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Wei B, Chen YH, Knochel P. Recent Advances in Halogen-Metal Exchange Reactions. Acc Chem Res 2024. [PMID: 38953535 DOI: 10.1021/acs.accounts.4c00242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
ConspectusThe halogen-metal exchange reaction is a very powerful method for preparing functionalized organometallic reagents in the fields of organic and organometallic chemistry. Since its inception, significant interest has been directed toward the on-demand development of new halogen-metal exchange reactions, primarily through the upgrading of exchange reagents. The enduring quest for optimal reactivity, superior functional group compatibility, and innovative synthetic applications of exchange reagents remains a fundamental objective. In the past several years, the emergence of some significant discoveries in halogen-metal exchange reactions has proclaimed a renaissance to this field. This Account outlines the latest advances within the domain contributed by the Knochel group, including the main points as follows.The stereoretentive I/Li exchange on stereodefined secondary alkyl iodides was developed for the synthesis of nonstabilized chiral secondary alkyllithium reagents. This provided a straightforward method to access chiral organolithium reagents, which can be trapped by various electrophiles or transmetalated with other metals such as copper, zinc, and magnesium, thus enabling the stereoselective synthesis of a series of functionalized compounds and natural products.Faster halogen-magnesium and halogen-zinc exchanges in toluene were realized using a novel kind of exchange reagent complexed with lithium alkoxide. These highly efficient exchange reactions are much faster than traditional ones and performed in an industrially friendly solvent. These advantages are of great value in practical synthesis, paving the way for new developments in this evolving area.Halogen-lanthanide exchanges and their novel applications in organic synthesis were established. These new exchanges introduced the lanthanide metals into halogen-metal exchange reactions for the first time, thereby opening new avenues in synthetic chemistry. Building on these achievements, a comparative analysis of the exchange reaction rates by kinetic study has quantified the relationship between the electronegativity of metals and the rates of halogen-metal exchanges.Br/Na exchange in continuous flow was achieved using a hexane-soluble exchange reagent, 2-ethylhexylsodium. This approach effectively circumvented the poor solubility of the organosodium reagent, which has proven to be of significant practical value and greatly enhanced the synthetic utility of the organosodium reagent in organic synthesis.These remarkable breakthroughs as mentioned above are fueled mainly by upgrading the exchange reagents, resulting in the development of new halogen-metal exchange reactions and innovative applications in organic synthesis. Given the importance of halogen-metal exchanges in synthetic chemistry, the pursuit of other types of exchange reactions, particularly those involving new metals, will be in continuous demand. This Account provides a timely summary of recent progress and will undoubtedly inspire further advances to drive this research field forward.
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Affiliation(s)
- Baosheng Wei
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan China
| | - Yi-Hung Chen
- Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei China
| | - Paul Knochel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München, Germany
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2
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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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3
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Evans MJ, Mullins J, Mondal R, Jones C. Reductions of Arenes using a Magnesium-Dinitrogen Complex. Chemistry 2024; 30:e202401005. [PMID: 38622992 DOI: 10.1002/chem.202401005] [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: 03/11/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/17/2024]
Abstract
In this contribution, we present "Birch-type", and other reductions of simple arenes by the potassium salt of an anionic magnesium dinitrogen complex, [{K(TCHPNON)Mg}2(μ-N2)] (TCHPNON=4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene), which acts as a masked dimagnesium(I) diradical in these reactions. This reagent is non-hazardous, easy-to-handle, and in some cases provides access to 1,4-cyclohexadiene reduction products under relatively mild reaction conditions. This system works effectively to reduce benzene, naphthalene and anthracene through magnesium-bound "Birch-type" reduction intermediates. Cyclohexadiene products can be subsequently released from the magnesium centres by protonolysis with methanol. In contrast, the reduction of substituted arenes is less selective and involves competing reaction pathways. For toluene and 1,3,5-triphenylbenzene, the structural authentication of "Birch-type" reduction intermediates is conclusive, although the formation of corresponding 1,4-cyclohexadiene derivatives was low yielding. Reduction of anisole did not yield an isolable "Birch-type" intermediate, but instead gave a C-O activation product. Treating triphenylphosphine with [{K(TCHPNON)Mg}2(μ-N2)] resulted in the extrusion of both biphenyl and dinitrogen to afford a magnesium(II) phosphanide [{K(TCHPNON)Mg(μ-PPh2)}2]. Reduction of fluorobenzene proceeded via C-F activation of the arene, and isolation of the magnesium(II) fluoride [{K(TCHPNON)Mg(μ-F)}2]. Finally, the two-electron reduction of 1,3,5,7-cyclooctatetraene (COT) with [{K(TCHPNON)Mg}2(μ-N2)] yielded a complex, [{K(TCHPNON)Mg}2(μ-COT)], incorporating the aromatic dianion (COT2-).
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Affiliation(s)
- Matthew J Evans
- School of Chemistry, Monash University, PO Box 23, 3800, Melbourne, Victoria, Australia
| | - Jeremy Mullins
- School of Chemistry, Monash University, PO Box 23, 3800, Melbourne, Victoria, Australia
| | - Rahul Mondal
- School of Chemistry, Monash University, PO Box 23, 3800, Melbourne, Victoria, Australia
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, 3800, Melbourne, Victoria, Australia
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4
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Logallo A, Maddock LCH, Mu M, Gravogl L, Jin N, Peñas-Defrutos MN, Meyer K, García-Melchor M, Hevia E. Unlocking the Metalation Applications of TMP-powered Fe and Co(II) bis(amides): Synthesis, Structure and Mechanistic Insights. Angew Chem Int Ed Engl 2024; 63:e202402907. [PMID: 38563772 DOI: 10.1002/anie.202402907] [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: 02/08/2024] [Revised: 03/19/2024] [Accepted: 04/02/2024] [Indexed: 04/04/2024]
Abstract
Typified by LiTMP and TMPMgCl.LiCl, (TMP=2,2,6,6-tetramethylpiperidide), s-block metal amides have found widespread applications in arene deprotonative metalation. On the contrary, transition metal amides lack sufficient basicity to activate these substrates. Breaking new ground in this field, here we present the synthesis and full characterisation of earth-abundant transition metals M(TMP)2 (M=Fe, Co). Uncovering a new reactivity profile towards fluoroarenes, these amide complexes can promote direct M-H exchange processes regioselectively using one or two of their basic amide arms. Remarkably, even when using a perfluorinated substrate, selective C-H metalation occurs leaving C-F bonds intact. Their kinetic basicity can be boosted by LiCl or NBu4Cl additives which enables formation of kinetically activated ate species. Combining spectroscopic and structural studies with DFT calculations, mechanistic insights have been gained on how these low polarity metalation processes take place. M(TMP)2 can also be used to access ferrocene and cobaltocene by direct deprotonation of cyclopentadiene and undergo efficient CO2 insertion of both amide groups under mild reaction conditions.
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Affiliation(s)
- Alessandra Logallo
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Lewis C H Maddock
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Manting Mu
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin College Green, Dublin, Ireland
| | - Lisa Gravogl
- Department of Chemistry and Pharmacy, Inorganic Chemistry Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058, Erlangen, Germany
| | - Na Jin
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Marconi N Peñas-Defrutos
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin College Green, Dublin, Ireland
- IU CINQUIMA, Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47071, Valladolid, Spain
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058, Erlangen, Germany
| | - Max García-Melchor
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin College Green, Dublin, Ireland
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
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Sreedharan R, Gandhi T. Masters of Mediation: MN(SiMe 3) 2 in Functionalization of C(sp 3)-H Latent Nucleophiles. Chemistry 2024; 30:e202400435. [PMID: 38497321 DOI: 10.1002/chem.202400435] [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: 01/31/2024] [Revised: 03/16/2024] [Accepted: 03/18/2024] [Indexed: 03/19/2024]
Abstract
Organoalkali compounds have undergone a far-reaching transformation being a coupling partner to a mediator in unusual organic conversions which finds its spot in the field of sustainable synthesis. Transition-metal catalysis has always been the priority in C(sp3)-H bond functionalization, however alternatively, in recent times this has been seriously challenged by earth-abundant alkali metals and their complexes arriving at new sustainable organometallic reagents. In this line, the importance of MN(SiMe3)2 (M=Li, Na, K & Cs) reagent revived in C(sp3)-H bond functionalization over recent years in organic synthesis is showcased in this minireview. MN(SiMe3)2 reagent with higher reactivity, enhanced stability, and bespoke cation-π interaction have shown eye-opening mediated processes such as C(sp3)-C(sp3) cross-coupling, radical-radical cross-coupling, aminobenzylation, annulation, aroylation, and other transformations to utilize readily available petrochemical feedstocks. This article also emphasizes the unusual reactivity of MN(SiMe3)2 reagent in unreactive and robust C-X (X=O, N, F, C) bond cleavage reactions that occurred alongside the C(sp3)-H bond functionalization. Overall, this review encourages the community to exploit the untapped potential of MN(SiMe3)2 reagent and also inspires them to take up this subject to even greater heights.
