Some substituted urea complexes of thorium tetranitrate; crystal structure of tetra(nitrato-O,O′)bis(tetramethylurea-O)thorium(IV), [Th(NO3)4{OC(NMe2)2}2]

Abstract

The complexes Th(NO₃)₄·xL [x= 2, L =(Me₂N)₂CO (tmu), (MePhN)₂CO, or (Buⁱ₂N)(Me₂N)CO; x= 2.67, L = tmu or (cyclo-C₆H₁₁NH)₂CO] have been prepared and their i.r. and Raman spectra are reported. The crystal structure of [Th(NO₃)₄(tmu)₂] has been determined from three-dimensional X-ray diffaction data. The compound crystallises in space group P2₁/a, with a= 19.523(2), b= 12.209(1), c= 10.026(1)Å, β= 99.4(1)°, and Z= 4. The structure was solved by Patterson and Fourier methods; full-matrix least-squares refinement based on 2 537 reflections gave final R values of R= 0.032 and R′= 0.037. The co-ordination about the thorium is best described as an octahedron with the two tmu molecules traps and the four bidentate nitrate groups occupying the equatorial positions.