Anja Edelmann

Unprecedented Bending and Rearrangement of f-Element Sandwich Complexes Induced by Superbulky Cyclooctatetraenide Ligands

The use of the superbulky cyclooctatetraenide dianion ligand [C(8)H(6)(SiPh(3))(2)](2-) (= COT(BIG)) in organo-f-element chemistry leads to unprecedented effects such as the formation of a significantly bent anionic Ce(III) sandwich complex, a novel cerocene formed by sterically induced SiPh(3) group migration, as well as the first example of a bent uranocene.

Strukturuntersuchungen an Diaryldichalkogeniden: Die Molekülstrukturen von [2,4,6-(CF3)3C6H2S]2,[2,4,6-Me3C6H2Te]2 und [2-Me2N-4,6-(CF3)2C6H2Te]2 / Structural Investigations of Diaryl Dichalcogenides: The Molecular Structures of [2,4,6-(CF3)3C6H2S]2, [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2

Abstract The Molecular Structures of [2,4,6-(CF3)3C6H2S]2 (1) [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2 (3) have been determined by X-ray diffraction. Crystal data: 1: orthorhombic, space group P212121, Z = 4, a = 822.3(2), b = 1029.2(2), c = 2526.6(5) pm (2343 observed independent reflexions, R = 0.042); 2: orthorhombic, space group Iba 2, Z = 8, a = 1546.5(2), b = 1578.4(2), c = 1483.9(1) pm (2051 observed independent reflexions, R = 0.030); 3: monoclinic, space group P 21/c, Z = 4, a = 1118.7(1), b = 1536.5(2), c = 1492.6(2) pm, β = 98.97(1)° (3033 observed independent reflexions, R = 0.025).

[N,N′-Bis(2,6-diisopropyl­phen­yl)methanimidamidato][η8-1,4-bis­(tri­methyl­sil­yl)cyclo­octa­tetra­enyl](tetra­hydro­furan)­samarium(III) toluene monosolvate

The title compound, [Sm(C25H35N2)(C14H24Si2)(C4H8O)]·C7H8, was prepared by treatment of anhydrous samarium trichloride with a 1:1 mixture of in situ-prepared Li(DippForm) [DippFormH = N,N′-bis(2,6-diisopropylphenyl)methanimidamide] and Li2(COT′′) [COT′′ = 1,4-bis(trimethylsilyl)cyclooctatetraenyl] in tetrahydrofuran (THF). Despite the presence of two very bulky ligands (COT′′ and DippForm), the molecule still contains one coordinated THF ligand. The overall coordination geometry around the SmIII atom resembles a three-legged piano-stool with the COT′′ ligand being η8-coordinated and the DippForm− anion acting as an N,N′-chelating ligand [Sm—N = 2.5555 (15) and 2.4699 (15) Å]. The asymmetric unit also contains a disordered molecule of toluene, the refined ratio of the two components being 0.80 (4):0.20 (4).