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Show COLLEGE OF SCIENCE COORDINATION-DRIVEN SELF-ASSEMBLY OF BODIPY-FUNCTIONALIZED SUPRAMOLEC-ULAR COORDINATION COMPLEXES Andrew S. Davies (Timothy Cook, Peter J. Stang) Department of Chemistry University of Utah Since its origins in the early 1990s, coordination-driven self-assembly (CDSA) has been a growing area of research, bridging the fields of inorganic, organic, and organometallic chemistry. CDSA utilizes metal ligand bonding to construct macromolecules of various shapes, such as polygons, polyhedra, and prisms. In recent years, these architectures have motivated a shift in research focus, moving from predominantly structural investigations to applications into small molecule storage, drug delivery, catalysis, and sensing. These applications are often based on the inherent internal cavities that 2D and 3D assemblies possess, which allows them to interact with small molecule substrates, oftentimes selectively. Biological environments make it difficult to track specific molecules which lack spectroscopic handles. Fluorescence is an excellent way of assessing the location and stability of a molecule; however, if a molecule is not inherently fluorescent this means of detection is obviated. O n e strategy to impart emissive properties to an otherwise "dark" molecule is to append known fluorophores using coupling reactions. Once coupled, the resulting fluorophore/assembly conjugate is easily tracked via fluorescence microscopy. The molecule 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is naturally fluorescent due to its aromatic structure. It has a high quantum yield, meaning it emits a photon almost every time it is excited via its low energy absorption manifold. This makes it an excellent candidate for fluorescence-based studies. BODIPY is also a particularly useful compound in biological environments because it can be readily functionalized with a carboxylic acid or amine that allows for a simple peptide coupling to substrates, making it very biocompatible. BODIPY fluoresces in the visible region, enabling one to easily detect it using modern microscopy. While an ideal fluorophore, the synthesis and purification of functionalized BODIPY molecules is not trivial. Since the synthesis involves condensation of aldehydes with pyrroles, the possibility arises for further oligimerization beyond the desired dipyrro-methane molecule. Full cyclization results in the formation of porphyrin, an undesirable byproduct. To circumvent porphyrin formation, 2,4-dimethyl pyrrole is used so that only one (3 carbon is available for condensation, the other being blocks by a methyl group. By utilizing the simple method of coordination-driven self-assembly, a BODIPY-functionalized cuboc-tahedron was synthesized. Twelve 120-degree cross-coupled BODIPY ligands and eight tri-nuclear platinum molecules were used to make the overall structure. The ligand and platinum molecule were synthesized, isolated, and then used in coordination-driven self-assembly to form the overall BODIPY-functionalized cuboctahedron. Peter J. Stang |