S-(−)-1-phenyl ethyl ammonium(1+) sulphate and S-(−)-1-phenyl ethyl ammonium(1+) hydrogen phosphate 2.5 hydrate, preparation and characterization of crystallographic, optical and dielectric properties

Abstract

S-(−)-1-phenyl ethyl ammonium(1+) sulphate and S-(−)-1-phenyl ethyl ammonium(1+) hydrogen phosphate 2.5 hydrate were prepared at laboratory temperature by slow evaporation of aqueous solutions of a mixture of S-(−)-1-phenyl ethyl amine and H 2SO 4 or H 3PO 4 in a molar ratio of 2: 1. The chirality on the organic amine was retained during the preparation and the obtained substances crystallized in non-centrosymmetric space groups. S-(−)-1-phenyl ethyl ammonium (1+) sulphate crystallizes in a monoclinic crystal system, space group C2, a = 10.8050(5) Å, b = 6.1080(4) Å, c = 13.3430(8) Å, β = 90.679(4)°, V = 880.54(9) Å 3, Z = 2, calculated density 1.284 g cm −3. S-(−)-1-phenyl ethyl ammonium(1+) hydrogen phosphate 2.5 hydrate crystallizes in a monoclinic crystal system, space group P2 1, a = 16.7810(10) Å, b = 6.2870(2) Å, c = 19.7060(12) Å, β = 109.160(2)°, V = 1963.86(18) Å 3, Z = 4, calculated density 1.303 g cm −3. Space groups C2 and P2 1 belong amongst “polar” groups, that could exhibit interesting dielectric properties, which have been studied (dependence of the polarization on an external electric field or of the relative permittivity on the temperature), and generation of the second harmonic frequency. Both substances were further characterized by chemical analysis, X-ray structural and powder analysis, infrared and Raman spectroscopy and thermal analysis (DTA, TGA).