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Affiliation(s)
- Ramdas Sreedharan
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - Thirumanavelan Gandhi
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
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6
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Abdul Rahman M, Neal TJ, Garden JA. Cooperative heterometallic catalysts: balancing activity and control in PCL- block-PLA copolymer synthesis. Chem Commun (Camb) 2024; 60:5530-5533. [PMID: 38695674 DOI: 10.1039/d4cc01664e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Heterometallic cooperativity is gaining momentum in cyclic ester ring-opening polymerisation, yet remains surprisingly underexplored in their block copolymerisations. Here, we report the first homogeneous heterometallic "ate" catalysts for poly(ε-caprolactone)-poly(lactic acid) block copolymers, showcasing the substantial differences in the polymer structures observed upon exchanging Zn for Mg or Ca.
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Affiliation(s)
| | - Thomas J Neal
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, UK.
| | - Jennifer A Garden
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, UK.
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7
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Rodríguez-Álvarez MJ, Ríos-Lombardía N, García-Garrido SE, Concellón C, del Amo V, Capriati V, García-Álvarez J. Recent Advancements in the Utilization of s-Block Organometallic Reagents in Organic Synthesis with Sustainable Solvents. Molecules 2024; 29:1422. [PMID: 38611702 PMCID: PMC11012548 DOI: 10.3390/molecules29071422] [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: 02/15/2024] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
This mini-review offers a comprehensive overview of the advancements made over the last three years in utilizing highly polar s-block organometallic reagents (specifically, RLi, RNa and RMgX compounds) in organic synthesis run under bench-type reaction conditions. These conditions involve exposure to air/moisture and are carried out at room temperature, with the use of sustainable solvents as reaction media. In the examples provided, the adoption of Deep Eutectic Solvents (DESs) or even water as non-conventional and protic reaction media has not only replicated the traditional chemistry of these organometallic reagents in conventional and toxic volatile organic compounds under Schlenk-type reaction conditions (typically involving low temperatures of -78 °C to 0 °C and a protective atmosphere of N2 or Ar), but has also resulted in higher conversions and selectivities within remarkably short reaction times (measured in s/min). Furthermore, the application of the aforementioned polar organometallics under bench-type reaction conditions (at room temperature/under air) has been extended to other environmentally responsible reaction media, such as more sustainable ethereal solvents (e.g., CPME or 2-MeTHF). Notably, this innovative approach contributes to enhancing the overall sustainability of s-block-metal-mediated organic processes, thereby aligning with several key principles of Green Chemistry.
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Affiliation(s)
- María Jesús Rodríguez-Álvarez
- Dipartimento di Farmacia—Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, Consorzio Interuniversitario Nazionale “Metodologie e Processi Innovativi di Sintesi” (C.I.N.M.P.I.S.), Via E. Orabona 4, I-70125 Bari, Italy
| | - Nicolás Ríos-Lombardía
- Laboratorio de Química Sintética Sostenible (QuimSinSos), Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica “Enrique Moles” (IUQOEM), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain
| | - Sergio E. García-Garrido
- Laboratorio de Química Sintética Sostenible (QuimSinSos), Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica “Enrique Moles” (IUQOEM), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain
| | - Carmen Concellón
- Laboratorio de Química Sintética Sostenible (QuimSinSos), Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica “Enrique Moles” (IUQOEM), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain
| | - Vicente del Amo
- Laboratorio de Química Sintética Sostenible (QuimSinSos), Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica “Enrique Moles” (IUQOEM), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain
| | - Vito Capriati
- Dipartimento di Farmacia—Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, Consorzio Interuniversitario Nazionale “Metodologie e Processi Innovativi di Sintesi” (C.I.N.M.P.I.S.), Via E. Orabona 4, I-70125 Bari, Italy
| | - Joaquín García-Álvarez
- Laboratorio de Química Sintética Sostenible (QuimSinSos), Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica “Enrique Moles” (IUQOEM), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain
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8
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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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Lachguar A, Pichugov AV, Neumann T, Dubrawski Z, Camp C. Cooperative activation of carbon-hydrogen bonds by heterobimetallic systems. Dalton Trans 2024; 53:1393-1409. [PMID: 38126396 PMCID: PMC10804807 DOI: 10.1039/d3dt03571a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023]
Abstract
The direct activation of C-H bonds has been a rich and active field of organometallic chemistry for many years. Recently, incredible progress has been made and important mechanistic insights have accelerated research. In particular, the use of heterobimetallic complexes to heterolytically activate C-H bonds across the two metal centers has seen a recent surge in interest. This perspective article aims to orient the reader in this fast moving field, highlight recent progress, give design considerations for further research and provide an optimistic outlook on the future of catalytic C-H functionalization with heterobimetallic complexes.
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Affiliation(s)
- Abdelhak Lachguar
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Andrey V Pichugov
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Till Neumann
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Zachary Dubrawski
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Clément Camp
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
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Anderson DE, Tortajada A, Hevia E. New Frontiers in Organosodium Chemistry as Sustainable Alternatives to Organolithium Reagents. Angew Chem Int Ed Engl 2024; 63:e202313556. [PMID: 37801443 DOI: 10.1002/anie.202313556] [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: 09/12/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/08/2023]
Abstract
With their highly reactive respective C-Na and N-Na bonds, organosodium and sodium amide reagents could be viewed as obvious replacements or even superior reagents to the popular, widely utilised organolithiums. However, they have seen very limited applications in synthesis due mainly to poor solubility in common solvents and their limited stability. That notwithstanding in recent years there has been a surge of interest in bringing these sustainable metal reagents into the forefront of organometallics in synthesis. Showcasing the growth in utilisation of organosodium complexes within several areas of synthetic chemistry, this Minireview discusses promising new methods that have been recently reported with the goal of taming these powerful reagents. Special emphasis is placed on coordination and aggregation effects in these reagents which can impart profound changes in their solubility and reactivity. Differences in observed reactivity between more nucleophilic aryl and alkyl sodium reagents and the less nucleophilic but highly basic sodium amides are discussed along with current mechanistic understanding of their reactivities. Overall, this review aims to inspire growth in this exciting field of research to allow for the integration of organosodium complexes within common important synthetic transformations.
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Affiliation(s)
- David E Anderson
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Andreu Tortajada
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Eva Hevia
- Department für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
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11
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Yolsal U, Shaw PJ, Lowy PA, Chambenahalli R, Garden JA. Exploiting Multimetallic Cooperativity in the Ring-Opening Polymerization of Cyclic Esters and Ethers. ACS Catal 2024; 14:1050-1074. [PMID: 38269042 PMCID: PMC10804381 DOI: 10.1021/acscatal.3c05103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/17/2023] [Accepted: 12/19/2023] [Indexed: 01/26/2024]
Abstract
The use of multimetallic complexes is a rapidly advancing route to enhance catalyst performance in the ring-opening polymerization of cyclic esters and ethers. Multimetallic catalysts often outperform their monometallic analogues in terms of reactivity and/or polymerization control, and these improvements are typically attributed to "multimetallic cooperativity". Yet the origins of multimetallic cooperativity often remain unclear. This review explores the key factors underpinning multimetallic cooperativity, including metal-metal distances, the flexibility, electronics and conformation of the ligand framework, and the coordination environment of the metal centers. Emerging trends are discussed to provide insights into why cooperativity occurs and how to harness cooperativity for the development of highly efficient multimetallic catalysts.
