Mn(iv) and Mn(v)-radical species supported by the redox non-innocent bis(2-amino-3,5-di-tert-butylphenyl)amine pincer ligand

Abstract

The electron-rich pincer ligand 1 has been synthesized and chelated to manganese. The octahedral Mn(iv) bis(diiminosemiquinonate) and Mn(v) (diiminobenzoquinone) (diiminosemiquinonate) radicals were structurally characterized.

Radical‐Type Reactivity and Catalysis by Single‐Electron Transfer to or from Redox‐Active Ligands

“…In cases where a more ambiguous overall electronic structure ensues from strong electronic coupling between a ligand and a metal center, the term redox‐noninnocence may be more appropriate . Well‐known examples of redox‐active ligands are dithiolenes, donor appended diarylamines, heterodienes such as 1,4‐diimine and related 2‐iminopyridines as well as bis(imino)pyridines, olefin‐appended diazadienes, salens and derivatives thereof, and dipyrrins as well as extended systems such as porphyrins . Newer additions have appeared as well, including verdazyl, and nindigo, formazanate, aminotropiminate, arylazopyridine, π‐coordinated arene and derivatives thereof, β‐diketiminate and various others .…”

Coordination Chemistry of the Redox Non‐Innocent Ligand Bis(2‐amino‐3,5‐di‐tert‐butylphenyl)amine with Group 10 Metal Ions (Ni, Pd, Pt)

“…were added to a degassed solution of H 3 L 3N (100 mg, 0.24 mmol, 1.0 equiv. ) in DMSO (20 mL). The resulting mixture was stirred at 120 °C for 1 h and progressively turned from colorless to purple.…”

“…We established that H 3 L 3N forms octahedral complexes with manganese in a 2:1 ligand/metal ratio (Figure a, Scheme ). The electron‐donating tert ‐butyl substituents enabled the deprotonated ligand to efficiently stabilize high oxidation states of the complexes, so that Mn V radical species could be structurally characterized . The coordination chemistry of H 4 L 4N was only investigated with nickel, but it was shown to be very versatile.…”

Complexes of the Bis(di‐tert‐butyl‐aniline)amine Pincer Ligand: The Case of Copper

“…We recently described the N 3 chelate analog of H 3 L O , namely H 3 L N[6a] and investigated its coordination chemistry with several transition metal ions (Scheme ) , . The easier oxidation of anilines compared to phenols allowed us to prepare complexes with unprecedented oxidation states.…”