1
|
Garcia NA, Tafuri VC, Abdu RB, Roberts CC. Elucidating the Impact of Rare Earth or Transition Metal Identity on the Physical and Electronic Structural Properties of a Series of Redox-Active Tris(amido) Complexes. Inorg Chem 2024. [PMID: 39102431 DOI: 10.1021/acs.inorgchem.4c01909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
The use of redox-active ligands with the f-block elements has been employed to promote unique chemical transformations and explore their unique emergent electronic properties for a myriad of applications. In this study, we report eight new tris(amido) metal complexes: 1-Ln (Ln = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, and Yb3+), 1-La, and 1-Ti (an early transition metal analogue). The one-electron oxidation of the tris(amido) ligand was conducted to generate semi-iminato complexes 2-Ln, 2-La, and 2-Ti, and these complexes were studied using EPR. Tris(amido) complexes 1-Ln, 1-La, and 1-Ti were fully characterized using a range of spectroscopic (NMR and UV-vis/NIR) and physical techniques (X-ray diffraction and cyclic voltammetry, with the exception of 1-La). Computational methods were employed to further elucidate the electronic structures of these complexes. Lastly, complexes 1-Ln, 1-La, and 1-Ti were probed as catalysts for alkyl-alkyl cross-coupling, and the initial rate of the reaction was measured to explore the influence of the metal ion.
Collapse
Affiliation(s)
- Nicholas A Garcia
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Victoria C Tafuri
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Rana B Abdu
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Courtney C Roberts
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
2
|
Chellali JE, Woodside AJ, Yu Z, Neogi S, Külaots I, Guduru PR, Robinson JR. Access to Stereoblock Polyesters via Irreversible Chain-Transfer Ring-Opening Polymerization (ICT-ROP). J Am Chem Soc 2024. [PMID: 38593434 DOI: 10.1021/jacs.4c02976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Precise control over polymer microstructure can enable the molecular tunability of material properties and represents a significant challenge in polymer chemistry. Stereoblock copolymers are some of the simplest stereosequenced polymers, yet the synthesis of stereoblock polyesters from prochiral or racemic monomers outside of "simple" isotactic stereoblocks remains limited. Herein, we report the development of irreversible chain-transfer ring-opening polymerization (ICT-ROP), which overcomes the fundamental limitations of single catalyst approaches by using transmetalation (e.g., alkoxide-chloride exchange) between two catalysts with distinct stereoselectivities as a means to embed temporally controlled multicatalysis in ROP. Our combined small-molecule model and catalytic polymerization studies lay out a clear molecular basis for ICT-ROP and are exploited to access the first examples of atactic-syndiotactic stereoblock (at-sb-st) polyesters, at-sb-st polyhydroxyalkanoates (PHAs). We achieve high levels of control over molecular weight, tacticity, monomer composition, and block structures in a temporally controlled manner and demonstrate that stereosequence control leads to polymer tensile properties that are independent of thermal properties.
Collapse
Affiliation(s)
- Jonathan E Chellali
- Department of Chemistry, Brown University, 324 Brook St., Providence, Rhode Island 02912, United States
| | - Audra J Woodside
- Department of Chemistry, Brown University, 324 Brook St., Providence, Rhode Island 02912, United States
| | - Ziyan Yu
- Department of Chemistry, Brown University, 324 Brook St., Providence, Rhode Island 02912, United States
| | - Srijan Neogi
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Indrek Külaots
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Pradeep R Guduru
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Jerome R Robinson
- Department of Chemistry, Brown University, 324 Brook St., Providence, Rhode Island 02912, United States
| |
Collapse
|
3
|
Singh V, Jain H, Nath S, Adhikari D. Multielectron Redox Afforded by a Pincer Ligand Promoting Kumada Cross-Coupling Reactions. Chemistry 2023:e202303189. [PMID: 37988192 DOI: 10.1002/chem.202303189] [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: 09/29/2023] [Revised: 11/21/2023] [Accepted: 11/21/2023] [Indexed: 11/23/2023]
Abstract
The redox-active nature of a pincer has been exploited to conduct C-C cross-coupling reactions under mild conditions. A nickel complex with a NNN pincer was dimeric in the solid state, and the structure displayed a Ni2 N2 diamond core. In the dimeric structure, both ligand backbones house an electron, in the iminosemiquinonate form, to keep the metal's oxidation state at +2. In the presence of an aryl Grignard reagent, only 3 mol % loading the nickel complex generates a Kumada cross-coupled product in good yield from a wide variety of aryl-X (X= I, Br, Cl) substrates. That the ligand-based radical remains responsible for promoting such a coupling reaction following a radical pathway is suggested by TEMPO quenching. Furthermore, a radical-clock experiment along with tracing product distribution unambiguously supported the radical's involvement through the catalytic cycle. A series of thorough mechanistic probation, including computational DFT analysis, disclosed the cooperative action of both redox-active pincer ligand and the metal centre to drive the reaction.
Collapse
Affiliation(s)
- Vikramjeet Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306, India
| | - Harshit Jain
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306, India
| | - Shounak Nath
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306, India
| |
Collapse
|
4
|
Sun D, Rajeshkumar T, Li Y, Xu J, Chen R, Wan Z, Lv Z, Maron L, Chen YH. Lanthanum-Catalyzed Stereospecific Cross-Coupling of Propargylic Substrates with Grignard Reagents. Org Lett 2023; 25:6730-6735. [PMID: 37671845 DOI: 10.1021/acs.orglett.3c02600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Transition-metal-catalyzed cross-coupling of propargylic electrophiles and Grignard reagents provides densely functionalized products that are extremely useful synthetic intermediates. However, examples of conversion of propargylic derivatives to form propargyl compounds remain limited due to the challenging regioselectivity. We use LaCl3·2LiCl to catalyze propargylation of Grignard reagents in the absence of ligand in high regioselectivity and stereospecificity. The approach shows a wide substrate scope using alkyl or (hetero)aryl Grignard reagents and alkynyl electrophiles with different leaving groups. Our protocol was further applied for the formal synthesis of frondosin B. It is worth exploring methodologies utilizing the naturally abundant and relatively nontoxic lanthanum catalysts.
