Ruthenium Nitrides: Redox Chemistry and Photolability of the Ru-Nitrido Group

Abstract

The metal nitride [1] group plays a key role in nitrogen transfer to organic [2±4] and inorganic [5] substrates. Such reactivity exists when the nitrido group is associated with a labile metal, which generally displays catalytic properties. To this end we considered the ruthenium ion in meso-octamethylporphyrinogen, [6] which is related to porphyrinÐthe macrocycle par excellence in ruthenium chemistry. Ruthenium nitride chemistry [7] has received considerable attention in the recent past, and some major issues are considered here: 1) the formation of the RuN group by cleavage of NÀN bonds [7] which mimic the N 2 molecule; 2) the redox chemistry associated with the [RuN] fragment, with the intent of tuning the nucleophilic ± electrophilic properties of the nitrido group; [7a,b] 3) the relationship between the terminal [Ru N] and the bridging [Ru N Ru] groups; 4) the photolabilization of RuÀN bonds; and 5) the use of a tetrapyrrolic macrocycle related to porphyrin, a key ligand in Ru chemistry and one with which the RuN group has so far not been associated. 559 Hz; 5 b). Elemental analysis (%): calcd for C 76 H 110 O 28 P 2 BF 4 Ag (1728.30): C 52.82, H 6.41; found: C 53.08, H 6.45; MS (FAB): m/z (%): 1657.4 (60) [M À BF 4 O], 1641.4 (100) [M À BF 4 ].

Vicinal Dinitridoruthenium‐Substituted Polyoxometalates γ‐[XW10O38{RuN}2]6− (X=Si or Ge)

“…Previously,78 we arrived at the same conclusion for polyoxometalates γ‐[XW 10 O 36 ] ( n –4)− with X=P 5+ , Si 4+ , Al 3+ , and S 6+ , that is, X from the same‐row elements. The ruthenium–nitrido bond length is almost identical in both species (1.594(10) Å in 1 a , 1.612(11) Å in 1 b ), and falls well within the relatively narrow range of values reported for Ru VI N (from 1.57 Å79 to 1.62 Å,80 except for two complexes at 1.66 Å32, 39). The average rutheniumoxygen bond lengths are 1.944(8) Å (RuO Ru ), 2.002(8) Å (RuO W ), and 2.696(8) Å (RuO Si ) for 1 a , 1.963(8) Å (RuO Ru ), 2.013(8) Å (RuO W ), and 2.523(8) Å (RuO Ge ) for 1 b .…”

Nitrido Ruthenium Porphyrins: Synthesis, Characterization, and Amination Reactions with Hydrocarbon or Silyl Enol Ethers

“…A wide variety of ruthenium porphyrins featuring axial RuN bonds have been prepared, including those bearing amine,1c, 3a,3b amido,3b–d,g imido,3a,c–e,g,j imine,3h, 4 methyleneamido,3h nitrile,1a, 2 hydrazido,3f nitrosoarene,1b, 3i nitrosyl,5 and dinitrogen1d axial ligands (Scheme , a – j ). This makes the lack of isolable ruthenium porphyrins with terminal nitrido axial ligands (Scheme 1, k ) especially conspicuous 6. 7…”

“…By employing indan instead of silyl enol ethers, the same reactions gave N ‐trifluoroacetyl indan‐1‐ylamine in 52 ( 1 a ) or 63 % ( 1 b ) yield (determined by GC), as shown in entries 5 and 6 in Table 1. These reactions are very striking, because many non‐porphyrin nitrido ruthenium complexes have been isolated, but none of these is reported to be reactive toward hydrocarbons or silyl enol ethers 6. 15, 16…”

Ion permeation through the gramicidin channel: Atomically detailed modeling by the stochastic difference equation

“…Die einzige terminale RuN‐Bindungslänge, die zu der in 1 vergleichbar ist, wurde in einer Ru V ‐Nitridospezies gefunden (ca. 1.74 Å),10 in der eines der drei d‐Elektronen des Ru V ‐Ions ein antibindendes Ru‐N‐π*‐Orbital besetzt, wodurch die Bindungsordnung verringert und die RuN‐Bindung verlängert wird.…”

“…Für diese Möglichkeit spricht, dass die RuN‐Bindung in 1 (1.76 Å) ähnlich lang ist wie in einem anderen Ru V ‐Nitridokomplex (ca. 1.74 Å),10 jedoch lassen die DFT‐Rechnungen zu 1 mod ein delokalisiertes System ohne gefüllte π*‐Orbitale vermuten. Zudem wurden keine N‐Hyperfeinwechselwirkungen im EPR‐Spektrum von 1 beobachtet, was für ein echtes Ru V ‐Nitridozentrum zu erwarten wäre.…”