Hydroxypyridine/pyridone interconversions within ruthenium complexes and their application in the catalytic hydrogenation of CO2
Hydroxypyridine/pyridone interconversions within ruthenium complexes and their application in the catalytic hydrogenation of CO2
Reaction of a new ligand 6-DiPPon (6-diisopropylphosphino-2-pyridone) with 0.5 equiv of [RuCl2(p-cymene)]2 resulted in the formation of a mixture of [RuCl2(p-cymene)(κ1-P-6-DiPPon)]2 (1) and [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]Cl ([2]Cl) (where 6-DiPPin = 6-diisopropylphosphino-2-hydroxypyridine). The ratio between the two products can be controlled by the nature of the solvent. The similar reaction between 6-DiPPon and [RuCl2(p-cymene)]2 in the presence of AgOTf and Na[BArF24] (where BArF24 = [{3,5-(CF3)2C6H3}4B]−) resulted in the formation of the complexes [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]OTf, ([2]OTf) and [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]BArF24 ([2]BArF24), respectively. Reactions between complex [2]Cl, [2]OTf, or [2]BArF24 and a base (either DBU or NaOMe) resulted in the deprotonation of the hydroxyl functional group to form a novel neutral orange-colored dearomatized complex, 3. The identity of complex 3 was confirmed as [RuCl(p-cymene)(κ2-P,N-6-DiPPon*)], where 6-DiPPon* is the anionic species (6-diisopropylphosphino-2-oxo-pyridinide), which contains the deprotonated moiety. The new 6-DiPPon ligand and its corresponding air stable half-sandwich derivative ruthenium complexes 1, [2]OTf, [2]BArF24, and 3 were all isolated in good yields and fully characterized by spectroscopic and analytical methods. The interconversions between the neutral and anionic forms of the ligands 6-DiPPon, 6-DiPPin, and 6-DiPPon* offer the potential for novel secondary sphere interactions and proton shuttling reactivity. The consequences for this have been explored in the activation of H2 and the subsequent catalytic hydrogenations of CO2 into formate salts in the presence of a base.
6704-6710
Ayyappan, Ramaraj
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Das, Uttam Kumar
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Abdalghani, Issam
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Da Costa, Rosenildo C.
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Tizzard, Graham J.
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Coles, Simon J.
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Owen, Gareth R.
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1 May 2023
Ayyappan, Ramaraj
e95cd20f-d494-4d7b-bdc6-f7b31b38fb12
Das, Uttam Kumar
fa75fdb8-a66e-43ac-8da6-1886e5645d9d
Abdalghani, Issam
c721a886-934e-4eb5-ba55-6de2c23118d8
Da Costa, Rosenildo C.
ce76806a-0dba-4086-99c2-626e9b932c80
Tizzard, Graham J.
8474c0fa-40df-43a6-a662-7f3c4722dbf2
Coles, Simon J.
3116f58b-c30c-48cf-bdd5-397d1c1fecf8
Owen, Gareth R.
fd633ee9-dcaa-438c-9b3b-82e9d091a1c6
Ayyappan, Ramaraj, Das, Uttam Kumar, Abdalghani, Issam, Da Costa, Rosenildo C., Tizzard, Graham J., Coles, Simon J. and Owen, Gareth R.
(2023)
Hydroxypyridine/pyridone interconversions within ruthenium complexes and their application in the catalytic hydrogenation of CO2.
Inorganic Chemistry, 62 (17), .
(doi:10.1021/acs.inorgchem.3c00287).
Abstract
Reaction of a new ligand 6-DiPPon (6-diisopropylphosphino-2-pyridone) with 0.5 equiv of [RuCl2(p-cymene)]2 resulted in the formation of a mixture of [RuCl2(p-cymene)(κ1-P-6-DiPPon)]2 (1) and [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]Cl ([2]Cl) (where 6-DiPPin = 6-diisopropylphosphino-2-hydroxypyridine). The ratio between the two products can be controlled by the nature of the solvent. The similar reaction between 6-DiPPon and [RuCl2(p-cymene)]2 in the presence of AgOTf and Na[BArF24] (where BArF24 = [{3,5-(CF3)2C6H3}4B]−) resulted in the formation of the complexes [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]OTf, ([2]OTf) and [RuCl(p-cymene)(κ2-P,N-6-DiPPin)]BArF24 ([2]BArF24), respectively. Reactions between complex [2]Cl, [2]OTf, or [2]BArF24 and a base (either DBU or NaOMe) resulted in the deprotonation of the hydroxyl functional group to form a novel neutral orange-colored dearomatized complex, 3. The identity of complex 3 was confirmed as [RuCl(p-cymene)(κ2-P,N-6-DiPPon*)], where 6-DiPPon* is the anionic species (6-diisopropylphosphino-2-oxo-pyridinide), which contains the deprotonated moiety. The new 6-DiPPon ligand and its corresponding air stable half-sandwich derivative ruthenium complexes 1, [2]OTf, [2]BArF24, and 3 were all isolated in good yields and fully characterized by spectroscopic and analytical methods. The interconversions between the neutral and anionic forms of the ligands 6-DiPPon, 6-DiPPin, and 6-DiPPon* offer the potential for novel secondary sphere interactions and proton shuttling reactivity. The consequences for this have been explored in the activation of H2 and the subsequent catalytic hydrogenations of CO2 into formate salts in the presence of a base.
Text
Hydroxypyridine Pyridone Interconversions within Ruthenium Complexes and Their Application in the Catalytic Hydrogenation of CO2
- Accepted Manuscript
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e-pub ahead of print date: 14 April 2023
Published date: 1 May 2023
Additional Information:
Funding Information:
The authors thank the Welsh Government for funding this work. The project is funded by a Sêr Cymru II Capacity Builder Accelerator Award (80761-USW208). The Sêr Cymru II scheme is partially funded by the European Regional Development Fund through the Welsh Government. The authors are also very grateful to the analytical services of the University of Cardiff for mass spectrometry data collection and elemental analysis service at London Metropolitan University.
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Local EPrints ID: 486664
URI: http://eprints.soton.ac.uk/id/eprint/486664
ISSN: 0020-1669
PURE UUID: f0593da0-0446-46d8-aa5c-808030150a25
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Date deposited: 31 Jan 2024 17:32
Last modified: 14 Apr 2024 04:01
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Author:
Ramaraj Ayyappan
Author:
Uttam Kumar Das
Author:
Issam Abdalghani
Author:
Rosenildo C. Da Costa
Author:
Gareth R. Owen
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