Collapse
Affiliation(s)
- Dandan Sun
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Thayalan Rajeshkumar
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Yifan Li
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Jiaxin Xu
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Runkai Chen
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Zhaohua Wan
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Zongchao Lv
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
- CMC Pharmaceutical Research Center, Wuhan RS Pharmaceutical Co., Ltd., Wuhan 430073, China
| | - Laurent Maron
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Yi-Hung Chen
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| |
Collapse
|
5
|
Seong CM, Roberts CC. Redox-Neutral Decarboxylative and Desulfonylative C(sp 3) Trifluoromethylation: Method Development and Mechanistic Inquiry. J Org Chem 2023. [PMID: 37467365 DOI: 10.1021/acs.joc.3c00872] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Sodium triflinate (CF3SO2Na) is an inexpensive bench-stable radical CF3 source that is often activated by external oxidants such as peroxides. However, despite the commercial accessibility of CF3SO2Na, the salt has never been applied to decarboxylative trifluoromethylation due to challenges in controlled cross-radical coupling. We report a redox-neutral approach to decarboxylative C(sp3) trifluoromethylation of carboxylic acid derivatives. Mechanistic inquiry is performed to address the limitations in scope.
Collapse
Affiliation(s)
- Chris M Seong
- University of Minnesota, Department of Chemistry, Minneapolis, Minnesota 55455, United States
| | - Courtney C Roberts
- University of Minnesota, Department of Chemistry, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
6
|
Underhill J, Yang ES, Schmidt-Räntsch T, Myers WK, Goicoechea JM, Abbenseth J. Dioxygen Splitting by a Tantalum(V) Complex Ligated by a Rigid, Redox Non-Innocent Pincer Ligand. Chemistry 2023; 29:e202203266. [PMID: 36281622 PMCID: PMC10098518 DOI: 10.1002/chem.202203266] [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: 10/19/2022] [Indexed: 12/05/2022]
Abstract
The reaction of TaMe3 Cl2 with the rigid acridane-derived trisamine H3 NNN yields the tantalum(V) complex [TaCl2 (NNNcat )]. Subsequent reaction with dioxygen results in the full four-electron reduction of O2 yielding the oxido-bridged bimetallic complex [{TaCl2 (NNNsq )}2 O]. This dinuclear complex features an open-shell ground state due to partial ligand oxidation and was comprehensively characterized by single crystal X-ray diffraction, LIFDI mass spectrometry, NMR, EPR, IR and UV/VIS/NIR spectroscopy. The mechanism of O2 activation was investigated by DFT calculations revealing initial binding of O2 to the tantalum(V) center followed by complete O2 scission to produce a terminal oxido-complex.
Collapse
Affiliation(s)
- Jack Underhill
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Eric S Yang
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Till Schmidt-Räntsch
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - William K Myers
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Jose M Goicoechea
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Josh Abbenseth
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| |
Collapse
|
7
|
Gavin JT, Belli RG, Roberts CC. Radical-Polar Crossover Catalysis with a d 0 Metal Enabled by a Redox-Active Ligand. J Am Chem Soc 2022; 144:21431-21436. [DOI: 10.1021/jacs.2c09114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Joshua T. Gavin
- Department of Chemistry, University of Minnesota─Twin Cities, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Roman G. Belli
- Department of Chemistry, University of Minnesota─Twin Cities, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Courtney C. Roberts
- Department of Chemistry, University of Minnesota─Twin Cities, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
8
|
Singh K, Kundu A, Adhikari D. Ligand-Based Redox: Catalytic Applications and Mechanistic Aspects. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kirti Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
| | - Abhishek Kundu
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
| |
Collapse
|
9
|
Cheng R, de Ruiter G, Li CJ. Cobalt-catalyzed cross-coupling of Umpolung carbonyls with alkyl halides under mild conditions. Chem Commun (Camb) 2022; 58:11563-11566. [PMID: 36165102 DOI: 10.1039/d2cc04302e] [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
While classical cross-couplings are dominated by palladium and nickel catalysts, cobalt-based catalysts have shown unique advantages for such cross-coupling reactions in terms of higher catalytic activity and lower toxicity. Herein, we describe a novel cobalt-catalyzed alkyl-alkyl cross-coupling reaction of hydrazone with alkyl halides under mild reaction conditions, where the use of a PNP-type pincer ligand is essential for catalysis. Both aldehyde and ketone hydrazones are compatible with this reaction, giving a series of C(sp3)-C(sp3) coupling products in moderate to good yields.
Collapse
Affiliation(s)
- Ruofei Cheng
- Department of Chemistry, and FQRNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 0B8, Canada.
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Chao-Jun Li
- Department of Chemistry, and FQRNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 0B8, Canada.
| |
Collapse
|
10
|
Belli RG, Tafuri VC, Roberts CC. Improving Alkyl–Alkyl Cross-Coupling Catalysis with Early Transition Metals through Mechanistic Understanding and Metal Tuning. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Roman G. Belli
- University of Minnesota, Minneapolis, Minnesota 55455, United States
| | | | | |
Collapse
|