Nitrene Photochemistry of Manganese NHaloamides** Academic Article uri icon

abstract

  • AbstractManganese complexes supported by macrocyclic tetrapyrrole ligands represent an important platform for nitrene transfer catalysis and have been applied to both CH amination and olefin aziridination catalysis. The reactivity of the transient highvalent Mn nitrenoids that mediate these processes renders characterization of these species challenging. Here we report the synthesis and nitrene transfer photochemistry of a family of MnIII Nhaloamide complexes. The S=2 Nhaloamide complexes are characterized by 1HNMR, UVvis, IR, highfrequency and field EPR (HFEPR) spectroscopies, and singlecrystal Xray diffraction. Photolysis of these complexes results in the formal transfer of a nitrene equivalent to both CH bonds, such as the CH bonds of tetrahydrofuran, and olefinic substrates, such as styrene, to afford aminated and aziridinated products, respectively. Lowtemperature spectroscopy and analysis of kinetic isotope effects for CH amination indicate halogendependent photoreactivity: Photolysis of Nchloroamides proceeds via initial cleavage of the MnN bond to generate MnII and amidyl radical intermediates; in contrast, photolysis of Niodoamides proceeds via NI cleavage to generate a MnIV nitrenoid (i.e., {MnNR}7 species). These results establish Nhaloamide ligands as viable precursors in the photosynthesis of metal nitrenes and highlight the power of ligand design to provide access to reactive intermediates in grouptransfer catalysis.

published proceedings

  • Angewandte Chemie

author list (cited authors)

  • Van Trieste, G. P., Reid, K. A., Hicks, M. H., Das, A., Figgins, M. T., Bhuvanesh, N., ... Powers, D. C.

citation count

  • 2

complete list of authors

  • Van Trieste, Gerard P||Reid, Kaleb A||Hicks, Madeline H||Das, Anuvab||Figgins, Matthew T||Bhuvanesh, Nattamai||Ozarowski, Andrew||Telser, Joshua||Powers, David C

publication date

  • December 2021

publisher