Beitrag zur Darstellung von Verbindungen niederer Oxydationsstufe

Gastinger, Ekkehard

doi:10.1002/zaac.19623160308

Cited by 6 publications

(1 citation statement)

References 15 publications

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“…As a group 13 element, the oxidation state +1 of gallium is thermodynamically only metastable . However, many univalent gallium compounds have been stabilized in the past decades: “GaI”, which in fact contains mixed-valence Ga 2 I 3 or (Ga + ) 2 [Ga 2 I 6 ] 2– and therefore is of limited use as a gallium(I) starting material; Ga + [GaCl 4 ] − , which gave rise to the first gallium(I) arene complexes but regarding further gallium(I) chemistry is limited by the chemically reactive and coordinating halogallate anions [GaX 4 ] − (X = halide anion); solid and dissolved GaCl, which is metastable and therefore disproportionates above temperatures of ±0 °C . Turning to the materials used for this article, our group developed a novel simple route to stable, univalent gallium salts of WCAs by oxidation of elemental gallium with the silver(I) salt Ag + [Al(OR F ) 4 ] − (R F = C(CF 3 ) 3 ) in fluorobenzene (C 6 H 5 F) and with ultrasonic activation .…”

Section: Results and Discussionmentioning

confidence: 99%

Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene

et al. 2013

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The scope of the univalent gallium salts [Ga-(C 6 H 5 F) 2 ] + [Al(OR F ) 4 ] − and the new completely characterized [Ga(1,3,5-Me 3 C 6 H 3 ) 2 ] + [Al(OR F ) 4 ] − (R F = C(CF 3 ) 3 ) was investigated in terms of initiating or catalyzing the synthesis of highly reactive poly(2-methylpropylene)highly reactive polyisobutylene (HR-PIB)in several solvents. A series of polymerization reactions proved the high efficiency and quality of the univalent gallium salts for the polymerization of isobutylene. The best results were obtained using very low concentrations of [Ga-(C 6 H 5 F) 2 ] + [Al(OR F ) 4 ] − (down to 0.007 mol%) while working at reaction temperatures of up to ±0 °C and in the noncarcinogenic and non-water hazardous solvent toluene. Under these conditions, HR-PIB with an α-content of terminal olefinic double bonds up to 91 mol% and a molecular weight of 1000−2000 was obtained in good yields. Upon changing [Ga(C 6 H 5 F) 2 ] + [Al(OR F ) 4 ] − for the electron richer [Ga(1,3,5-Me 3 C 6 H 3 ) 2 ] + [Al-(OR F ) 4 ] − , polymerization temperatures could be increased to +10 °C. The reactivity of the gallium(I) cations therefore seems to be tunable through ligand exchange reactions. Experimental results, density functional theory calculations, and mass spectrometric investigations point toward a coordinative polymerization mechanism. Article pubs.acs.org/Organometallics

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Section: Results and Discussionmentioning

confidence: 99%

Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene

et al. 2013

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Univalent Gallium Complexes of Simple and ansa‐Arene Ligands: Effects on the Polymerization of Isobutylene

