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Gentner T, Ballmann GM, Banerjee S, Kennedy AR, Robertson SD, Mulvey RE. Application of Bis(amido)alkyl Magnesiates toward the Synthesis of Molecular Rubidium and Cesium Hydrido-magnesiates. Organometallics 2024; 43:1393-1401. [PMID: 38938897 PMCID: PMC11200325 DOI: 10.1021/acs.organomet.4c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024]
Abstract
Rubidium and cesium are the least studied naturally occurring s-block metals in organometallic chemistry but are in plentiful supply from a sustainability viewpoint as highlighted in the periodic table of natural elements published by the European Chemical Society. This underdevelopment reflects the phenomenal success of organometallic compounds of lithium, sodium, and potassium, but interest in heavier congeners has started to grow. Here, the synthesis and structures of rubidium and cesium bis(amido)alkyl magnesiates [(AM)MgN'2alkyl]∞, where N' is the simple heteroamide -N(SiMe3)(Dipp), and alkyl is nBu or CH2SiMe3, are reported. More stable than their nBu analogues, the reactivities of the CH2SiMe3 magnesiates toward 1,4-cyclohexadiene are revealed. Though both reactions produce target hydrido-magnesiates [(AM)MgN'2H]2 in crystalline form amenable to X-ray diffraction study, the cesium compound could only be formed in a trace quantity. These studies showed that the bulk of the -N(SiMe3)(Dipp) ligand was sufficient to restrict both compounds to dimeric structures. Bearing some resemblance to inverse crown complexes, each structure has [(AM)(N)(Mg)(N)]2 ring cores but differ in having no AM-N bonds, instead Rb and Cs complete the rings by engaging in multihapto interactions with Dipp π-clouds. Moreover, their hydride ions occupy μ3-(AM)2Mg environments, compared to μ2-Mg2 environments in inverse crowns.
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Affiliation(s)
- Thomas
X. Gentner
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Gerd M. Ballmann
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Sumanta Banerjee
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Alan R. Kennedy
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Stuart D. Robertson
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Robert E. Mulvey
- WestCHEM, Department of Pure
and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K.
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2
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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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3
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Macdonald PA, Kennedy AR, Weetman CE, Robertson SD, Mulvey RE. Synthesis, characterisation, and catalytic application of a soluble molecular carrier of sodium hydride activated by a substituted 4-(dimethylamino)pyridine. Commun Chem 2024; 7:94. [PMID: 38678145 PMCID: PMC11055874 DOI: 10.1038/s42004-024-01184-5] [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: 02/14/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024] Open
Abstract
Recently main group compounds have stepped into the territory of precious transition metal compounds with respect to utility in the homogeneous catalysis of fundamentally important organic transformations. Inspired by the need to promote more sustainability in chemistry because of their greater abundance in nature, this change of direction is surprising since main group metals generally do not possess the same breadth of reactivity as precious transition metals. Here, we introduce the dihydropyridylsodium compound, Na-1,2-tBu-DH(DMAP), and its monomeric variant [Na-1,2-tBu-DH(DMAP)]·Me6TREN, and demonstrate their effectiveness in transfer hydrogenation catalysis of the representative alkene 1,1-diphenylethylene to the alkane 1,1-diphenylethane using 1,4-cyclohexadiene as hydrogen source [DMAP = 4-dimethylaminopyridine; Me6TREN = tris(N,N-dimethyl-2-aminoethyl)amine]. Sodium is appealing because of its high abundance in the earth's crust and oceans, but organosodium compounds have been rarely used in homogeneous catalysis. The success of the dihydropyridylsodium compounds can be attributed to their high solubility and reactivity in organic solvents.
