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Reactivity mapping with electrochemical gradients for monitoring reactivity at surfaces in space and time.

Krabbenborg SO, Nicosia C, Chen P, Huskens J - Nat Commun (2013)

Bottom Line: Because reaction kinetics is different at surfaces compared with solution, frequently, solution-characterization techniques cannot be used.For both systems, the kinetic data were spatially visualized in a two-dimensional reactivity map.In the case of the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, the reaction order (2) was deduced from it.

View Article: PubMed Central - PubMed

Affiliation: Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, Enschede 7500 AE, The Netherlands.

ABSTRACT
Studying and controlling reactions at surfaces is of great fundamental and applied interest in, among others, biology, electronics and catalysis. Because reaction kinetics is different at surfaces compared with solution, frequently, solution-characterization techniques cannot be used. Here we report solution gradients, prepared by electrochemical means, for controlling and monitoring reactivity at surfaces in space and time. As a proof of principle, electrochemically derived gradients of a reaction parameter (pH) and of a catalyst (Cu(I)) have been employed to make surface gradients on the micron scale and to study the kinetics of the (surface-confined) imine hydrolysis and the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, respectively. For both systems, the kinetic data were spatially visualized in a two-dimensional reactivity map. In the case of the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, the reaction order (2) was deduced from it.

No MeSH data available.


Reactivity mapping of the imine hydrolysis reaction.(a) Data and exponential fits (I(t)=(Imax−Io)*e−k1t+Io) of the surface-confined imine hydrolysis at some characteristic distances from the anode (low pH). (b) Resulting (averaged;±1 s.d.) values of the first-order rate constant, k1, of the imine hydrolysis versus distance from the anode. (c) A two-dimensional reactivity map of the imine hydrolysis kinetics showing the (averaged) k1 values mapped in space next to an anode (running vertically and ending at x=0).
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f3: Reactivity mapping of the imine hydrolysis reaction.(a) Data and exponential fits (I(t)=(Imax−Io)*e−k1t+Io) of the surface-confined imine hydrolysis at some characteristic distances from the anode (low pH). (b) Resulting (averaged;±1 s.d.) values of the first-order rate constant, k1, of the imine hydrolysis versus distance from the anode. (c) A two-dimensional reactivity map of the imine hydrolysis kinetics showing the (averaged) k1 values mapped in space next to an anode (running vertically and ending at x=0).

Mentions: The fluorescence data of the imine hydrolysis, shown in Fig. 2c versus distance, was plotted versus time as shown in Fig. 3a, as a function of the distance from the anode. Figure 3a shows representative graphs of the fitted data at three specific distances. These time traces were fitted to an exponential decay function:


Reactivity mapping with electrochemical gradients for monitoring reactivity at surfaces in space and time.

Krabbenborg SO, Nicosia C, Chen P, Huskens J - Nat Commun (2013)

Reactivity mapping of the imine hydrolysis reaction.(a) Data and exponential fits (I(t)=(Imax−Io)*e−k1t+Io) of the surface-confined imine hydrolysis at some characteristic distances from the anode (low pH). (b) Resulting (averaged;±1 s.d.) values of the first-order rate constant, k1, of the imine hydrolysis versus distance from the anode. (c) A two-dimensional reactivity map of the imine hydrolysis kinetics showing the (averaged) k1 values mapped in space next to an anode (running vertically and ending at x=0).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3644076&req=5

f3: Reactivity mapping of the imine hydrolysis reaction.(a) Data and exponential fits (I(t)=(Imax−Io)*e−k1t+Io) of the surface-confined imine hydrolysis at some characteristic distances from the anode (low pH). (b) Resulting (averaged;±1 s.d.) values of the first-order rate constant, k1, of the imine hydrolysis versus distance from the anode. (c) A two-dimensional reactivity map of the imine hydrolysis kinetics showing the (averaged) k1 values mapped in space next to an anode (running vertically and ending at x=0).
Mentions: The fluorescence data of the imine hydrolysis, shown in Fig. 2c versus distance, was plotted versus time as shown in Fig. 3a, as a function of the distance from the anode. Figure 3a shows representative graphs of the fitted data at three specific distances. These time traces were fitted to an exponential decay function:

Bottom Line: Because reaction kinetics is different at surfaces compared with solution, frequently, solution-characterization techniques cannot be used.For both systems, the kinetic data were spatially visualized in a two-dimensional reactivity map.In the case of the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, the reaction order (2) was deduced from it.

View Article: PubMed Central - PubMed

Affiliation: Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, Enschede 7500 AE, The Netherlands.

ABSTRACT
Studying and controlling reactions at surfaces is of great fundamental and applied interest in, among others, biology, electronics and catalysis. Because reaction kinetics is different at surfaces compared with solution, frequently, solution-characterization techniques cannot be used. Here we report solution gradients, prepared by electrochemical means, for controlling and monitoring reactivity at surfaces in space and time. As a proof of principle, electrochemically derived gradients of a reaction parameter (pH) and of a catalyst (Cu(I)) have been employed to make surface gradients on the micron scale and to study the kinetics of the (surface-confined) imine hydrolysis and the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, respectively. For both systems, the kinetic data were spatially visualized in a two-dimensional reactivity map. In the case of the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, the reaction order (2) was deduced from it.

No MeSH data available.