Synthesis, AACVD and X-ray crystallographic structures of group 13 monoalkoxometallanes

Knapp, Caroline E.; Pemberton, Leah; Carmalt, Claire J.; Pugh, David; McMillan, Paul F.; Barnett, Sarah A.; Tocher, Derek A.

doi:10.3233/mgc-2010-0002

Cited by 18 publications

(30 citation statements)

References 23 publications

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“…Interestingly, the presence of the bulky alkoxide group resulted in this case in asymmetric In 2 O 2 bridges (Figure ). Prior to the reactivity of 5 with the NHC, it must be noted that In–O bonds (2.152, 2.176, 2.178, and 2.191 Å) of the In 2 O 2 central ring were slightly longer in comparison with [Me 2 In(μ-OCH(Me)CH 2 OMe)] 2 (2.107, 2.179 Å); however, they were significantly shorter in comparison with rac -[Me 2 In( melac )] 2 (2.157, 2.216 Å) and [Me 2 In(( S )- melac )] 2 (2.156, 2.157, 2.217, and 2.231 Å) . Notably, the significant tension within the In 2 O 2 central ring, evidenced by In–O–In–O torsion angles of 14.32–14.67° (Figure ), in comparison with [Me 2 In(μ-OCR(Me)CH 2 OMe] 2 (R = H, Me) (0°), as well as rac -[Me 2 In( melac )] 2 (0°) and [Me 2 In(( S )- melac )] 2 (4.9°), could facilitate the breaking of In 2 O 2 bridges and the stabilization of Me 2 In(OCPh 2 Me)(NHC) complexes (see below).…”

Section: Results and Discussionmentioning

confidence: 99%

Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

et al. 2016

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The investigation of the reactivity of dialkylindium alkoxides toward N-heterocyclic carbenes (NHCs) has shown that both the character of the In−C NHC bond and alkyl and alkoxide substituents have a significant effect on the formation of R 2 InOR(NHC) complexes and the distribution of products. The reactions of simple dimethylindium alkoxides with the N-heterocyclic carbenes 1,3-bis(2,4,6trimethylphenyl)imidazolin-2-ylidene (SIMes) and 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) lead to the monomeric complexes Me 2 InOR(NHC), as shown by the isolation of Me 2 InOMe(NHC) (NHC = IMes (3), SIMes (4)). Compounds Me 2 InOR(NHC) are unstable in solution and instantly disproportionate, which can be associated with a weaker In−C NHC bond in comparison with stable gallium analogues. As a result, Me 3 In(NHC) (NHC = IMes (1), SIMes (2)) adducts, as well as Mitsubishi-type methylindium alkoxides, are formed. The exchange of a simple alkoxy group with chelating (S)-methyl lactate (S-melac) has resulted in the more stable Me 2 In(OCH(Me)CO 2 Me)(NHC) complexes. The use of the bulky alkoxide ligand OCPh 2 Me allows for the synthesis of stable Me 2 In(OCPh 2 Me)(NHC) (NHC = IMes (6), SIMes (7)) from [Me 2 In(μ-OCPh 2 Me)] 2 (5). While the strongest In−C NHC bond, among the characterized Me 2 In(OR)(NHC) complexes, is crucial for the stability of 6 and 7, it is still weaker in comparison with Ga−C NHC bonds in the analogous gallium complexes Me 2 Ga(OCPh 2 Me)(NHC) (NHC = IMes (8), SIMes (9)). For [ t Bu 2 In(μ-OCH 2 CH 2 OMe)] 2 , the introduction of a bulky tertbutyl group has resulted in a lack of reactivity toward NHCs. However, the structure of t Bu 2 In(OCPh 2 Me)(IMes) has confirmed the substantial effect of bulky alkyl substituents on the strength of the In−C NHC bond. The structures of 1, 2, 4−6, and 8 have been determined using both spectroscopic methods in solution and X-ray diffraction studies. Similarly to their gallium analogues, Me 2 In(OCH(Me)CO 2 Me)(NHC) complexes are highly active in the ring-opening polymerization of rac-lactide already at −20 °C, leading to isotactically enriched PLA (P m = 0.67−0.76). However, in contrast to the gallium complexes Me 2 GaOR(NHC), the noninnocent role of an NHC ligand, resulting in the formation of cyclic PLA, has been demonstrated for 6 and 7. ■ INTRODUCTIONRecently we reported Me 2 GaOR(NHC) (NHC = N-heterocyclic carbene) complexes, which constitute the first examples of well-characterized gallium, as well as group 13 metal, alkoxides with NHCs. 1 They were highly active and isoselective catalysts for the ring-opening polymerization (ROP) of lactide (LA) under mild conditions. 2,3 Moreover, the formation of isoselective Me 2 GaOR(NHC), upon coordination of the NHC to heteroselective [Me 2 GaOR] 2 , 4 allowed for the first facile stereoselectivity switch in the polymerization of rac-LA. 1,5 In addition to the gallium complexes mentioned above, a few main-group-metal complexes with NHCs have shown interesting catalytic properties in the ROP of heterocyclic monome...

