Contrasting photochemical and thermal reactivity of Ru(CO)2(PPh3)(dppe) towards hydrogen rationalised by parahydrogen NMR and DFT studies

Damir Blazina, John P. Dunne, Stuart Aiken, Simon B. Duckett, Charlotte Elkington, John E. McGrady, Rinaldo Poli, Sue J. Walton, M. Sabieh Anwar, Jonathan A. Jones, Hilary A. Carteret

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The synthesis, characterisation and thermal and photochemical reactivity of Ru(CO)2(PPh3)(dppe) 1 towards hydrogen are described. Compound 1 proved to exist in both fac (major) and mer forms in solution. Under thermal conditions, PPh3 is lost from 1 in the major reaction pathway and the known complex Ru(CO)2(dppe)(H)2 2 is formed. Photochemically, CO loss is the dominant process, leading to the alternative dihydride Ru(CO)(PPh3)(dppe)(H)2 3. The major isomer of 3, viz. 3a, contains hydride ligands that are trans to CO and trans to one of the phosphorus atoms of the dppe ligand but a second isomer, 3b, where both hydride ligands are trans to distinct phosphines, is also formed. On the NMR timescale, no interconversion of 3a and 3b was observed, although hydride site interchange is evident with activation parameters of ΔH = 95 ± 6 kJ mol-1 and ΔS = 26 ± 17 J K-1 mol-1. Density functional theory confirms that the observed species are the most stable isomeric forms, and suggests that hydride exchange occurs via a transition state featuring an η2- coordinated H2 unit.

LanguageEnglish
Pages2072-2080
Number of pages9
JournalDalton Transactions
Volume2006
Issue number17
DOIs
Publication statusPublished - 2 Feb 2006
Externally publishedYes

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Carbon Monoxide
Discrete Fourier transforms
Hydrogen
Hydrides
Nuclear magnetic resonance
Ligands
Isomers
Phosphines
Interchanges
Phosphorus
Density functional theory
Chemical activation
Hot Temperature
Atoms

Cite this

Blazina, Damir ; Dunne, John P. ; Aiken, Stuart ; Duckett, Simon B. ; Elkington, Charlotte ; McGrady, John E. ; Poli, Rinaldo ; Walton, Sue J. ; Anwar, M. Sabieh ; Jones, Jonathan A. ; Carteret, Hilary A. / Contrasting photochemical and thermal reactivity of Ru(CO)2(PPh3)(dppe) towards hydrogen rationalised by parahydrogen NMR and DFT studies. In: Dalton Transactions. 2006 ; Vol. 2006, No. 17. pp. 2072-2080.
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abstract = "The synthesis, characterisation and thermal and photochemical reactivity of Ru(CO)2(PPh3)(dppe) 1 towards hydrogen are described. Compound 1 proved to exist in both fac (major) and mer forms in solution. Under thermal conditions, PPh3 is lost from 1 in the major reaction pathway and the known complex Ru(CO)2(dppe)(H)2 2 is formed. Photochemically, CO loss is the dominant process, leading to the alternative dihydride Ru(CO)(PPh3)(dppe)(H)2 3. The major isomer of 3, viz. 3a, contains hydride ligands that are trans to CO and trans to one of the phosphorus atoms of the dppe ligand but a second isomer, 3b, where both hydride ligands are trans to distinct phosphines, is also formed. On the NMR timescale, no interconversion of 3a and 3b was observed, although hydride site interchange is evident with activation parameters of ΔH‡ = 95 ± 6 kJ mol-1 and ΔS‡ = 26 ± 17 J K-1 mol-1. Density functional theory confirms that the observed species are the most stable isomeric forms, and suggests that hydride exchange occurs via a transition state featuring an η2- coordinated H2 unit.",
author = "Damir Blazina and Dunne, {John P.} and Stuart Aiken and Duckett, {Simon B.} and Charlotte Elkington and McGrady, {John E.} and Rinaldo Poli and Walton, {Sue J.} and Anwar, {M. Sabieh} and Jones, {Jonathan A.} and Carteret, {Hilary A.}",
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Blazina, D, Dunne, JP, Aiken, S, Duckett, SB, Elkington, C, McGrady, JE, Poli, R, Walton, SJ, Anwar, MS, Jones, JA & Carteret, HA 2006, 'Contrasting photochemical and thermal reactivity of Ru(CO)2(PPh3)(dppe) towards hydrogen rationalised by parahydrogen NMR and DFT studies', Dalton Transactions, vol. 2006, no. 17, pp. 2072-2080. https://doi.org/10.1039/b510616h

