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Gómez S, Gómez S, Rojas-Valencia N, Hernández JG, Ardila-Fierro KJ, Gómez T, Cárdenas C, Hadad C, Cappelli C, Restrepo A. Interactions and reactivity in crystalline intermediates of mechanochemical cyclorhodation reactions. Phys Chem Chem Phys 2024; 26:2228-2241. [PMID: 38165158 DOI: 10.1039/d3cp04201d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
There is experimental evidence that solid mixtures of the rhodium dimer [Cp*RhCl2]2 and benzo[h] quinoline (BHQ) produce two different polymorphic molecular cocrystals called 4α and 4β under ball milling conditions. The addition of NaOAc to the mixture leads to the formation of the rhodacycle [Cp*Rh-(BHQ)Cl], where the central Rh atom retains its tetracoordinate character. Isolate 4β reacts with NaOAc leading to the same rhodacycle while isolate 4α does not under the same conditions. We show that the puzzling difference in reactivity between the two cocrystals can be traced back to fundamental aspects of the intermolecular interactions between the BHQ and [Cp*RhCl2]2 fragments in the crystalline environment. To support this view, we report a number of descriptors of the nature and strength of chemical bonds and intermolecular interactions in the extended solids and in a cluster model. We calculate formal quantum mechanical descriptors based on electronic structure, electron density, and binding and interaction energies including an energy decomposition analysis. Without exception, all descriptors point to 4β being a transient structure higher in energy than 4α with larger local and global electrophilic and nucleophilic powers, a more favorable spatial and energetic distribution of the frontier orbitals, and a more fragile crystal structure.
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Affiliation(s)
- Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Santiago Gómez
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Natalia Rojas-Valencia
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - José G Hernández
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Karen J Ardila-Fierro
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Tatiana Gómez
- Theoretical and Computational Chemistry Center, Institute of Applied Chemical Sciences, Faculty of Engineering, Universidad Autonoma de Chile, Avenida Pedro de Valdivia 425, Santiago, Chile
| | - Carlos Cárdenas
- Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
- Centro para el desarrollo de las Nanociencias y Nanotecnología, CEDENNA, Av. Ecuador 3493, Santiago, Chile
| | - Cacier Hadad
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Chiara Cappelli
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
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Kubota K, Jiang J, Kamakura Y, Hisazumi R, Endo T, Miura D, Kubo S, Maeda S, Ito H. Using Mechanochemistry to Activate Commodity Plastics as Initiators for Radical Chain Reactions of Small Organic Molecules. J Am Chem Soc 2024; 146:1062-1070. [PMID: 38134051 DOI: 10.1021/jacs.3c12049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Radical initiators such as azo compounds and organic peroxides have been widely used to facilitate numerous transformations of free radicals, which enable the efficient synthesis of structurally complex molecules, natural products, polymers, and functional materials. However, these high-energy reagents are potentially explosive and thus often require special precautions or delicate operating conditions. We postulated that a more convenient and safer alternative for radical chain initiation could be developed by mechanical activation of thermodynamically stable covalent bonds. Here, we show that commodity plastics such as polyethylene and poly(vinyl acetate) are capable of acting as efficient initiators for radical chain reactions under solvent-free mechanochemical conditions. In this approach, polymeric mechanoradicals, which are generated by homolytic cleavage of the polymer chains in response to the applied mechanical energy provided by ball milling, react with tris(trimethylsilyl)silane to initiate radical chain dehalogenation of organic halides. Preliminary calculations support our proposed force-induced radical chain mechanism.
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Affiliation(s)
- Koji Kubota
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
| | - Julong Jiang
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Yuri Kamakura
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Reon Hisazumi
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Tsubura Endo
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Daiyo Miura
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Shotaro Kubo
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
| | - Satoshi Maeda
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Hajime Ito
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Hokkaido, Japan
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