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Winkler L, Hinz A. Stabilisation of a Strontium Hydride with a Monodentate Carbazolyl Ligand and its Reactivity. Angew Chem Int Ed Engl 2025; 64:e202418558. [PMID: 39611319 PMCID: PMC11773309 DOI: 10.1002/anie.202418558] [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: 09/26/2024] [Revised: 11/19/2024] [Accepted: 11/19/2024] [Indexed: 11/30/2024]
Abstract
The molecular strontium hydride 2 [(dtbpCbz)SrH(L)]2 (L=benzene, toluene) was isolated and stabilized by employing a sterically demanding carbazole ligand (dtbpCbz=1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazolyl). Compound 2 was synthesized via phenylsilane metathesis with the corresponding amide (dtbpCbz)SrN(SiMe3)2 and characterized by 1H NMR, XRD and vibrational spectroscopy methods. We further investigated the stoichiometric reactivity of 2 towards carbon monoxide, azobenzene and trimethylsilylacetylene, showing three distinct reactivity pathways: addition, reduction and deprotonation. The reaction of 2 with carbon monoxide yields the ethenediolate complex 4 via addition, while with azobenzene reduction of the N-N double bond and release of hydrogen were observed, affording a heteroleptic strontium complex with a radical azobenzenyl ligand (5). The terminal alkyne is deprotonated by the hydride moiety to give the acetylide complex 6.
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Affiliation(s)
- Lucas Winkler
- Karlsruhe Institute of Technology (KIT)Institute of Inorganic Chemistry (AOC)Engesserstr. 15, Geb. 30.45KarlsruheGermany
| | - Alexander Hinz
- Karlsruhe Institute of Technology (KIT)Institute of Inorganic Chemistry (AOC)Engesserstr. 15, Geb. 30.45KarlsruheGermany
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2
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Gong X, Shi X, Deng P, Cheng J. Reactivity of Strontium Hydride Supported by the Superbulky Hydrotris(pyrazolyl)borate Ligand. Inorg Chem 2024; 63:20654-20663. [PMID: 39421973 PMCID: PMC11523258 DOI: 10.1021/acs.inorgchem.4c03296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2024] [Revised: 10/05/2024] [Accepted: 10/10/2024] [Indexed: 10/19/2024]
Abstract
Hydrogenolysis of [(TpAd,iPr)Sr{CH(SiMe3)2}] (1) (TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) in hexane solution under 20 atm of H2 allowed for the isolation of strontium hydride [(TpAd,iPr)Sr(μ-H)]2 (2) in good yield. Complex 2 exhibits the dimeric nature in solid state, featuring two different bond modes between the Sr center and TpAd,iPr ligand. Treatment of complex 2 with PhC(H)═NtBu or PhCH2Bpin (Bpin = pinacolateborane) afforded the strontium amide complex [(TpAd,iPr)Sr{N(CH2Ph)(tBu)}] (4) and hydroborate complex [(TpAd,iPr)Sr{μ-HBpin(CH2Ph)}] (5), respectively. Reactions of complex 2 with 2-picoline, 2-phenylquinoline, or 2-phenylpyridine led to the formation of strontium 2-pyridylmethylene/2-picoline complex [(TpAd,iPr)Sr(2-CH2-Py)(2-picoline)] (6), reductively coupling diphenyl-biquinolide complex [{(TpAd,iPr)Sr}2(2,2'-Ph2-4,4'-dihydro-4,4'-biquinolide)] (7), and diphenyl-bipyridyl radical complex [(TpAd,iPr)Sr(6,6'-Ph2-2,2'-bipyridyl)] (8), separately. All of the complexes have been well characterized, including NMR spectrum and single-crystal X-ray analysis.