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Section: Results and Discussionmentioning

confidence: 99%

Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

et al. 2016

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“…This is most notable within transparent films and has been particularly observed in the deposition of gallium oxide. 20,21 It is, however, unclear whether this contamination is a result of carbon retention from the solvent or from the precursor and the colouration can be easily removed by annealing in air, producing transparent films. The depositions of niobium and tantalum sulphide 18 and titanium dioxide 19 carried out using chlorinated solvents, namely dichloromethane and chloroform respectively, have shown no evidence of chlorine contamination.…”

Section: Dalton Transactions Perspectivementioning

confidence: 99%

“…This is in contrast to the deposition of Ga 2 O 3 via AACVD of dialkylalkoxogallanes of the type [R 2 Ga-(OR′)] 2 , which produced grey or brown films attributable to the retention of a Ga-C bond. 14,21,22,24,72 Indium oxide. The production of indium oxide (In 2 O 3 ) thin films by CVD methods has been limited due to the unavailability of suitable precursors with high vapour pressures and low decomposition temperatures.…”

Section: Electronicsmentioning

confidence: 99%

Aerosol-assisted delivery of precursors for chemical vapour deposition: expanding the scope of CVD for materials fabrication

et al. 2013

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The production of thin films of materials has become the attention of a great deal of research throughout academia and industry worldwide owing to the array of applications which utilise them, including electronic devices, gas sensors, solar cells, window coatings and catalytic systems. Whilst a number of deposition techniques are in common use, chemical vapour deposition (CVD) is an attractive process for the production of a wide range of materials due to the control it offers over film composition, coverage and uniformity, even on large scales. Conventional CVD processes can be limited, however, by the need for suitably volatile precursors. Aerosol-assisted (AA)CVD is a solution-based process which relies on the solubility of the precursor, rather than its volatility and thus vastly extends the range of potentially applicable precursors. In addition, AACVD offers extra means to control film morphology and concurrently the properties of the deposited materials. In this perspective we discuss the AACVD process, the influence of deposition conditions on film characteristics and a number of materials and applications to which AACVD has been found beneficial.

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“…The most commonly reported co‐ligands are alkyl groups (Me, Et) resulting from the reaction of donor‐functionalised alcohol with trialkylgallium reagents (Scheme ) 12. 13 Although both mono‐ and bis‐substituted alkoxides can be made by this method, only the former can be reliably synthesised in good yield 14. The other common co‐ligand that has been reported is chloride, originating either from 1) the direct reaction of alkali metal alkoxides with GaCl 3 or 2) the reaction of alcohols with chlorogallium amide complexes (Scheme ) 11.…”

Section: Introductionmentioning

confidence: 99%

Gallium Hydride Complexes Stabilised by Multidentate Alkoxide Ligands: Precursors to Thin Films of Ga₂O₃ at Low Temperatures

Pugh¹,

Bloor²,

Parkin³

et al. 2012

Chemistry A European J

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The donor‐functionalised alkoxides {Me3−xN(CH2CH2O)x} (Lx; x=1, 2) have been used to form gallium hydride complexes [{GaH2(L1)}2] and [{GaH(L2)}2] that are stable and isolable at room temperature. Along with a heteroleptic gallium tris(alkoxide) complex [Ga(L1)3] and the dimeric complex [{GaMe(L2)}2], these compounds have been used as single‐source precursors for the deposition of Ga2O3 by aerosol‐assisted chemical vapour deposition (AACVD) with toluene as solvent. The resulting films were mostly transparent, indicating low levels of carbon contamination, and they were also mainly amorphous. However, [Ga(L1)3] did contain visibly crystalline material deposited at a substrate temperature of 450 °C, by far the lowest ever observed for the CVD of gallium oxide.

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Synthesis, AACVD and X-ray crystallographic structures of group 13 monoalkoxometallanes

Cited by 18 publications

References 23 publications

Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Aerosol-assisted delivery of precursors for chemical vapour deposition: expanding the scope of CVD for materials fabrication

Gallium Hydride Complexes Stabilised by Multidentate Alkoxide Ligands: Precursors to Thin Films of Ga₂O₃ at Low Temperatures

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Synthesis, AACVD and X-ray crystallographic structures of group 13 monoalkoxometallanes

Cited by 18 publications

References 23 publications

Effect of In–CNHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Effect of In–CNHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Aerosol-assisted delivery of precursors for chemical vapour deposition: expanding the scope of CVD for materials fabrication

Gallium Hydride Complexes Stabilised by Multidentate Alkoxide Ligands: Precursors to Thin Films of Ga2O3 at Low Temperatures

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Product

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Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Effect of In–C_NHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

Gallium Hydride Complexes Stabilised by Multidentate Alkoxide Ligands: Precursors to Thin Films of Ga₂O₃ at Low Temperatures