The ribosome builds proteins by joining together amino acids in an order determined messenger RNA. Here, we report on the design, synthesis, and operation of artificial small-molecule machine that travels along a molecular strand, picking up block its path, to synthesize peptide sequence-specific manner. chemical structure is based rotaxane, ring threaded onto axle. carries thiolate group iteratively removes from strand transfers them peptide-elongation site through native ligation....

Force-controlled release of small molecules offers great promise for the delivery drugs and healing or reporting agents in a medical materials context

Mechanical force, with its ability to distort, bend, and stretch chemical bonds, is unique in the way it activates reactions. In polymer mechanochemistry, force transduced a directional fashion, efficiency of activation depends on how well from scissile bond mechanophore (i.e., mechanochemical coupling). We have investigated effects regio- stereochemistry rate force-accelerated retro-Diels–Alder reactions furan/maleimide adducts. Four adducts, presenting an endo or exo configuration proximal...

The activation mode of a rotaxane-based organocatalyst with both secondary amine and squaramide catalytic units can be switched acid or base. macrocycle blocks whichever the sites it is positioned over. switchable rotaxane catalyst generates different products from mixture three building according to location macrocyclic ring in rotaxane.

We report on an improved strategy for the preparation of artificial molecular machines that can pick up and assemble reactive groups in sequence by traveling along a track. In new approach preformed rotaxane synthon is attached to end otherwise fully formed strand building blocks. This "rotaxane-capping" protocol significantly more efficient than "final-step-threading" method employed previously enables synthesis threaded operate extended oligomer, potentially polymer, tracks. The...

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTPolymer Mechanochemistry and the Emergence of Mechanophore ConceptGuillaume De Bo*Guillaume BoDepartment Chemistry, University Manchester, Oxford Road, Manchester M13 9PL, United Kingdom*Email [email protected]More by Guillaume Bohttp://orcid.org/0000-0003-2670-6370Cite this: Macromolecules 2020, 53, 18, 7615–7617Publication Date (Web):September 22, 2020Publication History Published online22 September 2020Published inissue 22...

The unique topological features of Piezo proteins underlie the lever-like cellular mechanotransduction mechanism. This knowledge inspires us to seek topological/geometric control mechanochromophores with unprecedentedly amplified, synergistic changes in polymers serve as ideal stress probes. Here, by judicious placement two spirolactam rings into aminobenzopyranoxanthene, a series stereo- and regio-isomeric rhodamine-like mechanophores are developed. With labile bonds closely coupled one...

Molecular knots and entanglements form randomly spontaneously in both biological synthetic polymer chains. It is known that macroscopic materials, such as ropes, are substantially weakened by the presence of knots, but until now it has been unclear whether similar behaviour occurs on a molecular level. Here we show well-defined overhand knot chain increases rate scission under tension (≥2.6× faster) solution, because deformation backbone induced tightening activates otherwise unreactive...

The regioselective hydrosilylation of terminal and internal alkynes catalyzed by the novel (IPr)Pt(AE) ( 7) (IPr = bis(2,6-diisopropylphenyl)imidazo-2-ylidene, AE allyl ether) complex is presented. catalyst displays enhanced activity regioselectivity for with low loading (0.1 to 0.05 mol %) when compared parent (IPr)Pt(DVDS) 6) (DVDS divinyltetramethyldisiloxane). reaction leads exquisite in favor cis-addition product on less hindered terminus alkynes. solvent effects were examined difficult...

The hydrosilylation of terminal alkynes by silanes catalyzed N-heterocyclic carbene platinum(0) complexes has been investigated. included 1-octyne and phenylacetylene. investigated were bis(trimethylsilyloxy)methylsilane, (trimethylsilyloxy)dimethylsilane, tert-butyldimethylsilane, triphenylsilane, phenyldimethylsilane, triethylsilane, triethoxysilane. X-ray crystal structures for [Pt(N,N'-dicyclohexylimidazol-2-ylidene)(η2-dimethylacetylenedicarboxylate)2] (8)...