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Affiliation(s)
- Utku Yolsal
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Peter J. Shaw
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Phoebe A. Lowy
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Raju Chambenahalli
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Jennifer A. Garden
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
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12
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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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13
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Lynch JR, Kennedy AR, Barker J, Mulvey RE. Modification of a Common β-diketiminate NacNac Framework via Sequential Lithiation and Small Molecule Insertion. Chemistry 2023:e202303373. [PMID: 38032346 DOI: 10.1002/chem.202303373] [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: 10/13/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/01/2023]
Abstract
A widely utilised class of ligands in synthesis and catalysis, β-diketiminate (BDI) or NacNac compounds were initially considered innocent in the sense that they remained intact in all their applications. That changed when the γ-C-H unit of their NCCCN backbone was found to engage in reactions with electrophiles. Here, we show that this special reactivity can be used advantageously to prepare tripodal modifications of the common NacNac ligand derived from 2,6-diisopropylphenyl-β-methyldiketimine [NacNacH (Me, Dipp)]. Lithiation to give NacNacLi, followed by reactions with isocyanates, isothiocyanates and a carbodiimide, have afforded a series of tripodal NacNac variants having N,N,N,O; N,N,N,S; or N,N,N,N potential dentation sites, many of which have been crystallographically characterised. Distinct ligating modes of these new ligands have been elucidated through the crystal structures of their lithiated derivatives.
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Affiliation(s)
- Jennifer R Lynch
- 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
| | - Jim Barker
- Innospec Ltd., Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK
| | - Robert E Mulvey
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
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14
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R Judge N, Logallo A, Hevia E. Main group metal-mediated strategies for C-H and C-F bond activation and functionalisation of fluoroarenes. Chem Sci 2023; 14:11617-11628. [PMID: 37920337 PMCID: PMC10619642 DOI: 10.1039/d3sc03548d] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/11/2023] [Indexed: 11/04/2023] Open
Abstract
With fluoroaromatic compounds increasingly employed as scaffolds in agrochemicals and active pharmaceutical ingredients, the development of methods which facilitate regioselective functionalisation of their C-H and C-F bonds is a frontier of modern synthesis. Along with classical lithiation and nucleophilic aromatic substitution protocols, the vast majority of research efforts have focused on transition metal-mediated transformations enabled by the redox versatilities of these systems. Breaking new ground in this area, recent advances in main group metal chemistry have delineated unique ways in which s-block, Al, Ga and Zn metal complexes can activate this important type of fluorinated molecule. Underpinned by chemical cooperativity, these advances include either the use of heterobimetallic complexes where the combined effect of two metals within a single ligand set enables regioselective low polarity C-H metalation; or the use of novel low valent main group metal complexes supported by special stabilising ligands to induce C-F bond activations. Merging these two different approaches, this Perspective provides an overview of the emerging concept of main-group metal mediated C-H/C-F functionalisation of fluoroarenes. Showcasing the untapped potential that these systems can offer in these processes; focus is placed on how special chemical cooperation is established and how the trapping of key reaction intermediates can inform mechanistic understanding.
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Affiliation(s)
- Neil R Judge
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
| | - Alessandra Logallo
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
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15
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You Q, Collum DB. Carbon-Nitrogen Bond Formation Using Sodium Hexamethyldisilazide: Solvent-Dependent Reactivities and Mechanisms. J Am Chem Soc 2023; 145:23568-23584. [PMID: 37857357 DOI: 10.1021/jacs.3c07317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
The solvent-dependent reactivity of sodium hexamethyldisilazide (NaHMDS) toward carbon-centered electrophiles reveals reactions that are poorly represented or unrepresented in the literature, including direct aminolysis of aromatic methyl esters to give carboxamides, nitriles, or amidines, depending on the choice of solvent. SNAr substitutions of aryl halides and opening of terminal epoxides are also examined. A combination of 1H and 29Si nuclear magnetic resonance (NMR) spectroscopic studies using [15N]NaHMDS, kinetic studies, and computational studies reveals the complex mechanistic basis of the preferences for simple aryl carboxamides in toluene and dimethylethylamine and arylnitriles or amidines in tetrahydrofuran (THF). A prevalence of dimer- and mixed dimer-based chemistry even starting from the observable NaHMDS monomer in THF solution is notable.
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Affiliation(s)
- Qiulin You
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - David B Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
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16
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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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17
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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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18
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Vrána J, Růžičková Z, Růžička A, Dostál L. Synthesis and reactivity of alkali metal aluminates bearing bis(organoamido)phosphane ligand. Dalton Trans 2023; 52:12623-12631. [PMID: 37610275 DOI: 10.1039/d3dt01859h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
In this study, we report a group of alkali metal aluminates bearing bis(organoamido)phosphane ligand. The starting complex {[PhP(NtBu)2]AlMe2}Li·OEt2 (1) was prepared by stepwise deprotonation of the parent PhP(NHtBu)2 by nBuLi and AlMe3. Further derivatization of aluminate 1 was performed by the virtual substitution of lithium -{[PhP(NtBu)2]AlMe2}K (2), methyl substituents - {[PhP(NtBu)2]AlH2}Li·THF (3), modification of steric bulk and induction effects on the phosphorus atom - {[tBuP(N-2,6-iPr2C6H3)2]AlMe2}Li·(OEt2)2 (4), and phosphorus atom oxidation state {[Ph(Y)P(NtBu)2]AlMe2}Li (Y = O (5), S (6), Se (7), Te (8)). The structure causing non-covalent interactions in 1-4 were evaluated with the help of theoretical calculations and topological analysis ranging from π-electron system-metal to agostic interactions of various types. The further reactions of 1 with various nucleophiles were found to be a versatile tool for the preparation of iminophosphonamides via the formation of P-E bond (E = Si, Ge, Sn, Pb, P, and C) and followed by P(III) → P(V) tautomeric shift.
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Affiliation(s)
- Jan Vrána
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
| | - Libor Dostál
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
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19
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Navarro M, González-Lizana D, Sánchez-Barba LF, Garcés A, Fernández I, Lara-Sánchez A, Rodríguez AM. Development of Heterobimetallic Al/Mg Complexes for the Very Rapid Ring-Opening Polymerization of Lactides. Inorg Chem 2023; 62:14833-14837. [PMID: 37676111 PMCID: PMC10521010 DOI: 10.1021/acs.inorgchem.3c02410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 09/08/2023]
Abstract
The successful architecture of active catalytic species with enhanced efficiencies is critical for the optimal exploitation of sustainable resources in industrially demanded processes. In this work, we describe the preparation of novel helical heterobimetallic Al/Mg-based complexes of the type [AlMe2(pbpamd-)MgR{κ1-O-(OC4H8O)}] [R = Et (1a), tBu (2a)] as potential catalysts. The design was performed through the sequential addition of the Al fragment to the ligand, followed by the Mg platform, resulting in a planar π-C2N2(sp2)-Al/Mg bridging core between metals. The new heterobimetallic species have been unambiguously characterized by single-crystal X-ray analysis. NOESY, DOSY, and EXSY NMR studies as well as density functional theory calculations corroborate both a rearrangement in solution to scorpionate complexes containing an unprecedented apical carbanion with a direct σ-C(sp3)-Al covalent bond named [{Mg(R)(pbpamd-) Al(Me)2}] [R = Et (1b), tBu (2b)] and an interconversion equilibrium between both isomers. We verified their utility and high efficiency as catalysts in the well-controlled ring-opening polymerization of the biorenewable l- and rac-lactide (LA) at 23 °C, reaching a remarkable turnover frequency value close to 25000 h-1 for rac-LA at this temperature and exerting a significant level of heteroselectivity (Pr = 0.80). Very interestingly, the kinetics demonstrate apparent first-order with respect to the catalyst and LA, which supports a synergic intramolecular cooperation between centers with electronic modulation among them.
