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Luz C, Oppel K, Endres L, Dewhurst RD, Braunschweig H, Radius U. Construction of a Boron Chain on a Single Metal by Dehydrocoupling of Borane Ligands. J Am Chem Soc 2024; 146:23741-23751. [PMID: 39137023 DOI: 10.1021/jacs.4c04926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Borane coordination, B-H borane bond activation, and borane catenation via metal-mediated dehydrocoupling to form electron-precise B-B bonds are reported. The reaction of trans-[M(IMes)2Cl4] (M = W, Mo) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) with borates Li[BH3R] (R = Mes, Dur; Mes = 2,4,6-Me3C6H2 and Dur = 2,3,5,6-Me4C6H) afforded the complexes [M(IMes)(η2-H2BR)2(η1-H2BR)] (M = W: R = Mes 1, R = Dur 3; M = Mo: R = Mes 2, R = Dur 4). Three borane ligands are coordinated in 1-4 to the group 6 metal atom via five (σ-B-H) bonds. Reaction of 1 with the phosphines PMe3 and PEt3, respectively, led to the elimination of one of the borane ligands and afforded the hydrido (σ-B-H)-boryl bis(σ-B-H)-borane complexes trans-[W(IMes)(PR3)(η1-HBMes)(η2-H2BMes)(H)] (R = Me 5, R = Et 6), in which the metal atom inserted into one of the remaining σ-B-H bonds of the borane ligands. Reaction of 1 with an additional equivalent borane BH2Mes resulted in borane dehydrocoupling and formation of complex [W(IMes)(η4-BH2Mes-BMes-BMes-BH2Mes)] 7, featuring a unique B4 chain as a ligand. Reaction of trans-[W(IMes)2Cl4] with NaBH4 also led to B-B coupling, and the metallaborane cluster [{W(IMes)(BH4)}2(B5H9)] 9 was formed, in which two tungsten atoms bridge a B5 chain.
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Affiliation(s)
- Christian Luz
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Kai Oppel
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Lukas Endres
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
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Xue M, Peng Z, Tao K, Jia J, Song D, Tung CH, Wang W. Catalytic hydrogenation of olefins by a multifunctional molybdenum-sulfur complex. Nat Commun 2024; 15:797. [PMID: 38280870 PMCID: PMC10821942 DOI: 10.1038/s41467-024-45018-3] [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: 07/19/2023] [Accepted: 01/12/2024] [Indexed: 01/29/2024] Open
Abstract
Exploration of molybdenum complexes as homogeneous hydrogenation catalysts has garnered significant attention, but hydrogenation of unactivated olefins under mild conditions are scarce. Here, we report the synthesis of a molybdenum complex, [Cp*Mo(Ph2PC6H4S-CH = CH2)(Py)]+ (2), which exhibits intriguing reactivity toward C2H2 and H2 under ambient pressure. This vinylthioether complex showcases efficient catalytic activity in the hydrogenation of various aromatic and aliphatic alkenes, demonstrating a broad substrate scope without the need for any additives. The catalytic pathway involves an uncommon oxidative addition of H2 to the cationic Mo(II) center, resulting in a Mo(IV) dihydride intermediate. Moreover, complex 2 also shows catalytic activity toward C2H2, leading to the production of polyacetylene and the extension of the vinylthioether ligand into a pendant triene chain.
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Affiliation(s)
- Minghui Xue
- School of Chemistry and Chemical Engineering, Shandong University, 250100, Jinan, China
| | - Zhiqiang Peng
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Keyan Tao
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Jiong Jia
- School of Chemistry and Chemical Engineering, Shandong University, 250100, Jinan, China
| | - Datong Song
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, 250100, Jinan, China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, 250100, Jinan, China.
- College of Chemistry, Beijing Normal University, 100875, Beijing, China.
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Gayen S, Shyamal S, Mohapatra S, Antharjanam PKS, Ghosh S. B-P Coupling: Metal Stabilized Phosphinoborate Complexes. Chemistry 2024; 30:e202302362. [PMID: 38009462 DOI: 10.1002/chem.202302362] [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: 07/24/2023] [Revised: 10/28/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023]
Abstract
In an effort to establish B-P coupling reactions without the use of phosphine-borane dehydrocoupling agent, we have developed a new synthetic methodology employing group 8 metal σ-borate complex [{κ3 -H,S,S'-BH2 L2 }Ru{κ3 -H,H,S-BH3 L}] (L=NC5 H4 S), 1. Treatment of 1 with chlorodiphenyl phosphine (PPh2 Cl) yielded 1,5-P,S chelated Ru-dihydridoborate species [PPh2 H{κ3 -H,H,S-BH(OH)L}Ru{κ2 -P,S-(Ph2 P)BH2 L}], 2. The insertion of phosphine moiety (PPh2 ) by the cleavage of 3c-2e σ(Ru… H-B) bonding interaction led to the formation of B-P bond. The κ2 -P,S chelated six-membered ring adopted a boat conformation in complex 2. The heterocycle is made of all different atoms, which is one of the rarest examples of heteroatomic ring systems. Theoretical outcomes demonstrated the electronic insight of B-P coupling and stabilization through transition metal. In order to explore an alternate route of B-P bond formation, we have further explored the reaction of 1 and Ru-bis(dihydridoborate) complex, 5 with secondary phosphine oxide (SPO). Although, thermolysis of 1 with diphenylphosphine oxide yielded analogous σ-borate complex 3, the similar reaction of 5 at room temperature led to the formation of novel phosphinous(III) acid incorporated Ru(σ-borate)(dihydridoborate) complex, 6. In a similar fashion, the reaction of 5 with phosphite ligand generated Ru(σ-borate)(dihydridoborate) complex, 7, which is analogous to 6.
