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Aldajani AMO, Ma HZ, Yang Y, Canty AJ, O'Hair RAJ. The Magnesium Dication and Water Synergistically Promote the Protonolysis of Two of the B-C Bonds in the Tetraphenylborate Anion. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:636-641. [PMID: 38408905 DOI: 10.1021/jasms.4c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Analytes are sampled from both solution phase and gas-phase environments during the ESI process, and thus, the mass spectrum that is measured can reflect both solution and gas-phase conditions. In the gas-phase regime, ion-molecule reactions can influence the types of ions that are observed. Herein, the synergistic effects of a Lewis acid (Mg2+) and background water are shown to lead to protonolysis of two of the B-C bonds of the tetraphenylborate ion in the gas phase, giving rise to different ions at different reaction times in ESI-MS/MS experiments in a linear ion trap mass spectrometer. At short reaction times (1 ms), the expected adduct [Mg(BPh4)]+ is observed. At 10 ms, [(HO)Mg(BPh3)]+ and [(HO)2Mg(BPh2)]+ are observed. At 100 ms, the water adducts [(HO)2Mg(BPh2)(H2O)]+ and [(HO)2Mg(BPh2)(H2O)2]+ appear, and these become the dominant ions at longer reaction times. DFT calculations provide a plausible explanation as to why only [(HO)Mg(BPh3)]+ and [(HO)2Mg(BPh2)]+ but not [(HO)3Mg(BPh)]+ are observed.
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Affiliation(s)
- Asma M O Aldajani
- Department of Chemistry, College of Science, University of Bisha, P.O. Box 551, Bisha 61922, Saudi Arabia
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Howard Z Ma
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yang Yang
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Allan J Canty
- School of Physical Sciences - Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
| | - Richard A J O'Hair
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
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Bathie F, Stewart AWE, Canty AJ, O'Hair RAJ. Dissecting transmetalation reactions at the molecular level: C-B versus F-B bond activation in phenyltrifluoroborate silver complexes. Dalton Trans 2021; 50:1496-1506. [PMID: 33439189 DOI: 10.1039/d0dt03309j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The gas-phase unimolecular reactions of the silver(i) complex [Ag(PhBF3)2]-, formed via electrospray ionisation mass spectrometry of solutions containing the phenyltrifluoroborate salt and AgNO3, are examined. Upon collision induced dissociation (CID) three major reaction channels were observed for [Ag(PhBF3)2]-: Ph- group transfer via a transmetalation reaction to yield [PhAg(PhBF3)]-; F- transfer to produce [FAg(PhBF3)]-; and release of PhBF3-. The anionic silver product complexes of these reactions, [LAg(PhBF3)]- (where L = Ph and F), were then mass-selected and subjected to a further stage of CID. [PhAg(PhBF3)]- undergoes a Ph- group transfer via transmetalation to yield [Ph2Ag]- with loss of BF3. [FAg(PhBF3)]- solely fragments via loss of BF4-, a reaction that involves Ph- group transfer from B to Ag in conjunction with F- transfer from Ag to B. Density functional theory (DFT) calculations on the various competing pathways reveal that: (i) the overall endothermicities govern the experimentally observed product ion abundances; (ii) the Ph- group and F- transfer reactions proceed via late transition states; and (iii) formation of BF4- from [FAg(PhBF3)]- is a multistep reaction in which Ph- group transfer from B to Ag proceeds first to produce a [FAgPh(BF3)]- complex in which the BF3 moiety is initially weakly bound to the ipso-carbon of the phenyl group and then migrates across the linear [FAgPh]- moiety from C to Ag to F yielding [PhAg(BF4)]-, which can then dissociate via loss of PhAg.
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Affiliation(s)
- Fiona Bathie
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria 3010, Australia. and School of Natural Sciences - Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
| | - Adam W E Stewart
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria 3010, Australia. and School of Natural Sciences - Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
| | - Allan J Canty
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria 3010, Australia. and School of Natural Sciences - Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
| | - Richard A J O'Hair
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria 3010, Australia. and School of Natural Sciences - Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
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Cheng GJ, Zhong XM, Wu YD, Zhang X. Mechanistic understanding of catalysis by combining mass spectrometry and computation. Chem Commun (Camb) 2019; 55:12749-12764. [PMID: 31560354 DOI: 10.1039/c9cc05458h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The combination of mass spectrometry and computational chemistry has been proven to be powerful for exploring reaction mechanisms. The former provides information of reaction intermediates, while the latter gives detailed reaction energy profiles.
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Affiliation(s)
- Gui-Juan Cheng
- Lab of Computational Chemistry and Drug Design
- State Key Laboratory of Chemical Oncogenomics
- Peking University Shenzhen Graduate School
- Shenzhen
- China
| | - Xiu-Mei Zhong
- Lab of Computational Chemistry and Drug Design
- State Key Laboratory of Chemical Oncogenomics
- Peking University Shenzhen Graduate School
- Shenzhen
- China
| | - Yun-Dong Wu
- Lab of Computational Chemistry and Drug Design
- State Key Laboratory of Chemical Oncogenomics
- Peking University Shenzhen Graduate School
- Shenzhen
- China
| | - Xinhao Zhang
- Lab of Computational Chemistry and Drug Design
- State Key Laboratory of Chemical Oncogenomics
- Peking University Shenzhen Graduate School
- Shenzhen
- China
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