Chromium and tungsten complexes with a paramagnetic gallaimidazole ligand

The reaction of digallane [(dpp-bian)Ga—Ga(dpp-bian)] (1) (dpp-bian is 1,2-bis[(2,6-di-isopropylphenyl)imino]acenaphthene dianion) with chromium or tungsten hexacarbonyl affords the complexes [(dpp-bian)Ga—Cr(CO)₅] (2) and [(dpp-bian)Ga—W(CO)₅] (3), respectively, containing the neutral radical [(dpp-bian)Ga:]. In both cases, temperature-dependent solvation of the gallium center was observed in a tetrahydrofuran solution. The recrystallization of compound 2 from pyridine gave the new complex [(dpp-bian)(Py)Ga—Cr(CO)₅] (4). New compounds 2–4 were characterized by EPR and IR spectroscopy and elemental analysis. The molecular structures of complexes 2–4 were established by single-crystal X-ray diffraction.