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Liu XB, Tiznado W, Cui LJ, Barroso J, Leyva-Parra L, Miao LH, Zhang HY, Pan S, Merino G, Cui ZH. Exploring the Use of "Honorary Transition Metals" To Push the Boundaries of Planar Hypercoordinate Alkaline-Earth Metals. J Am Chem Soc 2024; 146:16689-16697. [PMID: 38843775 PMCID: PMC11191695 DOI: 10.1021/jacs.4c03977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/24/2024] [Accepted: 05/24/2024] [Indexed: 06/23/2024]
Abstract
The quest for planar hypercoordinate atoms (phA) beyond six has predominantly focused on transition metals, with dodecacoordination being the highest reported thus far. Extending this bonding scenario to main-group elements, which typically lack d orbitals despite their larger atomic radius, has posed significant challenges. Intrigued by the potentiality of covalent bonding formation using the d orbitals of the heavier alkaline-earth metals (Ae = Ca, Sr, Ba), the so-called "honorary transition metals", we aim to push the boundaries of planar hypercoordination. By including rings formed by 12-15 atoms of boron-carbon and Ae centers, we propose a design scheme of 180 candidates with a phA. Further systematic screening, structural examination, and stability assessments identified 10 potential clusters with a planar hypercoordinate alkaline-earth metal (phAe) as the lowest-energy form. These unconventional structures embody planar dodeca-, trideca-, tetradeca-, and pentadecacoordinate atoms. Chemical bonding analyses reveal the important role of Ae d orbitals in facilitating covalent interactions between the central Ae atom and the surrounding boron-carbon rings, thereby establishing a new record for coordination numbers in the two-dimensional realm.
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Affiliation(s)
- Xin-bo Liu
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - William Tiznado
- Centro
de Química Teórica & Computacional (CQT&C),
Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146 Santiago de Chile, Chile
| | - Li-Juan Cui
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Jorge Barroso
- Department
of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Luis Leyva-Parra
- Centro
de Química Teórica & Computacional (CQT&C),
Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146 Santiago de Chile, Chile
| | - Lin-hong Miao
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Hui-yu Zhang
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Sudip Pan
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Gabriel Merino
- Departamento
de Física Aplicada, Centro de Investigación
y de Estudios Avanzados Unidad Mérida, Km 6 Antigua Carretera a Progreso.
Apdo. Postal 73, Cordemex, 97310 Mérida, México
| | - Zhong-hua Cui
- Institute
of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
- Key
Laboratory of Physics and Technology for Advanced Batteries (Ministry
of Education), Jilin University, Changchun 130023, China
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2
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Liang Y, Efremenko I, Diskin-Posner Y, Avram L, Milstein D. Calcium-Ligand Cooperation Promoted Activation of N 2O, Amine, and H 2 as well as Catalytic Hydrogenation of Imines, Quinoline, and Alkenes. Angew Chem Int Ed Engl 2024; 63:e202401702. [PMID: 38533687 DOI: 10.1002/anie.202401702] [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: 01/24/2024] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 03/28/2024]
Abstract
Bond activation and catalysis using s-block metals are of great significance. Herein, a series of calcium pincer complexes with deprotonated side arms have been prepared using pyridine-based PNP and PNN ligands. The complexes were characterized by NMR and X-ray crystal diffraction. Utilizing the obtained calcium complexes, unprecedented N2O activation by metal-ligand cooperation (MLC) involving dearomatization-aromatization of the pyridine ligand was achieved, generating aromatized calcium diazotate complexes as products. Additionally, the dearomatized calcium complexes were able to activate the N-H bond as well as reversibly activate H2, offering an opportunity for the catalytic hydrogenation of various unsaturated molecules. DFT calculations were applied to analyze the electronic structures of the synthesized complexes and explore possible reaction mechanisms. This study is an important complement to the area of MLC and main-group metal chemistry.
