Highly Recyclable, Bona Fide Heterogeneous Catalysis by Dangling Metal-sulfur Functions within Robust Porous Solids

Project: Research

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Researcher(s)

Description

“Too many cooks spoil the soup” captures the issue we aim to address herein concerningthe notoriously poisonous effects thiol molecules impose on many transition metalcatalysts. Such poisoning primarily arises from the strong and intractable thiol-metalinteractions that effectively entrap the metal center and seal off the coordination sphereand suppress the bonding lability that is crucial for the catalytic process. Notice thatsuch entrapment most readily forms in the setting of a solution environment where thethiol groups can freely approach the metal center to fully cut it off from the catalyticcycle.By contrast, such poisoning from the thiol donors can be eliminated in the setting of arigid framework, where the thiol groups are confined to be too far apart to fully bondaround the Pd center—the sulfur atoms therefore would not block off the catalytic stepsas in the solution case. On the other hand, the use of such dangling, isolated thiol groupsto anchor Pd atoms serves to turn the intractable Pd-S bond on its head, as the verystrength of the Pd-S bond would prevent the leaching of Pd species from the hostframework, and to create more stable and recyclable solid-state catalysts.Based on this dangling effect recently discovered in our laboratory, we here propose tofurther explore thiol groups not only as robust anchors for catalytically active metalcenters within solid state framework, but also as a potentially effective ligand system foruncovering novel reactivities. Specifically, we propose novel molecules for constructingthe host networks, so as to provide the medium in which to improve the catalytic activity.For this we propose to systematically modulate the electronic conditions around as wellas the spacing among the thiol groups. We also propose to implant the thiol donors in achiral environment so as to provide for enantioselective transformations of greatrelevance to pharmaceutical industries.

Detail(s)

Project number9042246
Grant typeGRF
StatusFinished
Effective start/end date1/08/1530/01/20

    Research areas

  • metal-organic frameworks,heterogeneous catalysis,porous materials,coordination chemistry,