Metal-ligand cooperative κ1- N-pyrazolate Cp*RhIII-catalysts for dehydrogenation of dimethylamine-borane at room temperature

Shrinwantu Pal; Takanori Iwasaki; Kyoko Nozaki

doi:10.1039/d1dt01705e

Metal-ligand cooperative κ¹- N-pyrazolate Cp*Rh^III-catalysts for dehydrogenation of dimethylamine-borane at room temperature

Dalton Trans. 2021 Jun 15;50(23):7938-7943. doi: 10.1039/d1dt01705e.

Authors

Shrinwantu Pal¹, Takanori Iwasaki¹, Kyoko Nozaki¹

Affiliation

¹ Department of Chemistry and Biotechnology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. pal@chembio.t.u-tokyo.ac.jp nozaki@chembio.t.u-tokyo.ac.jp.

PMID: 34079977
DOI: 10.1039/d1dt01705e

Abstract

3,5-Dimethylpyrazole (Pz*H) in well-defined Cp*RhIII (Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl) complexes, or as an additive to [Cp*RhCl2]2 enhances catalytic activity in the dehydrogenation of dimethylamine-borane (DMAB) at room-temperature. Mechanistic studies indicate that the Lewis acidic RhIII-centre and dangling N-atom of the Pz* fragment operate cooperatively in accepting a hydride and proton from DMAB, respectively, leading directly to dimethylamino-borane and a RhIII-H complex. The rate limiting step involves protonation of the RhIII-H by the proximal NH fragment of the Pz*H moiety.