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Kanayama K, Nakamura H, Maruta K, Bodi A, Hemberger P. The Unimolecular Decomposition Mechanism of Trimethyl Phosphate. Chemistry 2024; 30:e202401750. [PMID: 38877823 DOI: 10.1002/chem.202401750] [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: 05/03/2024] [Revised: 06/05/2024] [Accepted: 06/14/2024] [Indexed: 06/16/2024]
Abstract
Trimethyl phosphate (TMP), an organophosphorus compound (OPC), is a promising fire-retardant candidate for lithium-ion battery (LIB) electrolytes to mitigate fire spread. This study aims to understand the mechanism of TMP unimolecular thermal decomposition to support the integration of a TMP chemical kinetic model into a LIB electrolyte surrogate model. Reactive intermediates and products of TMP thermal decomposition were experimentally detected using vacuum ultraviolet (VUV) synchrotron radiation and double imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy. Phosphorus-containing intermediates such as PO, HPO and HPO2 were identified. Sampling effects could successfully be obviated thanks to photoion imaging, which also showed evidence for isomerization reactions upon wall collisions in the ionization chamber. Quantum chemical calculations performed for the unimolecular decomposition of TMP revealed for the first time that isomerization channels via hydrogen and methyl transfer (barrier heights of 65.9 and 72.6 kcal/mol, respectively) are the lowest-energy primary steps of TMP decomposition followed by CH3OH/CH3/CH2O or dimethyl ether (DME) production, respectively. We found an analogous DME production channel in the unimolecular decomposition of dimethyl methylphosphonate (DMMP), another important OPC fire-retardant additive with a similar molecular structure to TMP, which are not included in currently available chemical kinetic models.
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Affiliation(s)
- Keisuke Kanayama
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH 5232, Villigen PSI, Switzerland
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, 980-8577, Sendai, Miyagi, Japan
- Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, 980-8579, Sendai, Miyagi, Japan
| | - Hisashi Nakamura
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, 980-8577, Sendai, Miyagi, Japan
| | - Kaoru Maruta
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, 980-8577, Sendai, Miyagi, Japan
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH 5232, Villigen PSI, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH 5232, Villigen PSI, Switzerland
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Hu C, Rees NH, Pink M, Goicoechea JM. Isolation and characterization of a two-coordinate phosphinidene oxide. Nat Chem 2024:10.1038/s41557-024-01586-x. [PMID: 39009793 DOI: 10.1038/s41557-024-01586-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 06/21/2024] [Indexed: 07/17/2024]
Abstract
Nitroso compounds, R-N=O, are common intermediates in organic synthesis, and are typically amenable to storage and manipulation at ambient temperature under aerobic conditions. By contrast, phosphorus-containing analogues, such as R-P=O (R = OH, CH3, OCH3, Ph), are extremely reactive and need to be studied in inert gas matrices at ultralow temperatures (3-15 K). These species are believed to be key intermediates in the degradation/combustion of organic phosphorus compounds, a class of chemicals that includes chemical warfare agents and flame retardants. Here we describe the isolation of a two-coordinate phosphorus(III) oxide under ambient conditions, enabled by the use of an extremely bulky amine ligand. Reactivity studies reveal that the phosphorus centre can be readily oxidized, and that in doing so, the P-O bond remains intact, an observation that is of interest to the proposed reactivity of transient phosphorus(III) oxides.
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Affiliation(s)
- Chenyang Hu
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Nicolas H Rees
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Maren Pink
- Department of Chemistry, Indiana University, Bloomington, IN, USA
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Lu B, Zeng X. Phosphinidenes: Fundamental Properties and Reactivity. Chemistry 2023:e202303283. [PMID: 38108540 DOI: 10.1002/chem.202303283] [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: 10/07/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 12/19/2023]
Abstract
Phosphinidenes are heavy congeners of nitrenes that have been broadly used as in situ reagents in synthetic phosphorus chemistry and also serve as versatile ligands in coordination with transition metals. However, the detection of free phosphinidenes is largely challenged by their high reactivity and also the lack of suitable synthetic methods, rendering the knowledge about the fundamental properties of this class of low-valent phosphorus compounds limited. Recently, an increasing number of free phosphinidenes bearing prototype structural and bonding properties have been prepared for the first time, thus enabling the exploration of their distinct reactivity from the nitrene analogues. This Concept article will discuss the experimental approaches for the generation of the highly unstable phosphinidenes and highlight their distinct reactivity from the nitrogen analogues so as to stimuate future studies about their potential applications in phosphorus chemistry.