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Affiliation(s)
- Peter A Macdonald
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Alan R Kennedy
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Catherine E Weetman
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Stuart D Robertson
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Robert E Mulvey
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
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4
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Gawron M, Gilch F, Schmidhuber D, Kelly JA, Horsley Downie TM, Jacobi von Wangelin A, Rehbein J, Wolf R. Counterion Effect in Cobaltate-Catalyzed Alkene Hydrogenation. Angew Chem Int Ed Engl 2024; 63:e202315381. [PMID: 38059406 DOI: 10.1002/anie.202315381] [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: 10/12/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
We show that countercations exert a remarkable influence on the ability of anionic cobaltate salts to catalyze challenging alkene hydrogenations. An evaluation of the catalytic properties of [Cat][Co(η4 -cod)2 ] (Cat=K (1), Na (2), Li (3), (Dep nacnac)Mg (4), and N(n Bu)4 (5); cod=1,5-cyclooctadiene, Dep nacnac={2,6-Et2 C6 H3 NC(CH3 )}2 CH)]) demonstrated that the lithium salt 3 and magnesium salt 4 drastically outperform the other catalysts. Complex 4 was the most active catalyst, which readily promotes the hydrogenation of highly congested alkenes under mild conditions. A plausible catalytic mechanism is proposed based on density functional theory (DFT) investigations. Furthermore, combined molecular dynamics (MD) simulation and DFT studies were used to examine the turnover-limiting migratory insertion step. The results of these studies suggest an active co-catalytic role of the counterion in the hydrogenation reaction through the coordination to cobalt hydride intermediates.
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Affiliation(s)
- Martin Gawron
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Franziska Gilch
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Daniel Schmidhuber
- Institute of Organic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - John A Kelly
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | | | | | - Julia Rehbein
- Institute of Organic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Robert Wolf
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
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5
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Wacker J, Lynch JR, Banerjee S, Macdonald PA, Kennedy AR, Sarkar B, Mulvey RE. Isolable rubidium and caesium derivatives of common organic carbonyl compounds. Chem Commun (Camb) 2023; 60:91-94. [PMID: 38019118 DOI: 10.1039/d3cc05527b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Light alkali metal (Li, Na, K) amides have a long history of synthetic utility, but heavier (Rb, Cs) congeners have barely been studied. This study reveals remarkable structurally complex outcomes of reacting AM(HMDS) (AM = Rb, Cs; HMDS = hexamethyldisilazide) with benzaldehyde and acetophenone. Though complicated, reactions give a diversity of eye-catching isolated products, an enolate with a hexagonal prismatic network, two dienolates with distinct extended ladder motifs, and two β-imino-alkoxides comprising zig-zag chains of metal-oxygen bonds in infinite cages.
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Affiliation(s)
- Jakoba Wacker
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart, 70569, Germany
| | - Jennifer R Lynch
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Sumanta Banerjee
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Peter A Macdonald
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart, 70569, Germany
| | - Robert E Mulvey
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
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Banerjee S, Ballmann GM, Evans MJ, O'Reilly A, Kennedy AR, Fulton JR, Coles MP, Mulvey RE. Three Oxidative Addition Routes of Alkali Metal Aluminyls to Dihydridoaluminates and Reactivity with CO 2. Chemistry 2023; 29:e202301849. [PMID: 37429823 DOI: 10.1002/chem.202301849] [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: 06/22/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp )(H)2 ] (AM=Li, Na, K, Rb, Cs; [NONDipp ]2- =[O(SiMe2 NDipp)2 ]2- ; Dipp=2,6-iPr2 C6 H3 ) starting from the alkali metal aluminyls, AM[Al(NONDipp )]. Direct H2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4-cyclohexadiene (1,4-CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li-Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp )(H)(SiH2 Ph)]. Probing the reaction of Cs[Al(NONDipp )] with 1,4-CHD provided access to a novel inverse sandwich complex, [{Cs(Et2 O)}2 {Al(NONDipp )(H)}2 (C6 H6 )], containing the 1,4-dialuminated [C6 H6 ]2- dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4-CHD to benzene has been trapped. The synthetic utility of the newly installed Al-H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis-formate AM[Al(NONDipp )(O2 CH)2 ] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures.
