1
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Griffin LP, Ellwanger MA, Crumpton AE, Roy MMD, Heilmann A, Aldridge S. Mercury-Group 13 Metal Covalent Bonds: A Systematic Comparison of Aluminyl, Gallyl and Indyl Metallo-ligands. Angew Chem Int Ed Engl 2024; 63:e202404527. [PMID: 38545953 DOI: 10.1002/anie.202404527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 03/28/2024] [Indexed: 04/23/2024]
Abstract
Bimetallic compounds containing direct metal-group 13 element bonds have been shown to display unprecedented patterns of cooperative reactivity towards small molecules, which can be influenced by the identity of the group 13 element. In this context, we present here a systematic appraisal of group 13 metallo-ligands of the type [(NON)E]- (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) for E=Al, Ga and In, through a comparison of structural and spectroscopic parameters associated with the trans L or X ligands in linear d10 complexes of the types LM{E(NON)} and XM'{E(NON)}. These studies are facilitated by convenient syntheses (from the In(I) precursor, InCp) of the potassium indyl species [{K(NON)In}⋅KCp]n (1) and [(18-crown-6)2K2Cp] [(NON)In] (1'), and lead to the first structural characterisation of Ag-In and Hg-E (E=Al, In) covalent bonds. The resulting structural, spectroscopic and quantum chemical probes of Ag/Hg complexes are consistent with markedly stronger σ-donor capabilities of the aluminyl ligand, [(NON)Al]-, over its gallium and indium counterparts.
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Affiliation(s)
- Liam P Griffin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Mathias A Ellwanger
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Agamemnon E Crumpton
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Matthew M D Roy
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Andreas Heilmann
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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2
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Griffin LP, Ellwanger MA, Clark J, Myers WK, Roper AF, Heilmann A, Aldridge S. Bis(Aluminyl)Magnesium: A Source of Nucleophilic or Radical Aluminium-Centred Reactivity. Angew Chem Int Ed Engl 2024; 63:e202405053. [PMID: 38536728 DOI: 10.1002/anie.202405053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Indexed: 04/23/2024]
Abstract
The homoleptic magnesium bis(aluminyl) compound Mg[Al(NON)]2 (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) can be accessed from K2[Al(NON)]2 and MgI2 and shown to possess a non-linear geometry (∠Al-Mg-Al=164.8(1)°) primarily due to the influence of dispersion interactions. This compound acts a four-electron reservoir in the reductive de-fluorination of SF6, and reacts thermally with polar substrates such as MeI via nucleophilic attack through aluminium, consistent with the QT-AIM charges calculated for the metal centres, and a formal description as a Al(I)-Mg(II)-Al(I) trimetallic. On the other hand, under photolytic activation, the reaction with 1,5-cyclooctadiene leads to the stereo-selective generation of transannular cycloaddition products consistent with radical based chemistry, emphasizing the covalent nature of the Mg-Al bonds and a description as a Al(II)-Mg(0)-Al(II) synthon. Consistently, photolysis of Mg[Al(NON)]2 in hexane in the absence of COD generates [Al(NON)]2 together with magnesium metal.
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Affiliation(s)
- Liam P Griffin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Mathias A Ellwanger
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Jonathon Clark
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - William K Myers
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Aisling F Roper
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Andreas Heilmann
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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3
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Evans MJ, Jones C. Low oxidation state and hydrido group 2 complexes: synthesis and applications in the activation of gaseous substrates. Chem Soc Rev 2024; 53:5054-5082. [PMID: 38595211 DOI: 10.1039/d4cs00097h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Numerous industrial processes utilise gaseous chemical feedstocks to produce useful chemical products. Atmospheric and other small molecule gases, including anthropogenic waste products (e.g. carbon dioxide), can be viewed as sustainable building blocks to access value-added chemical commodities and materials. While transition metal complexes have been well documented in the reduction and transformation of these substrates, molecular complexes of the terrestrially abundant alkaline earth metals have also demonstrated promise with remarkable reactivity reported towards an array of industrially relevant gases over the past two decades. This review covers low oxidation state and hydrido group 2 complexes and their role in the reduction and transformation of a selection of important gaseous substrates towards value-added chemical products.
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Affiliation(s)
- Matthew J Evans
- School of Chemistry, Monash University, PO Box 23, Melbourne, Victoria, 3800, Australia.
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, Melbourne, Victoria, 3800, Australia.
