Al–H σ-bond coordination: expanded ring carbene adducts of AlH3 as neutral bi- and tri-functional donor ligands

Abdalla, Joseph A. B.; Riddlestone, Ian M.; Tirfoin, Rémi; Phillips, Nicholas; Bates, Joshua I.; Aldridge, Simon

doi:10.1039/c3cc42342e

Cited by 40 publications

(38 citation statements)

References 37 publications

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“…In light of the accessibility of σ‐alane complexes featuring bulky NHCs as supporting donors,11b the novel gallane adducts of 6Mes and 6Dipp were prepared with a view to exploring their coordination chemistry (Scheme ). Reaction of the respective carbenes with LiGaH 4 at low temperature cleanly yields 6Mes⋅GaH 3 ( 3 a ) and 6Dipp⋅GaH 3 ( 3 b ) by elimination of LiH.…”

Section: Resultsmentioning

confidence: 99%

“…Both compounds have been characterised by standard spectroscopic and analytical methods, and their molecular structures in the solid state determined by X‐ray crystallography (see the Supporting Information). Each is essentially isostructural with its alane congener 11b. Thus, the EC carbene bond lengths ( 3 a : 2.084(2) Å; 3 b : 2.101(2) Å) are statistically identical to those in the corresponding alane adducts 2 a and 2 b (2.087(3) and 2.101(2) Å, respectively),11b consistent with the near identical covalent radii of aluminium and gallium (1.21(4) and 1.22(3) Å) 15.…”

Section: Resultsmentioning

confidence: 99%

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Coordination and Activation of AlH and GaH Bonds

Abdalla

Riddlestone

Turner

et al. 2014

Chemistry A European J

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The modes of interaction of donor-stabilized Group 13 hydrides (E=Al, Ga) were investigated towards 14- and 16-electron transition-metal fragments. More electron-rich N-heterocyclic carbene-stabilized alanes/gallanes of the type NHC⋅EH3 (E=Al or Ga) exclusively generate κ(2) complexes of the type [M(CO)4 (κ(2)-H3 E⋅NHC)] with [M(CO)4 (COD)] (M=Cr, Mo), including the first κ(2) σ-gallane complexes. β-Diketiminato ('nacnac')-stabilized systems, {HC(MeCNDipp)2 }EH2 , show more diverse reactivity towards Group 6 carbonyl reagents. For {HC(MeCNDipp)2 }AlH2, both κ(1) and κ(2) complexes were isolated, while [Cr(CO)4 (κ(2)-H2 Ga{(NDippCMe)2 CH})] is the only simple κ(2) adduct of the nacnac-stabilized gallane which can be trapped, albeit as a co-crystallite with the (dehydrogenated) gallylene system [Cr(CO)5 (Ga{(NDippCMe)2 CH})]. Reaction of [Co2 (CO)8] with {HC(MeCDippN)2 }AlH2 generates [(OC)3 Co(μ-H)2 Al{(NdippCme)2 CH}][Co(CO)4] (12), which while retaining direct AlH interactions, features a hitherto unprecedented degree of bond activation in a σ-alane complex.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Coordination and Activation of AlH and GaH Bonds

Abdalla

Riddlestone

Turner

et al. 2014

Chemistry A European J

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“…1) have been described. 20,21 The particular character of the aluminium hydride moiety in transition-metal complexes will most certainly be subject to ongoing profound study. For advocating the diversity of ligand systems employed in the field we would select the phosphinimide V 22 (Fig.…”

Section: 13-15mentioning

confidence: 99%

Synthesis, characterization and reactivity of an imidazolin-2-iminato aluminium dihydride