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Affiliation(s)
- Sumanta Banerjee
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - Gerd M Ballmann
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Andrea O'Reilly
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - J Robin Fulton
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
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7
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Evans MJ, Jones C. Synthesis and Reactivity of Alkali Metal Hydrido-Magnesiate Complexes which Exhibit Group 1 Metal Counter-Cation Specific Stability. Inorg Chem 2023; 62:14393-14401. [PMID: 37602922 DOI: 10.1021/acs.inorgchem.3c02086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Reactions of the series of alkali metal amides M(HMDS) (M = Li-Cs; HMDS = [N(SiMe3)2]-) with the neutral magnesium(II) hydride compound [Mg(BDIDipp)(μ-H)]2 (BDIDipp = [CH{C(Me)NDipp}2], Dipp = 2,6-iPr2-C6H3) have been carried out. When M = Li or Na, the reactions yielded Mg(BDIDipp)(HMDS) and MH as the primary products. In the sodium amide reaction, [Na2(HMDS)][{Mg(BDIDipp)}2(H)3] was obtained as a low-yield by-product. When M = K-Cs, the reactions gave the group 1 metal hydrido-magnesiates, M2[Mg(BDIDipp)(HMDS)(H)]2·(benzene)n (n = 0 or 1), the thermal stability of which increases with the increasing molecular weight of the alkali metal involved. Reactions of Cs2[Mg(BDIDipp)(HMDS)(H)]2·(benzene) with 18-crown-6 and CO gave the first monomeric alkali metal hydrido-magnesiate [Cs(18-crown-6)][Mg(BDIDipp)(HMDS)(H)] and the ethenediolate complex Cs2[{Mg(BDIDipp)(HMDS)}2(μ-C2H2O2)], respectively. The new synthetic route to alkali metal hydrido-magnesiates described herein may facilitate further reactivity studies of this rare compound class.
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Affiliation(s)
- Matthew J Evans
- School of Chemistry, Monash University, P.O. Box 23, Melbourne, Victoria 3800, Australia
| | - Cameron Jones
- School of Chemistry, Monash University, P.O. Box 23, Melbourne, Victoria 3800, Australia
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Macdonald PA, Banerjee S, Kennedy AR, van Teijlingen A, Robertson SD, Tuttle T, Mulvey RE. Alkali Metal Dihydropyridines in Transfer Hydrogenation Catalysis of Imines: Amide Basicity versus Hydride Surrogacy. Angew Chem Int Ed Engl 2023; 62:e202304966. [PMID: 37132607 PMCID: PMC10952797 DOI: 10.1002/anie.202304966] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/04/2023]
Abstract
Catalytic reduction of a representative set of imines, both aldimines and ketimines, to amines has been studied using transfer hydrogenation from 1,4-dicyclohexadiene. Unusually, this has been achieved using s-block pre-catalysts, namely 1-metallo-2-tert-butyl-1,2-dihydropyridines, 2-tBuC5 H5 NM, M(tBuDHP), where M=Li-Cs. Reactions have been monitored in C6 D6 and tetrahydrofuran-d8 (THF-d8 ). A definite trend is observed in catalyst efficiency with the heavier alkali metal tBuDHPs outperforming the lighter congeners. In general, Cs(tBuDHP) is the optimal pre-catalyst with, in the best cases, reactions producing quantitative yields of amines in minutes at room temperature using 5 mol % catalyst. Supporting the experimental study, Density Functional Theory (DFT) calculations have also been carried out which reveal that Cs has a pathway with a significantly lower rate determining step than the Li congener. In the postulated initiation pathways DHP can act as either a base or as a surrogate hydride.
