Volatile adducts of uranyl nitrate. Sublimation and mass spectra

Adducts of uranyl nitrate with strong neutral ligands: trimethyl phosphate (TMP), triethyl phosphate (TEP), trimethylphosphine oxide (TMPO), hexamethylphosphoric triamide (HMPTA), with a 1:2 composition, and phenanthroline (phen) (with a 1:1 composition), and also a complex with a composition of UO2(NO3) (NCS) x 2HMPTA were synthesized. The above enumerated compounds sublime in vacuo (adducts with TMP and TEP in a vapor current of the corresponding trialkyl phosphate) with a partial decomposition at temperatures of 160-2800C. A mass-spectrometric examination of the complexes synthesized has been carried out. It was shown that after splitting off of the ligand, the fragmentation of the adducts with TMPO and phen proceeds by the path consisting in splitting off of the NO2 group, while in the case of an adduct with TEP, a rearrangement takes places with the elimination of C2H5NO3. The last path is similar to the processes proceeding during the thermal decomposition of UO2(NO3)2 x 2TBP