A Synthetic Cycle for Nitrogen Atom Transfer Featuring a Diruthenium Nitride Intermediate

Abstract

A new Ru2 azido complex, [Ru2(chp)4N3] (4, chp = 2‐chloro‐6‐hydroxypyridinate), was investigated under photolytic conditions to study the chemical reactivity of the corresponding Ru2 nitride species, [Ru2(chp)4N] (6), towards intermolecular N atom transfer to triphenylphosphane (PPh3). Photolysis of a dichloromethane solution of 4 at λ > 350 nm leads to a characteristic color change from purple to magenta. Upon acidic workup, triphenylphosphanamine chloride ([H2NPPh3]Cl) is produced and [Ru2(chp)4Cl] (5), the precursor to 4, is regenerated. The first stoichiometric cycle for intermolecular N atom transfer from a Ru2 nitride is thus presented.

A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex

“…This is also similar to the case of Ru 2 -azide compounds that show Ru 2 N signals in their mass spectra due to photolysis. 2 To further support this hypothesis, we used labeled 18 O-nitrate (N 18 O 3 − ) to form Ru 2 (chp) 4 18 ON 18 O 2 ( 4 *), and we found that the Ru 2 O feature shifts in the mass spectrum to m/z = 735 amu (Figure 5). This shift clearly indicates that the axial O atom in the [Ru 2 (chp) 4 O] + ion derives from nitrate and is fully consistent with photo-dissociation of NO 2 • or NO 2 − from 4 .…”

“…As with the chloride precursor 3 22 and azide analog Ru 2 (chp) 4 N 3 , 2d the equatorial chp ligands in 4 and 5 are bound in a (4,0) orientation, which allows for the oxyanionic ligand to bind only to the exposed Ru axial site.…”

“…All materials were commercially available and used as received, unless otherwise noted. Compounds 1 26b,36 and 3 2d,22 were prepared according to literature procedures. Photolysis of frozen samples of 4 were performed in a Rayonet RPR-200 photochemical reactor with light from 254 and 350 nm mercury vapor lamps.…”

Formation of a Stannyl Amido Complex by the Reaction of a Terminal Iridium Nitrido Complex with a Stannane

“…For the characterization of the main product, the observation of a broad singlet in the 1 H NMR spectrum at δ = 8.25 ppm in [D 8 ]THF proved to be instructive, which shows 1 J coupling to the amido nitrogen atom (δ 15N = 122 ppm; 15 N, 1 H HSQC). A similar observation was made by us for the reaction of complex 1 and a related Ir nitrido complex with silanes (R 3 SiH, R = Et, Ph), which resulted in silyl amido complexes.…”

“…Recent reports evidenced the potential of isolated and putative nitrido complexes in intramolecular C-H [11] and dihydrogen [7,8] activation. Further prominent reactions include an hydrogen atom abstraction, [12] the dimerization to dinitrogen complexes, [13] nitrogen transfer, [14,15] and the reactions with the nucleophiles Me 3 NO [8,10] and Ph 3 P. [4,15] For the later reaction Smith et al have recently shown, that both, electron donation to and from the nitrido nitrogen atom take place in the transition state. [16] Recently, we have shown that square-planar iridium complexes with a terminal nitrido unit also react with silanes under insertion of the nitrido nitrogen atom into the Si-H bond.…”