Actinide and lanthanide complexes with bidentate ligands. Crystal structure of methanolbis(N-phenylbenzoylhydroxomato)dioxouranium(VI)

✍ Scribed by U. Casellato; P.A. Vigato; S. Tamburini; R. Graziani; M. Vidali

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 279 KB
• Volume: 94
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(00)94526-2

✦ Synopsis

Th(NCS)4*4dmpa (2) (ThCs4HMNs04S4) M = 821 .O, monoclinic P, = 22.759(6), b =

13.763(4), c = 11.910&%: fi = 91.4(l)", Z = 4 A(MoK,-J 0.71069 A. 3729 reflections with I $ 2.50(l) used in the structure solution and refinement, R = 0.049, R, = 0.053.

The coordination geometry for (I) is pentagonal bipyramidal as shown in Fig. 1, with two chlorine atoms occupying the axial positions. This kind of geometry is common in sevencoordinate dioxouranium(V1) complexes, rather unusual for U(W) compounds and the first example for that concerning mononuclear Th(IV) derivatives.

The Th-Cl axial bond distances (2.69 A av.) are shorter respect to the ThhCl equatorials (2.75 A av.) as consequence of the different steric hindrance experienced by the anionic ligands.

The Th-0 bond distances have an averaged value of 2.34 A.

The coordination geometry for (2) (see Fig. 2) is nearly square antiprismatic. The substitution of the chlorine with the less hindering isothiocyanate ligand allows a higher coordination number around the thorium ion, while the change of the neutral ligand does not seem of some effect. The Th-N and Th-0 bond distances have the averaged values of 2.50 A and 2.38 A respectively.