Homolytic N-H activation of ammonia: hydrogen transfer of parent iridium ammine, amide, imide, and nitride species.

Markus G Scheibel,Markus Kinauer,Bas De Bruin,Sven Schneider,Christian Würtele,Frank W Heinemann,Josh Abbenseth

doi:10.1021/acs.inorgchem.5b00829

Markus G Scheibel, Markus Kinauer + Show 5 more

Open Access

https://doi.org/10.1021/acs.inorgchem.5b00829

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Abstract

The redox series [Irn(NHx)(PNP)] (n = II–IV, x = 3–0; PNP = N(CHCHPtBu2)2) was examined with respect to electron, proton, and hydrogen atom transfer steps. The experimental and computational results suggest that the IrIII imido species [Ir(NH)(PNP)] is not stable but undergoes disproportionation to the respective IrII amido and IrIV nitrido species. N–H bond strengths are estimated upon reaction with hydrogen atom transfer reagents to rationalize this observation and are used to discuss the reactivity of these compounds toward E–H bond activation.

Highlights

The chemistry of transition metal (TM) complexes with covalently bound nitrogen ligands, i.e. amido, imido, and nitrido species LnM−NRx, has undergone a renaissance in recent years due to their relevance to catalytic transformations.[1]
Within an experimental and computational study, we describe the reactivity of a redox series of iridium(II−IV) pincer complexes with parent ammine, amide, imide, and nitride ligands relevant to ammonia functionalization
Once again the isolobal relationship with octahedral group 8 complexes shall be stressed (Figure 6). This analogy emphasizes the conservation of a square-planar geometry around iridium, which relies on steric shielding through the bulky pincer ligand

Summary

Introduction

The chemistry of transition metal (TM) complexes with covalently bound nitrogen ligands, i.e. amido, imido, and nitrido species LnM−NRx, has undergone a renaissance in recent years due to their relevance to catalytic transformations.[1]. Some terminal nitrides were directly demonstrated to undergo C−H amination or proposed as transient intermediates in HAA reactions toward amido or imido complexes.[42] Within group 9, Chirik observed intramolecular nitrogen insertion into a secondary C−H bond upon irradiation of a cobalt azide complex (Scheme 11).[43] In comparison, the generation of 3a/b in the presence of H atom donors like 1,4-

Results

Conclusion