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Affiliation(s)
- Marta Navarro
- Departamento
de Biología y Geología, Física y Química
Inorgánica, Universidad Rey Juan
Carlos, 28933 Móstoles, Madrid, Spain
- Departamento
de Química Inorgánica, Orgánica y Bioquímica,
Centro de Innovación en Química Avanzada (ORFEO-CINQA),
Campus Universitario, Universidad de Castilla—La
Mancha, 13071 Ciudad Real, Spain
| | - David González-Lizana
- Departamento
de Biología y Geología, Física y Química
Inorgánica, Universidad Rey Juan
Carlos, 28933 Móstoles, Madrid, Spain
| | - Luis F. Sánchez-Barba
- Departamento
de Biología y Geología, Física y Química
Inorgánica, Universidad Rey Juan
Carlos, 28933 Móstoles, Madrid, Spain
| | - Andrés Garcés
- Departamento
de Biología y Geología, Física y Química
Inorgánica, Universidad Rey Juan
Carlos, 28933 Móstoles, Madrid, Spain
| | - Israel Fernández
- Departamento
de Química Orgánica I and Centro de Innovación
en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Agustín Lara-Sánchez
- Departamento
de Química Inorgánica, Orgánica y Bioquímica,
Centro de Innovación en Química Avanzada (ORFEO-CINQA),
Campus Universitario, Universidad de Castilla—La
Mancha, 13071 Ciudad Real, Spain
| | - Ana M. Rodríguez
- Departamento
de Química Inorgánica, Orgánica y Bioquímica,
Centro de Innovación en Química Avanzada (ORFEO-CINQA),
Campus Universitario, Universidad de Castilla—La
Mancha, 13071 Ciudad Real, Spain
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20
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de Giovanetti M, Hopen Eliasson SH, Castro AC, Eisenstein O, Cascella M. Morphological Plasticity of LiCl Clusters Interacting with Grignard Reagent in Tetrahydrofuran. J Am Chem Soc 2023. [PMID: 37471267 PMCID: PMC10401704 DOI: 10.1021/jacs.3c04238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Ab initio molecular dynamics simulations are used to explore tetrahydrofuran (THF) solutions containing pure LiCl and LiCl with CH3MgCl, as model constituents of the turbo Grignard reagent. LiCl aggregates as Li4Cl4, which preferentially assumes compact cubane-like conformations. In particular, an open-edge pseudotetrahedral frame is promoted by solvent-assisted Li-Cl bond cleavage. Among the Grignard species involved in the Schlenk equilibrium, LiCl prefers to coordinate MgCl2 through μ2-Cl bridges. Using a 1:1 Li:Mg ratio, the plastic tetranuclear LiCl cluster decomposes to a highly solvated mixed LiCl·MgCl2 aggregate with prevalent Li-(μ2-Cl)2-Mg rings and linear LiCl entities. The MgCl2-assisted disaggregation of Li4Cl4 occurs through transient structures analogous to those detected for pure LiCl in THF, also corresponding to moieties observed in the solid state. This study identifies a synergistic role of LiCl for the determination of the compounds present in turbo Grignard solutions. LiCl shifts the Schlenk equilibrium promoting a higher concentration of dialkylmagnesium, while decomposing into smaller, more soluble, mixed Li:Mg:Cl clusters.
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Affiliation(s)
- Marinella de Giovanetti
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
| | - Sondre H Hopen Eliasson
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
| | - Abril C Castro
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
| | - Odile Eisenstein
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
- ICGM, University Montpellier, CNRS, ENSCM, 34090 Montpellier, France
| | - Michele Cascella
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
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21
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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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22
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Bashir M, Mantoo IA, Arjmand F, Tabassum S, Yousuf I. An overview of advancement of organoruthenium(II) complexes as prospective anticancer agents. Coord Chem Rev 2023; 487:215169. [DOI: 10.1016/j.ccr.2023.215169] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
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23
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Borys AM, Hevia E. Organolithium aggregation as a blueprint to construct polynuclear lithium nickelate clusters. Chem Commun (Camb) 2023. [PMID: 37191064 DOI: 10.1039/d3cc01729j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
By exploiting the high aggregation of aliphatic lithium acetylides, here we report the synthesis and structural analysis of polynuclear lithium nickelate clusters in which up to 10 equivalents of organolithium can co-complex per Ni(0) centre. Exposure of the Ni(0)-ate clusters to dry air provides an alternative route to homoleptic Ni(II)-ates.
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Affiliation(s)
- Andryj M Borys
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Bern 3012, Switzerland.
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Bern 3012, Switzerland.
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24
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Sun X, Hinz A, Schulz S, Zimmermann L, Scheer M, Roesky PW. Snapshots of sequential polyphosphide rearrangement upon metallatetrylene addition. Chem Sci 2023; 14:4769-4776. [PMID: 37181779 PMCID: PMC10171192 DOI: 10.1039/d3sc00806a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/30/2023] [Indexed: 05/16/2023] Open
Abstract
Insertion and functionalization of gallasilylenes [LPhSi-Ga(Cl)LBDI] (LPh = PhC(NtBu)2; LBDI = [{2,6-iPr2C6H3NCMe}2CH]) into the cyclo-E5 rings of [Cp*Fe(η5-E5)] (Cp* = η5-C5Me5; E = P, As) are reported. Reactions of [Cp*Fe(η5-E5)] with gallasilylene result in E-E/Si-Ga bond cleavage and the insertion of the silylene in the cyclo-E5 rings. [(LPhSi-Ga(Cl)LBDI){(η4-P5)FeCp*}], in which the Si atom binds to the bent cyclo-P5 ring, was identified as a reaction intermediate. The ring-expansion products are stable at room temperature, while isomerization occurred at higher temperature, and the silylene moiety further migrates to the Fe atom, forming the corresponding ring-construction isomers. Furthermore, reaction of [Cp*Fe(η5-As5)] with the heavier gallagermylene [LPhGe-Ga(Cl)LBDI] was also investigated. All the isolated complexes represent rare examples of mixed group 13/14 iron polypnictogenides, which could only be synthesized by taking advantage of the cooperativity of the gallatetrylenes featuring low-valent Si(ii) or Ge(ii) and Lewis acidic Ga(iii) units/entities.
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Affiliation(s)
- Xiaofei Sun
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstraße 15 Karlsruhe 76131 Germany
| | - Alexander Hinz
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstraße 15 Karlsruhe 76131 Germany
| | - Stephan Schulz
- Institute for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (Cenide), University of Duisburg-Essen Universitätsstraße 5-7 Essen 45117 Germany
| | - Lisa Zimmermann
- Institute of Inorganic Chemistry, University of Regensburg Universitätsstr. 31 Regensburg 93040 Germany
| | - Manfred Scheer
- Institute of Inorganic Chemistry, University of Regensburg Universitätsstr. 31 Regensburg 93040 Germany
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstraße 15 Karlsruhe 76131 Germany
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25
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Feng Y, Yukioka T, Matsuyama M, Mori A, Okano K. Deprotonative Generation and Trapping of Haloaryllithium in a Batch Reactor. Org Lett 2023; 25:3013-3017. [PMID: 37083303 DOI: 10.1021/acs.orglett.3c00800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
A method for the regioselective functionalization of haloarenes through deprotonative lithiation is disclosed. The generated haloaryllithiums were trapped in a batch reactor with a zinc chloride diamine complex to provide organozinc species without aryne formation, which reacted with electrophiles to afford the corresponding products in 38-98% yields. This method was applied to the five-step total synthesis of carbazomycin A on a gram scale in 33% overall yield.
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Affiliation(s)
- Yuxuan Feng
- Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Taro Yukioka
- Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Mei Matsuyama
- Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Atsunori Mori
- Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Research Center for Membrane and Film Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Kentaro Okano
- Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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26
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Logallo A, Hevia E. Applying Na/Co(II) bimetallic partnerships to promote multiple Co-H exchanges in polyfluoroarenes. Chem Commun (Camb) 2023; 59:5383-5386. [PMID: 37060131 PMCID: PMC10152514 DOI: 10.1039/d3cc01216f] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Heterobimetallic base NaCo(HMDS)3 [HMDS = N(SiMe3)2] enables regioselective di-cobaltation of activated polyfluoroarenes under mild reaction conditions. For 1,3,5-C6H2X3 (X= Cl, F), NaCo(HMDS)3 in excess at 80 °C impressively induces the collective cleavage of five bonds (two C-H and three C-X) of the substrates via a cascade activation process that cannot be replicated by LiCo(HMDS)3 or KCo(HMDS)3.
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Affiliation(s)
- Alessandra Logallo
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Bern, Switzerland.
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Bern, Switzerland.
