Title: Hydrogenolysis of Dinuclear PCN ^R Ligated Pd ^II μ‐Hydroxides and Their Mononuclear Pd ^II Hydroxide Analogues

Abstract

Abstract The hydrogenolysis of mono‐ and dinuclear Pd ^II hydroxides was investigated both experimentally and computationally. It was found that the dinuclear μ‐hydroxide complexes {[(PCN ^R )Pd] ₂ (μ‐OH)}(OTf) (PCN ^H =1‐[3‐[(di‐ tert ‐butylphosphino)methyl]phenyl]‐1 H ‐pyrazole; PCN ^Me =1‐[3‐[(di‐ tert ‐butylphosphino)methyl]phenyl]‐5‐methyl‐1 H ‐pyrazole) react with H ₂ to form the analogous dinuclear hydride species {[(PCN ^R )Pd] ₂ (μ‐H)}(OTf). The dinuclear μ‐hydride complexes were fully characterized, and are rare examples of structurally characterized unsupported singly bridged μ‐H Pd ^II dimers. The {[(PCN ^Me )Pd] ₂ (μ‐OH)}(OTf) hydrogenolysis mechanism was investigated through experiments and computations. The hydrogenolysis of the mononuclear complex (PCN ^H )Pd‐OH resulted in a mixed ligand dinuclear species [(PCN ^H )Pd](μ‐H)[(PCC)Pd] (PCC=a dianionic version of PCN ^H bound through phosphorus P, aryl C, and pyrazole C atoms) generated from initial ligand “rollover” C−H activation. Further exposure to H ₂ yields the bisphosphine Pd ⁰ complex Pd[(H)PCN ^H ] ₂ . When the ligand was protected at the pyrazole 5‐position in the (PCN ^Me )Pd−OH complex, no hydride formed under the same conditions; the reaction proceeded directly to the bisphosphine Pd ⁰ complex Pd[(H)PCN ^Me ] ₂ . Reaction mechanisms for the hydrogenolysis of the monomeric and dimeric hydroxidesmore » are proposed.« less

Authors:

Bailey, Wilson D.  ^[1];

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Phearman, Alexander S.  ^[2];

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Luconi, Lapo  ^[3];

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Rossin, Andrea  ^[3];

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Yakhvarov, Dmitry G.  ^[4];

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D'Accolti, Lucia ^[5]; Flowers, Sarah E. ^[1]; Kaminsky, Werner  ^[1];

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Kemp, Richard A. ^[6]; Giambastiani, Giuliano  ^[7];

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Goldberg, Karen I. ^[8]

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+ Show Author Affiliations

1. Department of Chemistry University of Washington Box 351700 Seattle Washington 98195-1700 USA
2. Department of Chemistry University of Pennsylvania Philadelphia PA 19104 USA
3. Institute of Chemistry of Organometallic Compounds, ICCOM-CNR and Consorzio INSTM Via Madonna del Piano 10-50019 Sesto Fiorentino Florence Italy
4. Kazan Federal University 420008 Kazan Russian Federation, Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS 420008 Kazan Russian Federation
5. Università di Bari “A. Moro” Via Orabona 4 70126 Bari Italy
6. Department of Chemistry and Chemical Biology University of New Mexico Albuquerque New Mexico 87131 USA, Advanced Materials Laboratory Sandia National Laboratories Albuquerque New Mexico 87106 USA
7. Institute of Chemistry of Organometallic Compounds, ICCOM-CNR and Consorzio INSTM Via Madonna del Piano 10-50019 Sesto Fiorentino Florence Italy, Kazan Federal University 420008 Kazan Russian Federation, Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES) UMR 7515 CNRS–University of Strasbourg (UdS) 25, rue Becquerel 67087 Strasbourg Cedex 02 France
8. Department of Chemistry University of Washington Box 351700 Seattle Washington 98195-1700 USA, Department of Chemistry University of Pennsylvania Philadelphia PA 19104 USA

Publication Date:

2019-07-03

Sponsoring Org.:

USDOE

OSTI Identifier:

1530896

Grant/Contract Number:  

SC0018057 and DEFG02-06ER15765

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Chemistry - A European Journal

Additional Journal Information:

Journal Name: Chemistry - A European Journal Journal Volume: 25 Journal Issue: 42; Journal ID: ISSN 0947-6539

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

Germany

Language:

English