Synthesis, structure, and reactivity of crystalline molecular complexes of the {[C5H3(SiMe3)2]3Th}1− anion containing thorium in the formal +2 oxidation state. Issue 1 (3rd November 2014)

• Record Type: Journal Article
• Authors: Langeslay, Ryan R.; Fieser, Megan E.; Ziller, Joseph W.; Furche, Filipp; Evans, William J.
• Is Part Of: Chemical science. Volume 6:Issue 1(2015:Jan.)
• Page Start: 517
• Page End: 521
• Publication Date: 2014-11-03
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c4sc03033h
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Structural, spectroscopic, and DFT analysis of the first molecular complexes of Th 2+ indicate they have a 6d 2 electron configuration of the type expected for the transactinide ions Rf 2+ and Db 3+ . Abstract : Reduction of the Th 3+ complex Cp′′3Th, 1 [Cp′′ = C5 H3 (SiMe3 )2 ], with potassium graphite in THF in the presence of 2.2.2-cryptand generates [K(2.2.2-cryptand)][Cp′′3Th], 2, a complex containing thorium in the formal +2 oxidation state. Reaction of1 with KC8 in the presence of 18-crown-6 generates the analogous Th 2+ compound, [K(18-crown-6)(THF)2 ][Cp′′3Th], 3 . Complexes2 and3 form dark green solutions in THF with ε = 23 000 M −1 cm −1, but crystallize as dichroic dark blue/red crystals. X-ray crystallography revealed that the anions in2 and3 have trigonal planar coordination geometries, with 2.521 and 2.525 Å Th–(Cp′′ ring centroid) distances, respectively, equivalent to the 2.520 Å distance measured in1 . Density functional theory analysis of (Cp′′3Th) 1− is consistent with a 6d 2 ground state, the first example of this transition metal electron configuration. Complex3 reacts as a two-electron reductant with cyclooctatetraene to make Cp′′2Th(C8 H8 ), 4, and [K(18-crown-6)]Cp′′.