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4
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Dankert F, Hevia E. Synthesis and Modular Reactivity of Low Valent Al/Zn Heterobimetallics Supported by Common Monodentate Amides. Chemistry 2024; 30:e202304336. [PMID: 38189633 DOI: 10.1002/chem.202304336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/09/2024]
Abstract
Recent advances on low valent main group metal chemistry have shown the excellent potential of heterobimetallic complexes derived from Al(I) to promote cooperative small molecule activation processes. A signature feature of these complexes is the use of bulky chelating ligands which act as spectators providing kinetic stabilization to their highly reactive Al-M bonds. Here we report the synthesis of novel Al/Zn bimetallics prepared by the selective formal insertion of AlCp* into the Zn-N bond of the utility zinc amides ZnR2 (R=HMDS, hexamethyldisilazide; or TMP, 2,2,6,6-tetramethylpiperidide). By systematically assessing the reactivity of the new [(R)(Cp*)AlZn(R)] bimetallics towards carbodiimides, structural and mechanistic insights have been gained on their ability to undergo insertion in their Zn-Al bond. Disclosing a ligand effect, when R=TMP, an isomerization process can be induced giving [(TMP)2AlZn(Cp*)] which displays a special reactivity towards carbodiimides and carbon dioxide involving both its Al-N bonds, leaving its Al-Zn bond untouched.
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Affiliation(s)
- Fabian Dankert
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
| | - Eva Hevia
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
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5
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Zatsepin P, Moriyama T, Chen C, Muratsugu S, Tada M, Yamashita M. Vanadium Alumanyl Complex: Synthesis, Characterization, Reactivity, and Application as a Catalyst for C-H Alumanylation of Alkenes. J Am Chem Soc 2024; 146:3492-3497. [PMID: 38279921 DOI: 10.1021/jacs.3c13418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024]
Abstract
A complex containing a V-Al bond is described. This species can be prepared by either transmetalation of a previously disclosed alumanylpotassium with Cp2VCl or photolytic oxidative alumination of Cp2V using the corresponding dialumane. Reaction of the resulting V-Al complex with H2 gave a Cp2V-dihydridoaluminate complex. These complexes were studied with X-ray crystallography, vanadium K-edge XANES spectroscopy, and DFT calculations. Finally, the reactivity of these molecules was studied opening the way to a catalytic C-H alumanylation of alkenes.
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Affiliation(s)
- Pavel Zatsepin
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Aichi, Japan
| | - Takumi Moriyama
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Aichi, Japan
| | - Chaoqi Chen
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Aichi, Japan
| | - Satoshi Muratsugu
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Aichi, Japan
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Tokai National Higher Education and Research System, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Mizuki Tada
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Aichi, Japan
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Tokai National Higher Education and Research System, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
- Research Center for Materials Science (RCMS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Aichi, Japan
| | - Makoto Yamashita
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Aichi, Japan
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Tokai National Higher Education and Research System, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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Pérez-Jiménez M, Corona H, de la Cruz-Martínez F, Campos J. Donor-Acceptor Activation of Carbon Dioxide. Chemistry 2023; 29:e202301428. [PMID: 37494303 DOI: 10.1002/chem.202301428] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/23/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023]
Abstract
The activation and functionalization of carbon dioxide entails great interest related to its abundance, low toxicity and associated environmental problems. However, the inertness of CO2 has posed a challenge towards its efficient conversion to added-value products. In this review we discuss one of the strategies that have been widely used to capture and activate carbon dioxide, namely the use of donor-acceptor interactions by partnering a Lewis acidic and a Lewis basic fragment. This type of CO2 activation resembles that found in metalloenzymes, whose outstanding performance in catalytically transforming carbon dioxide encourages further bioinspired research. We have divided this review into three general sections based on the nature of the active sites: metal-free examples (mainly formed by frustrated Lewis pairs), main group-transition metal combinations, and transition metal heterobimetallic complexes. Overall, we discuss one hundred compounds that cooperatively activate carbon dioxide by donor-acceptor interactions, revealing a wide range of structural motifs.
