J. Barycki

New hydrogen-bonded molecular crystals with nonlinear second-order optical properties

Abstract Fifteen new hydrogen-bonded crystals exhibiting nonlinear optical properties were obtained. For the morpholinium dihydrogenphosphate crystal, the structure was determined by the X-ray diffraction methods. This crystal belongs to the P 2 1 space group of the monoclinic system. The lattice parameters are as follows: a =8.345(2), b =6.156(1), c=9.109(2) A ; β =116.64(3)°. The crystal is built up of the layers parallel to the (001) crystallographic planes. The layer consists of the dihydrogenphosphate chains running parallel to the [010] direction. The morpholinium cation participates in two hydrogen bonds with the O(4) oxygen atoms of dihydrogenphosphate anions belonging to two neighbour chains shifted by the a distance. In such a way, the chains of dihydrogenphosphates are joined by the morpholinium cations into the layer parallel to the (001) crystallographic plane. Additionally, the powder IR and Raman spectra are presented for this crystal.

Novel nonlinear optical crystals of noncentrosymmetric structure based on hydrogen bonds interactions between organic and inorganic molecules

Abstract For second harmonic generation (SHG), well-established inorganic crystals are now in direct competition with more efficient organic molecular crystals, made of highly polarizable conjugated molecules suitably packed to build up a noncentrosymmetrical structure. In recent years, a new strategy has been developed in material engineering, with intent to associate the strong quadratic nonlinear coefficients of some remarkable organic crystals to the mechanical and thermal stabilities of mineral structures, owing to the complexion of organic and inorganic molecules based on acid–base interactions. We present several hydrogen-bonded molecular crystals composed of various nonlinear organic molecules (cations) linked to the anions corresponding to phosphoric, selenic, orthoarsenic, and phenyloarsenic acids, respectively. SHG activity was measured using the Kurtz and Perry powder technique, crystal structure was determined from X-ray measurements, TF-IR and TF-Raman spectra were used to characterize the formation of hydrogen bonds.

Structural and vibrational study of a novel nonlinear optical material: 3-nitrobenzoic acid hydrazide

Abstract 3-Nitrobenzoic acid hydrazide is a good second harmonic generator (2.0 relative to KDP). The crystal structure has been found to belong to the P212121 space group of the orthorhombic system, with Z=4, a=3.8890(10) A , b=7.1370(10) A , and c=28.604(6) A . The molecules are linked ‘head-to-head’ through hydrogen bonds and short C–H⋯X contacts between the acid hydrazide groups forming a lamellar-like network extending in the ab plane, with the lamellae linked along the c direction by short C–H⋯O contacts. Infrared and Raman spectra of powder samples have been measured and assigned with the aid of density functional theory calculations.

AM1 and Ab Initio Studies of Aminomethylphosphonic Acid

Abstract The molecular properties of aminomethylphosphonic acid in the zwitterionic and molecular forms were calculated using the AMI and ab initio methods with the STO-3G ∗ , 3-21G ∗ and 6-31G ∗ basis sets at the self-consistent-field and electron-correlation level. It was found that the molecular form of this acid is 10.4 kcal mol −1 more stable than the zwitterionic one in the gas phase.

CNDO/2 studies of aminomethylphosphonic and aminomethyl-p-methylphosphinic acids

Abstract Molecular properties of aminomethylphosphonic and aminomethyl-P-methylphosphinic acids in the zwitterionic and molecular forms have been evaluated by the CNDO/2 method. It is found that the molecular form of both acids is more stable than the zwitterionic one in the gas phase. The preferred hydration sites are evaluated.