Binuclear Zinc Complexes with Radical-Anionic Diimine Ligands

The reactions of (dpp-BIAN)Zn−Zn(dpp-BIAN) ( 1 ) with PhC≡CH and of [(dpp-BIAN)Zn(μ-I)] 2 ( 2 ) with potassium hydride yield the binuclear complexes [(dpp-BIAN)Zn(μ-C≡CPh)] 2 ( 3 ) and [(dpp-BIAN)Zn(μ-H)] 2 ( 4 ), respectively (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene). Complex 3 is also obtained by thermal dehydrogenation of [dpp-BIAN(H)]Zn(C≡CPh) ( 5 ), which in turn can be prepared by reacting ZnI 2 with equimolar amounts of [dpp-BIAN(H)]Na and PhC≡CNa. The paramagnetic compounds 3 and 4 have been characterized by ESR spectroscopy; the diamagnetic complex 5, by 1 H NMR spectroscopy. The molecular structures of 3 and 4 have been determined by single-crystal X-ray diffraction. The electronic structure of complex 4 has been examined by DFT.