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Affiliation(s)
- Sourav Gayen
- Department of Chemistry, Indian Institution of Technology, Madras, Chennai, 600036, India
| | - Sampad Shyamal
- Department of Chemistry, Indian Institution of Technology, Madras, Chennai, 600036, India
| | - Stutee Mohapatra
- Department of Chemistry, Indian Institution of Technology, Madras, Chennai, 600036, India
| | | | - Sundargopal Ghosh
- Department of Chemistry, Indian Institution of Technology, Madras, Chennai, 600036, India
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Pathak K, Mishra S, Nandi C, Saha S, Ghosh S. Synthesis and Chemistry of Dihydridoborate Group 7 Metal Complexes with Varied N,E-Chelated Ligands (E = O, NH, or S). Inorg Chem 2023; 62:160-169. [PMID: 36574500 DOI: 10.1021/acs.inorgchem.2c03095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several dihydridoborate group 7 metal complexes have been synthesized and their structural aspects have been described from various N,S-, N,N-, and N,O-chelated borate species, such as Na[(H3B)mp] (mp = 2-mercaptopyridyl), Na[(H3B)amt] (amt = 2-amino-5-mercapto-1,3,4-thiadiazolyl), Na[(H3B)hp] (hp = 2-hydroxypyridyl), Na[(H2B)bap] (bap = bis(2-aminopyridyl)), and Na[(H2B)bdap] (bdap = bis(2,6-diaminopyridyl)). Room temperature photolysis of [M2(CO)10] (M = Mn or Re) with these borate species afforded dihydridoborate complexes [(CO)3M(μ-H)2BHL] 1-6 (1, M = Mn, L = mp; 2, M = Re, L = mp; 3, M = Mn, L = amt; 4, M = Mn, L = hp; 5, M = Mn, L = ap; 6, M = Mn, L = dap, ap = 2-aminopyridyl, dap = 2,6-diaminopyridyl). In complexes 1-3, the corresponding (H2BHL) units are coordinated to the metal centers through the (κ3-H,H,S) mode. However, in complexes 4 and 5 (or 6), the connection is via (κ3-H,H,O) and (κ3-H,H,N) modes of coordination, respectively. Complexes 1 and 5 underwent hydroboration reactions with terminal alkynes that yielded trans-hydroborated species [Mn(CO)3(μ-H)2(NC5H4E)B(PhC═CH2)] (7, E = S; 8, E = NH). Density functional theory (DFT) calculations have been carried out to investigate the electronic structures of these dihydridoborate species as well as the nature of bonding in them.
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Affiliation(s)
- Kriti Pathak
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Shivankan Mishra
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Chandan Nandi
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Suvam Saha
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sundargopal Ghosh
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
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Pathak K, Gayen S, Saha S, Nandi C, Mishra S, Ghosh S. Coordination and Hydroboration of Ru(II)‐Borate Complexes: Dihydridoborate vs. Bis(dihydridoborate). Chemistry 2022; 28:e202104393. [DOI: 10.1002/chem.202104393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Kriti Pathak
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
| | - Sourav Gayen
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
| | - Suvam Saha
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
| | - Chandan Nandi
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
| | - Shivankan Mishra
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
| | - Sundargopal Ghosh
- Department of Chemistry Indian Institute of Technology, Madras Chennai 600036 India
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Kar S, Kar K, Bairagi S, Bhattacharyya M, Chowdhury MG, Ghosh S. Chalcogen stabilized borate complexes of tantalum. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Saha K, Roy DK, Dewhurst RD, Ghosh S, Braunschweig H. Recent Advances in the Synthesis and Reactivity of Transition Metal σ-Borane/Borate Complexes. Acc Chem Res 2021; 54:1260-1273. [PMID: 33565872 DOI: 10.1021/acs.accounts.0c00819] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The coordination of an element-element σ bond to a transition metal (TM) is both a fundamentally intriguing binding mode and of critical importance to metal-mediated bond activation mechanisms and catalysis, particularly the hotly contested field of C-H activation. TM σ complexes of dihydrogen (i.e., H-H) and silanes (H-SiR3) have been extensively studied, the latter being of interest as models for the (generally unstable and unisolable) σ complexes of alkanes (i.e., H-CR3). TM σ complexes of hydroboranes and hydroborates (i.e., H-BR2, H-BR3, (H-)2BR2) are somewhat less well studied but similarly have relevance to catalytic borylation reactions that are of high current interest to organic synthesis. Our two research groups have made significant contributions to elaborating the family of σ-borane/-borate complexes using two distinct approaches: while the Ghosh group generally starts from hydrogen-rich tetracoordinate boron species such as borates, the Braunschweig group starts from hypovalent and/or hypocoordinate boron building blocks. Through these two approaches, a wide range of species containing one or two σ-bound B-H ligands have been prepared, some with additional chelating donor sites. Over the past 2 years, the body of work on σ-borane/-borate complexes from our two research groups has significantly expanded, with a combined nine published articles in 2019-2020 alone. Very recent work from the Braunschweig group has led to the synthesis of the first bis(σ)-borane complexes of group 6 metals, as well as the synthesis of a series of novel bis(σ)-borane and bis(σ)-borate complexes of ruthenium and iridium, the former being useful precursors for pentacoordinate borylene complexes of Ru. Recent work from the Ghosh group has uncovered a remarkable diversity of structures with σ(B-H)-bound ligands from the combination of borohydrides and nitrogen/chalcogen-containing groups and heterocycles. These reactions, while in some cases producing conventional scorpionate-type chelating products, more frequently undergo fascinating rearrangements with unpredictable outcomes. This Account aims to highlight this recent acceleration of research progress in this area, particularly the distinct but related approaches of-and complexes produced by-our two research groups, in addition to relevant works from other groups where appropriate.