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Affiliation(s)
- Peter A. Macdonald
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Sumanta Banerjee
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Alan R. Kennedy
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | | | - Stuart D. Robertson
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Tell Tuttle
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Robert E. Mulvey
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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Borys AM, Hevia E. Diphenylacetylene stabilised alkali-metal nickelates: synthesis, structure and catalytic applications. Dalton Trans 2023; 52:2098-2105. [PMID: 36722457 PMCID: PMC9926332 DOI: 10.1039/d3dt00069a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Whilst low-valent nickelates have recently been proposed as intermediates in Ni-catalysed reactions involving polar organometallics, their isolation and characterisation is often challenging due to their high sensitivity and reactivity. Advancing the synthetic, spectroscopic and structural insights of these heterobimetallic systems, here we report a new family of alkyne supported alkali-metal nickelates of the formula Li4(solv)n(Ar)4Ni2{μ2:η2,η2-Ph-CC-Ph} (where solv = Et2O, THF; Ar = Ph, o-Tol, naphthyl, 4-tBu-C6H4) which can be accessed through the combination of Ni(COD)2, Ph-CC-Ph and the relevant lithium aryl in a 2 : 1 : 4 ratio. Demonstrating the versatility of this approach, the sodium and potassium nickelates can also be accessed when using PhNa or via alkali-metal exchange with AMOtBu (AM = Na, K). When employing bulky or structurally constrained aryl-lithiums, mononickel complexes of the formula Li2(solv)n(Ar)2Ni{η2-Ph-CC-Ph} are instead obtained, highlighting the structural diversity of alkali-metal nickelates bearing alkyne ligands. Expanding the catalytic potential of these systems, their ability to promote the catalytic cyclotrimerisation of diphenylacetylene to hexaphenylbenzene was explored, with mononickel compounds bearing electron rich aryl-substituents displaying the best performance.
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Affiliation(s)
- Andryj M. Borys
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern3012 BernSwitzerland
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, 3012 Bern, Switzerland.
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10
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McMullen JS, Huo R, Vasko P, Edwards AJ, Hicks J. Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers. Angew Chem Int Ed Engl 2023; 62:e202215218. [PMID: 36344462 PMCID: PMC10100151 DOI: 10.1002/anie.202215218] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Indexed: 11/09/2022]
Abstract
The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be "terminal", but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.
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Affiliation(s)
- Jacob S. McMullen
- Research School of ChemistryAustralian National UniversityActonACT 2601Australia
| | - Ryan Huo
- Research School of ChemistryAustralian National UniversityActonACT 2601Australia
| | - Petra Vasko
- Department of ChemistryUniversity of HelsinkiA.I. Virtasen aukio 1, P.O. Box 5500014HelsinkiFinland
| | - Alison J. Edwards
- Australian Centre for Neutron ScatteringAustralian Nuclear Science and Technology OrganisationSydneyNSW 2234Australia
| | - Jamie Hicks
- Research School of ChemistryAustralian National UniversityActonACT 2601Australia
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11
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Structural Characterization of the 1-Metallo-2-t-Butyl-1,2-Dihydropyridyl Rubidium and Caesium Complexes. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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12
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Banerjee S, Macdonald PA, Orr SA, Kennedy AR, van Teijlingen A, Robertson SD, Tuttle T, Mulvey RE. Hydrocarbon Soluble Alkali-Metal-Aluminium Hydride Surrog[ATES]. Chemistry 2022; 28:e202201085. [PMID: 35811447 PMCID: PMC9804340 DOI: 10.1002/chem.202201085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Indexed: 01/05/2023]
Abstract
A series of group 1 hydrocarbon-soluble donor free aluminates [AM(t BuDHP)(TMP)Al(i Bu)2 ] (AM=Li, Na, K, Rb) have been synthesised by combining an alkali metal dihydropyridyl unit [(2-t BuC5 H5 N)AM)] containing a surrogate hydride (sp3 C-H) with [(i Bu)2 Al(TMP)]. These aluminates have been characterised by X-ray crystallography and NMR spectroscopy. While the lithium aluminate forms a monomer, the heavier alkali metal aluminates exist as polymeric chains propagated by non-covalent interactions between the alkali metal cations and the alkyldihydropyridyl units. Solvates [(THF)Li(t BuDHP)(TMP)Al(i Bu)2 ] and [(TMEDA)Na(t BuDHP)(TMP)Al(i Bu)2 ] have also been crystallographically characterised. Theoretical calculations show how the dispersion forces tend to increase on moving from Li to Rb, as opposed to the electrostatic forces of stabilization, which are orders of magnitude more significant. Having unique structural features, these bimetallic compounds can be considered as starting points for exploring unique reactivity trends as alkali-metal-aluminium hydride surrog[ATES].
