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Abstract

Tracking mass through harsh environments requires surrogate particles that withstand the event and endure until sampling. Silica-covered quantum dots have been shown to withstand a range of environmental pHs from months to years; in this work they are shown to endure in anticipated local environments. Two methods of particle synthesis were employed to produce luminescent silica with particle diameters 0.1–4 μm. These tracer particles scale for mass production, tolerate harsh environments, and endure in debris. They could be deployed in places such as chemical explosions, industrial processes, geologic test beds, oil and gas fields, nuclear reactors, and geothermal plants to track mass under harsh conditions. Graphical abstract

This letter describes the one-step conversion of heteroatom-substituted potassium organotrifluoroborates (KRBF) to metal monoorganoborohydrides (MRBH) using alkali metal aluminum hydrides. The method tolerates a variety of functional groups, expanding MRBH diversity. Hydride removal with MeSiCl in the presence of dimethylaminopyridine (DMAP) affords the organoborane·DMAP (RBH·DMAP) adducts.

The title compound [systematic name: 4-(dimethylamino)pyridine–4-methoxyphenylborane (1/1)], C14H19BN2O, contains two independent molecules in the asymmetric unit. Both molecules exhibit coplanar, mostlysp2-hybridized methoxy and dimethylamino substituents on their respective aromatic rings, consistent with π-donation into the aromatic systems. The B—H groups exhibit an intramolecular close contact with a C—H group of the pyridine ring, which may be evidence of electrostatic attraction between the hydridic B—H and the electropositive aromatic C—H. There appears to be weak C—H...π(arene) interactions between two of the H atoms of an aminomethyl group and the methoxy-substituted benzene ring of the other independent molecule, and another C—H...π (arene) interaction between one of the pyridine ring H atoms and the same benzene ring.