Preparation, crystal structure, vibrational spectra and thermal behavior of selenites of ethylene diamine, 1,3-propylene diamine and 1,4-butylene diamine

Selenites of ethylene diamine, propylene diamine and butylene diamine were prepared by crystallization from aqueous solution. The crystal structure was solved for all the substances. Ethylene diammonium(2+) selenite crystallizes in the orthorhombic space group P21212, a=11.3710(2) A, b=11.4390(5) A, c= 4.6290(4) A, V= 602.11(6) A3, Z=4, R=0.0341 for 5729 observed reflections. 1,3-Propylene diammonium(2+) selenite dihydrate crystallizes in the monoclinic space group C2/c, a=16.241(14) A, b=6.673(5) A, c=17.731(14) A, β=110.88(2) deg. , V=1795(3) A3, Z=8, R=0.0271 for 12,233 observed reflections. 1,4-Butylene diammonium(2+) selenite dihydrate crystallizes in the monoclinic space group P21/c, a=6.686(5) A, b=16.597(14) A, c=9.282(8) A, β=96.653(14) deg. , V=1023.2(14) A3, Z=4, R=0.0465 for 2918 observed reflections. The FTIR an FT Raman spectra of all the compounds were recorded and interpreted. The thermoanalytical properties were studied by the TG, DTG, and DTA methods in the 293-633 K temperature range. DSC measurements were carried out in the range from 98 K to the temperature of decomposition of the compounds. No thermal effect indicating a phase transition was observed in this temperature region