Contrasting photochemical and thermal reactivity of Ru(CO)2(PPh3)(dppe) towards hydrogen rationalised by parahydrogen NMR and DFT studies. / Blazina, Damir; Dunne, John P.; Aiken, Stuart; Duckett, Simon B.; Elkington, Charlotte; McGrady, John E.; Poli, Rinaldo; Walton, Sue J.; Anwar, M. Sabieh; Jones, Jonathan A.; Carteret, Hilary A.

In: Dalton Transactions, Vol. 2006, No. 17, 02.02.2006, p. 2072-2080.

Research output: Contribution to journalArticle

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T1 - Contrasting photochemical and thermal reactivity of Ru(CO)2(PPh3)(dppe) towards hydrogen rationalised by parahydrogen NMR and DFT studies

AU - Blazina, Damir

AU - Dunne, John P.

AU - Aiken, Stuart

AU - Duckett, Simon B.

AU - Elkington, Charlotte

AU - McGrady, John E.

AU - Poli, Rinaldo

AU - Walton, Sue J.

AU - Anwar, M. Sabieh

AU - Jones, Jonathan A.

AU - Carteret, Hilary A.

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N2 - The synthesis, characterisation and thermal and photochemical reactivity of Ru(CO)2(PPh3)(dppe) 1 towards hydrogen are described. Compound 1 proved to exist in both fac (major) and mer forms in solution. Under thermal conditions, PPh3 is lost from 1 in the major reaction pathway and the known complex Ru(CO)2(dppe)(H)2 2 is formed. Photochemically, CO loss is the dominant process, leading to the alternative dihydride Ru(CO)(PPh3)(dppe)(H)2 3. The major isomer of 3, viz. 3a, contains hydride ligands that are trans to CO and trans to one of the phosphorus atoms of the dppe ligand but a second isomer, 3b, where both hydride ligands are trans to distinct phosphines, is also formed. On the NMR timescale, no interconversion of 3a and 3b was observed, although hydride site interchange is evident with activation parameters of ΔH‡ = 95 ± 6 kJ mol-1 and ΔS‡ = 26 ± 17 J K-1 mol-1. Density functional theory confirms that the observed species are the most stable isomeric forms, and suggests that hydride exchange occurs via a transition state featuring an η2- coordinated H2 unit.

AB - The synthesis, characterisation and thermal and photochemical reactivity of Ru(CO)2(PPh3)(dppe) 1 towards hydrogen are described. Compound 1 proved to exist in both fac (major) and mer forms in solution. Under thermal conditions, PPh3 is lost from 1 in the major reaction pathway and the known complex Ru(CO)2(dppe)(H)2 2 is formed. Photochemically, CO loss is the dominant process, leading to the alternative dihydride Ru(CO)(PPh3)(dppe)(H)2 3. The major isomer of 3, viz. 3a, contains hydride ligands that are trans to CO and trans to one of the phosphorus atoms of the dppe ligand but a second isomer, 3b, where both hydride ligands are trans to distinct phosphines, is also formed. On the NMR timescale, no interconversion of 3a and 3b was observed, although hydride site interchange is evident with activation parameters of ΔH‡ = 95 ± 6 kJ mol-1 and ΔS‡ = 26 ± 17 J K-1 mol-1. Density functional theory confirms that the observed species are the most stable isomeric forms, and suggests that hydride exchange occurs via a transition state featuring an η2- coordinated H2 unit.

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