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Affiliation(s)
- Sumanta Banerjee
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Peter A. Macdonald
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Samantha A. Orr
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Alan R. Kennedy
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | | | - Stuart D. Robertson
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Tell Tuttle
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Robert E. Mulvey
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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13
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Ballmann GM, Gentner TX, Kennedy AR, Hevia E, Mulvey RE. Heavy Alkali Metal Manganate Complexes: Synthesis, Structures and Solvent-Induced Dissociation Effects. Chemistry 2022; 28:e202201716. [PMID: 35775467 PMCID: PMC9804227 DOI: 10.1002/chem.202201716] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Indexed: 01/05/2023]
Abstract
Rare examples of heavier alkali metal manganates [{(AM)Mn(CH2 SiMe3 )(N'Ar )2 }∞ ] (AM=K, Rb, or Cs) [N'Ar =N(SiMe3 )(Dipp), where Dipp=2,6-iPr2 -C6 H3 ] have been synthesised with the Rb and Cs examples crystallographically characterised. These heaviest manganates crystallise as polymeric zig-zag chains propagated by AM⋅⋅⋅π-arene interactions. Key to their preparation is to avoid Lewis base donor solvents. In contrast, using multidentate nitrogen donors encourages ligand scrambling leading to redistribution of these bimetallic manganate compounds into their corresponding homometallic species as witnessed for the complete Li - Cs series. Adding to the few known crystallographically characterised unsolvated and solvated rubidium and caesium s-block metal amides, six new derivatives ([{AM(N'Ar )}∞ ], [{AM(N'Ar )⋅TMEDA}∞ ], and [{AM(N'Ar )⋅PMDETA}∞ ] where AM=Rb or Cs) have been structurally authenticated. Utilising monodentate diethyl ether as a donor, it was also possible to isolate and crystallographically characterise sodium manganate [(Et2 O)2 Na(n Bu)Mn[(N'Ar )2 ], a monomeric, dinuclear structure prevented from aggregating by two blocking ether ligands bound to sodium.
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Affiliation(s)
- Gerd M. Ballmann
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Thomas X. Gentner
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Alan R. Kennedy
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Eva Hevia
- Department für Chemie und BiochemieUniversität BernFreiestrasse 33012BernSwitzerland
| | - Robert E. Mulvey
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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Grams S, Mai J, Langer J, Harder S. Alkali metal influences in aluminyl complexes. Dalton Trans 2022; 51:12476-12483. [PMID: 35904400 DOI: 10.1039/d2dt02111k] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The previously reported potassium aluminyl complex [(BDI-H)Al-K+]2 was converted in Li+ or Na+ salts by a salt metathesis reaction with Li(BPh4) or Na(BPh4), respectively; BDI-H = dianionic [(DIPP)N-C(Me)C(H)-C(CH2)-N(DIPP)2-] and DIPP = 2,6-diisopropylphenyl. The Rb and Cs aluminyl complexes were obtained by reaction of (BDI)Al with RbC8 or CsC8; BDI = HC[C(Me)N(DIPP)]2. Crystal structures of two monomers, (BDI-H)Al-Li+·(Et2O)2 and (BDI-H)Al-Na+·(Et2O)(TMEDA), and four dimers [(BDI-H)Al-M+]2 (M = Li, Na, Rb, Cs) are discussed. Lewis base-free dimers [(BDI-H)Al-M+]2 crystallize either as slipped dimers (Li+, Na+) in which each Al center features only one Al-M contact or as a symmetric dimer (K+, Rb+, Cs+) in which the cation bridges both Al centers. The dimer with the largest cation (Cs+) shows Cs⋯CH2C interactions between dimers, resulting in a coordination polymer. AIM and charge analysis reveal highly ionic Al-M bonds with strong polarization of the Al lone-pair towards the smaller cation Li+ and Na+. The Al-M bonds become weaker from Li to Cs. Calculated dimerization energies suggest that in apolar solvents only complexes with the heavier metals Rb and Cs may be in a monomer-dimer equilibrium. This is confirmed by DOSY measurements in benzene. Dimeric aluminyl complexes with heavier alkali metals (K-Cs) react with benzene to give a double C-H activation in para-positions.
