The remarkable technical advances in mass spectrometry during the last decades, including soft ionisation techniques, the coupling of electrospray ionisation to flow reactors, and the broad scope of tandem mass spectrometric experiments applicable to mass-selected ions allow investigating the chemistry of molecular capsules in solution as well as in the absence of any environment. With these methods, mass spectrometry is capable of answering many questions starting from providing analytical characterisation data (elemental composition, stoichiometry, etc.) to structural aspects (connectivities, positions of building blocks in supramolecular complexes) and to the examination of solution and gas-phase reactivity including reactions inside molecular containers. The present article reviews this work with a focus rather on the chemical questions that can be answered than on the technical specialities of (tandem) mass spectrometry.
We demonstrate that
the reproducibility of sensors for nitroaromatics
based on surface-enhanced Raman spectroscopy (SERS) can be significantly
improved via a hierarchical aqueous self-assembly approach mediated
by the multifunctional macrocyclic molecule cucurbit[7]uril (CB[7]).
Our approach is enabled by the novel host–guest complexation
between CB[7] and an explosive marker 2,4-dinitrotoluene (DNT). Binding
studies are performed using experimental and computation techniques
to quantify key binding parameters for the first time. This supramolecular
complexation allows DNT to be positioned in close proximity to the
plasmonic hotspots within aggregates of CB[7] and gold nanoparticles,
resulting in significant SERS signals with a detection limit of ∼1
μM. The supramolecular ensemble is selective against a structurally
similar nitroaromatics owing to the molecular-recognition nature of
the complexation as well as tolerant against the presence of model
organic contaminants that bind strongly to the SERS substrates.
Supramolecular ‘gluing’ of quantum dots is demonstrated with cucurbituril and we present the opportunity to create molecular host–guest sensing schemes.
Solution precursor plasma spray (SPPS) synthesis is a simple, single-step, and rapid technique for synthesizing nano-ceramic materials from solution precursors. This innovative method uses molecularly mixed precursors as liquids, avoiding a separate processing method for the preparation of powders and enabling the synthesis of a wide range of metal oxide powders and coatings. Also, this technique is considered to be promising for the formation of nonequilibrium phases in multi-component oxide systems. This short review provides an insight into the important aspects of SPPS, the properties obtained in comparison to conventional plasma spray, and the potential applications of the SPPS process.
S. Seal is a professor, K.S. Babu is a research associate, and E. Brinley is a graduate student with the Surface Engineering and Nanotechnology Facility, Advanced Materials Processing and Analysis Center, Mechanical Materials and AerospaceEngineering, Nanoscience and Technology Center, University of Central Florida, Orlando, Florida. S. Seal can be reached at sseal@mail.ucf.edu.
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