Lichtenthaler

Maurer

Mangan

et al. 2014

Chemistry A European J

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Using [Ga(C6 H5 F)2 ](+) [Al(OR(F))4 ](-) (1) (R(F) =C(CF3)3) as starting material, we isolated bis- and tris-η(6) -coordinated gallium(I) arene complex salts of p-xylene (1,4-Me2 C6 H4), hexamethylbenzene (C6 Me6 ), diphenylethane (PhC2 H4 Ph), and m-terphenyl (1,3-Ph2 C6 H4): [Ga(1,4-Me2 C6 H4 )2.5 ](+) (2(+)), [Ga(C6 Me6 )2 ](+) (3(+)), [Ga(PhC2 H4 Ph)](+) (4(+)) and [(C6 H5 F)Ga(μ-1,3-Ph2 C6 H4)2 Ga(C6 H5 F)](2+) (5(2+)). 4(+) is the first structurally characterized ansa-like bent sandwich chelate of univalent gallium and 5(2+) the first binuclear gallium(I) complex without a Ga-Ga bond. Beyond confirming the structural findings by multinuclear NMR spectroscopic investigations and density functional calculations (RI-BP86/SV(P) level), [Ga(PhC2 H4 Ph)](+) [Al(OR(F))4](-) (4) and [(C6 H5 F)Ga(μ-1,3-Ph2 C6 H4)2 Ga(C6 H5 F)](2+) {[Al(OR(F) )4] (-)}2 (5), featuring ansa-arene ligands, were tested as catalysts for the synthesis of highly reactive polyisobutylene (HR-PIB). In comparison to the recently published 1 and the [Ga(1,3,5-Me3 C6 H3)2](+) [Al(OR(F))4](-) salt (6) (1,3,5-Me3 C6 H3 =mesitylene), 4 and 5 gave slightly reduced reactivities. This allowed for favorably increased polymerization temperatures of up to +15 °C, while yielding HR-PIB with high contents of terminal olefinic double bonds (α-contents=84-93 %), low molecular weights (Mn =1000-3000 g mol(-1)) and good monomer conversions (up to 83 % in two hours). While the chelate complexes delivered more favorable results than 1 and 6, the reaction kinetics resembled and thus concurred with the recently proposed coordinative polymerization mechanism.

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Univalent Gallium Complexes of Simple andansa-Arene Ligands: Effects on the Polymerization of Isobutylene

Lichtenthaler¹,

Maurer²,

Mangan³

et al. 2014

Chem. Eur. J.

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Using [Ga(C H F) ] [Al(OR ) ] (1) (R =C(CF ) ) as starting material, we isolated bis- and tris-η -coordinated gallium(I) arene complex salts of p-xylene (1,4-Me C H ), hexamethylbenzene (C Me ), diphenylethane (PhC H Ph), and m-terphenyl (1,3-Ph C H ): [Ga(1,4-Me C H ) ] (2 ), [Ga(C Me ) ] (3 ), [Ga(PhC H Ph)] (4 ) and [(C H F)Ga(μ-1,3-Ph C H ) Ga(C H F)] (5 ). 4 is the first structurally characterized ansa-like bent sandwich chelate of univalent gallium and 5 the first binuclear gallium(I) complex without a GaGa bond. Beyond confirming the structural findings by multinuclear NMR spectroscopic investigations and density functional calculations (RI-BP86/SV(P) level), [Ga(PhC H Ph)] [Al(OR ) ] (4) and [(C H F)Ga(μ-1,3-Ph C H ) Ga(C H F)] {[Al(OR ) ] } (5), featuring ansa-arene ligands, were tested as catalysts for the synthesis of highly reactive polyisobutylene (HR-PIB). In comparison to the recently published 1 and the [Ga(1,3,5-Me C H ) ] [Al(OR ) ] salt (6) (1,3,5-Me C H =mesitylene), 4 and 5 gave slightly reduced reactivities. This allowed for favorably increased polymerization temperatures of up to +15 °C, while yielding HR-PIB with high contents of terminal olefinic double bonds (α-contents=84-93 %), low molecular weights (M =1000-3000 g mol ) and good monomer conversions (up to 83 % in two hours). While the chelate complexes delivered more favorable results than 1 and 6, the reaction kinetics resembled and thus concurred with the recently proposed coordinative polymerization mechanism.

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Beitrag zur Darstellung von Verbindungen niederer Oxydationsstufe

Abstract: Es wird eine Apparatur zur Darstellung niederer Halogenide, Oxyde und Sulfide beschrieben.

Cited by 6 publications

References 15 publications

Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene

Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene

Univalent Gallium Complexes of Simple and ansa‐Arene Ligands: Effects on the Polymerization of Isobutylene

Univalent Gallium Complexes of Simple andansa-Arene Ligands: Effects on the Polymerization of Isobutylene

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