Narratives of Undergraduate Research, Mentorship, and Teaching at UCLA.

This work describes select narratives pertaining to undergraduate teaching and mentorship at UCLA Chemistry and Biochemistry by Alex Spokoyny and his junior colleagues. Specifically, we discuss how individual undergraduate researchers contributed and jump-started multiple research themes since the conception of our research laboratory. This work also describes several recent innovations in the inorganic and general chemistry courses taught by Spokoyny at UCLA with a focus of nurturing appreciation for research and creative process in sciences including the use of social media platforms.

Nanostructuring of Strontium Hexaboride via Lithiation.

We describe the top-down nanostructuring of a metal boride using SrB6 as an example. To accomplish this transformation, we demonstrate (1) the direct lithiation of a metal boride using n-butyllithium and then (2) the reactive disassembly of Li-SrB6 into nanoparticles using water. The identity of the Li-SrB6 intermediate, a mixture of Li2B6, LixSr1-2xB6, and SrB6 phases, was established by powder X-ray diffraction (PXRD), solid-state 11B and 7Li NMR, transmission electron microscopy, selected-area electron diffraction, and scanning electron microscopy. The necessary 2Li+/Sr2+ substitution is enabled by cation mobility within the hexaboride lattice. The subsequent reaction with water results in Li2B6 decomposition and the release of <100 nm SrB6 nanoparticles, which were characterized by PXRD, solid-state 11B and 7Li NMR, and high-resolution TEM. This chemistry opens new solution-based modification and processing options for metal borides.

Sonochemical Synthesis of Small Boron Oxide Nanoparticles.

The synthesis of small boron oxide nanoparticles (NPs) is reported. A sonochemical approach in the presence of a capping agent was employed to produce approximately 4-5-nm-sized B2O3 NPs, including the 10B isotopically enriched form. The morphology and composition of the NPs were established using transmission electron microscopy and diffraction, respectively. X-ray photoelectron and Fourier transform infrared spectroscopies provided information about surface functionalization of the B2O3 NPs, which can be further modified through a facile, one-step ligand-exchange process. The toxicity of the synthesized NPs was investigated in Chinese hamster ovarian cells, indicating that these systems were nontoxic up to 1.7 mM concentrations.

Cross-linked porous polyurethane materials featuring dodecaborate clusters as inorganic polyol equivalents.

We report the discovery that a perhydroxylated dodecaborate cluster ([B12(OH)12]2-) can act as an inorganic polyol, serving as a molecular cross-linker in the synthesis of polyurethane-based materials. We further demonstrate how the inherent robustness of the utilized boron cluster can effectively enhance the thermal stability of the produced polyurethane materials incorporating [B12(OH)12]2- building blocks compared to analogous polymers made from carbon-based polyols. Ultimately, this approach provides a potential route to tune the chemical and physical properties of soft materials through incorporation of polyhedral boron-rich clusters into the polymer network.