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Affiliation(s)
- Bo Lu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
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Jiang J, Zhu B, Jiang X, Lu B, Zeng X. Photochemistry of phosphenic chloride (ClPO 2): isomerization with chlorine metaphosphite (ClOPO) and reduction by carbon monoxide. Phys Chem Chem Phys 2022; 24:20828-20836. [PMID: 36040114 DOI: 10.1039/d2cp02986c] [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
Phosphenic chloride (ClPO2) is an elusive congener of nitryl chloride (ClNO2). By high-vacuum flash pyrolysis of 2-chloro-1,3,2-dioxaphospholane in the gas phase, ClPO2 has been efficiently generated and subsequently isolated in cryogenic N2, Ar, and CO matrices (10 K) for a first time study on its photochemistry. Upon 193 nm laser irradiation, ClPO2 isomerizes to the novel chlorine metaphosphite (ClOPO) by initial cleavage of the Cl-P bond (→ ˙Cl + ˙PO2) with subsequent Cl-O bond formation inside the N2 and Ar matrix cages. The reverse transformation becomes feasible under further irradiation at 266 nm. This photochemistry is consistent with the observed absorptions of ClPO2 and ClOPO at 207 and 250 nm, respectively. When the photolysis was performed in solid CO ice, no isomerization occurs due to CO-trapping of the initially generated ˙Cl atoms by forming caged radical pair ClCO˙⋯˙PO2. Concomitantly, photolytic reduction of ClPO2 to ClPO by CO has been observed, yielding a weakly bonded molecular complex consisting of ClPO and CO2 bonded through short intermolecular C⋯O contact (2.910 Å). The characterization of ClPO, ClPO2, ClOPO, and the molecular complexes of ClPO2-CO and ClPO-CO2 using matrix-isolation IR and UV-vis spectroscopy is supported by the theoretical calculations at the B3LYP/6-311 + G(3df) level, and the photochemistry of ClPO2 is also compared with the revisited photochemistry of ClNO2 in the N2-matrix.
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Affiliation(s)
- Junjie Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
| | - Bifeng Zhu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
| | - Xin Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
| | - Bo Lu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
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Liu Z, McKay AI, Zhao L, Forsyth CM, Jevtović V, Petković M, Frenking G, Vidović D. Carbodiphosphorane-Stabilized Parent Dioxophosphorane: A Valuable Synthetic HO 2P Source. J Am Chem Soc 2022; 144:7357-7365. [PMID: 35436104 DOI: 10.1021/jacs.2c00936] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Introducing a small phosphorus-based fragment into other molecular entities via, for example, phosphorylation/phosphonylation is an important process in synthetic chemistry. One of the approaches to achieve this is by trapping and subsequently releasing extremely reactive phosphorus-based molecules such as dioxophosphoranes. In this work, electron-rich hexaphenylcarbodiphosphorane (CDP) was used to stabilize the least thermodynamically favorable isomer of HO2P to yield monomeric CDP·PHO2. The title compound was observed to be a quite versatile phosphonylating agent; that is, it showed a great ability to transfer, for the first time, the HPO2 fragment to a number of substrates such as alcohols, amines, carboxylic acids, and water. Several phosphorous-based compounds that were generated using this synthetic approach were also isolated and characterized for the first time. According to the initial computational studies, the addition-elimination pathway was significantly more favorable than the corresponding elimination-addition route for "delivering" the HO2P unit in these reactions.
