Catalytic Activity of Molybdenum Complexes Bearing PNP-Type Pincer Ligand toward Ammonia Formation

Taichi Mitsumoto; Yuya Ashida; Kazuya Arashiba; Shogo Kuriyama; Akihito Egi; Hiromasa Tanaka; Kazunari Yoshizawa; Yoshiaki Nishibayashi

doi:10.1002/anie.202306631

Catalytic Activity of Molybdenum Complexes Bearing PNP-Type Pincer Ligand toward Ammonia Formation

Angew Chem Int Ed Engl. 2023 Oct 23;62(43):e202306631. doi: 10.1002/anie.202306631. Epub 2023 Jul 24.

Authors

Taichi Mitsumoto¹, Yuya Ashida¹, Kazuya Arashiba¹, Shogo Kuriyama¹, Akihito Egi², Hiromasa Tanaka³, Kazunari Yoshizawa², Yoshiaki Nishibayashi¹

Affiliations

¹ Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.
² Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-ku, Fukuoka, Japan.
³ School of Liberal Arts and Sciences, Daido University, Minami-ku, Nagoya, Japan.

PMID: 37382559
DOI: 10.1002/anie.202306631

Abstract

We newly designed and prepared a novel molybdenum complex bearing a 4-[3,5-bis(trifluoromethyl)phenyl]pyridine-based PNP-type pincer ligand, based on the bond dissociation free energies (BDFEs) of the N-H bonds in molybdenum-imide complexes bearing various substituted pyridine-based PNP-type pincer ligands. The complex worked as an excellent catalyst toward ammonia formation from the reaction of an atmospheric pressure of dinitrogen with samarium diiodide as a reductant and water as a proton source under ambient reaction conditions, where up to 3580 equivalents of ammonia were formed based on the molybdenum atom of the catalyst. The catalytic activity was significantly improved by one order of magnitude larger than that observed when using the complex before modification.

Keywords: Ammonia; Molybdenum; PNP-Type Pincer Ligand; Substituent Effect; Water.