Thorium Compounds with Bonds to Sulfur or Selenium: Synthesis, Structure, and Thermolysis

Thorium chalcogenolates Th(ER)4 (E = S, Se; R = Ph, C6F5) form pyridine complexes with a variety of coordination numbers. Four compounds, (py)4Th(SPh)4, (py)3Th(SePh)4, (py)3Th(SC6F5)4, and (py)4Th(SeC6F5)4, have been isolated and characterized by spectroscopic methods and low-temperature single crystal X-ray diffraction. Two of the products, (py)4Th(SPh)4 and (py)4Th(SeC6F5)4, have classic eight coordinate A4B4 square-antiprism geometries. The SePh compound is the only seven coordinate (4Se, 3N) product, and the fluorinated thiolate is distinctive in that the structure contains two dative interactions between Th and fluoride, to give a nine coordinate (3N, 4S, 2F) structure. The EPh compounds decompose thermally to give ThE2 and EPh2, while the fluorinated compounds give primarily ThF4, E2(C6F5)2, and E(C6F5)2.