Using TOF-SIMS Spectrometry to Study the Kinetics of the Interfacial Retro Diels-Alder Reaction
Lilia Hassouna1,2, Sachin Kumar Enganati1,2, Florence Bally-Le Gall3
1Materials and Research Technology Department, Luxembourg Institute of Science and Technology, 5 Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
Materials (Basel, Switzerland)
|June 2, 2021
Summary
Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) effectively monitors interfacial retro Diels-Alder reactions on self-assembled monolayers. This technique quantizes reaction conversion by tracking molecular fragment release during thermal treatment.
Area of Science:
- Surface science
- Chemical kinetics
- Analytical chemistry
Background:
- Self-assembled monolayers (SAMs) provide controlled surfaces for studying interfacial reactions.
- The retro Diels-Alder (retro DA) reaction is a thermally driven process crucial in materials science and organic synthesis.
- Monitoring interfacial reaction kinetics requires sensitive and spatially resolved analytical techniques.
Purpose of the Study:
- To investigate Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) as a method for real-time monitoring of interfacial retro Diels-Alder reactions.
- To quantify reaction conversion on self-assembled monolayers (SAMs) as a function of temperature and time.
- To compare the efficacy of TOF-SIMS with traditional methods like 1H NMR spectroscopy.
Main Methods:
- Grafting Diels-Alder (DA) adduct molecules onto well-defined SAMs.
- Heating the modified SAMs at various temperatures to induce the retro DA reaction.
- Analyzing the surface using TOF-SIMS to detect and quantify released molecular fragments.
- Correlating the decay of fragment peak integrals with reaction conversion.
Main Results:
- TOF-SIMS successfully detected a specific molecular fragment released during the interfacial retro DA reaction.
- The decay of the fragment's peak integral directly correlated with reaction conversion.
- Reaction conversion was successfully determined as a function of time and temperature using TOF-SIMS.
- The results demonstrated the viability of TOF-SIMS for monitoring interfacial retro DA reactions.
Conclusions:
- TOF-SIMS is a powerful surface-sensitive technique for real-time monitoring of interfacial retro Diels-Alder reactions.
- This method allows for precise quantification of reaction kinetics on SAMs.
- TOF-SIMS offers a valuable alternative or complementary approach to conventional spectroscopic methods for studying interfacial chemistry.
Related Concept Videos
01:31Diels–Alder vs Retro-Diels–Alder Reaction: Thermodynamic Factors
5.4K
The Diels–Alder reaction is thermally reversible, meaning that the reaction reverts to the starting diene and dienophile under suitable temperatures. The forward reaction gives a cyclohexene derivative and is favored at low to medium temperatures. The reverse process, also called retro-Diels–Alder reaction, is a ring-opening process favored at high temperatures.
5.4K
01:06Interfacial Electrochemical Methods: Overview
548
Interfacial electrochemical methods focus on the phenomena occurring at the boundary between an electrode and a solution, as opposed to bulk methods that concentrate on the solution's overall properties. These interfacial methods are classified as either static or dynamic based on the presence of a nonzero current in the electrochemical cell and the consistency of analyte concentrations. Static methods, such as potentiometry, measure the cell's potential without any significant current...
548
02:45E2 Reaction: Kinetics and Mechanism
11.2K
SN2 substitutions and E2 eliminations of alkyl halides proceed via a concerted pathway. While the nucleophile attacks the alpha carbon in SN2 reactions, it functions as a strong base and abstracts a beta hydrogen in the E2 mechanism. The rate-limiting transition state in E2 elimination reactions is characterized by partially broken carbon–hydrogen and carbon–halogen bonds and a partially formed pi bond between the alpha and beta carbons. The beta hydrogen and halide are eliminated...
11.2K
03:09Measuring Reaction Rates
26.8K
Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical...
26.8K
02:46E1 Reaction: Kinetics and Mechanism
16.3K
Here, in contrast to the E2 reaction mechanism, we delve into the aspects of the E1 reaction mechanism, which has two steps: rate-limiting loss of the leaving group and abstraction of the beta hydrogen by a weak base. Typically, the experimental proof for the E1 mechanism is via kinetic studies or isotope studies. While the former demonstrates the first-order kinetics—the dependence of the reaction solely on substrate concentration—the latter proves the abstraction of hydrogen only...
16.3K
01:21Tandem Mass Spectrometry
1.7K
Tandem mass spectrometry is a technique that uses multiple mass analyzers in series to obtain a higher selectivity and signal-to-noise ratio for the analyte. Instruments with multiple analyzers separated by an interaction cell enable secondary fragmentation and selected study of the fragment ions.
Secondary fragmentations occur in the interaction cell and can be induced by various factors. Fragmentation induced by collision with inert gases, such as N2, Ar, He, etc., is called collision-induced...
Secondary fragmentations occur in the interaction cell and can be induced by various factors. Fragmentation induced by collision with inert gases, such as N2, Ar, He, etc., is called collision-induced...
1.7K