An unexpected deboronation of [tBuB(3-tBuC3H2N2)3]− in a reaction with iron(II) chloride, and the X-ray crystal structure of trans-FeCl2(tBuC3H3N2)4

The reaction between FeCl2(THF)1.5 and the sterically hindered thallium salt of tert-butyl-tris(3-tert-butylpyrazol-1-yl)borate, Tl[tBuB(3-tBu-pz)3], gives the complex trans-FeCl2(tBu-pzH)4 (1) as the only isolable product in 19% yield. Compound 1 has been crystallographically characterized and appears to be a typical high-spin octahedral iron(II) complex (μeff=5.1±0.3 BM).