A new ionophilic ligand and a new ionically tagged imidazolium-based iron(III) complex were synthesized and applied in the air oxidation (also hydrogen peroxide) of alkenes in imidazolium-based ionic liquids. At least ten recycling reactions were performed. The epoxidized olefin was obtained in very good yields of 84-91 %. Some important mechanistic insights are also provided based on electrospray ionization quadrupole-time of flight mass spectrometry for the oxidation reaction. These results indicate that oxidations can take place by two different pathways, depending on the reaction condition: a radical or a concerted mechanism. These results contribute towards a better understanding of iron-catalyzed oxidation mechanisms.

The 3D metal-organic framework (MOF) [Eu(BTC)] (where BTC = trimesic acid) was synthesized in 20 min by a microwave-assisted hydrothermal method with a yield of 89%. A structural and spectroscopic study, performed by X-ray diffraction, thermogravimetry, and photoluminescence spectroscopy, showed that this framework has high crystallinity, thermal stability, and luminescence. This MOF had a red-orange luminescence when excited with ultraviolet (UV) radiation (λ = 254 nm) and a high potential for use as a luminescent marker for gunshot residues (GSR). When added to 9 mm nontoxic ammunition, it greatly improved quality of the crime scene investigation, allowing for direct visualization of the luminescent GSR on the shooter's hand and firearm and at the firing range using only a portable UV lamp. The marked luminescent GSR was easily collected and characterized by nondestructive techniques, including with a Video Spectral Comparator and scanning electron microscopy/energy-dispersive spectroscopy, wherein the presence of Eu ions was confirmed. Furthermore, the oral acute toxicity of this MOF was assessed in adult female Wistar rats using the Organisation for Economic Cooperation and Development 423 guidelines. This study classified the MOF [Eu(BTC)] in a less toxic Globally Harmonized System category (category 5), with a LD (lethal dose) of 5000 mg/kg, ensuring a wide security range for its application.

Herein we report on the sampling and characterization via electrospray ionization (tandem) mass spectrometry of free, longlived N-heterocyclic carbenes (NHC) bearing negative-charge tags. To facilitate electrospray ''ion fishing'' via electrostatic ejection directly to the gas phase, negative-charge tagged NHC were formed in imidazolium-based ionic liquid solutions via double deprotonation of imidazolium cations bearing acid side groups, viz. CH 2 CO 2 H or (CH 2) 3 SO 3 H. Via ESI-MS/MS experiments, the gaseous N-heterocyclic carbenes were found to display structurally diagnostic dissociations and bimolecular reactions. In perfect parallel to solution chemistry, the gaseous negative-charge tagged NHC were found to react promptly with CO 2 by carboxylation to form negative-charge tagged imidazolium carboxylates. Neutral carbenes were inaccessible for mass spectrometry, but the charge tag strategy opens many new possibilities to explore the intrinsic chemistry of these key but elusive species.

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