Significant loss of life and property results each year from fires fueled by polyurethane found in household furnishings. Established layer-by-layer flame retardant systems were combined to produce a stacked nanocoating for flame retarding polyurethane foam. A bilayer system of chitosan (CH) and vermiculite provides a nanobrick wall exoskeleton, protecting the polyurethane long enough for an intumescing system of CH and ammonium polyphosphate to activate and form a bubbled char layer. Stacking these two recipes allows the foam to self-extinguish when exposed to a butane torch without any flame spread or shrinking of the foam, two things commonly observed with either coating alone. Cone calorimetry revealed a significant peak heat release rate reduction of 66 % relative to the uncoated foam. This study demonstrates the ability to combine flame retardant mechanisms sequentially. This nanocoating acts as an environmentally benign template for flame retarding various complex substrates, especially those found in household furnishings.

Syntheses of a new tripodal alane/tris(phosphine) ligand (AlP3) based on 2-(diisopropylphosphino)pyrrole, and AlP3-supported Ni complexes are reported. The central tris(pyrrolyl)aluminum moeity acts as a stronger Lewis acid towards Ni that...

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Palladium, rhodium and platinum bis(phosphino)silyl pincer complexes featuring pyrrole-based linkers were synthesized and their properties studied.

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The demand for sustainable synthetic methods has motivated the development of a myriad of strategies for substrate oxidation chemistry that reflect the goals of green chemistry. Here we present a two-part laboratory module that provides undergraduate chemistry students hands-on experience with the concepts of sustainable chemistry in the context of C–N bond-forming chemistry. First, students perform a traditional Pd-catalyzed C–N cross-coupling reaction between an aryl halide and an amine (i.e., C–X/N–H coupling). In the second part, students investigate a hypervalent iodine-catalyzed reaction that uses O2 as a terminal oxidant for direct C–H/N–H coupling. On the basis of these two methods for accessing the same arylated amine product, students evaluate aspects of sustainability qualitatively by discussing the 12 Principles of Green Chemistry and quantitatively via green chemistry metric pentagons. These investigations highlight the complex balance of variables that must be considered when evaluating the sustainability of chemical processes. Through these activities, students explore the concepts of aerobic oxidation, hypervalency, green chemistry, and organocatalysis, while enforcing laboratory skills such as Schlenk-line technique, gas handling, and NMR spectroscopy.

Syntheses of Rh complexes of the phosphine-amido-silane SiNP ligand are reported. The reaction of the parent (SiNP)H ligand (4) with 0.5 equiv. [(COE)RhCl]2 (COE = cis-cyclooctene) in the presence of...

Catalyst confinement within microporous media provides the opportunity to site isolate reactive intermediates, enforce intermolecular functionalization chemistry by co-localizing reactive intermediates and substrates in molecular-scale interstices, and harness non-covalent host-guest...