2014

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The reaction of bis(2,6-diisopropylphenyl)imidazolin-2-imine (LH, 1) with Me 3 N·AlH 3 furnishes {μ-LAlH 2 } 2 (2). The marked tendency of 2 to release its hydride substituents is ascribed to the strong electron-donor character of the imidazolin-2-iminato ligand. This is supported by its reactivity study and DFT calculations.In fact, compound 2 was further converted with Me 3 SiOTf, Me 2 S·BH 3 , Me 2 S·BBr 3 , and BX 3 (with X = Cl, Br, and I) into {μ-LAl(H)OTf} 2 (3), {μ-LAl(BH 4 ) 2 } 2 (4), and {μ-LAlX 2 } 2 (5, X = Br; 6, X = Cl; 7, X = I), respectively.For all new aluminium complexes the formulation as dimers was evidenced by high resolution mass spectrometry, as well as single-crystal X-ray diffraction analysis. A prominent structural motif of these compounds is the square-planar four-membered Al 2 N 2 ring with two bridging bulky imidazolin-2-imino moieties. IntroductionAluminium hydrides -versatile reagents with rich chemistry For many years, chemical synthesis has been gaining immense benefit from the distinct reactivity of the aluminium-hydrogen bond. The strong need for highly selective transformations, increased focus on safety considerations, and efficiency in handling and storage are only some reasons why we find the chemically rogue parent aluminium hydride tamed into more suitable forms today. A variety of hydridoalanes has been tailored and very often reactivity adjustment is realized by steric congestion at the aluminium centre and by attaching strongly electron-donating substituents to the aluminium atom. Furthermore, hydridoalanes are used in a diverse range of applications. For instance, the hydroalumination of carbonyl 1,2 and alkyne 3-7 functionalities is a common application for this class of compounds in organic synthesis. Though the intermediate aluminium species in these reactions are often elusive, the use of aluminium hydrides such as I 8 ( Fig. 1) that bear highly sophisticated ligands grants access to all types of isolatable and well-defined model complexes. Compound I can be categorized as an aluminium dihydride and is related to the parent aluminium trihydride by replacement of one hydride for an anionic ligand. Thus, an ancillary ligand may be introduced, and yet, two reactive functional groups at the metal centre are preserved for the purpose of follow-up chemistry. The β-diketimino group, in particular, has been a key ligand to a rich chemistry of respective aluminium dihydrides. 9-12 A prominent example is II (Fig. 1), which can View Article OnlineView Journal | View Issue be used for the activation of non-polar element-element bonds as demonstrated by its conversion with elemental sulphur or selenium. 9,10 In a different field of applied science one finds chemical vapour deposition technology exploiting the thermodynamic properties of molecular aluminium hydrides for the purpose of creating composite materials. 1,13-15Aluminium hydrides are considered as fuel storagematerials with reasonable prospects in a hydrogen-based alternate energy-supply concept. 16,17 Moreover, the...

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“…Some other noteworthy spurious outliers are caused by inaccurate sum formulae ( Figure 2). These extend from typographic errors in the number of atoms (such as in "C119.8 H1137.2 Al4 F6.6 Mo4 N8 O12") [20], through flawed treatments of multiplicities (as in "Cl H12") [21] to mistyped sum formulae (as in "Ct H20 N2 O2 wo23") [22]. It is important to note that in cases of mis-entered sum formulae, the program calculates the molecular mass from the sum formula by using an internal dictionary for the atomic masses.…”

Section: Outlier Treatmentmentioning

confidence: 99%

“…(DoE) targets, while the green dashed line corresponds to the ultimate DoE targets. Some prominent outliers are denoted with their sum formula as taken from the respective cif files [20][21][22].…”

Section: Outlier Treatmentmentioning

confidence: 99%

The Search for Hydrogen Stores on a Large Scale; A Straightforward and Automated Open Database Analysis as a First Sweep for Candidate Materials

Breternitz

Gregory

2015

Crystals

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Abstract:The storage of hydrogen is considered as the bottleneck in the implementation of portable fuel cell power generating systems. The necessary experimental studies to discover and develop appropriate storage materials are always time-limited. We discuss herein the approach of an uncomplicated and accessible computationally based analysis of database knowledge towards the identification of promising storage systems. The open access policy of the Crystallography Open Database (COD) invites researchers to grasp the opportunity to formulate targeted analyses of crystalline solids, unfettered by material resources. We apply such an approach to the initial evaluation of potential solid-state hydrogen stores, although the method could potentially be transferred to other material analysis tasks.

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Al–H σ-bond coordination: expanded ring carbene adducts of AlH3 as neutral bi- and tri-functional donor ligands

Cited by 40 publications

References 37 publications

Coordination and Activation of AlH and GaH Bonds

Coordination and Activation of AlH and GaH Bonds

Synthesis, characterization and reactivity of an imidazolin-2-iminato aluminium dihydride

The Search for Hydrogen Stores on a Large Scale; A Straightforward and Automated Open Database Analysis as a First Sweep for Candidate Materials

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