Kurze inter-und intramolekulare W asserstoffbrückenbindungen in sauren Salzen halogensubstituierter Orthophthalsäuren/ Short Inter-and Intramolecular Hydrogen Bonds in Acid Salts of Halogen-Substituted o-Phthalic Acids

Abstract

Abstract The hydrogen bonding in several acid salts of 4,5-dichlorophthalic, 3,6-dichlorophthalic and 3-fluorophthalic acid have been studied by IR spectroscopy and X-ray structure analysis. NH4H [3,6-Cl2C8H2O4] and KH[3-FC8H3O4], with O···O distances of 247 and 254.1(4) pm, respectively, belong to Speakman’s type B2 of acid salts of dicarboxylic acids. In NH4H[4,5-Cl2C8H2O4] · H2O a short hydrogen bond of 253(1) pm is formed to the H2O molecule. A very short intramolecular hydrogen bond of only 234.0(10) pm length was found in N(C4H9)4H[4,5-Cl2C8H2O4], In the [3,6-Cl2C8H2O4]2- dianion both carboxylate groups are nearly orthogonal to the phenyl ring.