Synthesis, spectroscopy, and crystal structure of a new stable biscyclopentadienyl uranium(IV) dichloride containing two C5H4-rings interlinked by a metal-coordinated 2,6-bis(methylene)pyridyl unit

Article abstract of DOI:10.1016/0022-328X(91)86077-4

Reaction of the new disodium salt: Na2<2,6-C5H3N(CH2C5H4)2 (2; 2,6-C5H3N = 2,6-pyridyl) with UCl4 in THF affords the reddish-green, mononuclear Cp2U^IVCl2-derivative (Cp = η⁵-C5H5): μ-<2,6-CH2C5H3NCH2>(η⁵-C5H4)2U^IVCl2 (1).According to a single-crystal X-ray study, 1 involves a notably strong U-N bond (U-N_av: 2.62(1) Angstroem) along with two nonequivalent Cl ligands (U-Cl: 2.615(3) and 2.636(3) Angstroem).The low-temperature 1H NMR spectrum of the paramagnetic complex is in full accord with the solid state structure 1.Up to room temperature, the dissolved molecules of 1 show no fluxionality on the NMR time scale, although the two CH2 proton resonances appear to undergo coalescence.