Tetrametallic Thorium Compounds with ThE (E = S, Se) Cubane Cores.

Tetrametallic thorium compounds with a ThE core (E = S, Se) having a distorted cubane structure can be prepared by ligand-based reductions of elemental E with thorium chalcogenolates, prepared by in situ oxidation of Th metal with a 3:1 mixture of PhEEPh and FCEECF. Four compounds, (py)ThS(μ-SPh)(SCF), (py)ThS(μ-SPh)(SeCF), (py)ThSe(μ-SePh)(SeCF), and (py)ThSe(μ-SePh)(SCF), were isolated and characterized by NMR spectroscopy and X-ray diffraction. These compounds clearly demonstrate the chemical impact of ring fluorination, with the less-nucleophilic ECF ligands occupying the terminal binding sites and the EPh ligands bridging two metal centers. For this series of compounds, crystal packing and intermolecular π···π and H-bonding interactions result in a consistent motif and crystallization in a body-centered tetragonal unit cell. Solution-state Se NMR spectroscopy reveals that the solid-state structures are maintained in pyridine.