L-Argininium phosphite - a new candidate for NLO materials.

In order to investigate the possibility of salt formation in the L-Arg-H3PO3-H2O system, single crystals of L-argininium phosphite, C6H15N4O2(+)·H2PO3(-), were prepared by evaporation of an aqueous solution containing equimolar quantities of L-arginine and phosphorous acid. The asymmetric unit contains one L-argininium(+) cation and one phosphite [HPO2(OH)](-) anion. The phosphite anions form chains parallel to [010] by O-H...O hydrogen bonding, with an O...O distance of 2.630 (3) Å. The protonated amine and guanidyl groups of the L-argininium(+) cations form N-H...O hydrogen bonds with the carboxylate groups and anions. The IR and Raman spectra are discussed in relation to the crystal structure. The salt displays nonlinear optical (NLO) properties. Another salt was obtained from a solution with a 1:2 molar ratio of components, but was characterized by vibrational spectra only.

Diaquaiodidotetrasarcosinepotassium: an overview of sarcosine metal halogenide structures.

The monoclinic crystal structure of tetrasarcosine potassium iodide dihydrate {or catena-poly[[potassium-tetra-µ-sarcosine-κ(4)O:O';κ(4)O:O] iodide dihydrate]}, {[K(C(3)H(7)NO(2))(4)]I·2H(2)O}(n) or Sar(4)·KI·2H(2)O (space group C2/c), comprises two crystallographically different sarcosine molecules and one water molecule on general positions, and one K(+) cation and one I(-) anion located on twofold axes. The irregular eight-coordinated K(+) polyhedra are connected into infinite chains along [001] via sarcosine molecules. This compound is the first sarcosine metal halogenide salt with a 4:1 ratio. A short overview of other sarcosine metal halogenide salts is presented and relationships to similar glycine salts are discussed.