To bend or not to bend: experimental and computational studies of structural preference in Ln(Tp(iPr)2)2 (Ln = Sm, Tm).

The synthesis and characterization of Ln(Tp(iPr2))2 (Ln = Sm, 3Sm; Tm, 3Tm) are reported. While the simple (1)H NMR spectra of the compounds indicate a symmetrical solution structure, with equivalent pyrazolyl groups, the solid-state structure revealed an unexpected, "bent sandwich-like" geometry. By contrast, the structure of the less sterically congested Tm(Tp(Me2,4Et))2 (4) adopts the expected symmetrical structure with a linear B-Tm-B arrangement.

Synthesis and structure of divalent thulium borohydrides, and their application in ε-caprolactone polymerisation.

The new divalent thulium compound [Tm(BH(4))(2)(DME)(2)] could be prepared by reduction of [Tm(BH(4))(3)(THF)(3)] or from TmI(2) and KBH(4). It was used as a precursor to the divalent [(Tp(tBu,Me))Tm(BH(4))(THF)] by reaction with potassium tris(2-tBu-4-Me)pyrazolylborate (KTp(tBu,Me)). Both Tm(II) compounds were found active as ε-caprolactone polymerisation catalysts.

Synthesis of a stable radical anion via the one electron reduction of a 1,1-bis-phosphinosulfide alkene derivative.

A new type of stable radical ligand featuring a 1,1-bis-phosphinosulfide alkene backbone has been prepared and characterized on the basis of X-ray diffraction, EPR and DFT studies.