Magnesium and calcium complexes with two diimine radical-anion ligands.Molecular structure of the Ca complex with 1,2-bis[(2,6-diisopropylphenyl)iminp]acenaphthene

摘要

Four- and five-coordinate magnesium and calcium complexes containing two diimine radical-anion ligands with compositions (dpp-BIAN)_2Mg (1),(dpp-BIAN)_2Ca (2),(dtb-BIAN)_2Mg (3),and (dtb-BIAN)_2Ca(THF) (4) (dpp-BIAN is l,2-bis[(2,6-diiso-propylphenyl)imino]acenaphthene and dtb-BIAN is l,2-bis[(2,5-di-tert-butylphenyl)imi-no]acenaphthene) were synthesized.At 120 K,the ESR spectra of complexes 1-4 in a toluene matrix show signals characteristic of biradical derivatives.The molecular structure of compound 2 was established by X-ray diffraction analysis.At 293 K,the magnetic moments of compounds 1,2,3,and 4 are 2.55,2.57,2.76,and 2.79 mu_B,respectively,which are indicative of the presence of two unpaired electrons localized on the ligands.