Synthesis and structure of fluorosilicic acid compounds with 4-aminobenzoic acid and with 4-aminobenzenesulfonamide - The role of H-bonding in crystal structure formation

Preparation and characterization of the ammonium hexafluorosilicate salts, 2[R](+)[SiF6](2-) (R = 4-(aminosulfonyl)benzenammonium) (1). and 2[R](+)[SiF6](2-)(.)4H(2)O (R = 4-carboxybenzenammonium), (2), are described. These salts, prepared from the reaction of the aminobenzenesulfonamide or the 4-aminobenzoic acid with fluorosilicic acid, were characterized by IR, mass spectrometry and X-ray diffraction. 1 and 2 crystallize in monoclinic crystal system (space group P2(1)/c and P2(1)/n, respectively), with Z = 2 in both cases. Compounds exhibit an extensive system of hydrogen bonding. (C) 2004 Elsevier B.V. All rights reserved.