Synthesis and Structural Characterization of Compounds Containing the Al–O–Al Motif

Yang, Zhi; Hao, Pengfei; Liu, Zhihong; Ma, Xiaoli; Roesky, Herbert W.; Yang, Ying; Li, Jiarong

doi:10.1002/zaac.201300386

Cited by 12 publications

(3 citation statements)

References 47 publications

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“…This leads to conflicting results regarding the exclusive formation of eight-membered ring systems for aluminum borates and six-membered rings for gallium borate derivatives when our synthetic approach is used. However, it is noteworthy that the six-membered aluminum boroloxides [ i Pr L Al{OB(C 5 H 9 )} 2 (μ-O)] ( i Pr L = CH{CMe(NAr)} 2 – , Ar = 2, 6- i Pr 2 C 6 H 3 ) and [ i Pr L Al{OB(3-XC 6 H 4 )} 2 (μ-O)] (X = H, F, CH 3 ), , as well as with a Al 2 BO 3 ring in [( i Pr L AlO) 2 B(2,6-OCH 3 C 6 H 4 )(μ-O)], are accessible from the reaction of aluminum hydrides or alkyls and boronic or borinic acids but not from aluminum hydroxides and boron hydrides as studied in this work. On the one hand, the latter can be explained in terms of the reactivity of Al–O–Al moiety in the presence of BH 3 complexes leading to the cleavage of Al–O bonds and the consequent formation of eight-membered ring systems.…”

Section: Resultsmentioning

confidence: 99%

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃

et al. 2017

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The reaction of metalloxanes [{LM(OH)}(μ-O)] [M = Al (1), Ga (2); L = CH{CMe(NAr)}, Ar = 2,4,6-MeCH, Me = methyl] with an excess of BH·D (D = tetrahydrofuran (THF), SMe) affords annular metallaborate systems achieved through M-O-M cleavage. Compound 1 led exclusively to the formation of eight-membered ring systems [{LAl(μ-O){B(OBu)}(μ-O)}] (3) and [{LAl(μ-O)(BH)(μ-O)}] (6), while for 2 the unprecedented six-membered ring systems [{(LGa)(μ-O)}(μ-O){B(OBu)}] (4) and [(LGa)(μ-O){(BOBu)(μ-O)}] (5) were observed. The use of BH·THF with 1 and 2 led to the concomitant THF ring-opening reaction, while with BH·SMe in THF no such reaction was observed. The metallaborates [LAl{OB(pinacol)}(OH)] (7) and [{LGa(OB(pinacol))}(μ-O)] (8) were synthesized from pinacolborane and the corresponding metalloxane, providing structural evidence that supports the reaction pathways proposed for the formation of 3-6. Density functional theory studies were performed on 3-5 to assess the effect of the metal exchange between aluminum and gallium atoms on the energy of the general ring structures.

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Section: Resultsmentioning

confidence: 99%

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃

et al. 2017

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“…Since the presented O^N chelating ligands can possibly coordinate the metal center as monoanionic or neutral ligands, they are of potential interest as redox-active ligand complexes. There has been lots of interest in the field of redox-active main-group-element complexes in recent years, − especially aluminum complexes containing β-ketoimines, ,− α-diimines, ,− and N-heterocyclic carbenes demonstrating unique characteristics and interesting reactivity.…”

Section: Introductionmentioning

confidence: 99%

Ligand-Modulated Chemical and Structural Implications in Four-, Five-, and Six-fold Coordinated Aluminum Heteroaryl Alkenolates

