Title: Deciphering a Reaction Network for the Switchable Production of Tetrahydroquinoline or Quinoline with MOF-Supported Pd Tandem Catalysts

Abstract

A mechanistic study of heterogeneous tandem catalytic systems is crucial for understanding and improving catalyst activity and selectivity but remains challenging. Here, we demonstrate that a thorough mechanistic study of a multistep reaction can guide us to the controllable selective synthesis of phenyltetrahydroquinoline or phenylquinoline with easily accessible precursors. The one-pot production can be achieved, catalyzed by a well-defined, bifunctional metal–organic framework-supported Pd nanoparticles, with only water as the side product. Our mechanistic study identifies six transient intermediates and ten transformation steps from the operando magic angle spinning nuclear magnetic resonance study under 27.6 bar H₂. In particular, reactive intermediate 2-phenyl-3,4-dihydroquinoline cannot be observed with conventional chromatographic techniques but is found to reach the maximal concentration of 0.11 mol L^–1 under the operando condition. The most probable reaction network is further deduced based on the kinetic information of reaction species, obtained from both operando and ex situ reaction studies. This deep understanding of the complex reaction network enables the kinetic control of the conversions of key intermediate, 2-phenyl-3,4-dihydroquinoline, with the addition of a homogeneous co-catalyst, allowing the selective production of tetrahydroquinoline or quinoline on demand. Finally, the demonstrated methods in this work open up new avenues toward efficient modulation ofmore » reactions with a complex network to achieve desired selectivities.« less

Authors:

Qi, Long  ^[1];

• Search DOE PAGES for author "Qi, Long"
• Search DOE PAGES for ORCID "0000-0002-1213-2946"

Chen, Jingwen ^[2]; Zhang, Biying ^[1]; Nie, Renfeng  ^[3];

• Search DOE PAGES for author "Nie, Renfeng"
• Search DOE PAGES for ORCID "0000-0002-4311-3465"

Qi, Zhiyuan ^[3]; Kobayashi, Takeshi  ^[1];

• Search DOE PAGES for author "Kobayashi, Takeshi"
• Search DOE PAGES for ORCID "0000-0002-6366-0925"

Bao, Zongbi  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-4327-3028"

Yang, Qiwei  ^[4];

• Search DOE PAGES for author "Yang, Qiwei"
• Search DOE PAGES for ORCID "0000-0002-6469-5126"

Ren, Qilong ^[4]; Sun, Qi ^[4]; Zhang, Zhiguo  ^[4];

• Search DOE PAGES for author "Zhang, Zhiguo"
• Search DOE PAGES for ORCID "0000-0003-1681-4853"

Huang, Wenyu  ^[1]

• Search DOE PAGES for author "Huang, Wenyu"
• Search DOE PAGES for ORCID "0000-0003-2327-7259"

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+ Show Author Affiliations

1. Ames Lab., and Iowa State Univ., Ames, IA (United States)
2. Zhejiang Univ., Hangzhou (China); Ames Lab., and Iowa State Univ., Ames, IA (United States)
3. Iowa State Univ., Ames, IA (United States)
4. Zhejiang Univ., Hangzhou (China)

Publication Date:

Tue Mar 17 00:00:00 EDT 2020

Research Org.:

Ames Lab., Ames, IA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences, & Biosciences Division; National Key Research and Development Program of China; National Natural Science Foundation of China (NSFC); National Science Foundation (NSF)

OSTI Identifier:

1616739

Report Number(s):

IS-J-10,207
Journal ID: ISSN 2155-5435

Grant/Contract Number:  

AC02-07CH11358; 2016YFA0202900; 21878266; 21722609; CHE-1566445

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 10; Journal Issue: 10; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; tandem catalysis; reaction network; metal-organic frameworks; metal nanoparticles; operando spectroscopy; mechanistic study