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Affiliation(s)
- Marina Pérez-Jiménez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Helena Corona
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Felipe de la Cruz-Martínez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Jesús Campos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
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7
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Fernández S, Fernando S, Planas O. Cooperation towards nobility: equipping first-row transition metals with an aluminium sword. Dalton Trans 2023; 52:14259-14286. [PMID: 37740303 DOI: 10.1039/d3dt02722h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The exploration for noble metals substitutes in catalysis has become a highly active area of research, driven by the pursuit of sustainable chemical processes. Although the utilization of base metals holds great potential as an alternative, their successful implementation in predictable catalytic processes necessitates the development of appropriate ligands. Such ligands must be capable of controlling their intricate redox chemistry and promote two-electron events, thus mimicking well-established organometallic processes in noble metal catalysis. While numerous approaches for infusing nobility to base metals have been explored, metal-ligand cooperation has garnered significant attention in recent years. Within this context, aluminium-based ligands offer interesting features to fine-tune the activity of metal centres, but their application in base metal catalysis remains largely unexplored. This perspective seeks to highlight the most recent breakthroughs in the reactivity of heterobimetallic aluminium-base-metal complexes, while also showcasing their potential to develop novel and predictable catalytic transformations. By turning the spotlight on such heterobimetallic species, we aim to inspire chemists to explore aluminium-base-metal species and expand the range of their applications as catalysts.
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Affiliation(s)
- Sergio Fernández
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
| | - Selwin Fernando
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
| | - Oriol Planas
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
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8
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Liu HY, Hill MS, Mahon MF, McMullin CL, Schwamm RJ. Seven-Membered Cyclic Diamidoalumanyls of Heavier Alkali Metals: Structures and C-H Activation of Arenes. Organometallics 2023; 42:2881-2892. [PMID: 37829511 PMCID: PMC10565898 DOI: 10.1021/acs.organomet.3c00323] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Indexed: 10/14/2023]
Abstract
Like the previously reported potassium-based system, rubidium and cesium reduction of [{SiNDipp}AlI] ({SiNDipp} = {CH2SiMe2NDipp}2) with the heavier alkali metals [M = Rb and Cs] provides dimeric group 1 alumanyl derivatives, [{SiNDipp}AlM]2. In contrast, similar treatment with sodium results in over-reduction and incorporation of a formal equivalent of [{SiNDipp}Na2] into the resultant sodium alumanyl species. The dimeric K, Rb, and Cs compounds display a variable efficacy toward the C-H oxidative addition of arene C-H bonds at elevated temperatures (Cs > Rb > K, 110 °C) to yield (hydrido)(organo)aluminate species. Consistent with the synthetic experimental observations, computational (DFT) assessment of the benzene C-H activation indicates that rate-determining attack of the Al(I) nucleophile within the dimeric species is facilitated by π-engagement of the arene with the electrophilic M+ cation, which becomes increasingly favorable as group 1 is descended.
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Affiliation(s)
- Han-Ying Liu
- Department of Chemistry, University
of Bath, Claverton
Down, Bath BA2 7AY, U.K.
| | - Michael S. Hill
- Department of Chemistry, University
of Bath, Claverton
Down, Bath BA2 7AY, U.K.
| | - Mary F. Mahon
- Department of Chemistry, University
of Bath, Claverton
Down, Bath BA2 7AY, U.K.
| | - Claire L. McMullin
- Department of Chemistry, University
of Bath, Claverton
Down, Bath BA2 7AY, U.K.
| | - Ryan J. Schwamm
- Department of Chemistry, University
of Bath, Claverton
Down, Bath BA2 7AY, U.K.
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9
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Boronski JT, Thomas-Hargreaves LR, Ellwanger MA, Crumpton AE, Hicks J, Bekiş DF, Aldridge S, Buchner MR. Inducing Nucleophilic Reactivity at Beryllium with an Aluminyl Ligand. J Am Chem Soc 2023; 145:4408-4413. [PMID: 36786728 PMCID: PMC9983009 DOI: 10.1021/jacs.3c00480] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The reactions of anionic aluminium or gallium nucleophiles {K[E(NON)]}2 (E = Al, 1; Ga, 2; NON = 4,5-bis(2,6-diisopropylanilido)-2,7-ditert-butyl-9,9-dimethylxanthene) with beryllocene (BeCp2) led to the displacement of one cyclopentadienyl ligand at beryllium and the formation of compounds containing Be-Al or Be-Ga bonds (NON)EBeCp (E = Al, 3; Ga, 4). The Be-Al bond in the beryllium-aluminyl complex [2.310(4) Å] is much shorter than that found in the small number of previous examples [2.368(2) to 2.432(6) Å], and quantum chemical calculations suggest the existence of a non-nuclear attractor (NNA) for the Be-Al interaction. This represents the first example of a NNA for a heteroatomic interaction in an isolated molecular complex. As a result of this unusual electronic structure and the similarity in the Pauling electronegativities of beryllium and aluminium, the charge at the beryllium center (+1.39) in 3 is calculated to be less positive than that of the aluminium center (+1.88). This calculated charge distribution suggests the possibility for nucleophilic behavior at beryllium and correlates with the observed reactivity of the beryllium-aluminyl complex with N,N'-diisopropylcarbodiimide─the electrophilic carbon center of the carbodiimide undergoes nucleophilic attack by beryllium, thereby yielding a beryllium-diaminocarbene complex.
