Three-Coordinate Cationic Aluminum Alkyl Complexes Incorporating β-Diketiminate Ligands

Radzewich, Catherine E.; Guzei, Ilia A.; Jordan, Richard F.

doi:10.1021/ja991759h

Cited by 163 publications

(127 citation statements)

References 40 publications

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“…The lack of stability of cations 3a,b + prompted us to generate them in the presence of a Lewis base such as NMe 2 Ph, which is expected to trap the Ga cations to yield stable fourcoordinate Ga-NMe 2 Ph cationic adducts. Thus, the reaction of the bis(oxazolinato)dimethylgallium complexes (2a,b) with one equivalent of B(C 6 + at room temperature contrasts with the nonlabile coordination of this amine to Al in the cationic Al analogs under identical conditions, which may reflect a more Lewis acidic cationic Al vs. Ga center. [10] The Lewis acid character of the Ga-NMe 2 Ph adduct 4a + was also tested with PO.…”

Section: Reaction Of Bis(oxazolinato)dimethylgallium Complexes 2a Andmentioning

confidence: 99%

“…[6,7] Thus far, most of the investigations in this area have concerned aluminum derivatives, where it has been found that the structure and the stability of the formed Al cations are greatly dependent upon the steric properties of the ancillary LX -bidentate ligand and the nature of the counterion. [7] More specifically, the presence of an extremely bulky LX -ligand and the use of an inert counterion [B(C 6 F 5 ) 4 -or MeB(C 6 F 5 ) 3 -] are required to obtain, in some cases, reasonably stable Al cations.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Structure of Neutral and Cationic Gallium Complexes Incorporating Bis(oxazolinato) Ligands

et al. 2005

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Section: Reaction Of Bis(oxazolinato)dimethylgallium Complexes 2a Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and Structure of Neutral and Cationic Gallium Complexes Incorporating Bis(oxazolinato) Ligands

et al. 2005

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“…The relationship between structure of the catalytic complexes and stereoselectivity of the polymerization has been investigated and elucidated [6][7][8][9][10]22]. Recent organometallic literature has featured reports of many alkylaluminum compounds bearing bidentate N,N-, N,S-, or N,O-donor ligands [23][24][25][26][27][28][29][30]. These species have the potential to function as active catalysts because of their less coordinatively saturated nature.…”

Section: Dimethyl(salicilaldiminato)aluminum Complexesmentioning

confidence: 99%

Aluminum Alkyl Complexes Bearing Salicylaldiminato Ligands: Versatile Initiators in the Ring-Opening Polymerization of Cyclic Esters

Fuoco

Pappalardo

2017

Catalysts

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Linear aliphatic polyesters are degradable thermoplastic polymers, which can be obtained by ring-opening polymerization (ROP) of cyclic esters through a coordination-insertion mechanism. Aluminum based organometallic complexes have a leading position as efficient catalysts for this polymerization process. Aluminumalkyl complexes bearing salicylaldiminato ligands, although less explored, have been shown to be efficient and versatile catalysts for the ROP of various cyclic esters. These species have the potential to function as active catalysts in the ROP because of their less coordinatively saturated nature with respect to analogous SALEN-type complexes. They have been used as efficient catalysts in the ROP of commercially available cyclic esters, such as ε-caprolactone, L-lactide, rac-lactide, and glycolide. Moreover, they resulted in efficient catalysts for the ROP of cyclic esters with large ring-size and for the ROP of functionalized lactide. Furthermore, they have been used in the co-and ter-polymerization of various cyclic esters affording well controlled polymerization and a plethora of microstructural architectures, ranging from random to block to multiblock.

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“…[10] On the more applied side, there have been several studies of the potential of low-coordinate cationic organoaluminum compounds as catalysts for olefin oligomerization and polymerization. [11][12][13][14] Three-coordinate species have been obtained using monoanionic bidentate ligands, [15,16] and quasi-two-coordination has been achieved by employing two large m-terphenyl substituents at a single ionic species are stable at room temperature for days or weeks, although their combinations with the borate anion [B-(C 6 F 5 ) 4 ]…”

Section: M]mentioning

confidence: 99%

m‐Terphenylaluminum and ‐gallium Compounds: Synthesis and Conversion into Low‐Coordinate Organogallium Cations

et al. 2007

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The reaction of two or 3 equiv. of m‐terphenyllithium with MCl3 or AlH3·NMe3 (M = Al, Ga) affords the bis(terphenyl)aluminum and ‐gallium chloride compounds [{2,6‐(4‐tBuC6H4)2C6H3}2GaCl] (1), [{2,6‐(3,5‐Me2C6H3)2C6H3}2GaCl] (2), [{2,6‐(4‐tBuC6H4)2C6H3}3Ga] (3), [(2,6‐Mes2C6H3)2AlCl] (5), and [(2,6‐Mes2C6H3)2AlH] (7; Mes = 2,4,6‐Me3C6H2). While the gallium compounds can be obtained at room temperature, heating is required for the aluminum derivatives. The dibutyl compounds [(2,6‐Mes2C6H3)GaBu2] (8) and[(2,6‐Dipp2C6H3)GaBu2] (9; Dipp = 2,6‐iPr2C6H3) have also been synthesized by the reaction of m‐terphenyllithium with ClGaBu2. A metathesis reaction of 2 with Li[Al{OCH(CF3)2}4] gives the ionic species [(2,6‐Mes2C6H3)2Ga]+[Li{Al[OCH(CF3)2]4}2]– (11). The cationic butyl(terphenyl)gallium compounds [(2,6‐Mes2C6H3)GaBu]+ ([13]+) and [(2,6‐Dipp2C6H3)GaBu]+ ([14]+) have been prepared by butanide abstraction with the trityl salts of the weakly coordinating anions [B(C6F5)4]–, [CHB11Br6Me5]–, and [CHB11Cl11]–. These ionic species are stable at room temperature for days or weeks, although their combinations with the borate anion [B(C6F5)4]– suffer from C6F5 migration, which is slow at room temperature and faster at elevated temperatures. The compound [14]+[CHB11Cl11]– is stable at 70 °C for at least 23 h. Addition of 1‐octene to a solution of [14]+[CHB11Cl11]– in C6D6 results in olefin exchange and formation of the octyl species [(2,6‐Dipp2C6H3)Ga(octyl)]+ ([17]+), and a slow alkylation of the solvent to afford various octylbenzenes. Hydrolysis of 8 and [13]+[CHB11Br6Me5]– gives the compounds [{(2,6‐Mes2C6H3)GaBu(μ‐OH)}2] (10) and [(BuGa)4(μ‐OH)6]2+[CHB11Br6Me5]–2 (16). All compounds have been characterized by 1H and 13C{1H} NMR spectroscopy and mass spectrometry, and compounds 3, 5, 7, 10, and 16·4.5C6H6 have also been characterized by single‐crystal X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Three-Coordinate Cationic Aluminum Alkyl Complexes Incorporating β-Diketiminate Ligands

Cited by 163 publications

References 40 publications

Synthesis and Structure of Neutral and Cationic Gallium Complexes Incorporating Bis(oxazolinato) Ligands

Synthesis and Structure of Neutral and Cationic Gallium Complexes Incorporating Bis(oxazolinato) Ligands

Aluminum Alkyl Complexes Bearing Salicylaldiminato Ligands: Versatile Initiators in the Ring-Opening Polymerization of Cyclic Esters

m‐Terphenylaluminum and ‐gallium Compounds: Synthesis and Conversion into Low‐Coordinate Organogallium Cations

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