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Affiliation(s)
- Samuel Grams
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Jonathan Mai
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Jens Langer
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany.
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Gentner TX, Evans MJ, Kennedy AR, Neale SE, McMullin CL, Coles MP, Mulvey RE. Rubidium and caesium aluminyls: synthesis, structures and reactivity in C-H bond activation of benzene. Chem Commun (Camb) 2022; 58:1390-1393. [PMID: 34994367 DOI: 10.1039/d1cc05379e] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Expanding knowledge of low valent aluminium chemistry, rubidium and caesium aluminyls are reported to complete the group 1 (Li-Cs) set of metal aluminyls. Both compounds crystallize as a contacted dimeric pair supported by M⋯π(arene) interactions with a pronounced twist between aluminyl units. Density functional theory calculations show symmetrical bonding between the M and Al atoms, with an Al centred lone-pair donating into vacant Rb and Cs orbitals. Interestingly, despite their structural similarity the Cs aluminyl enables C-H bond activation of benzene, but not the Rb aluminyl reflecting the importance of the alkali metal in these heterobimetallic systems.
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Affiliation(s)
- Thomas X Gentner
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand.
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
| | - Sam E Neale
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | | | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand.
| | - Robert E Mulvey
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
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16
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Petrus R, Lis T, Kowaliński A. Use of heterometallic alkali metal–magnesium aryloxides in ring-opening polymerization of cyclic esters. Dalton Trans 2022; 51:9144-9158. [DOI: 10.1039/d2dt00731b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The alkali metal–magnesium aryloxides of the general formula [Mg2M′2(OAr)6(THF)x] (for M′ = Li, Na, K, and x = 0, 2, 4) were used to investigate the cooperativity effect of different metal sites on the ring-opening polymerization of l-lactide.
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Affiliation(s)
- Rafał Petrus
- Faculty of Chemistry, Wrocław University of Science and Technology, 23 Smoluchowskiego, 50-370 Wrocław, Poland
| | - Tadeusz Lis
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Adrian Kowaliński
- Faculty of Chemistry, Wrocław University of Science and Technology, 23 Smoluchowskiego, 50-370 Wrocław, Poland
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17
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Pollard VA, Fuentes MA, Robertson SD, Weetman C, Kennedy AR, Brownlie J, Angus FJ, Smylie C, Mulvey RE. Reactivity studies and structural outcomes of a bulky dialkylaluminium amide in the presence of the N-heterocyclic carbene, ItBu. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Roy MMD, Omaña AA, Wilson ASS, Hill MS, Aldridge S, Rivard E. Molecular Main Group Metal Hydrides. Chem Rev 2021; 121:12784-12965. [PMID: 34450005 DOI: 10.1021/acs.chemrev.1c00278] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.
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Affiliation(s)
- Matthew M D Roy
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Alvaro A Omaña
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Andrew S S Wilson
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Michael S Hill
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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20
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Wiesinger M, Knüpfer C, Elsen H, Mai J, Langer J, Harder S. Heterometallic Mg−Ba Hydride Clusters in Hydrogenation Catalysis. ChemCatChem 2021. [DOI: 10.1002/cctc.202101071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Michael Wiesinger
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Christian Knüpfer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Holger Elsen
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jonathan Mai
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
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