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27
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Davison N, McMullin CL, Zhang L, Hu SX, Waddell PG, Wills C, Dixon C, Lu E. Li vs Na: Divergent Reaction Patterns between Organolithium and Organosodium Complexes and Ligand-Catalyzed Ketone/Aldehyde Methylenation. J Am Chem Soc 2023; 145:6562-6576. [PMID: 36890641 PMCID: PMC10037334 DOI: 10.1021/jacs.3c01033] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
Organosodium chemistry is underdeveloped compared with organolithium chemistry, and all the reported organosodium complexes exhibit similar, if not identical, reactivity patterns to their lithium counterparts. Herein, we report a rare organosodium monomeric complex, namely, [Na(CH2SiMe3)(Me6Tren)] (1-Na) (Me6Tren: tris[2-(dimethylamino)ethyl]amine) stabilized by a tetra-dentate neutral amine ligand Me6Tren. Employing organo-carbonyl substrates (ketones, aldehydes, amides, ester), we demonstrated that 1-Na features distinct reactivity patterns compared with its lithium counterpart, [Li(CH2SiMe3)(Me6Tren)] (1-Li). Based on this knowledge, we further developed a ligand-catalysis strategy to conduct ketone/aldehyde methylenations, using [NaCH2SiMe3]∞ as the CH2 feedstock, replacing the widely used but hazardous/expensive C═O methylenation methods, such as Wittig, Tebbe, Julia/Julia-Kocieński, Peterson, and so on.
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Affiliation(s)
- Nathan Davison
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Claire L McMullin
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Lu Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Shu-Xian Hu
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Paul G Waddell
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Corinne Wills
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Casey Dixon
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Erli Lu
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
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28
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Li Y, Chen J, Ng JJW, Chiba S. Generation of Allylmagnesium Reagents by Hydromagnesiation of 2-Aryl-1,3-dienes. Angew Chem Int Ed Engl 2023; 62:e202217735. [PMID: 36637448 DOI: 10.1002/anie.202217735] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 01/14/2023]
Abstract
A protocol for the generation of allylmagnesium reagents from 2-aryl-1,3-dienes was developed using magnesium hydride (MgH2 ) that is generated in situ by solvothermal treatment of sodium hydride (NaH) and magnesium iodide (MgI2 ) in tetrahydrofuran (THF). Downstream functionalization of the resulting allylmagnesium reagents with carbonyl compounds or alkyl (pseudo)halides delivers branched products having an allylic quaternary carbon center, whereas that with chlorosilanes resulted in formation of linear allylsilanes in regio and stereoselective manners. Further derivatizations of the homoallylic alcohols and allylsilanes were also demonstrated.
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Affiliation(s)
- Yihang Li
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
| | - Jiahua Chen
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
| | - Jaslyn Jing Wen Ng
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
| | - Shunsuke Chiba
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
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29
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Sengupta S, Schüler P, Liebing P, Westerhausen M. Synthesis of Sterically Encumbered Alkaline-Earth Metal Amides Applying the In Situ Grignard Reagent Formation. Chemistry 2023; 29:e202300035. [PMID: 36734181 DOI: 10.1002/chem.202300035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/04/2023]
Abstract
Magnesium and calcium are too inert to deprotonate amines directly. For the synthesis of bulky amides alternative strategies are required and in the past, N-bound trialkylsilyl groups have been used to ease metalation reactions. The in situ Grignard reagent formation in stirred suspensions of magnesium or calcium with hydryl halide and imine in THF allows the synthesis of a plethora of amides with bulky silyl-free substituents. Ball milling protocols partially favor competitive side reactions such as aza-pinacol coupling reactions. Calcium is the advantageous choice for the in situ Grignard reagent formation and subsequent addition onto the imines yielding bulky calcium bis(amides) whereas the stronger reducing heavier alkaline-earth metals strontium and barium are less selective and hence, the aza-pinacol coupling reaction becomes competitive. Exemplary, the solid-state molecular structures of [(Et2 O)Mg(N(Ph)(CHPh2 )2 ] and [(Et2 O)2 Ca(N(Ph)(CHPh2 )2 ] have been determined.
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Affiliation(s)
- Simon Sengupta
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Philipp Schüler
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Phil Liebing
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
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30
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Lebon J, Mortis A, Maichle-Mössmer C, Manßen M, Sirsch P, Anwander R. Schlenk's Legacy-Methyllithium Put under Close Scrutiny. Angew Chem Int Ed Engl 2023; 62:e202214599. [PMID: 36409199 PMCID: PMC10108226 DOI: 10.1002/anie.202214599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/23/2022]
Abstract
Commercially available stock solutions of organolithium reagents are well-implemented tools in organic and organometallic chemistry. However, such solutions are inherently contaminated with lithium halide salts, which can complicate certain synthesis protocols and purification processes. Here, we report the isolation of chloride-free methyllithium employing K[N(SiMe3 )2 ] as a halide-trapping reagent. The influence of distinct LiCl contaminations on the 7 Li-NMR chemical shift is examined and their quantification demonstrated. The structural parameters of new chloride-free monomeric methyllithium complex [(Me3 TACN)LiCH3 ], ligated by an azacrown ether, are assessed by comparison with a halide-contaminated variant and monomeric lithium chloride [(Me3 TACN)LiCl], further emphasizing the effect of halide impurities.
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Affiliation(s)
- Jakob Lebon
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Alexandros Mortis
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Manfred Manßen
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Peter Sirsch
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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31
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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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32
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Borys AM, Dell'Aera M, Capriati V, Hevia E. Structural and synthetic insights into the chemistry of lithium tetraorganozincates. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2023. [DOI: 10.1016/bs.adomc.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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33
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Ballmann GM, Evans MJ, Gentner TX, Kennedy AR, Fulton JR, Coles MP, Mulvey RE. Synthesis, Characterization, and Structural Analysis of AM[Al(NON Dipp)(H)(SiH 2Ph)] ( AM = Li, Na, K, Rb, Cs) Compounds, Made Via Oxidative Addition of Phenylsilane to Alkali Metal Aluminyls. Inorg Chem 2022; 61:19838-19846. [PMID: 36503245 DOI: 10.1021/acs.inorgchem.2c03010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We report the oxidative addition of phenylsilane to the complete series of alkali metal (AM) aluminyls [AM{Al(NONDipp)}]2 (AM = Li, Na, K, Rb, and Cs). Crystalline products (1-AM) have been isolated as ether or THF adducts, [AM(L)n][Al(NONDipp)(H)(SiH2Ph)] (AM = Li, Na, K, Rb, L = Et2O, n = 1; AM = Cs, L = THF, n = 2). Further to this series, the novel rubidium rubidiate, [{Rb(THF)4}2(Rb{Al(NONDipp)(H)(SiH2Ph)}2)]+ [Rb{Al(NONDipp)(H)(SiH2Ph)}2]-, was isolated during an attempted recrystallization of Rb[Al(NONDipp)(H)(SiH2Ph)] from a hexane/THF mixture. Structural and spectroscopic characterizations of the series 1-AM confirm the presence of μ-hydrides that bridge the aluminum and alkali metals (AM), with multiple stabilizing AM···π(arene) interactions to either the Dipp- or Ph-substituents. These products form a complete series of soluble, alkali metal (hydrido) aluminates that present a platform for further reactivity studies.
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Affiliation(s)
- Gerd M Ballmann
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, U.K
| | - Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Thomas X Gentner
- 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
| | - 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, Glasgow G1 1XL, U.K
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34
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Brieger L, Schrimpf T, Scheel R, Unkelbach C, Strohmann C. Towards Substrate-Reagent Interaction of Lochmann-Schlosser Bases in THF: Bridging THF Hides Potential Reaction Site of a Chiral Superbase. Chemistry 2022; 28:e202202660. [PMID: 36098179 PMCID: PMC10092790 DOI: 10.1002/chem.202202660] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Indexed: 12/14/2022]
Abstract
The metalation of N,N-dimethylaminomethylferrocene in THF by the superbasic mixture of n BuLi/KOt Bu proceeds readily at low temperatures to afford a bimetallic Li2 K2 aggregate containing ferrocenyl anions and tert-butoxide. Starting from an enantiomerically enriched ortho-lithiated aminomethylferrocene, an enantiomerically pure superbase can be prepared. The molecular compound exhibits superbasic behavior deprotonating N,N-dimethylbenzylamine in the α-position and is also capable of deprotonating toluene. Quantum chemical calculations provide insight into the role of the bridging THF molecule to the possible substrate-reagent interaction. In addition, a benzylpotassium alkoxide adduct gives a closer look into the corresponding reaction site of the Lochmann-Schlosser base that is reported herein.
