Monomeric alkylaluminum complexes (dpp-BIAN)ALR2 (R = Me, Et, iBu) supported by the rigid chelating radical-anionic -: 1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene ligand (dpp-BIAN)

Me2AlCl, Et2AlBr, and (Bu2AlCl)-Bu-i react with (dpp-BIAN)Na (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino] acenaphthene) in Et2O to give the dialkylaluminum complexes (dppBIAN)AlR2 (R = Me (1), Et (2), Bu-i (3)). Compounds 1-3 have been characterized by elemental analysis, IR and ESR spectroscopy, and X-ray crystal structure analysis. In the molecules of 1-3 the Al atoms are tetrahedrally coordinated by two alkyl groups and the two N atoms of the dpp-BIAN ligand. The ESR spectra of the complexes prove the radical character of the dpp-BIAN ligand and show a hyperfine structure due to the coupling of the unpaired electron with the N-14, Al-27, and H-1 nuclei.