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Affiliation(s)
- Xun Gong
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, No. 5625 Renmin Street, Changchun 130022, China
- School
of Applied Chemistry and Engineering, University
of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xianghui Shi
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, No. 5625 Renmin Street, Changchun 130022, China
| | - Peng Deng
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, No. 5625 Renmin Street, Changchun 130022, China
- School
of Applied Chemistry and Engineering, University
of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jianhua Cheng
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, No. 5625 Renmin Street, Changchun 130022, China
- School
of Applied Chemistry and Engineering, University
of Science and Technology of China, Hefei, Anhui 230026, China
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Kennedy DB, Evans MJ, Jones DDL, Parr JM, Hill MS, Jones C. A series of neutral alkaline earth metal hydride complexes supported by a bulky, unsymmetrical β-diketiminate ligand, [{( Dip/TCHPNacnac)M(μ-H)} 2] (M = Mg, Ca, Sr or Ba). Chem Commun (Camb) 2024; 60:10894-10897. [PMID: 39253901 DOI: 10.1039/d4cc04286g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
A bulky, unsymmetrical β-diketiminate ligand, [HC{MeCN(Dip)}{MeCN(TCHP)}]- (Dip/TCHPNacnac; Dip = 2,6-diisopropylphenyl, TCHP = 2,4,6-tricyclohexylphenyl), has been utilised in the preparation of a series of magnesium alkyl and calcium, strontium and barium amide complexes. Reaction of these with PhSiH3 afforded the first complete series of β-diketiminato heavier group 2 metal hydride complexes, [{(Dip/TCHPNacnac)M(μ-H)}2] (M = Mg, Ca, Sr or Ba). The unsymmetrical nature of the β-diketiminate ligand seemingly promotes stabilising interactions of ligand Dip groups with the metal centres in the Ca, Sr and Ba hydride complexes.
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Affiliation(s)
- Dominic B Kennedy
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Matthew J Evans
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
| | - Dafydd D L Jones
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
| | - Joseph M Parr
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
| | - Michael S Hill
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
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4
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Shi X, Deng P, Rajeshkumar T, Maron L, Cheng J. Multi-electron redox reactivity of a samarium(ii) hydrido complex. Chem Sci 2024; 15:11965-11971. [PMID: 39092133 PMCID: PMC11290423 DOI: 10.1039/d4sc03104k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Accepted: 06/14/2024] [Indexed: 08/04/2024] Open
Abstract
Well-defined low-valent molecular rare-earth metal hydrides are rare, and limited to Yb2+ and Eu2+ centers. Here, we report the first example of the divalent samarium(ii) hydrido complex [(CpAr5)SmII(μ-H)(DABCO)]2 (4) (CpAr5 = C5Ar5, Ar = 3,5-iPr2-C6H3; DABCO = 1,4-diazabicyclooctane) supported by a super-bulky penta-arylcyclopentadienyl ligand, resulting from the hydrogenolysis of the samarium(ii) alkyl complex [(CpAr5)SmII{CH(SiMe3)2}(DABCO)] (3). Complex 4 exhibits multi-electron redox reactivity toward a variety of substrates. Exposure of complex 4 to CO2 results in the formation of the trivalent samarium(iii) mixed-bis-formate/carbonate complex [(CpAr5)SmIII(μ-η2:η1-O2CH)(μ-η2:η2-CO3)(μ-η1:η1-O2CH)SmIII(CpAr5)(DABCO)] (8), mediated by hydride insertion and reductive disproportionation reactions. Complex 4 shows four-electron reduction toward four equivalents of CS2 to afford the trivalent samarium(iii) bis-trithiocarbonate complex [(CpAr5)SmIII(μ-η2:η2-CS3)(DABCO)]2 (9). A mechanistic study of the formation of complex 8 was carried out using DFT calculations.
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Affiliation(s)
- Xianghui Shi
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Peng Deng
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- School of Applied Chemistry and Engineering, University of Science and Technology of China Hefei Anhui 230026 China
| | - Thayalan Rajeshkumar
- LPCNO, CNRS & INSA, UPS, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Laurent Maron
- LPCNO, CNRS & INSA, UPS, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Jianhua Cheng
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- School of Applied Chemistry and Engineering, University of Science and Technology of China Hefei Anhui 230026 China
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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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Hadlington TJ. An anionic beryllium hydride dimer with an exceedingly short Be⋯Be distance. Dalton Trans 2024; 53:882-886. [PMID: 38168968 DOI: 10.1039/d3dt03976e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Heteroleptic hydride complexes of the group 2 metals have seen considerable attention as Earth-abundant synthetic tools, yet anionic derivatives are exceedingly rare. We described the facile synthesis and in-depth characterisation of an anionic beryllium hydride dimer, featuring a dynamic [Be2H3] cluster at its core with a short Be⋯Be distance. Despite this, there is no formal Be-Be bond in this complex, with only hydride bridging interactions leading to this remarkable structural attribute.
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Affiliation(s)
- Terrance J Hadlington
- Fakultät für Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
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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: 9] [Impact Index Per Article: 4.5] [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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Cationic barium benzyl and hydride complexes that contain an eighteen-membered N,N,N,N,N,N-type macrocycle. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.121198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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