Bis-(thiosemicarbazonato) Zn(ii) complexes as building blocks for construction of supramolecular catalysts

Bocokić, Vladica; Lutz, Martin; Spek, Anthony L.; Reek, Joost N. H.

doi:10.1039/c2dt12096h

Cited by 15 publications

(8 citation statements)

References 75 publications

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“…The association constants ( K 1.1 ) of A with meta ‐ and para ‐substituted 2 , 3 , 5 and 6 halopyridine derivatives determined by UV/Vis titrations using toluene as solvent were found to be 1.0×10 4 , 9.0×10 3 , 1.9×10 4 , and 1.9×10 4 m −1 , respectively (see the Supporting Information) . Although UV/Vis changes during titration were small, they were sufficient to produce well‐behaved titration curves, which were used to calculate the association constants K 1.1 (see the Supporting Information) ,. The binding constants K 1.1 determined for 2 ⋅ A and 5 ⋅ A are only slightly higher compared to previous reports in which the titrations were performed using a different solvent; that is, dichloromethane .…”

Section: Resultsmentioning

confidence: 77%

Palladium‐Catalysed Cross‐Coupling Reactions Controlled by Noncovalent Zn⋅⋅⋅N Interactions

Kadri

Hou

Dorcet

et al. 2017

Chemistry A European J

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Non-covalent interactions between halopyridine substrates and catalytically inert building blocks, namely zinc(II)-porphyrins and zinc(II)-salphens, influence the catalytic outcome of Suzuki-Miyaura and Mizoroki-Heck palladium-catalysed cross-coupling reactions. The weak Zn⋅⋅⋅N interactions between halopyridine substrates and zinc(II)-containing porphyrins and salphens, respectively, were studied by a combination of H NMR spectroscopy, UV/Vis studies, Job-Plot analysis and, in some cases, X-ray diffraction studies. Additionally, the former studies revealed unique supramolecular polymeric and dimeric rearrangements in the solid state featuring weak Br⋅⋅⋅N (halogen bonding), C-H⋅⋅⋅π, Br⋅⋅⋅π and π⋅⋅⋅π interactions. The reactivity of halopyridine substrates in homogeneous palladium-catalysed cross-coupling reactions was found to correlate with the binding strength between the zinc(II)-containing scaffolds and the corresponding halopyridine. Such observation is explained by the unfavourable formation of inactive over-coordinated halopyridine⋅⋅⋅palladium species. The presented approach is particularly appealing for those cases in which substrates and/or products deactivate (or partially poison) a transition-metal catalyst.

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Section: Resultsmentioning

confidence: 77%

Palladium‐Catalysed Cross‐Coupling Reactions Controlled by Noncovalent Zn⋅⋅⋅N Interactions

Kadri

Hou

Dorcet

et al. 2017

Chemistry A European J

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“…57 The pyridylphosphine ligands employed in this seminal study differ by the nature (para-pyridyl or meta- led to an even more selective catalyst (l:b ratio = 0.4). 256 The higher activity can be explained by the fact than monoligated rhodium catalysts are more active than the respective bis-ligated catalysts, but the 262 platforms gave slightly less efficient catalysts than the ones based on porphyrin scaffolds. First attempts to get asymmetric version of these catalysts were not successful 50 either using a chiral salen building block or chiral pyridylphosphite ligands.…”

Section: Ligandligand Additive Interaction 41 Modification Of Monodementioning

confidence: 99%

“…261 Various zinc-porphyrin platforms, as well as pyridylphosphines and pyridylphosphites, were evaluated demonstrating the wide range of catalysts that can be built by the ligand-template strategy. With ligand 80, assemblies with zinc-salphen 260 or zinc-bis(thiosemicarbazonato) 262 platforms gave slightly less efficient catalysts than the ones based on porphyrin scaffolds. First attempts to get an asymmetric version of these catalysts were not successful either using a chiral salen building block or using chiral pyridylphosphite ligands.…”

Section: Modification Of Monodentate Ligandsmentioning

confidence: 99%

Supramolecular catalysis. Part 1: non-covalent interactions as a tool for building and modifying homogeneous catalysts

et al. 2014

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Supramolecular catalysis is a rapidly expanding discipline which has benefited from the development of both homogeneous catalysis and supramolecular chemistry. The properties of classical metal and organic catalysts can now be carefully tailored by means of several suitable approaches and the choice of reversible interactions such as hydrogen bond, metal-ligand, electrostatic and hydrophobic interactions. The first part of these two subsequent reviews will be dedicated to catalytic systems for which non-covalent interactions between the partners of the reaction have been designed although mimicking enzyme properties has not been intended. Ligand, metal, organocatalyst, substrate, additive, and metal counterion are reaction partners that can be held together by non-covalent interactions. The resulting catalysts possess unique properties compared to analogues lacking the assembling properties. Depending on the nature of the reaction partners involved in the interactions, distinct applications have been accomplished, mainly (i) the building of bidentate ligand libraries (intra ligand-ligand), (ii) the building of di- or oligonuclear complexes (inter ligand-ligand), (iii) the alteration of the coordination spheres of a metal catalyst (ligand-ligand additive), and (iv) the control of the substrate reactivity (catalyst-substrate). More complex systems that involve the cooperative action of three reaction partners have also been disclosed. In this review, special attention will be given to supramolecular catalysts for which the observed catalytic activity and/or selectivity have been imputed to non-covalent interaction between the reaction partners. Additional features of these catalysts are the easy modulation of the catalytic performance by modifying one of their building blocks and the development of new catalytic pathways/reactions not achievable with classical covalent catalysts.

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“…The generality of the ligand-template approach is demonstrated by the application of a variety of building blocks. The ligand-template can be combined with zinc salphens ( 75a–75d ) and zinc bis(thiosemicarbazonato) complexes ( 76 ) (Figure ), which both display a supramolecular binding with pyridine that is stronger than that of zinc porphyrins. As these building blocks are significantly smaller, the exclusive formation of encapsulated catalysts cannot be enforced.…”

Section: Hydroformylation Catalysis In Confined Spacesmentioning

confidence: 99%

Supramolecular Approaches To Control Activity and Selectivity in Hydroformylation Catalysis

et al. 2018

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The hydroformylation reaction is one of the most intensively explored reactions in the field of homogeneous transition metal catalysis, and many industrial applications are known. However, this atom economical reaction has not been used to its full potential, as many selectivity issues have not been solved. Traditionally, the selectivity is controlled by the ligand that is coordinated to the active metal center. Recently, supramolecular strategies have been demonstrated to provide powerful complementary tools to control activity and selectivity in hydroformylation reactions. In this review, we will highlight these supramolecular strategies. We have organized this paper in sections in which we describe the use of supramolecular bidentate ligands, substrate preorganization by interactions between the substrate and functional groups of the ligands, and hydroformylation catalysis in molecular cages.

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Bis-(thiosemicarbazonato) Zn(ii) complexes as building blocks for construction of supramolecular catalysts

Cited by 15 publications

References 75 publications

Palladium‐Catalysed Cross‐Coupling Reactions Controlled by Noncovalent Zn⋅⋅⋅N Interactions

Palladium‐Catalysed Cross‐Coupling Reactions Controlled by Noncovalent Zn⋅⋅⋅N Interactions

Supramolecular catalysis. Part 1: non-covalent interactions as a tool for building and modifying homogeneous catalysts

Supramolecular Approaches To Control Activity and Selectivity in Hydroformylation Catalysis

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