We have investigated the mechanical dissociation of an ammonium/crown ether rotaxane using experimental (sonication) and computational (CoGEF) methods found that it breaks faster than its noninterlocked or uncoupled interlocked (i.e., pulled from both sides axle) counterparts. This was confirmed by analysis fragments, which are results a selective unstoppering reaction. Interestingly, initial also triggered elimination axle segment separating stopper ammonium binding station. CoGEF...

We report on the synthesis and operation of a three-barrier, rotaxane-based, artificial molecular machine capable sequence-specific β-homo (β3) peptide synthesis. The utilizes nonproteinogenic β3-amino acids, class amino acids not generally accepted by ribosome, particularly consecutively. Successful via native chemical ligation (NCL) demonstrates that even challenging 15- 19-membered transition states are suitable for information translation using this machine. peptide-bond-forming catalyst...

Mechanophores (mechanoresponsive molecules) offer great promises for the development of smart force-responsive materials. The activity a mechanophore can be tuned by altering its structure or composition actuating polymer. Here we show that [2]catenane act as mechanical protecting group diverting tensional forces away from mechanically active functional embedded in one rings. This property emerges mobility two rings catenane, which are able to rotate along each other until tension equalizes...

Mechanical bonds are known to efficiently absorb mechanical energy at low forces, but their behavior high forces is unknown. Here we investigate the impact of a bond on rate activation Diels-Alder mechanophore. Using combination experimental and computational techniques, found that retro-Diels-Alder reaction under tension decreased when mechanophore embedded in axle rotaxane due presence competing high-stress region junction between macrocycle axle.

We report on the synthesis of [2]rotaxanes driven by stabilization axle-forming transition state. A bifunctional macrocycle, with hydrogen bond donors at one end and acceptors other, is used to stabilize charges that develop during addition a primary amine cyclic sulfate.

An external mechanical force larger than 1 nN induces a switch from concerted to stepwise mechanism in the rupture of proximal dimethyl furan–maleimide [4 + 2] Diels–Alder adducts. The intermediate formed after first bond has diradical character.

We just clicked: A convergent approach consisting of two successive copper(I)-catalyzed azide–alkyne cycloaddition "click" reactions leads to a diblock copolymer in which the blocks are linked by rotaxane-type mechanical bond (see scheme). Rotaxane formation is templated square-planar PdII complex. Detailed facts importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted authors. Please...

A pair of enantioselective switchable bifunctional catalysts are shown to promote a range conjugate addition reactions in up 95 : 5 e.r. and 95% conversion.

Mechanophores (mechanosensitive molecules) are usually activated by pulling them with covalently attached polymers. A rotaxane actuator offers a new geometry of activation as the macrocycle pushes against stoppering mechanophore. Here we compare both and pushing activations show that is more efficient selective than pulling. We found bulky furan/maleimide adduct occurs via two competing dissociation pathways: retrocycloaddition heterolytic cleavage (generating trityl cation in process),...

Force sensing at the molecular level has enabled study of materials failure and it offers great promises for investigation mechanobiological processes. Traditional force probes rely on reversible or irreversible activation mechanochromic precursors to assess transient permanent changes in polymer networks. A promising approach involves force‐controlled release molecules, as accumulation chromic molecules specific sites would enable recording deformation histories. However, many fluorescent...

Force sensing at the molecular level has enabled study of materials failure and it offers great promises for investigation mechanobiological processes. Traditional force probes rely on reversible or irreversible activation mechanochromic precursors to assess transient permanent changes in polymer networks. A promising approach involves force‐controlled release molecules, as accumulation chromic molecules specific sites would enable recording deformation histories. However, many fluorescent...

We report an artificial molecular machine that moves along a track, iteratively joining building blocks to form oligomer of single sequence with continuous backbone carbon-carbon bonds. The rotaxane features macrocycle bearing aldehyde-terminated chain and axle containing different phosphonium ylides separated by rigid spacers. Each ylide is large enough block the passage macrocycle, trapping ring between stopper at terminus original threading next track. Once reachable, it removed from...