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Affiliation(s)
- Yaoyu Liang
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Irena Efremenko
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yael Diskin-Posner
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Liat Avram
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - David Milstein
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 7610001, Israel
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3
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Ruppert H, Meister A, Pfretzschner R, Vieira AF, Greb L. Concatenating Structural Constraint Effects at Tin for the Sequential Generation, Stabilization, and Transfer of Acyclic Aminocarbenes. J Am Chem Soc 2024; 146. [PMID: 38604608 PMCID: PMC11048120 DOI: 10.1021/jacs.4c02446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Structural constraint approaches have been employed toward different ends in recent years, from augmenting the nucleophilicity in pyramidalized low-valent p-block compounds to enhancing the Lewis acidities at planarized tetravalent p-block elements. While previous studies exploited these effects separately, this work introduces a strategy to concatenate structural constraint approaches at individual stages of a reaction sequence in a row to unlock a synthetic path unattainable by conventional methodologies. The boosted nucleophilicity resulting from the constrained tetracoordinated calix[4]pyrrolato stannate(II) dianion enables the reductive formation of sterically unprotected acyclic aminocarbenes. These amino carbenes are stabilized at the concomitantly formed square-planar stannane(IV) as air-stable adducts. Transfer of the carbenes onto copper(I) by cooperativity of the calix[4]pyrrole ligand finalizes this protocol to hitherto unreported yet prototypical carbene complexes. Detailed spectroscopic and quantum theoretical analyses establish the synergy of structural constraints and element-ligand cooperation as the linchpin to this reaction path and its selectivity.
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Affiliation(s)
- Heiko Ruppert
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
| | - Arne Meister
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
| | - Ronja Pfretzschner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
| | - André Faria Vieira
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
| | - Lutz Greb
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
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4
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Hannah TJ, Chitnis SS. Ligand-enforced geometric constraints and associated reactivity in p-block compounds. Chem Soc Rev 2024; 53:764-792. [PMID: 38099873 DOI: 10.1039/d3cs00765k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
The geometry at an element centre can generally be predicted based on the number of electron pairs around it using valence shell electron pair repulsion (VSEPR) theory. Strategies to distort p-block compounds away from these predicted geometries have gained considerable interest due to the unique structural outcomes, spectroscopic properties or reactivity patterns engendered by such distortion. This review presents an up-to-date group-wise summary of this exciting and rapidly growing field with a focus on understanding how the ligand employed unlocks structural features, which in turn influences the associated reactivity. Relevant geometrically constrained compounds from groups 13-16 are discussed, along with selected stoichiometric and catalytic reactions. Several areas for advancement in this field are also discussed. Collectively, this review advances the notion of geometric tuning as an important lever, alongside electronic and steric tuning, in controlling bonding and reactivity at p-block centres.
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Affiliation(s)
- Tyler J Hannah
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, NS, B3H 4R2, Canada.
| | - Saurabh S Chitnis
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, NS, B3H 4R2, Canada.
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Jin B, Yan M, Feng LY, Miao CQ, Wang YJ. CBe 2 H 5 - : Unprecedented 2σ/2π Double Aromaticity and Dynamic Structural Fluxionality in a Planar Tetracoordinate Carbon Cluster. Chemistry 2024:e202304134. [PMID: 38205620 DOI: 10.1002/chem.202304134] [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: 12/11/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/12/2024]
Abstract
A 14-electron ternary anionic CBe2 H5 - cluster containing a planar tetracoordinate carbon (ptC) atom is designed herein. Remarkably, it can be stabilized by only two beryllium atoms with both π-acceptor/σ-donor properties and two hydrogen atoms, which means that the conversion from planar methane (transition state) to ptC species (global minimum) requires the substitution of only two hydrogen atoms. Moreover, two ligand H atoms exhibit alternate rotation, giving rise to interesting dynamic fluxionality in this cluster. The electronic structure analysis reveals the flexible bonding positions of ligand H atoms due to C-H localized bonds, highlighting the rotational fluxionality in the cluster, and two CBe2 3c-2e delocalized bonds endow its rare 2σ/2π double aromaticity. Unprecedentedly, the fluxional process exhibits a conversion in the type of bonding (σ bond↔π bond), which is an uncommon fluxional mechanism. The cluster can be seen as an attempt to apply planar hypercoordinate carbon species to molecular motors.
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Affiliation(s)
- Bo Jin
- Department of Chemistry, Xinzhou Normal University, 1 East Dunqi Street, Xinzhou, Shanxi, 034000, People's Republic of China
| | - Miao Yan
- Department of Chemistry, Xinzhou Normal University, 1 East Dunqi Street, Xinzhou, Shanxi, 034000, People's Republic of China
| | - Lin-Yan Feng
- Department of Chemistry, Xinzhou Normal University, 1 East Dunqi Street, Xinzhou, Shanxi, 034000, People's Republic of China
| | - Chang-Qing Miao
- Department of Chemistry, Xinzhou Normal University, 1 East Dunqi Street, Xinzhou, Shanxi, 034000, People's Republic of China
| | - Ying-Jin Wang
- Department of Chemistry, Xinzhou Normal University, 1 East Dunqi Street, Xinzhou, Shanxi, 034000, People's Republic of China
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