Metal vapor synthesis of (C5Me5)2Sm(THF)2 and (C5Me4Et)2Sm(THF)2 and their reactivity with organomercurial reagents. Synthesis and X-ray structural analysis of (C5Me5)2Sm(C6H5)(THF)

Article abstract of DOI:10.1021/om00120a019

The reaction of samarium metal vapor with hexane solutions of C₅Me₅H and C₅Me₄EtH at -110 to -125 °C followed by suitable workup gives (C₅Me₅)₂Sm and (C₅Me₄Et)₂Sm, respectively, as well as products which dissolve in THF to give (C₅Me₅)₂Sm(THF)₂ and (C₅Me₄Et)₂Sm(THF)₂, respectively. Evidence is found for hydride- and nitrogen-containing intermediates that decompose to the above compounds upon workup. (C₅Me₅)₂Sm(THF)₂ reacts with Hg(C₆H₅)₂ to form (C₅Me₅)₂Sm(C₆H₅)(THF) that has been characterized by X-ray crystallography. The phenyl complex crystallizes in space group P2₁/c with unit-cell dimensions a = 9.680 (5) A?, b = 17.291 (7) A?, c = 17.140 (7) A?, β = 103.78 (4)°, and Z = 4 for D_calcd = 1.36 g cm^-3. Least-squares refinement on the basis of 3308 observed reflections led to a final R value of 0.034. The two C₅Me₅ ring centroids, the phenyl carbon attached to Sm, and the THF oxygen describe a distorted tetrahedral structure around Sm in a structure typical of bent metallocene derivatives. Average Sm-C (ring) distances are 2.73 (1) and 2.745 (9) A?, the Sm-C(phenyl) distance is 2.511 (8) A?, and the Sm-O(THF) distance is 2.511 (4) A?.