Aluminum complexes with mono-and dianionic diimine ligands

Abstract

The metathesis reaction of the magnesium complex [(dpp BIAN) 2-Mg 2+ (THF) 3 ] (dpp BIAN is 1,2 bis[(2,6 diisopropylphenyl)imino]acenaphthene) with one equivalent of AlCl 3 in toluene gave the [(dpp BIAN) 2-AlCl 2 ] -[Mg 2 Cl 3 (THF) 6 ] + complex (1). Reduction of dpp BIAN with aluminum metal in the presence of AlCl 3 and AlI 3 in toluene and diethyl ether afforded the radical anionic complex [(dpp BIAN) -AlCl 2 ] (2) and the dianionic complexes [(dpp BIAN) 2-AlI(Et 2 O)] (3) and [(dpp BIAN) 2-AlCl(Et 2 O)] (4), respectively. Compounds 1-4 were isolated in the crystalline state and characterized by IR spectroscopy and elemental analysis. The structures of compounds 1-3 were established by X ray diffraction. Compound 2 was characterized by ESR spectroscopy. Compounds 3 and 4 were studied by 1 H and 13 C NMR spectroscopy.Transition metal complexes with 1,2 bis[(2,6 di isopropylphenyl)imino]acenaphthene (dpp BIAN) are known 1-10 to be used for the preparation of catalysts for various organic reactions, including olefin polymeriza tion catalysts. Recently, it has been found 11,12 that acenaphthene 1,2 diimines can be reduced by alkali met als to mono , di , tri , and tetraanions. Alkaline earth metals reduce dpp BIAN only to the dianion, 13-15 and the resulting complexes show high specific reactivity to ward such organic compounds as ketones, 16,17 nitriles, 18 alkyl halides, 19 and C-H acids. 20 Derivatives of Group 13 elements with dpp BIAN can be prepared by the reactions of metal halides with neutral dpp BIAN. 21 In 2004, a gallium compound of composi tion (dpp BIAN) -GaI 2 with the radical anionic ace naphthenediimine ligand was synthesized for the first time. 22 The low valent compound "GaI," which was ul trasonically prepared from gallium and iodine in toluene, was used as the starting compound in this synthesis. Re cently, 23 we have synthesized the nonsolvated dialkyl aluminum derivatives [(dpp BIAN) -AlR 2 ] by the meta thesis reaction of the sodium salt (dpp BIAN) -Na + with R 2 AlHal (R = Me, Et, or Bu i ; Hal = Cl or Br). 23 The aim of the present study was to develop new con venient procedures for the synthesis of aluminum com plexes with diimine dpp BIAN. New aluminum com plexes with various reduced forms of dpp BIAN were syn thesized starting from aluminum metal and its halides.

Electron Release and Proton Acceptance Reactions of (dpp-BIAN)Mg(THF)3

“…Redox isomerism in transition metal SQ complexes, and reversible addition of oxygen by triphenylantimony amidophenolate. minum reacts with dpp-BIAN forming the complexes (dpp-BIAN) n− AlX m (n = 1, m = 2; n = 2, m = 1; X = Cl, I) in which the ligand adopts the oxidation state of a monoanionic radical or a dianion [5]. Furthermore, dpp-BIAN complexes of Al(III) [6] and Ge(II) [7] have been prepared by reacting aluminum and germanium halides with dpp-BIAN complexes of the alkali and alkaline earth metals.…”

Sodium Cation Migration Above the Diimine π‐System of Solvent Coordinated dpp‐BIAN Sodium Aluminum Complexes (dpp‐BIAN=1,2‐Bis[(2,6‐diisopropylphenyl)imino]acenaphthene)

“…[12] Alkylaluminum complexes with dpp-BIAN radical anions and dianions as ligands are obtained by the reaction of NaA C H T U N G T R E N N U N G [dpp-BIAN] with one equivalent of R 2 AlX (R = Me, Et, iBu; X = Cl, Br) (A) [13] and…”

Coordination of benzene to a sodium cation

“…Table 2. Selected bond lengths (d) and bond angles (ω) in Na(η 6 C 6 H 6 )(dpp BIAN)AlMe 2 (4), Na(Et 2 O)(dpp BIAN)AlEt 2 (5), and Na(η 6 C 6 H 6 )(dpp BIAN)AlEt 2 (6) Parameter 4 (6). A solution of (C 2 H 5 ) 2 AlCl (1.0 mol L -1 ) in hexane (1.0 mL) was added to a solution of Na 2 (dpp BIAN), which was prepared from dpp BIAN (0.5 g, 1.0 mmol) in benzene (30 mL).…”

“…Recently, 6 we have synthesized several aluminum complexes with the radical anion and dianionic diimine * Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. ** Institut für Chemie der Technischen Universität Berlin, Straße des 17.…”