Catalysis
On–off allosteric control of a bifunctional catalyst
Open access · cc by · source: Europe PMC
A Pt(II) weak-link tweezer and a sulfonate regulator switch a squaramide–amine co-catalyst fully on or off in situ.
How this study connects
Role on claims
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A Pt(II) weak-link tweezer and a sulfonate regulator switch a squaramide–amine co-catalyst fully on or off in situ.
Evidence for the claim as stated.
Mechanism papers use NMR as one reporter among several. ¹³C NMR plus crystallography showed how crotonaldehyde inactivates DERA via K167 and C47; isotope-resolved NMR with ThT and cryo-TEM showed Aβ40 and Aβ42 forming separate homomolecular fibrils after mixed nucleation; ¹H NMR Ka ≈ 75 558 M⁻¹ for DMA binding tracked allosteric opening of a Pt tweezer catalyst.
Evidence for the claim as stated.
Study at a glance
- Design
- Animal / in-vitro — Pt(II) weak-link tweezer with chloride toggling, 1H NMR binding, and timed Michael addition
- N
- Multiple catalyst states and kinetic runs rather than a single sample N
- Population
- In situ bifunctional squaramide–amine catalysis in organic solvent
- Outcome
- Fully closed Na+ complex binds DMA and catalyzes nearly quantitative Michael addition; chloride switching turns activity off
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Inspect source passages
On–off allosteric control of a bifunctional catalyst
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Closed-state TOF is 2.69 × 10−4 s−1 with nearly quantitative conversion.
As can be seen in , FC 2 gives the product with nearly quantitative conversion (TOF = 2.69 × 10 –4 s –1 ).
What architecture enables reversible allosteric switching here?
our group has developed the weak-link approach (WLA) to supramolecular coordination chemistry, which is a powerful tool for the synthesis of multi-component catalytically active complexes
Key findings
The fully closed Na+ complex binds DMA strongly (Ka ≈ 75 558 M−1) while the semi-open state shows no recognition. Closed-state catalysis gives nearly quantitative conversion (TOF = 2.69 × 10−4 s−1), and chloride toggling reverses activity. Embedding the catalyst in the WLA scaffold improves activity versus free ligand.
Methodology
Authors assembled a heteroligated Pt(II) tweezer with a squaramide–tertiary amine ligand and a sodium sulfonate hydrogen-bond acceptor, switched it between semi-open and fully closed states with chloride, measured DMA binding by 1H NMR, and timed the Michael addition of nitroethane to β-nitrostyrene.
Limitations
Scope beyond a few conjugate additions is proposed rather than demonstrated at scale; polymer-length control of lactide ROP is suggested but not shown here.
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