Salts of guanine and alkali metals: preparation and structural study at broad range of T, P

A high-pressure single-crystal X-ray diffraction study of potassium guaninate hydrate, K+·C5H4N5O−·H2O

“…The crystal structure of K + ÁC 5 H 4 N 5 O À ÁH 2 O was discussed in detail by Gaydamaka et al (2021). The asymmetric unit consists of two symmetry-independent, singly deprotonated guaninate anions which differ in the positions of the protons, two potassium cations that differ in coordination type and two water molecules (Fig.…”

“…Potassium guaninate hydrate was crystallized by slow evaporation from ethanol solutions containing guanine (Sigma-Aldrich) and an excess amount of potassium hydroxide at room temperature as described by Gaydamaka et al (2021). Two needle-like crystals (80 mm  20 mm  20 mm and 140 mm  80 mm  80 mm) were extracted and studied by single-crystal X-ray diffraction.…”

“…The initial crystal structure model for refinement was taken from single-crystal diffraction data collected under ambient conditions (CCDC reference 2098604, refcode UBUJOU04; Gaydamaka et al, 2021).…”

“…The previous measurement in a synchrotron experiment was at a pressure of 3.9 GPa, when no modulation was observed. If satellites are neglected, the structure at 4.9 GPa could be solved and refined as periodic, very similar to that of the low-pressure phase (Gaydamaka et al, 2021). On further increasing the pressure, and processing the diffraction data by neglecting satellites, the low-pressure phase model could still give the values of the unit-cell para-…”

“…In the crystalline salt hydrates of alkali metals guaninate anions form channels in which metal cations interact with water molecules and the channel walls. In our previous work we studied the effect of temperature variation on the crystal structure of potassium guaninate hydrate, K + ÁC 5 H 4 N 5 O À ÁH 2 O (Gaydamaka et al, 2021) and compared the structural strain with the distortions induced in a sodium guaninate hydrate, 2Na + Á-C 5 H 3 N 5 O 2À Á7H 2 O, on cooling (Gaydamaka et al, 2021) and under hydrostatic compression (Gaydamaka et al, 2019). The aim of the present contribution is to complete these studies by investigating the crystal structure of K + ÁC 5 H 4 N 5 O À ÁH 2 O under hydrostatic compression.…”