et al. 2014

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Synthesis and characterization (gas phase, solution, and solid-state) of a series of four-, five- and six-fold coordinated heteroaryl-alkenolato aluminum complexes were performed to demonstrate the delicate interplay of structural and chemical influences of ligands in the design of new precursors for chemical vapor deposition. We are investigating the properties of heteroaryl alkenols as O^N chelating ligands [where O^N is 3,3,3-trifluoro(pyridin-2-yl)propen-2-ol (H-PyTFP), 3,3,3-trifluoro(1,3-benzimidazol-2-yl)propen-2-ol (H-BITFP), 3,3,3-trifluoro(dimethyl-1,3-oxazol-2-yl)propen-2-ol (H-DMOTFP), 3,3,3-trifluoro(1,3-benzoxazol-2-yl)propen-2-ol (H-BOTFP), 3,3,3-trifluoro(1,3-benzthiazol-2-yl)propen-2-ol (H-BTTFP), and 3,3,3-trifluoro(dimethyl-1,3-thiazol-2-yl)propen-2-ol (H-DMTTFP)] to prepare volatile and air-stable compounds. All three methyl groups in highly reactive AlMe3 could be replaced by H-PyTFP, H-BITFP, H-DMOTFP, and H-BOTFP yielding octahedral complexes of the type Al(O^N)3; under similar conditions H-BTTFP and H-DMTTFP produced heteroleptic MeAl(O^N)2 compounds with five-fold coordinated aluminum centers. Various attempts to obtain tris-alkenolato derivatives by choosing higher temperatures and prolonged reaction times were not successful. The reaction of H-PyTFP with [Al(O(t)Bu)3]2 produced the dimeric heteroleptic [Al(PyTFP)(O(t)Bu)2]2 complex with Al atoms present in both octahedral (Oh) and tetrahedral (Td) coordination in a single molecular unit. The introduction of the chelating ligand H-PyTFP in the dimeric framework of [Al(O(t)Bu)3]2 enhanced the stability against hydrolyses significantly. The tendency of Al(III) centers to preferably coordinate in Td or Oh environment was elucidated by hydrolysis studies of monomeric Al(PyTFP)3, Al(BOTFP)3, and MeAl(BTTFP)2 that produced hydroxo-bridged dimers to retain the octahedral environment for Al atoms. Surprisingly, hydrolysis of monomeric MeAl(DMTTFP)2 yielded an oxo-bridged dimer with two five-fold coordinated aluminum centers. The structural features of all new complexes were investigated in solution, vapor, and solid state by multinuclear NMR spectroscopy, EI-MS spectrometry, and single-crystal X-ray diffraction analyses, respectively.

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“…However, there have not been intensive studies on aluminum compounds supported by bulky β-diketiminato ligands for ε-caprolactone polymerization, although they could be applied for commercial production . According to our recent research on the synthesis of organoaluminum compounds, we are able to shift selectively the functionalities at the Al center intentionally to design and control the reaction procedure. Herein we report on a series of novel compounds containing the C–O–Al–O–C structural unit.…”

Section: Introductionmentioning

confidence: 99%

Aluminum Complexes Containing the C–O–Al–O–C Framework as Efficient Initiators for Ring-Opening Polymerization of ε-Caprolactone

Hao

Yang

et al. 2014

Organometallics

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Three aluminum complexes, LAl(OCH2C6H4-2-NH2)2 (2), LAl(9-OC13H9)2 (3), and LAl(OC6H10-4-NH2)2 (4), were synthesized in good yield by reacting one equivalent of LAlH2 (1) (L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3) with two equivalents of 2-aminobenzyl alcohol, 9-hydroxyfluorene, and trans-4-aminocyclohexanol, respectively. All complexes (2, 3, and 4) contain the C–O–Al–O–C framework. These complexes have been characterized by IR, 1H and 13C NMR, elemental analyses, and single-crystal X-ray structural analysis. Furthermore, the excellent catalytic activities of 2, 3, and 4 for ring-opening polymerization of ε-caprolactone in the presence of isopropyl alcohol were investigated.

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Synthesis and Structural Characterization of Compounds Containing the Al–O–Al Motif

Abstract: Abstract. The reaction of LAlMe 2 (1) [L = HC(CMeNAr) 2 , Ar = 2,6-iPr 2 C 6 H 3 ] with diphenylstannanediol resulted in the methylalumoxane compound L(Me)Al(μ-O)Al(Me)L (3). Compound (LAlO) 2 B(2,6-OCH 3 C 6 H 4 )(μ-O) (4) containing the Al 2 BO 3 six-membered ring was

Cited by 12 publications

References 47 publications

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃

Ligand-Modulated Chemical and Structural Implications in Four-, Five-, and Six-fold Coordinated Aluminum Heteroaryl Alkenolates

Aluminum Complexes Containing the C–O–Al–O–C Framework as Efficient Initiators for Ring-Opening Polymerization of ε-Caprolactone

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Synthesis and Structural Characterization of Compounds Containing the Al–O–Al Motif

Abstract: Abstract. The reaction of LAlMe 2 (1) [L = HC(CMeNAr) 2 , Ar = 2,6-iPr 2 C 6 H 3 ] with diphenylstannanediol resulted in the methylalumoxane compound L(Me)Al(μ-O)Al(Me)L (3). Compound (LAlO) 2 B(2,6-OCH 3 C 6 H 4 )(μ-O) (4) containing the Al 2 BO 3 six-membered ring was

Cited by 12 publications

References 47 publications

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH3

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH3

Ligand-Modulated Chemical and Structural Implications in Four-, Five-, and Six-fold Coordinated Aluminum Heteroaryl Alkenolates

Aluminum Complexes Containing the C–O–Al–O–C Framework as Efficient Initiators for Ring-Opening Polymerization of ε-Caprolactone

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Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃

Molecular Group 13 Metallaborates Derived from M–O–M Cleavage Promoted by BH₃