Bimetallic complexes that merge metallocene and pincer-metal building blocks: synthesis, stereochemistry and catalytic reactivity
This perspective is to illustrate the synthesis and applications of bimetallic complexes by merging a metallocene and a (cyclopentadienyl/aryl) pincer metal complex. Four possible ways to merge metallocene and pincer-metal motifs are reported and representative examples are discussed in more detail....
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| Published in | Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 5; pp. 1724 - 1744 |
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| Main Authors | , , , |
| Format | Journal Article |
| Language | English |
| Published |
England
Royal Society of Chemistry
01.02.2022
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| Subjects | |
| Online Access | Get full text |
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| Summary: | This perspective is to illustrate the synthesis and applications of bimetallic complexes by merging a metallocene and a (cyclopentadienyl/aryl) pincer metal complex. Four possible ways to merge metallocene and pincer-metal motifs are reported and representative examples are discussed in more detail. These bimetallic complexes have been employed in some important catalytic reactions such as cross-coupling, transfer hydrogenation or synthesis of ammonia. The metallocene fragment may tune the electronic properties of the pincer ligand, due to its redox reversible properties. Also, the presence of two metals in a single complex allows their electronic communication, which proved beneficial for,
e.g.
, the catalytic activity of some species. The presence of the metallocene fragment provides an excellent opportunity to develop chiral catalysts, because the metallocene merger generally renders the two faces of the pincer-metal catalytic site diastereotopic. Besides, an extra chiral functionality may be added to the bimetallic species by using pincer motifs that are planar chiral,
e.g.
by using the different substituents of pincer ligand "arms" or non-symmetrical arene groupings. Post-functionalization of pre-formed pincer-metal complexes,
via
η
6
-coordination with an areneophile such as [CpRu]
+
and [Cp*Ru]
+
presents a striking strategy to obtain diastereomeric metallocene-pincer type derivatives, that actually involve half-sandwich metallocenes. This approach offers the possibility to create diastereomerically pure derivatives by using the chiral TRISPHAT anion. The authors hope that this report of the synthetic, physico-chemical properties and remarkable catalytic activities of metallocene-based pincer-metal complexes will inspire other researchers to continue exploring this realm.
This perspective paper presents the synthesis and applications of bimetallic complexes merging (four possible ways) a metallocene and a (cyclopentadienyl/aryl)pincer metal complex, with representative examples of the four ways discussed in detail. |
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| Bibliography: | Dr Juan M. Germán obtained his PhD from the Universidad Nacional Autónoma de México (UNAM) in 2009. After a postdoctoral fellowship at Universidad Autónoma del Estado de Morelos he joined to the Universidad Autónoma Metropolitana as visitant Professor from 2011-2014. From 2014-2020 he was appointed as an Associate Researcher at the UNAM. In 2021 he was promoted as a tenured Researcher. Prof. Dr David Morales-Morales earned his BSc and MSc degrees from the Chemistry School of the Universidad Nacional Autónoma de México (UNAM) and his PhD degree from the University of Essex under the supervision of Prof. Dr Jonathan R. Dilworth on organometallic chemistry and catalysis. After a postdoctoral stay in Prof. Dr Craig M. Jensen's group at the University of Hawaii at Manoa, he took his current position at the Instituto de Química-UNAM. His research interests lay in the realm of coordination and organometallic chemistry and their applications, with special emphasis on the chemistry of pincer compounds, NHC complexes, the synthesis of phosphorus- and sulfur-based compounds and their use as ligands with transition metals, metal-mediated organic synthesis, mechanistic studies, catalysis, and medicinal chemistry. He has been part of the advisory board of the International Symposium on Homogeneous Catalysis (ISHC) and of the journals ChemCatChem (Wiley), SN Applied Sciences (Springer), Current Organic Chemistry and Clinical Cancer Drugs (Bentham) and has served as the editor of the books The Chemistry of Pincer Compounds (co-edited with C. M. Jensen, Elsevier, 2007) and Pincer Compounds. Chemistry and Applications (Elsevier, 2018) and currently for the journal Current Organic Synthesis (Bentham). Most recently he has been appointed as Associate Editor of the Journal Applied Organometallic Chemsitry edited by John Wiley & Sons Ltd. See also Prof. Dr Gerard van Koten is Honorary Distinguished University Professor of Utrecht University. He is member of the Royal Netherlands Academy of Arts and Sciences (KNAW). He is well known for his ground breaking fundamental and applied research on Pincer metal complexes, a field of research that his research group started during the early 1970ies. Preparation and use of the first examples of homogeneous metallo-dendrimer catalysts demonstrate his interest for supramolecular systems with organometallic, catalytically active, functionalities. More recent developments involved the introduction of Pincer metal units, either functioning as sensor or as catalyst, in polypeptide chains, in carbohydrates and in the active site of serine hydrolases. See also Twitter @dmorales_group; @iquimicaunam. https://iquimica.unam.mx/david-morales-morales http://www.gerardvankoten.nl Dr Hugo Valdés received his bachelor's in Chemistry from the National Autonomous University of Mexico (UNAM) in 2011 and completed his PhD degree with honors at University Jaume I in 2015, under the supervision of Prof. Eduardo Peris and Dr Macarena Poyatos. Then, he moved to the group of Prof. David Morales-Morales, at the Institute of Chemistry, UNAM for postdoctoral studies. Thereafter he joined the group of Prof. Xavi Ribas at the QBIS-CAT group in the University of Girona as post-doc. His research interest involves the development of catalysts for C-C and C-heteroatom cross-coupling reactions through C-H activation. He is also interested in pincer and N-heterocyclic carbene chemistry. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-3 content type line 23 ObjectType-Review-1 |
| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/d1dt03870b |