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Affiliation(s)
- Lukas Brieger
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Tobias Schrimpf
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Rebecca Scheel
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Christian Unkelbach
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
| | - Carsten Strohmann
- Inorganic Chemistry, TU Dortmund University, Otto-Hahn-Str. 6/6a, 44227, Dortmund, Germany
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35
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Mullins JC, Yuvaraj K, Jiang Y, Van Trieste GP, Maity A, Powers DC, Jones C. C-H Activation of Inert Arenes using a Photochemically Activated Guanidinato-Magnesium(I) Compound. Chemistry 2022; 28:e202202103. [PMID: 36017712 PMCID: PMC9828268 DOI: 10.1002/chem.202202103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Indexed: 01/12/2023]
Abstract
UV irradiation of solutions of a guanidinate coordinated dimagnesium(I) compound, [{(Priso)Mg}2 ] 3 (Priso=[(DipN)2 CNPri 2 ]- , Dip=2,6-diisopropylphenyl), in either benzene, toluene, the three isomers of xylene, or mesitylene, leads to facile activation of an aromatic C-H bond of the solvent in all cases, and formation of aryl/hydride bridged magnesium(II) products, [{(Priso)Mg}2 (μ-H)(μ-Ar)] 4-9. In contrast to similar reactions reported for β-diketiminate coordinated counterparts of 3, these C-H activations proceed with little regioselectivity, though they are considerably faster. Reaction of 3 with an excess of the pyridine, p-NC5 H4 But (pyBut ), gave [(Priso)Mg(pyBut H)(pyBut )2 ] 10, presumably via reduction of the pyridine to yield a radical intermediate, [(Priso)Mg(pyBut ⋅)(pyBut )2 ] 11, which then abstracts a proton from the reaction solvent or a reactant. DFT calculations suggest two possible pathways to the observed arene C-H activations. One of these involves photochemical cleavage of the Mg-Mg bond of 3, generating magnesium(I) doublet radicals, (Priso)Mg⋅. These then doubly reduce the arene substrate to give "Birch-like" products, which subsequently rearrange via C-H activation of the arene. Circumstantial evidence for the photochemical generation of transient magnesium radical species includes the fact that irradiation of a cyclohexane solution of 3 leads to an intramolecular aliphatic C-H activation process and formation of an alkyl-bridged magnesium(II) species, [{Mg(μ-Priso-H )}2 ] 12. Furthermore, irradiation of a 1 : 1 mixture of 3 and the β-diketiminato dimagnesium(I) compound, [{(Dip Nacnac)Mg}2 ] (Dip Nacnac=[HC(MeCNDip)2 ]- ), effects a "scrambling" reaction, and the near quantitative formation of an unsymmetrical dimagnesium(I) compound, [(Priso)Mg-Mg(Dip Nacnac)] 13. Finally, the EPR spectrum (77 K) of a glassed solution of UV irradiated 3 is dominated by a broad featureless signal, indicating the presence of a doublet radical species.
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Affiliation(s)
- Jeremy C. Mullins
- School of ChemistryPO Box 23Monash UniversityMelbourne, <countryPartVIC3800Australia
| | - K. Yuvaraj
- School of ChemistryPO Box 23Monash UniversityMelbourne, <countryPartVIC3800Australia
| | - Yixiao Jiang
- School of ChemistryPO Box 23Monash UniversityMelbourne, <countryPartVIC3800Australia
| | | | - Asim Maity
- Department of ChemistryTexas A&M University College Station, TX 77843USA
| | - David C. Powers
- Department of ChemistryTexas A&M University College Station, TX 77843USA
| | - Cameron Jones
- School of ChemistryPO Box 23Monash UniversityMelbourne, <countryPartVIC3800Australia
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36
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Ma Y, Lui NM, Keresztes I, Woltornist RA, Collum DB. Sodium Isopropyl(trimethylsilyl)amide: A Stable and Highly Soluble Lithium Diisopropylamide Mimic. J Org Chem 2022; 87:14223-14229. [PMID: 36282953 PMCID: PMC10042304 DOI: 10.1021/acs.joc.2c01745] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The preparation, structure, physical properties, and reactivities of sodium isopropyl(trimethylsilyl)amide (NaPTA) are described. The solubilities at room temperature range from n-heptane (0.55 M), n-hexane (0.60 M), toluene (0.65 M), MTBE (1.7 M), Et3N (3.2 M), and THF (>6.0 M). The half-life to destruction in neat THF is >1 year at 25 °C and 7 days at 70 °C, which compares favorably to 2.5 months and 1.5 days, respectively, for LDA in neat THF. This study focuses on NaPTA in THF. 29Si NMR spectroscopy shows exclusively a mixture of cis and trans stereoisomeric dimers in 0.10-12 M THF in hexane. Density functional theory (DFT) computations suggest that the pKb is intermediate between dimeric sodium diisopropylamide (NaDA) and dimeric sodium hexamethyldisilazide (NaHMDS). Metalations of arenes, epoxides, ketones, hydrazones, alkenes, and alkyl halides show higher reactivities than LDA (kNaPTA/LDA = 1-30). While the rates of arene metalation are high, the lower pKb of NaPTA limits the substrates. Metalation of pseudoephedrate-based carboxamides to form disodiated Myers enolates solves several challenging technical problems.
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Affiliation(s)
- Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - Nathan M Lui
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - Ivan Keresztes
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - Ryan A Woltornist
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
| | - David B Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
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37
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Navarro M, Moreno JJ, Pérez-Jiménez M, Campos J. Small molecule activation with bimetallic systems: a landscape of cooperative reactivity. Chem Commun (Camb) 2022; 58:11220-11235. [PMID: 36128973 PMCID: PMC9536487 DOI: 10.1039/d2cc04296g] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/06/2022] [Indexed: 11/22/2022]
Abstract
There is growing interest in the design of bimetallic cooperative complexes, which have emerged due to their potential for bond activation and catalysis, a feature widely exploited by nature in metalloenzymes, and also in the field of heterogeneous catalysis. Herein, we discuss the widespread opportunities derived from combining two metals in close proximity, ranging from systems containing multiple M-M bonds to others in which bimetallic cooperation occurs even in the absence of M⋯M interactions. The choice of metal pairs is crucial for the reactivity of the resulting complexes. In this context, we describe the prospects of combining not only transition metals but also those of the main group series, which offer additional avenues for cooperative pathways and reaction discovery. Emphasis is given to mechanisms by which bond activation occurs across bimetallic structures, which is ascribed to the precise synergy between the two metal atoms. The results discussed herein indicate a future landscape full of possibilities within our reach, where we anticipate that bimetallic synergism will have an important impact in the design of more efficient catalytic processes and the discovery of new catalytic transformations.
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Affiliation(s)
- Miquel Navarro
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla, Avenida Américo Vespucio 49, 41092 Sevilla, Spain.
| | - Juan José Moreno
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla, Avenida Américo Vespucio 49, 41092 Sevilla, Spain.
| | - Marina Pérez-Jiménez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla, 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), Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla, Avenida Américo Vespucio 49, 41092 Sevilla, Spain.
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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] [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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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] [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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40
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Influence of reaction conditions on kumada catalytic transfer polymerization for synthesis of poly(p-phenylene) for organic semiconductors. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-022-03261-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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41
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Sengupta S, Schüler P, Görls H, Liebing P, Krieck S, Westerhausen M. In Situ Grignard Metalation Method for the Synthesis of Hauser Bases. Chemistry 2022; 28:e202201359. [PMID: 35686618 PMCID: PMC9546396 DOI: 10.1002/chem.202201359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Indexed: 12/03/2022]
Abstract
The in situ Grignard Metalation Method (iGMM) is a straightforward one‐pot procedure to quickly produce multigram amounts of Hauser bases R2N‐MgBr which are valuable and vastly used metalation reagents and novel electrolytes for magnesium batteries. During addition of bromoethane to a suspension of Mg metal and secondary amine at room temperature in an ethereal solvent, a smooth reaction yields R2N‐MgBr under evolution of ethane within a few hours. A Schlenk equilibrium is operative, interconverting the Hauser bases into their solvated homoleptic congeners Mg(NR2)2 and MgBr2 depending on the solvent. Scope and preconditions are studied, and side reactions limiting the yield have been investigated. DOSY NMR experiments and X‐ray crystal structures of characteristic examples clarify aggregation in solution and the solid state.
