Uranyl nitrate complexes with lactams

The preparation, characterization and spectroscopy of complexes of uranyl n itrate with the lactams: delta -valerolactam (delta -val, C5H9NO), epsilon -caprolactam (epsilon -capro, C6H11NO), 2-azacyclononanone (2-aza, C8H15NO) and 2-azacyclotridecanone (2-actd, C12H23NO) are described. They were prep ared by reaction of hydrated uranyl nitrate with the ligands in ethanolic s olution (molar ratio 1:2) and presented the general composition UO2(NO3)(2) .2L, except for the epsilon -capro complex that is dimeric, with compositio n: (UO2)(2)(NO3)(2)(O-2)(epsilon -capro)(4). The peroxo bridge was introduc ed when 2,2-dimethoxypropane contaminated with peroxide was used to precipi tate the crystals. They were characterized by CHN microanalyses, IR spectra , TG and DSC analyses and emission spectra in the visible region. The struc ture of the epsilon -capro complex was determined by X-ray single crystal a nalysis. (C) 2001 Published by Elsevier Science B.V.