K. Rajarajan

Growth, spectroscopic and physicochemical properties of bis mercury ferric chloride tetra thiocyanate: A nonlinear optical crystal

Single crystal of bis mercury ferric chloride tetra thiocyanate [Hg2FeCl3(SCN)4; (MFCTC)] was grown from ethanol-water (3:1) mixed solvent using slow evaporation solvent technique (SEST) for the first time. The cell parameters of the grown crystal were confirmed by single crystal XRD. The coordination of transition metal ions with the SCN ligand is well-identified using FT-IR spectral analysis. The chemical composition of MFCTC was confirmed using CHNS elemental test. The ESR spectral profile of MFCTC was recorded from 298 K to 110K, which strongly suggests the incorporation of Fe(3+) ion and its environment with respect to SCN ligand. The HPLC chromatogram of MFCTC highlights the purity of the compound. The UV-Vis-NIR studies revealed the ultra violet cut-off wavelength of MFCTC in ethanol as 338 nm. The dielectric constant and dielectric loss of the sample were studied as a function of frequency and temperature. The TGA-DTA and DSC thermal analysis show that the sample is thermally stable up to 234.31 °C, which is comparatively far better than the thermal stability of Hg3CdCl2(SCN)6; (171.3 °C) and other metal-organic coordination complex crystals such as CdHg(SCN)4 (198.5 °C), Hg(N2H4CS)4Mn(SCN)4 (199.06 °C) and Hg(N2H4CS)4Zn(SCN)4 (185 °C). The SHG conversion efficiency of MFCTC is found to be higher than KDP.

(Thio­cyanato-κS)­tris­(thio­urea-κS)mercury(II) chloride

In the title salt, [Hg(NCS)(CH4N2S)3]Cl, the Hg2+ ion is coordinated in a severely distorted tetrahedral manner by three thiourea groups and one thiocyanate anion through their S atoms. The S—Hg—S angles vary widely from 87.39 (5) to 128.02 (4)°. Weak intramolecular N—H⋯S hydrogen bonds are observed, which form S(6) ring motifs. In the crystal, the ions are linked by N—H⋯N and weak N—H⋯Cl interactions, generating a three-dimensional network.

catena-Poly[ammonium (cadmium-tri-μ-thio­cyanato-κ4S:N;κ2N:S)–1,4,10,13,16-hexa­oxa­cyclo­octa­decane (1/1)]

In the title compound, {(NH4)[Cd(NCS)3]·C12H24O6}n, the Cd2+ ion, the ammonium cation, one of the SCN− ligands and the macrocycle are located on mirror planes. The thiocyanate anions act as bridging ligands between the CdII ions, leading to a polymeric chain arrangement extending along [001] around a twofold screw axis. The ammonium ions are contained within the bowl of the macrocycle via extensive N—H⋯O hydrogen bonding.

Diammonium tetra­kis­(iso­thio­cyanato)­zincate–1,4,10,13,16-hexa­oxa­cyclo­octa­deca­ne–water (1/2/1)

The title compound, (NH4)2[Zn(NCS)4]·2C12H24O6·H2O, the result of the reaction of ammonium thiocyanate, 18-crown-6 and zinc(II) chloride in aqueous solution, exhibits an unusual supramolecular structure. The Zn atom, two of the thiocyanate chains and a water molecule, disordered over two positions, lie on a mirror plane. The macrocycle adopts a conformation with approximate D 3d symmetry. The ammonium molecules are contained within the bowl of the macrocycle via extensive N—H⋯O hydrogen bonds and the complex molecules are linked via N—H⋯S hydrogen bonds, forming chains along the c-axis direction. The macrocycle is disordered over two positions [refined occupancy ratio = 0.666 (8):0.334 (8)]. The S atoms of two isothiocyanate ligands are disordered within and about the mirror plane.

catena-Poly[[bis-(thio-cyanato-κN)cobalt(II)]-di-μ-thio-urea-κ(4)S:S].

