Inorganic Salts of N -phenylbiguanidium(1+)-Novel Family with Promising Representatives for Nonlinear Optics

Seven inorganic salts containing -phenylbiguanide as a prospective organic molecular carrier of nonlinear optical properties were prepared and studied within our research of novel hydrogen-bonded materials for nonlinear optics (NLO). All seven salts, namely -phenylbiguanidium(1+) nitrate ( 2/ ), -phenylbiguanidium(1+) perchlorate ( -1), -phenylbiguanidium(1+) hydrogen carbonate ( 2 / ), bis( -phenylbiguanidium(1+)) sulfate ( 2), bis( -phenylbiguanidium(1+)) hydrogen phosphate sesquihydrate ( -1), bis( -phenylbiguanidium(1+)) phosphite ( 2 ), and bis( -phenylbiguanidium(1+)) phosphite dihydrate ( 2 / ), were characterised by X-ray diffraction (powder and single-crystal X-ray diffraction) and by vibrational spectroscopy (FTIR and Raman). Two salts with non-centrosymmetric crystal structures-bis( -phenylbiguanidium(1+)) sulfate and bis( -phenylbiguanidium(1+)) phosphite-were further studied to examine their linear and nonlinear optical properties using experimental and computational methods. As a highly SHG-efficient and phase-matchable material transparent down to 320 nm and thermally stable to 483 K, bis( -phenylbiguanidium(1+)) sulfate is a promising novel candidate for NLO.