Hydro-coupling of isocyanates promoted by 1,2-bis(arylimino)acenaphthene aluminum hydrides.

The interaction of aluminum hydrides [(dpp-bian)AlH2] (1) and [(ArBIG-bian)AlH2(THF)] (2) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; ArBIG-bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene) with isocyanates RNCO (R = Ph, Cy, 3,5-Cl2Ph) proceeds via insertion of two molecules of isocyanates into each Al-H bond with the formation of unique Al carboxamides [(Ar-bian)Al{OC(H)N(R)C(NR)O}2] (Ar = dpp, R = Ph, 3; Ar = ArBIG, R = Ph, 4; Ar = ArBIG, R = Cy, 5; Ar = ArBIG, R = 3,5-Cl2C6H3, 6). In contrast, the reactions of 1 and 2 with an excess of tert-butylisocyanate afford formimidate derivatives [(Ar-bian)Al{OC(H)N(tBu)}2] (Ar = dpp, 7; Ar = ArBIG, 8). The reactions of N,N'-dicyclohexylcarbodiimide with 1 and 2 give [(dpp-bian)Al{(NCy)2CH}2] (9) and [(ArBIG-bian)Al(H){(NCy)2CH}] (10), correspondingly. New compounds 3-10 have been characterized by ESR spectroscopy; their molecular structures have been established by single-crystal X-ray analysis.

Diversity of transformation of heteroallenes on acenaphthene-1,2-diimine aluminum oxide.

The reactions of oxide [(dpp-bian)Al(µ2-O)2Al(dpp-bian)] (1) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with phenyl- or cyclohexylisocyanates result in the formation of carbonimidate derivatives [(dpp-bian)Al(µ-O)(µ-RNCO2)Al(dpp-bian)] (R = Ph, 2; Cy, 3). Addition of N,N'-dicyclohexylcarbodiimide to compound 1 leads to the formation of ureate complex [(dpp-bian)Al(µ-O)(µ-(CyN)2CO)Al(dpp-bian)] (4). The reactions of the oxide 1 with pinacolborane and catecholborane afford oxo-bridged hydride [{(dpp-bian)Al(H)}(µ-O){Al(OBpin)(dpp-bian)}] (5) and compound [{(dpp-bian)Al(OBCat)}2(µ-O)] (7), respectively. Insertion of cyclohexylisocyanate into the Al-H bond of compound 5 gives CO insertion product [{(dpp-bian)Al(OC(H)NCy)}(µ-O){Al(OBpin)(dpp-bian)}] (6). New compounds have been characterized by ESR and IR spectroscopy; their molecular structures have been established by single-crystal X-ray analysis. The oxide 1 serves as a catalyst for the hydroboration of heteroallenes (isocyanates, carbodiimides) with pinacolborane.

Reduction of CO2 with Aluminum Hydrides Supported with Ar-BIAN Radical-Anions (Ar-BIAN = 1,2-Bis(arylimino)acenaphthene).

The reactions of H2AlCl with [(dpp-Bian)Na(Et2O)n] and [(ArBIG-Bian)Na(THF)] produce respective aluminum hydrides supported by radical-anionic 1,2-bis(arylimino)acenaphthene ligands, [(dpp-Bian)AlH2] (1) and [(ArBIG-Bian)AlH2(THF)] (2) (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene); ArBIG-Bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene). The reaction of 1 with CO2 proceeds with reduction of both C═O bonds and results in diolate [{(dpp-Bian)Al(µ-O2CH2)}2] (3). Complex 2 reacts with CO2 to carbonate [{(ArBIG-Bian)Al(µ-OCH2OCO2)}2] (4) that is a result of the insertion of CO2 into the Al-O bond in diolate species formed initially. Aluminum monohydrides [(dpp-Bian)AlH(X)] (X = Cl, 5; Me, 6) react with CO2 to form respective alumoxanes [{(dpp-Bian)AlX}2(µ-O)] (X = Cl, 7 and X = Me, 8). Compounds 1-4, 7, and 8 have been characterized by ESR and IR spectroscopy, and their molecular structures have been determined by single-crystal X-ray analysis.

Synthesis and ε-Caprolactone Polymerization Activity of Electron-Deficient Gallium and Aluminum Species Containing a Charged Redox-Active dpp-Bian Ligand.

The synthesis of electron-deficient gallium- and aluminum-centered species containing a redox-active dpp-Bian ligand (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) is described. The reaction of digallane [(dpp-Bian)Ga-Ga(dpp-Bian)] with [Ph3C][PF6] or AgPF6 resulted in polyoxidized species [(dpp-Bian)GaF2]2 (1), [(dpp-Bian)H2][PF6] (2), and [(dpp-Bian)GaF(O2PF2)]2 (3). The reaction of digallane with B(C6F5)3 led to electron-deficient gallylene [(dpp-Bian)GaB(C6F5)3] 4 of a dpp-Bian radical anion. The soft oxidation of digallane with tosyl cyanide gave the trinuclear cationic species [(dpp-Bian)Ga(Tos)3Ga(Tos)3Ga(dpp-Bian)][Ga(CN)4] (5) containing dpp-Bian radical anions. The reaction of [(dpp-Bian)AlEt2] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the cationic complex [(dpp-Bian)AlEt2][B(C6F5)4] (6) of neutral dpp-Bian, while the treatment of [(dpp-Bian)AlEt(Et2O)] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the compound [(dpp-Bian)AlEt(Et2O)][B(C6F5)4] (7) of a dpp-Bian radical anion. The reaction of diethylaluminum derivative [(dpp-Bian)AlEt2] with 1 equiv of B(C6F5)3 gave the cationic complex [{(dpp-Bian)AlEt}2F][EtB(C6F5)3] (8) containing radical-anion dpp-Bian ligands. The paramagnetic compounds 1, 2, 4, 5, 7, and 8 were characterized by electron paramagnetic resonance spectroscopy, and the diamagnetic complex 6 was characterized by NMR spectroscopy. The molecular structures of 1-6 and 8 were established by single-crystal X-ray diffraction analysis. Compounds 4 and 6-8 were found to be active initiators for immortal ring-opening polymerization of ε-caprolactone.

1,2-Bis(imino)acenaphthene complexes of molybdenum and nickel.

Molybdenum hexacarbonyl reacts with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (, dpp-BIAN) and 1,2-bis[(trimethylsilyl)imino]acenaphthene (, tms-BIAN) in toluene to produce (dpp-BIAN)Mo(CO)(4) () and (tms-BIAN)Mo(CO)(4) (), respectively. The reaction of [CpNi(CO)](2) with yields (dpp-BIAN)NiCp (). Metathesis between Li(2)(tms-BIAN) and NiCl(2)(dppe) affords the Ni(0) complex (tms-BIAN)Ni(dppe) (). The diamagnetic compounds , and have been characterized by (1)H, (29)Si and (31)P NMR spectroscopy, IR spectroscopy and elemental analysis. The ESR spectrum of the paramagnetic compound indicates the presence of Ni(i) coordinated by Cp and a neutral dpp-BIAN ligand. The molecular structures of have been determined by single-crystal X-ray analysis.