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Affiliation(s)
- Zhizhou Liu
- School of Chemistry, Faculty of Sciences, Monash University, Clayton 3800, Australia.,Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China
| | - Alasdair I McKay
- School of Chemistry, Faculty of Sciences, Monash University, Clayton 3800, Australia
| | - Lili Zhao
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Craig M Forsyth
- School of Chemistry, Faculty of Sciences, Monash University, Clayton 3800, Australia
| | - Violeta Jevtović
- Department of Chemistry, College of Science, University of Hail, Ha'il 81451, Kingdom of Saudi Arabia
| | - Milena Petković
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11 158, Serbia
| | - Gernot Frenking
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.,Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Dragoslav Vidović
- School of Chemistry, Faculty of Sciences, Monash University, Clayton 3800, Australia
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Zhu B, Jiang J, Lu B, Li X, Jiang X, Rauhut G, Zeng X. Phosphenic isocyanate (O2PNCO): Gas-phase generation, characterization, and photodecomposition reactions. Chem Commun (Camb) 2022; 58:10703-10706. [DOI: 10.1039/d2cc03178g] [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
Phosphenic isocyanate (O2PNCO), a novel phosphorus-containing small molecule has been generated by thermolysis of a dioxaphospholane-based precursor. The characterization of O2PNCO with IR and UV-vis spectroscopy in solid N2 and...
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Qian W, Lu B, Tan G, Rauhut G, Grützmacher H, Zeng X. Vibrational spectrum and photochemistry of phosphaketene HPCO. Phys Chem Chem Phys 2021; 23:19237-19243. [PMID: 34524290 DOI: 10.1039/d1cp02860j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The vibrational spectra of the simplest phosphaketene HPCO and its isotopologue DPCO in solid Ar-matrices at 12.0 K have been analyzed with the aid of the computations at the CCSD(T)-F12a/cc-pVTZ-F12 level using configuration-selective vibrational configuration interaction (VCI). In addition to the four IR fundamentals, four overtone and ten combination bands have been unambiguously identified. Furthermore, the photochemistry of HPCO in the matrix has been investigated for the first time. Upon UV-light irradiation (365 or 266 nm), CO-elimination occurs by forming the parent phosphinidene HP that can be trapped by ˙NO to yield the elusive phosphinimine-N-oxyl radical HPNO˙. In contrast, an excimer laser (193 nm) irradiation of HPCO causes additional decomposition to H˙ and ˙PCO with concomitant formation of the long-sought phosphaethyne HOCP.
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Affiliation(s)
- Weiyu Qian
- Department of Chemistry, Fudan University, 200433 Shanghai, China.
| | - Bo Lu
- Department of Chemistry, Fudan University, 200433 Shanghai, China.
| | - Gengwen Tan
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | | | - Xiaoqing Zeng
- Department of Chemistry, Fudan University, 200433 Shanghai, China.
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Hu D, Lu B, Song C, Zhu B, Wang L, Bernhardt E, Zeng X. Synthesis and characterization of phosphorous(III) diisocyanate and triisocyanate. Dalton Trans 2021; 50:3299-3307. [PMID: 33595037 DOI: 10.1039/d1dt00261a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two phosphorous(iii) isocyanates, ClP(NCO)2 and P(NCO)3 were isolated as neat substances and characterized with IR (gas-phase and Ne-matrix), Raman (solid), and 31P NMR spectroscopy. Their vibrational spectra were analyzed in terms of a single conformer with the aid of quantum chemical computations at the B3LYP/6-311+G(3df) level of theory. In line with the theoretically computed favorable syn-configuration of the NCO ligands with the sterically active lone-pair electrons on the central phosphorous atom (nP), low-temperature single-crystal X-ray diffraction (XRD) of solid ClP(NCO)2 reveals a Cs symmetric syn-configuration for both NCO ligands with weak CO (r = 2.9692(4) Å) van der Waals (vdW) interactions. In the binary isocyante P(NCO)3, all the three NCO ligands adopt similar syn-configuration with nP, leading to a propeller-shaped structure with slightly distorted C3v symmetry due to steric repulsion of the NCO ligands and the PO vdW interactions (r = 3.1901(1) Å) in the solid state.
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Affiliation(s)
- Dandan Hu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Bo Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Chao Song
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Bifeng Zhu
- Department of Chemistry, Fudan University, Shanghai, 200433, China.
| | - Lina Wang
- Department of Chemistry, Fudan University, Shanghai, 200433, China.
| | - Eduard Bernhardt
- FB C-Anorganische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, Wuppertal, 42119, Germany
| | - Xiaoqing Zeng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China and Department of Chemistry, Fudan University, Shanghai, 200433, China.
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