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Abstract:

Recent results concerning the synthesis and reactivity of low-coordinate transition-metal complexes featuring sterically encumbering m-terphenyl isocyanide ligands are presented. Given the isolobal relationship between organoisocyanides and carbon monoxide, these complexes serve as mimics of the unsaturated binary metal carbonyls. The latter have traditionally been studied in either the gas phase or by matrix-isolation techniques and, consequently, their condensed-phase reactivity patterns are largely unknown. Specifically addressed will be synthetic studies that have delivered homoleptic and heteroleptic isocyanide complexes that mimic several unsaturated binary carbonyls for the middle and late transition metals. An emphasis is placed on the generation of anionic isocyanide complexes and their use as metal-based nucleophiles. The constrained steric environment enabled by m-terphenyl isocyanides has allowed for the isolation of unique organometallic complexes when these anionic isocyanide complexes are treated with main group electrophiles. It has been recently reported that such systems support the stabilization of the simple 10e^– diatomic molecule boron monofluoride (BF) as a terminal ligand. The reactivity of this complex is detailed, with purpose of establishing the electronic structure features of the BF ligand. Also discussed is the synthesis of other,unusual 10e^– diatomic ligands within the protective environment of the m-terphenyl isocyanide framework.

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Bio:

Joshua S. Figueroa completed his graduate studies at the Massachusetts Institute of Technology in 2005 under the direction of Christopher C. Cummins. From 2005-2007, he was a National Institutes of Health Postdoctoral Fellow at Columbia University in the laboratory of Gerard Parkin. He started his independent career in 2007 and is currently a Professor of Chemistry and Materials Science, and the Leslie E. Orgel Faculty Scholar, in the Department of Chemistry and Biochemistry at the University of California, San Diego (UCSD). Figueroa’s research and educational efforts have been recognized with a number of awards, including National Science Foundation CAREER Award (2009), an Alfred P. Sloan Research Fellowship (2011), the Presidential Early Career Award for Scientists and Engineers (PECASE, 2011), Department of Energy Early Career Research Award (2012) and the Camille Dreyfus Teacher-Scholar Award (2012). He was named a Fellow of the Royal Society of Chemistry (UK) in 2014 and an Alexander von Humboldt Research Fellow in 2017. Most recently he received a 2021 NSF Award for Special Creativity for his synthetic work on low-valent transition metal isocyanide compounds. Figueroa’s research interests are focused broadly on synthetic inorganic, organometallic and materials chemistry, as well as applications in catalysis.