Mechanical Rupture of Mono- and Bivalent Transition Metal Complexes in Experiment and Theory

Gensler, Manuel; Eidamshaus, Christian; Galstyan, Arthur; Knapp, Ernst‐Walter; Reißig, Hans‐Ulrich; Rabe, Jürgen P.

doi:10.1021/jp511104m

Cited by 9 publications

(24 citation statements)

References 99 publications

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“…63 For the second set of measurements Pyridine-PEG conjugates (as shown in Figure 1c)) are synthesized and surface films of the polymers are prepared as described before. 27 In short, a 1 mM solution of the polymer in water is applied to gold coated silicon nitride cantilevers (Olympus Biolever A, Olympus Cooperation, Tokyo, Japan) and template stripped surfaces (JPK Instruments, Berlin, Germany) for 12-24 h at room temperature. Afterwards surface and cantilever are rinsed thoroughly with water.…”

Section: Resultsmentioning

confidence: 99%

Hydration Effects Turn a Highly Stretched Polymer from an Entropic into an Energetic Spring

Liese¹,

et al. 2016

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Polyethylene glycol (PEG) is a structurally simple and nontoxic water-soluble polymer that is widely used in medical and pharmaceutical applications as molecular linker and spacer. In such applications, PEG's elastic response against conformational deformations is key to its function. According to text-book knowledge, a polymer reacts to the stretching of its end-to-end separation by a decrease in entropy that is due to the reduction of available conformations, which is why polymers are commonly called entropic springs. By a combination of single-molecule force spectroscopy experiments with molecular dynamics simulations in explicit water, we show that entropic hydration effects almost exactly compensate the chain conformational entropy loss at high stretching. Our simulations reveal that this entropic compensation is due to the stretching-induced release of water molecules that in the relaxed state form double hydrogen bonds with PEG. As a consequence, the stretching response of PEG is predominantly of energetic, not of entropic, origin at high forces and caused by hydration effects, while PEG backbone deformations only play a minor role. These findings demonstrate the importance of hydration for the mechanics of macromolecules and constitute a case example that sheds light on the antagonistic interplay of conformational and hydration degrees of freedom.

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Section: Resultsmentioning

confidence: 99%

Hydration Effects Turn a Highly Stretched Polymer from an Entropic into an Energetic Spring

Liese¹,

et al. 2016

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“…The next example is a model for a two‐pathway surface where we assume that the directed mechanical force,

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, enables a reaction pathway which is energetically disfavored in the forceless case . Of course, the two‐pathway‐model is still in the framework of minimal models as well.…”

Section: Resultsmentioning

confidence: 99%

“…Throughout the present work we assume that the plane of two intrinsic coordinates ( x , y ) is the stage where the pulling works. These coordinates may describe the weakest point of a molecule where it breaks preferentially . We note that the theory and the use of NTs can be applied to N ‐dimensional systems .…”

Section: Methodsmentioning

confidence: 99%

Reaction rates in a theory of mechanochemical pathways

Quapp

Bofill

2016

J Comput Chem

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If one applies mechanical stress to a molecule in a defined direction then one generates a new, effective potential energy surface (PES). Changes for minima and saddle points (SP) by the stress are described by Newton trajectories on the original PES (Quapp and Bofill, Theor. Chem. Acc. 2016, 135, 113). The barrier of a reaction fully breaks down for the maximal value of the norm of the gradient of the PES along a pulling Newton trajectory. This point is named barrier breakdown point (BBP). Depending on the pulling direction, different reaction pathways can be enforced. If the exit SP of the chosen pulling direction is not the lowest SP of the reactant valley, on the original PES, then the SPs must change their role anywhere: in this case the curve of the log(rate) over the pulling force of a forward reaction can show a deviation from the normal concave curvature. We discuss simple, two-dimensional examples for this model to understand more deeply the mechanochemistry of molecular systems under a mechanical stress. © 2016 Wiley Periodicals, Inc.

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“…These coordinates may describe the weakest point of a molecule where it breaks preferentially. 59 We note that the theory and the use of NTs can be applied to N-dimensional systems with any large n for the number of included atoms.…”

Section: Methodsmentioning

confidence: 99%

“…One sort of corridors leads over the low energy SP, but the other SP is energetically disfavored in the forceless case. 59 Of course, the two-pathway-model is still in the framework of minimal models, 55 The putative simplicity of this two-dimensional PES model should not conceal our view on the variety of pulling corridors. To study the possible pulling corridors, we first show the singular NTs which form the corresponding borders of the corridors, in Figure 12.…”

Section: Alternate Pathways With Intermediates: the Rhee-pande Pes 102mentioning

confidence: 99%

Analysis of the Acting Forces in a Theory of Catalysis and Mechanochemistry

Quapp

Bofill²,

Ribas‐Ariño³

2017

J. Phys. Chem. A

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The theoretical description of a chemical process resulting from the application of mechanical or catalytical stress to a molecule is performed by the generation of an effective potential energy surface (PES). Changes for minima and saddle points by the stress are described by Newton trajectories (NTs) on the original PES. From the analysis of the acting forces we postulate the existence of pulling corridors built by families of NTs that connect the same stationary points. For different exit saddles of different height we discuss the corresponding pulling corridors; mainly by simple two-dimensional surface models. If there are different exit saddles then there can exist saddles of index two, at least, between. Then the case that a full pulling corridor crosses a saddle of index two is the normal case. It leads to an intrinsic hysteresis of such pullings for the forward or the backward reaction. Assuming such relations we can explain some results in the literature. A new finding is the existence of roundabout corridors that can switch between different saddle points by a reversion of the direction. The findings concern the mechanochemistry of molecular systems under a mechanical load as well as the electrostatic force and can be extended to catalytic and enzymatic accelerated reactions. The basic and ground ansatz includes both kinds of forces in a natural way without an extra modification.

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Mechanical Rupture of Mono- and Bivalent Transition Metal Complexes in Experiment and Theory

Cited by 9 publications

References 99 publications

Hydration Effects Turn a Highly Stretched Polymer from an Entropic into an Energetic Spring

Hydration Effects Turn a Highly Stretched Polymer from an Entropic into an Energetic Spring

Reaction rates in a theory of mechanochemical pathways

Analysis of the Acting Forces in a Theory of Catalysis and Mechanochemistry

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