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Affiliation(s)
- Simon Sengupta
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Philipp Schüler
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Phil Liebing
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Sven Krieck
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
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42
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Evans MJ, Iliffe GH, Neale SE, McMullin CL, Fulton JR, Anker MD, Coles MP. Isolating elusive 'Al(μ-O)M' intermediates in CO 2 reduction by bimetallic Al-M complexes (M = Zn, Mg). Chem Commun (Camb) 2022; 58:10091-10094. [PMID: 35997148 DOI: 10.1039/d2cc04028j] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of compounds containing Al-Mg and Al-Zn bonds with N2O enabled isolation of the corresponding Al(μ-O)M complexes. Electronic structure analysis identified largely ionic Al-O and O-M bonds, featuring an anionic μ-oxo centre. Reaction with CO2 confirmed that these species correspond to the proposed intermediates in the formation of μ-carbonate compounds.
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Affiliation(s)
- Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Kelburn, Wellington, 6012, New Zealand.
| | - George H Iliffe
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Kelburn, Wellington, 6012, New Zealand.
| | - Samuel E Neale
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | | | - J Robin Fulton
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Kelburn, Wellington, 6012, New Zealand.
| | - Mathew D Anker
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Kelburn, Wellington, 6012, New Zealand.
| | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Kelburn, Wellington, 6012, New Zealand.
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43
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Piesch M, Nicolay A, Haimerl M, Seidl M, Balázs G, Don Tilley T, Scheer M. Binding, Release and Functionalization of Intact Pnictogen Tetrahedra Coordinated to Dicopper Complexes. Chemistry 2022; 28:e202201144. [PMID: 35575052 PMCID: PMC9541576 DOI: 10.1002/chem.202201144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Indexed: 01/07/2023]
Abstract
The bridging MeCN ligand in the dicopper(I) complexes [(DPFN)Cu2(μ,η1 : η1‐MeCN)][X]2 (X=weakly coordinating anion, NTf2 (1 a), FAl[OC6F10(C6F5)]3 (1 b), Al[OC(CF3)3]4 (1 c)) was replaced by white phosphorus (P4) or yellow arsenic (As4) to yield [(DPFN)Cu2(μ,η2 : η2‐E4)][X]2 (E=P (2 a–c), As (3 a–c)). The molecular structures in the solid state reveal novel coordination modes for E4 tetrahedra bonded to coinage metal ions. Experimental data and quantum chemical computations provide information concerning perturbations to the bonding in coordinated E4 tetrahedra. Reactions with N‐heterocyclic carbenes (NHCs) led to replacement of the E4 tetrahedra with release of P4 or As4 and formation of [(DPFN)Cu2(μ,η1 : η1‐MeNHC)][X]2 (4 a,b) or to an opening of one E−E bond leading to an unusual E4 butterfly structural motif in [(DPFN)Cu2(μ,η1 : η1‐E4DippNHC)][X]2 (E=P (5 a,b), E=As (6)). With a cyclic alkyl amino carbene (EtCAAC), cleavage of two As−As bonds was observed to give two isomers of [(DPFN)Cu2(μ,η2 : η2‐As4EtCAAC)][X]2 (7 a,b) with an unusual As4‐triangle+1 unit.
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Affiliation(s)
- Martin Piesch
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Amélie Nicolay
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Maria Haimerl
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Michael Seidl
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Gábor Balázs
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States
| | - Manfred Scheer
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
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Waseem W, Anwar F, Saleem U, Ahmad B, Zafar R, Anwar A, Saeed Jan M, Rashid U, Sadiq A, Ismail T. Prospective Evaluation of an Amide-Based Zinc Scaffold as an Anti-Alzheimer Agent: In Vitro, In Vivo, and Computational Studies. ACS OMEGA 2022; 7:26723-26737. [PMID: 35936440 PMCID: PMC9352245 DOI: 10.1021/acsomega.2c03058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Alzheimer's disease is the most common progressive neurodegenerative mental disorder associated with loss of memory, decline in cognitive function, and dysfunction of language. The prominent pathogenic causes of this disease involve deposition of amyloid-β plaques, acetylcholine neurotransmitter deficiency, and accumulation of neurofibrillary tangles. There are multiple pathways that have been targeted to treat this disease. The inhibition of the intracellular cyclic AMP regulator phosphodiesterase IV causes the increase in CAMP levels that play an important role in the memory formation process. Organometallic chemistry works in a different way in treating pharmacological disorders. In the field of medicinal chemistry and pharmaceuticals, zinc-based amide carboxylates have been shown to be a preferred pharmacophore. The purpose of this research work was to investigate the potential of zinc amide carboxylates in inhibition of phosphodiesterase IV for the Alzheimer's disease management. Swiss Albino mice under controlled conditions were divided into seven groups with 10 mice each. Group I was injected with carboxymethylcellulose (CMC) at 1 mL/100 g dose, group II was injected with Streptozotocin (STZ) at 3 mg/kg dose, group III was injected with Piracetam acting as a standard drug at 200 mg/kg dosage, while groups IV-VII were injected with a zinc scaffold at the dose regimen of 10, 20, 40, and 80 mg/kg through intraperitoneal injection. All groups except group I were injected with Streptozotocin on the first day and third day of treatment at the dose of 3 mg/kg through an intracerebroventricular route to induce Alzheimer's disease. Afterward, respective treatment was continued for all groups for 23 days. In between the treatment regimen, groups were analyzed for memory and learning improvement through various behavioral tests such as open field, elevated plus maze, Morris water maze, and passive avoidance tests. At the end of the study, different biochemical markers in the brain were estimated like neurotransmitters (dopamine, serotonin and adrenaline), oxidative stress markers (superoxide dismutase, glutathione, and catalase), acetylcholinesterase (AchE), tau proteins, and amyloid-β levels. A PCR study was also performed. Results showed that the LD50 of the zinc scaffold is greater than 2000 mg/kg. Research indicated that the zinc scaffold has the potential to improve the memory impairment and learning behavior in Alzheimer's disease animal models in a dose-dependent manner. At the dose of 80 mg/kg, a maximum response was observed for the zinc scaffold. Maximum reduction in the acetylcholinesterase enzyme was observed at 80 mg/kg dose, which was further strengthened and verified by the PCR study. Oxidative stress was restored by the zinc scaffold due to the significant activation of the endogenous antioxidant enzymes. This research ended up with the conclusion that the zinc-based amide carboxylate scaffold has the potential to improve behavioral disturbances and vary the biochemical markers in the brain.