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Affiliation(s)
- Josef T. Boronski
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;,
| | | | - Mathias A. Ellwanger
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Agamemnon E. Crumpton
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Jamie Hicks
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Deniz F. Bekiş
- Fachbereich
Chemie, Philipps-Universität Marburg, Marburg 35037, Germany
| | - Simon Aldridge
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;,
| | - Magnus R. Buchner
- Fachbereich
Chemie, Philipps-Universität Marburg, Marburg 35037, Germany,
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10
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Abstract
The chemistry of low valent p-block metal complexes continues to elicit interest in the research community, demonstrating reactivity that replicates and in some cases exceeds that of their more widely studied d-block metal counterparts. The introduction of the first aluminyl anion, a complex containing a formally anionic Al(I) centre charge balanced by an alkali metal (AM) cation, has established a platform for a new area of chemical research. The chemistry displayed by aluminyl compounds is expanding rapidly, with examples of reactivity towards a diverse range of small molecules and functional groups now reported in the literature. Herein we present an account of the structure and reactivity of the growing family of aluminyl compounds. In this context we examine the structural relationships between the aluminyl anion and the AM cations, which now include examples of AM = Li, Na, K, Rb and Cs. We report on the ability of these compounds to engage in bond-breaking and bond-forming reactions, which is leading towards their application as useful reagents in chemical synthesis. Furthermore we discuss the chemistry of bimetallic complexes containing direct Al-M bonds (M = Li, Na, K, Mg, Ca, Cu, Ag, Au, Zn) and compounds with Al-E multiple bonds (E = NR, CR2, O, S, Se, Te), where both classes of compound are derived directly from aluminyl anions.
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Affiliation(s)
- Martyn P Coles
- School of Chemical of Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6012, New Zealand.
| | - Matthew J Evans
- School of Chemistry, Monash University, Melbourne, Victoria, Australia
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11
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Morris LJ, Mahawar P, Okuda J. Hydroboration and Deoxygenation of CO 2 Mediated by a Gallium(I) Cation. J Org Chem 2022; 88:5090-5096. [PMID: 36413220 DOI: 10.1021/acs.joc.2c02229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Hydroboration of CO2 to formoxy borane occurs under ambient conditions in acetonitrile using pinacolborane HBpin in the presence of gallium(I) cation [(Me4TACD)Ga][BAr4] (1; Me4TACD = N,N',N″,N'''-tetramethyl-1,4,7,10-tetraazacyclododecane; Ar = C6H3-3,5-Me2). Slow turnover was accompanied by side reactions including ligand scrambling of HBpin to give BH3(CH3CN) and crystalline B2pin3. When 1 was reacted with CO2 alone, the formation of the gallium(III) carbonato complex [(Me4TACD)Ga(κ2-O2CO)][BAr4] (3) along with CO was observed. This complex was assumed to form via the unstable oxido cation [(Me4TACD)Ga=O]+ (4). Reaction of 1 with N2O in the presence of BPh3 confirmed the formation of the oxido cation, which was spectroscopically characterized as a triphenylborane adduct [(Me4TACD)Ga=O(BPh3)][BAr4] (4·BPh3). CO was also detected when CO2 was reacted with 1 in the presence of HBpin, suggesting that compound 3 may also be formed in initial stages of catalysis. Compound 3 reacts with HBpin to give formoxy borane, borane redistribution products, and an unidentified Me4TACD-containing species 5, which was also observed in "catalytic" runs starting from 1, HBpin, and CO2. Hydroboration of CO2 using HBpin with slow turnover and competitive ligand scrambling was also observed in the presence of gallium(III) hydride dication [(Me4TACD)GaH][BAr4]2 (2), which is unreactive toward CO2 in the absence of HBpin.
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Affiliation(s)
- Louis J. Morris
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Pritam Mahawar
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Jun Okuda
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
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