Trimethylphosphine oxide complexes of thorium and uranium tetra-nitrates; crystal structures of ten- and twelve-co-ordinate complex ions, bis[trinitratotetrakis(trimethylphosphine oxide)thorium(IV)] hexa-nitratothorate(IV) and tetraphenylphosphonium pentanitratobis(tri-methylphosphine oxide)thorate(IV)

Abstract

The complexes M(NO₃)₄·xPMe₃O (x= [graphic omitted], M = Th; x= [graphic omitted], M = U), [M(NO₃)₂(PM₃O)₅][BPh₄]₂(M = Th or U), and [PPh₄][Th(NO₃)₅(PMe₃O)₂] have been prepared and the formation of [M(NO₃)₄·5PMe₃O] has been confirmed: their i.r. spectra are discussed. The crystal and molecular structures of [Th(NO₃)₃(PMe₃O)₄]₂-[Th(NO₃)₆](1) and [PPh₄][Th(NO₃)₅(PMe₃O)₂](2) have been determined by the heavy-atom method from X-ray diffractometer data and refined by least squares to R 0.090 and 0.054 respectively. Crystal parameters are as follows: (1), monoclinic, space group Pn, a= 9.523(l), b= 14.507(2), c= 27.302(5) 8Å, β= 95.322(13)˙, and Z= 2; (2). orthorhombic, space group Pnma, a= 24.626(6), b= 12.922(2), c= 12.777(2)Å, and Z= 4. The structure analyses are based on 5 131 (1) and 3 326 (2) intensities above background. Both crystals contain discrete ions. The co-ordination numbers for thorium in (1) are 10 (1 : 5 : 4 geometry) for the cation and 12 (icosahedron) for the anion, while in (2) the co-ordination number in the disordered anion is 12. The Th–O co-ordination distances are in the ranges: (l), 2.24–2.53 for the PMe₃O groups (average 2.34), 2.46–2.94 for the nitrate groups (average 2.61 Å); (2), 2.34–2.42 (average 2.38) and 2.52–2.75 (average 2.64 Å) respectively.