Synthesis, characterisation, phase transitions and electrical properties of 4-benzylpyridinium dihydrogenmonophosphate and monohydrogensulfate

Two new organo-phosphate and organo-sulfate compounds were synthesized at room temperature. They have been firstly characterised by X-ray diffraction (XRD)-C6H5CH2C5H4NH+·H2PO4− is monoclinic P21/c with following unit cell dimensions: a = 5.7950(3) Å, b = 9.3490(18) Å, c = 23.537(5) Å and β = 97.328(11)°. C6H5CH2C5H4NH+·HSO4− is monoclinic P21/a with following unit cell dimensions: a = 8.990(6) Å, b = 9.925(7) Å, c = 14.081(9) Å and β = 105.18(8)°. In both cases the structure consists of infinite parallel two-dimensional planes built of mutually H2PO4−/HSO4− anions and C6H5CH2C5H4NH+ cations connected by strong O-H⋯O and N-H⋯O hydrogen bonds. Then, in order to detect phase transitions and watch changes in the conductivity behaviour, investigations by differential scanning calorimetry (DSC), electrical conductivity measurements were carried out. A substitution of H2PO4− by HSO4− increases the conductivity even at room temperature.