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Affiliation(s)
- Wajeeha Waseem
- Riphah
Institute of Pharmaceutical Sciences, Riphah
International University, Lahore Campus, Lahore 54000, Pakistan
| | - Fareeha Anwar
- Riphah
Institute of Pharmaceutical Sciences, Riphah
International University, Lahore Campus, Lahore 54000, Pakistan
| | - Uzma Saleem
- Faculty
of Pharmaceutical Sciences, Government College
University (GCU) Faisalabad, Faisalabad 38000, Pakistan
| | - Bashir Ahmad
- Riphah
Institute of Pharmaceutical Sciences, Riphah
International University, Lahore Campus, Lahore 54000, Pakistan
| | - Rehman Zafar
- Department
of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Riphah International University, Islamabad 44000, Pakistan
| | - Asifa Anwar
- Department
of Pharmacy, Islamia University Bahawalpur, Bahawalpur 63100, Pakistan
| | | | - Umer Rashid
- Department
of Chemistry, Comsat University, Abbottabad 22060, Pakistan
| | - Abdul Sadiq
- Department
of Pharmacy, University of Malakand, Chakdara 18000, Dir, KPK, Pakistan
| | - Tariq Ismail
- Department
of Pharmacy, COMSAT University, Abbottabad 22060, Pakistan
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45
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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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Chlupatý T, Růžičková Z, Kampová H, Merna J, Růžička A. Lithium, Magnesium, and Zinc Centers N,N'-Chelated by an Amine-Amide Hybrid Ligand. Inorg Chem 2022; 61:9392-9404. [PMID: 35706334 DOI: 10.1021/acs.inorgchem.1c03850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis and structure of lithium, magnesium, and zinc complexes N,N'-chelated by a hybrid amine-amido ligand ([2-(Me2NCH2)C6H4NR]-, abbreviated as LNR, where R = H, SiMe3, or Bn) are reported. The reaction of the least sterically demanding LNH with various magnesium sources gives the hexameric imide [LNMg]6 (4) by the elimination of n-butane from LNHMgnBu (2) or by the reaction of LNHLi (1) with MeMgBr. [LNH]2Mg (3) is obtained through the addition of 0.5 equiv of nBu2Mg or Mg[N(SiMe3)2]2 to LNH2 and with 1 equiv of nBu2Mg reacting to 2. Both LNHMgN(SiMe3)2 (6) and isostructural LNHZnN(SiMe3)2 (16) have been prepared using two different approaches: monodeprotonation of LNH2 by Zn/Mg[N(SiMe3)2]2 in a 1:1 ratio or ligand substitution of 2 or LNHZnEt (12) by 0.5 equiv of Sn[N(SiMe3)2]2. The reactions of 2 or 3 with 1 provide the heterotrimetallic complex [LNH]4Li2Mg (5). Benzyl- or trimethylsilyl-substituted anilines [LN(SiMe3)H (7) and LN(Bn)H (8)] with 0.5 equiv of nBu2Mg allow the formation of homoleptic bis(amides) of the [LN(R)]2Mg type (10 and 11). Nevertheless, only the silylated secondary amine 7 is able to provide the heteroleptic n-butylmagnesium amide LN(SiMe3)MgnBu (9) upon reaction with an equimolar amount of nBu2Mg. Similarly, 12, [LNH]2Zn (13), LN(R)ZnEt (17 and 18), and [LN(R)]2Zn [R = SiMe3 (19) and Bn (20)] were prepared by the monodeprotonation of LNH2 or LN(R)H using Et2Zn in the corresponding stoichiometric ratio. LNHZnI was prepared by the nucleophilic substitution of an ethyl chain in 12 by molecular iodine. A heterometallic complex, [LNH]4Li2Zn (14), analogous to 5 was prepared from 12 or 13 with 1 or 2 equiv of 1, respectively.
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Affiliation(s)
- Tomáš Chlupatý
- Faculty of Chemical Technology, Department of General and Inorganic Chemistry, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
| | - Zdeňka Růžičková
- Faculty of Chemical Technology, Department of General and Inorganic Chemistry, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
| | - Hana Kampová
- Faculty of Chemical Technology, Department of General and Inorganic Chemistry, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
| | - Jan Merna
- Faculty of Chemical Technology, Department of Polymers, University of Chemistry and Technology, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Aleš Růžička
- Faculty of Chemical Technology, Department of General and Inorganic Chemistry, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
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47
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Lassalle S, Petit J, Falconer RL, Hérault V, Jeanneau E, Thieuleux C, Camp C. Reactivity of Tantalum/Iridium and Hafnium/Iridium Alkyl Hydrides with Alkyl Lithium Reagents: Nucleophilic Addition, Alpha-H Abstraction, or Hydride Deprotonation? Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sébastien Lassalle
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Julien Petit
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Rosalyn L. Falconer
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Valentin Hérault
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Erwann Jeanneau
- Centre de Diffractométrie Henri Longchambon Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Chloé Thieuleux
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
| | - Clément Camp
- Laboratory of Catalysis, Polymerization, Processes and Materials, CP2M UMR 5128 CNRS, Université de Lyon, Institut de Chimie de Lyon, Université Claude Bernard Lyon 1, ESCPE Lyon 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
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48
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Tortajada A, Anderson DE, Hevia E. Gram‐Scale Synthesis, Isolation and Characterisation of Sodium Organometallics: nBuNa and NaTMP. Helv Chim Acta 2022. [DOI: 10.1002/hlca.202200060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andreu Tortajada
- Universitat Bern Department of Chemistry, Biochemistry and Pharmaceutical Sciences SWITZERLAND
| | - David E Anderson
- Universitat Bern Department of Chemistry, Biochemistry and Pharmaceutical Sciences SWITZERLAND
| | - Eva Hevia
- Universitat Bern Department of Chemistry and Biochemistry Freiestrasse 3 3012 Bern SWITZERLAND
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49
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Pérez-Pérez J, Hernández-Balderas U, Martínez-Otero D, Moya-Cabrera M, Jancik V. Hetero-bimetallic alkali titanosilicates [MOTi{OSi(O tBu) 3} 3] 2 (M = Li-Cs) with terminal Ti-O - groups. Dalton Trans 2022; 51:6148-6152. [PMID: 35363240 DOI: 10.1039/d2dt00939k] [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 molecular titanosilicate [(tBuO3)3SiO]3TiNEt2 (1) was obtained from the reaction between silanol (tBuO3)3SiOH and titanium amide Ti(NEt2)4. The reaction of 1 with alkali metal hydroxides MOH (M = Li, Na, K, Rb, Cs) offers a straightforward route to the alkaline salts of titanosilicates [MOTi{OSi(OtBu)3}3]2 with a terminal Ti-O- moiety. All compounds were characterised by single-crystal X-ray diffraction studies. Hirshfeld atom refinement and QTAIM analysis of the electron density in 1 and in the Rb salt 5 revealed the D-A nature of the Ti-O and Ti-N bonds and the presence of agostic C-H⋯Rb interactions.
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Affiliation(s)
- Jovana Pérez-Pérez
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510, Mexico. .,Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca-Atlacomulco km 14.5, 50200 Toluca, Estado de México, Mexico
| | - Uvaldo Hernández-Balderas
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510, Mexico. .,Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca-Atlacomulco km 14.5, 50200 Toluca, Estado de México, Mexico
| | - Diego Martínez-Otero
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510, Mexico. .,Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca-Atlacomulco km 14.5, 50200 Toluca, Estado de México, Mexico
| | - Mónica Moya-Cabrera
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510, Mexico. .,Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca-Atlacomulco km 14.5, 50200 Toluca, Estado de México, Mexico
| | - Vojtech Jancik
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510, Mexico. .,Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca-Atlacomulco km 14.5, 50200 Toluca, Estado de México, Mexico
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Lüert D, Kreyenschmidt AK, Legendre CM, Herbst-Irmer R, Stalke D. A Sodium Sodate as Precursor for Lanthanide Bis(4- R-benzoxazol-2-yl)methanide Single-Molecule Magnets. Inorg Chem 2022; 61:5234-5244. [PMID: 35316598 DOI: 10.1021/acs.inorgchem.1c03714] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
From the sodium sodate precursor [(Na(thf)6][Na{(4-Me-NCOC6H3)2CH}2] (1) three isostructural dinuclear lanthanide complexes [(μ-Cl)LnIII{(4-MeNCOC6H3)2CH}2]2 with Ln = Gd (2), Dy (3), and Er (4) based on the N,N'-chelating monoanionic bis(4-methylbenzoxazol-2-yl)methanide ligand (titled "Mebox") were synthesized and characterized by X-ray diffraction and magnetic measurements. The sodium precursor 1 was analyzed via X-ray diffraction and diffusion-ordered NMR spectroscopy experiments (DOSY-NMR) in order to investigate its aggregation in solution and the solid state. The sodium analog [(thf)3Na(NCOC6H4)2CH] (1') based on the bis(benzoxazol-2-yl)-methanide ligand (titled "box") was prepared and analyzed for comparison reasons. From the lanthanide derivatives 2-4, the DyIII complex 3 displays slow relaxation of magnetization at zero field, with a relaxation barrier of U = 315.7 cm-1. The coupling strength between the two lanthanide centers was estimated with the GdIII equivalent 2, giving a weak antiferromagnetic coupling of J = -0.035 cm-1.
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Affiliation(s)
- Daniel Lüert
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Anne-Kathrin Kreyenschmidt
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Christina M Legendre
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Regine Herbst-Irmer
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Dietmar Stalke
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
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