Preparation, crystal structure, vibrational spectra and thermal behaviour of piperazinium(2+) selenite monohydrate and piperazinium(2+) diselenite
Abstrakt
Measuring of the FTIR and Raman spectra and study at lab. temperature. Piperazinium(2+) selenite monohydrate and piperazinium(2+) diselenite were prepared by crystallization from aqueous solutions.
The crystal structures of both substances were solved. Piperazinium(2+) selenite monohydrate crystallizes in the monoclinic space group P2(1)/c, a = 12.308(2), b = 6.5530(7), c = 10.4936(6) Angstrom; beta = 92.915(7)degrees, Z = 4, R = 0.0193 for 1492 observed reflections.
Piperazinium(2+) diselenite crystals belong to triclinic space group P (1) over bar, a = 7.0801(8), b = 8.325(1), c = 8.496(1) Angstrom; alpha = 97.130(10), beta = 105.927(9), gamma = 101.240(10)degrees: Z = 2, R = 0.0390 for 1621 observed reflections. The lattice parameters of the substances were also refined using powder diffraction methods.
The piperazinium(2+) cations in the chair conformation are arranged almost plane-parallel above one another in the structure of the first substance, while the second substance contains piperazinium(2+) rings almost perpendicular to one another. The FTIR and FT Raman spectra were measured and studied at laboratory temperature for both the prepared substances.
Their thermoanalytical properties were studied using TG, DTG and DTA methods in the temperature range 293-573 K. DSC measurements were carried out in the temperature range 95-423 K.
No phase transitions were observed within this temperature interval.
