123835-08-5Relevant academic research and scientific papers
Phosphine complexes of trivalent early transition metals. X-ray crystal structure of the d1-d1 dimer [TiCl3(dippe)]2 and synthesis of the alkyl CrMeCl2(dippe)(thf)
Hermes, Ann R.,Girolami, Gregory S.
, p. 313 - 317 (2008/10/08)
Treatment of TiCl3(thf)3 (thf = tetrahydrofuran) with the chelating phosphine 1,2-bis(diisopropylphosphino)ethane (dippe) gives two products: the purple dimer [TiCl3(dippe)]2 and the green monomer TiCl3(dippe)(thf). The two compounds may be readily interconverted by loss or addition of the thf ligand. The dimer is coupled antiferromagnetically, and its X-ray crystal structure reveals an octahedral geometry about each titanium(III) center and a Ti?Ti distance of 3.44 ?. The dippe ligands each chelate a titanium atom and are trans to the bridging chlorides; the dimer thus possesses approximate D2h symmetry. Reactions of MCl3(thf)3, where M is vanadium or chromium, with dippe yield the monomeric thf adducts MCl3(dippe)(thf). The bromovanadium analogue VBr3(dippe)(thf) and the chromium acetonitrile adduct CrCl3(dippe)(MeCN) are also described. Addition of dippe to CrMeCl2(thf)3 gives the chromium(III) alkyl CrMeCl2(dippe)(thf) which has been shown to be a slow ethylene polymerization catalyst at room temperature. NMR and EPR studies of the dippe adducts are described. Crystal data for [TiCl3(dippe)]2·PhMe: orthorhombic, space group Pbcn, with a = 15.586 (5) ?, b = 14.442 (4) ?, c = 21.639 (6) ?, V = 4871 (2) ?3, Z = 4, RF = 6.4%, RwF = 6.6% for 196 variables and 1231 data with I > 2.58σ(I).
