of the groups present in the crystal indicating bond formation between the metal ion and the amino acid.

The main focus of this work had been to grow good quality crystals from amino acids and amino acid based materials for spectroscopic applications. Growth of crystals from aqueous solution is one of the methods of crystal growth which is extremely popular in the production of technologically important crystals. For the first time, Mn(II) doped Ni LHistidine Hydrochloride monohydrate, Mn-NiLHICL crystals were grown from aqueous solution at room temperature by slow evaporation technique. The Mn(II) doped crystals were characterized by spectroscopic techniques such as X-Ray diffraction studies, Electron Paramagnetic Resonance(EPR), Optical absorption and FTIR studies. From the powder diffraction patterns of the grown crystals, lattice cell parameters were evaluated, a = 1.5186 nm, b = 0.8917 nm and c = 0.6889 nm. Values calculated from EPR studies for ‘g’ and Hyperfine Splitting factor for Mn(II) ion in the host crystal, g = 2.071, A= 103 x 10 -4 cm -1 indicated octahedral symmetry. Optical absorption studies confirmed the octahedral symmetry of Mn(II) ions in the host crystal. Crystal field and inter electronic parameters were evaluated for Mn 2+ ion as Dq = 855cm -1 , B = 810 cm -1 and C = 2480 cm -1 . Characteristic vibrations of the structure in the crystal confirmed the nature of bonding between the doped metal ion and the amino acid complex.

The main focus of this work had been to grow good quality crystals from amino acids and amino acid-based materials for nonlinear optics (NLO) applications. For the first time, a series of amino acid complexes doped with transition metal ions were grown in our laboratory from aqueous solutions by slow evaporation technique. Ni(II) ion doped Manganese L-Histidine hydrochloride monohydrate (Ni(II)-MnLHICl) crystals were grown on the same lines and were characterized by powder X-ray diffraction (XRD), optical absorption, electron paramagnetic resonance, and infrared absorption studies. From Powder XRD, the unit cell lattice parameters were calculated as a=1.5301 nm, b=0.8928 nm and c=0.6851 nm. From electron paramagnetic resonance (EPR) spectra, isotropic “ g ” factor and spin hamiltonian parameter A all were calculated as 2.0439 and 20×10−4, respectively. From optical absorption studies, crystal field splitting value (Dq) and the interelectron repulsion parameters B and C were calculated for Ni 2+ and Mn 2+ as Dq=850 cm −1 , B=725 cm −1 , C=2640 cm −1 and Dq=915 cm −1 , B=810 cm −1 , C=2780 cm −1 , respectively. The presence of various functional groups and the modes of vibrations were confirmed by FTIR studies.

Single crystals of pure and cupric ion (Cu(II))-doped magnesium rubidium sulfate hexahydrate (MRSH) were prepared by slow evaporation of saturated solution technique (SEST) and the influence of dopant Cu(II) on the MRSH crystals has been investigated. Incorporation of Cu(II) into the crystalline matrix was confirmed by energy dispersive spectroscopy (EDS) and electron paramagnetic resonance (EPR) spectroscopy. Thermogravimetric (TG) analysis of the doped sample reveals the faster rate of degradation. EPR spectrum of the MRSH both at room temperature and at 77 K indicates the presence of Cu(II) in the interstitial position. The grown crystals were also characterized by UV–VIS and IR spectroscopy. The surface morphology of the doped sample studied by scanning electron microscopy (SEM) indicates different morphology at various magnifications. The non-linear optical (NLO) property measured using second harmonic generation (SHG) efficiency test reveals that the non-linearity is not facilitated by doping of Cu(II).