Tunable Luminescent Properties of Tricyanoosmium Nitrido Complexes Bearing a Chelating O^N Ligand

Abstract

We have recently reported a strongly luminescent osmium­(VI) nitrido complex [OsVI(N)­(NO2-L)­(CN)3]− [HNO2-L = 2-(2-hydroxy-5-nitrophenyl)­benzoxazole]. The excited state of this complex readily activates the strong C–H bonds of alkanes and arenes (Commun. Chem. 2019, 2, 40). In this work, we attempted to tune the excited-state properties of this complex by introducing various substituents on the bidentate L ligand. The series of nitrido complexes were characterized by IR, UV/vis, 1H NMR, and electrospray ionization mass spectrometry. The molecular structures of five of the nitrido compounds have been determined by X-ray crystallography. The photophysical and electrochemical properties of these complexes have been investigated. The luminescence of these nitrido complexes in the solid state, in a CH2Cl2 solution, and in a CH2Cl2 solid matrix at 77 K glassy medium clearly shows that these emissions are due to 3LML′CT [L ligand to OsN] phosphorescence. The presence of strongly electron-withdrawing substituents in these complexes enhances the LML′CT emission. Our result demonstrates that the excited-state properties of this novel class of luminescent osmium­(VI) nitrido complexes can be fine-tuned by introducing various substituents on the bidentate L ligand.

Visible Light-Induced Oxidation of Alcohols by a Luminescent Osmium(VI) Nitrido Complex: Evidence for the Generation of PhIO+ as a Highly Active Oxidant in the Presence of PhIO

“…When 98% 18 O-labeled PhI 18 O was used, 27 the ESI/MS of complexes 4−9 remained unchanged, revealing that the −OH groups in these complexes are all derived from R−OH rather than from PhIO. On the other hand, when 15 N-labeled Os 15 N was used, the parent peaks of the products in MS increased by one mass unit, indicating that the N atoms in these complexes are derived from the nitrido ligand.…”

“…In search for highly reactive M≡N species for the functionalization of a variety of organic substrates, we have initialized a program to study the reactivity of metal nitrides in the excited state. Accordingly, a highly luminescent Os­(VI) nitrido complex [Os VI (N)­(L)­(CN) 3 ] − ( OsN , HL = 2-(2-hydroxy-5-nitrophenyl)­benzoxazole) with strongly oxidizing LMCT excited states has been developed . Upon excitation by visible light, OsN* readily activates the stable C–H bonds of alkanes and arenes and undergoes oxidative N -dealkylation of tertiary amines, C–O bond cleavage of dihydroxybenzenes, ring nitrogenation of aromatic amines, and N-atom transfer to aliphatic secondary amines .…”

C−H Activation by an Iron‐Nitrido Bis‐Pocket Porphyrin Species

“…Their roles as nitrogen synthons in organic reactions have aroused increasing interest in recent years [3f, 28] . While C−H activation has been reported/proposed for several terminal metal‐nitrido species, [29] reactivity study of this elementary step remains relatively sparse and has so far been limited to an isolable Ru‐nitrido complex, [29g,i] a metastable dinuclear Ru‐nitrido complex, [29f, 30] and the LML′CT excited state of an Os‐nitrido complex [29m, 31] . In this work, we have studied the HAT reactivity of a highly reactive and short‐lived Fe porphyrin nitrido species by employing the nanosecond LFP technique.…”

Osmium(vi) nitride triggers mitochondria-induced oncosis and apoptosis

“…22 Although the two Os–O bond distances are non-equivalent [1.988(2) and 2.081(2) Å] due to the trans influence of the nitride, the tetradentate N 2 O 2 minimised the influence by its chelate effect, given that the respective trans Os–O (phenoxy) bond distances are >2.1 Å in other osmium( vi ) nitrides. 32,33…”