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Affiliation(s)
- Koushik Saha
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Dipak Kumar Roy
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India
| | - Rian D. Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sundargopal Ghosh
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Zafar M, Ramalakshmi R, Ahmad A, Antharjanam PKS, Bontemps S, Sabo-Etienne S, Ghosh S. Cooperative B-H and Si-H Bond Activations by κ 2- N, S-Chelated Ruthenium Borate Complexes. Inorg Chem 2021; 60:1183-1194. [PMID: 33390001 DOI: 10.1021/acs.inorgchem.0c03306] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cooperative E-H (E = B, Si) bond activations employing κ2-N,S-chelated ruthenium borate species, [PPh3{κ2-N,S-(NS2C7H4)}Ru{κ3-H,S,S'-H2B(NC7H4S2)2}], (1) are established. Treatment of 1 with BH3·SMe2 yielded the six-membered ruthenaheterocycle [PPh3{κ2-S,H-(BH3NS2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (2) formed by a hemilabile ring opening of a Ru-N bond and capturing of a BH3 unit coordinated in an "end-on" fashion. On the other hand, the bulky borane H2BMes shows different reactivity with 1 that led to the formation of the two dihydroborate complexes [{κ3-S,H,H-(NBH2Mes)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (3) and [PPh3{κ3-S,H,H-(NBH2Mes)(S2C7H4)}Ru(κ2-N,S-C7H4NS2)] (4), in which H2BMes has been inserted into the Ru-N bond of the initial κ2-N,S-chelated ligand. In an attempt to directly activate hydrosilanes by 1, reactions were carried out with H2SiPh2 that yielded two isomeric five-membered ruthenium silyl complexes, namely [PPh3{κ2-S,Si-(NSiPh2)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (5a,b), and the hydridotrisilyl complex [Ru(H){κ2-S,Si-(SiPh2NC7H4S2}3] (6). These complexes were generated by Si-H bond activation with the release of H2 and the formation of N-Si and Ru-Si bonds. When the reaction of 1 was carried out in the presence of PhSiH3, the reaction only produced the analogous complexes [PPh3{κ2-S,Si-(NSiPhH)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (5a',b'). Density functional theory (DFT) calculations have been used to probe the bonding modes of boranes/silane with the ruthenium center.
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Affiliation(s)
| | | | | | | | - Sébastien Bontemps
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
| | - Sylviane Sabo-Etienne
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
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Two octahedral σ-borane metal (MnI and RuII) complexes containing a tripod κ3N,H,H-ligand: Synthesis, structural characterization, and theoretical topological study of the charge density. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127217] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Adding to the Family of Copper Complexes Featuring Borohydride Ligands Based on 2-Mercaptopyridyl Units. INORGANICS 2019. [DOI: 10.3390/inorganics7080093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Borohydride ligands featuring multiple pendant donor functionalities have been prevalent in the chemical literature for many decades now. More recent times has seen their development into new families of so-called soft scorpionates, for example, those featuring sulfur based donors. Despite all of these developments, those ligands containing just one pendant group are rare. This article explores one ligand family based on the 2-mercaptopyridine heterocycle. The coordination chemistry of the monosubstituted ligand, [H3B(mp)]− (mp = 2-mercaptopyridyl), has been explored. Reaction of Na[BH3(mp)] with one equivalent of Cu(I)Cl in the presence of either triphenylphosphine or tricyclohexylphosphine co-ligands leads to the formation of [Cu{H3B(mp)}(PR3)] (R = Ph, 1; Cy, 2), respectively. Structural characterization confirms a κ3-S,H,H coordination mode for the borohydride-based ligand within 1 and 2, involving a dihydroborate bridging interaction (BH2Cu) with the copper centers.
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