Synthesis and characterization of thorium and uranium tetraphenylimidophosphinate complexes. Crystal and molecular structures of Th(tpip)(4), U(tpip)(4) and UCl(tpip)(3)

Tetra(tetraphenylimidophosphinato)thorium, Th(tpip)(4) (1), was obtained fr om Th(NO4). 4H(2)O and Ktpip in aqueous medium. The analogous uranium compo und, U(tpip)(4) (2), has been prepared by reacting UCl4 with Ktpip in a 1:4 stoichiometric ratio, either in THF or in aqueous solution. X-ray diffract ion analysis showed that compounds 1 and 2 were isostructural. The metal ce nter is eight-coordinate by way of four bidentate tetraphenylimidophosphina te ligands in a square antiprismatic configuration. UCl(tpip)(3) (3) has be en isolated from the reaction of uranium tetrachloride with 3 equiv. of Ktp ip in aqueous solution. When this reaction was run in THF both compounds, U (tpip)(4) and UCl(tpip)(3), were obtained. The molecular structure of 3 has been determined by X-ray crystallography. The uranium atom is seven-coordi nate in a pentagonal bipyramidal configuration. These compounds were also c haracterized by infrared and H-1 and P-31 NMR spectroscopies. (C) 2000 Else vier Science Ltd. All rights reserved.