In the title polymeric complex, [Co(NCS)2{SC(NH2)2}2]n, the asymmetric unit comprises a CoII ion, which is situated on an inversion centre, an N-bound thiocyanate anion and a μ2-bridging thiourea molecule. The CoII atom is coordinated in a distorted octahedral fashion within an N2S4 donor set. The bridging thiourea ligands link CoII ions into a polymeric chain extending along [100]. The molecular conformation is stabilized by intramolecular N—H⋯N hydrogen bonds, which generate S(6) ring motifs. The crystal packing is stabilized by N—H⋯S interactions, which connect the chains into a three-dimensional architecture.

catena-Poly[[bis­(μ2-1,4,7,10,13,16-hexa­oxacyclo­octa­deca­ne)dipotassium]-μ2-iodido-(iodidocadmium)-di-μ2-iodido-(iodidocadmium)-μ2-iodido]

The reaction of CdCl2, 18-crown-6 and KI in water yields the title coordination polymer, [{K(C12H24O6)}2Cd2I6]n. The potassium ion lies approximately in the plane of the crown ether, coordinated by all six crown ether O atoms and also by an iodide anion bound to a cadmium atom. A C atom of the crown ether is disordered over two positions with site occupancies of 0.77 (2) and 0.23 (2). Two K(18-crown-6)+ units are linked by inversion symmetry, forming a [bis(μ2-18-crown-6)dipottasium] system with approximately square-planar K2O2 units. Inversion symmetry also generates the Cd2I6 fragment and the polymeric system is extended along the c axis by the formation of K—I—Cd bridges.

A comparative analysis on optical, photo luminescence and laser damage properties of conventional and uniaxial method grown semi organic nonlinear optical material – sodium potassium tartrate tetrahydrate

Abstract Bulk growth of (010) oriented Sodium Potassium Tartrate Tetrahydrate (SPTT), a Nonlinear Optical single crystal was grown by solution growth technique in uniaxial and conventional methods. Optically transparent single crystal of diameter 20 mm and length 150 mm was harvested by uniaxial method in a period of 25 days and dimensions upto10 mm ×5 mm ×3 mm by conventional method within 15 days. The grown crystal was confirmed by single crystal X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis. Phase purity was checked with Powder XRD (PXRD) analysis. Uniaxial method grown crystal has higher transmittance than the conventional grown crystal. The Second Harmonic Generation (SHG) efficiency was found to be 0.9 times higher than KDP and laser damage threshold also measured and reported. Broad Photoluminescence (PL) emission was observed at 350–449 nm from the crystals grown by both the methods and it arises due to the ultraviolet and violet of visible spectral emissions. Positive photo conducting nature of the grown crystals was confirmed by photoconductivity measurements.

Growth and comparison of physicochemical properties of Lewis base adduct of MMTC and CMTC: Efficient nonlinear optical single crystals

In the present investigation, single crystals of CMTG and MMTG were conveniently grown by slow evaporation technique. The grown crystals were confirmed by single crystal XRD. The physicochemical properties of the grown crystals were analyzed and compared. The SHG efficiency of CMTG is found to be three times higher than that of urea and for MMTG, it is equal to that of urea. Thermal stability of CMTG and MMTG was found to be 105 °C and 145 °C.

Crystal structure of bis­(thio­cyanato-κS)bis­(thio­urea-κS)mercury(II)

In the title complex, [Hg(NCS)2(CH4N2S)2], the HgII atom is four-coordinated having an irregular four-coordinate geometry composed of four thione S atoms of two thiocyanate groups and two thiourea groups. The S—Hg—S angles are 172.02 (9)° for the trans-thiocyanate S atoms and 90.14 (5)° for the cis-thiourea S atoms. The molecular structure is stabilized by an intramolecular N—H⋯S hydrogen bond, which forms an S(6) ring motif. In the crystal, molecules are linked by a number of N—H⋯N and N—H⋯S hydrogen bonds, forming a three-dimensional framework. The first report of the crystal structure of this compound appeared in 1966 [Korczynski (1966 ▸). Rocz. Chem. 40, 547–569] with an extremely high R factor of 17.2%, and no mention of how the data were collected.

Experimental investigations on the synthesis, growth and characterization of MCCTC single crystals

Single crystals of mercury cadmium chloride thiocyanate [Hg3CdCl2(SCN)6; (MCCTC)] were grown from ethanol solvent using slow solvent evaporation technique for the first time. The cell parameters of the grown crystals of MCCTC were confirmed by single crystal X-ray diffraction technique. The various functional groups of resulting compound were well-identified using FT-IR analysis. The UV-Vis-NIR studies revealed that the ultra violet cut off wavelength lies at 270 nm. It is also interesting to note that the sample exhibited wide range of optical transparency from 270 to 2000 nm in ethanol solution, which might be due to the incorporation of the halogen ion (Cl-) in the grown crystal of MCCTC. The second harmonic generation efficiency of MCCTC is found to be superior (about seventeen times) to KDP and (about three times) urea. TGA-DTA and DSC analysis showed that the thermal stability of the sample is retained up to 171.3°C above which phase change occurred from HgCdCl2(SCN)6 to CdHg(SCN)4 with other fragme...