Synthesis and isocyanate insertion reactions of tungsten(IV) imido complexes formed from W(CO)(acac)(N3)(PMe3)3 with azide as the oxidant

Reactivity of molybdenum–nitride complex bearing pyridine-based PNP-type pincer ligand toward carbon-centered electrophiles

“…An ureate ligand is coordinated to the molybdenum center with a Mo1-N2-C24 angle of 164.9(2)°at the apical position to the nitrogen atom of the pyridine ring, where the bond distances between Mo1-N2 and N2-C24 are 1.755(3) Å and 1.394(4) Å, respectively, which are in the typical bond ranges of metalureate complexes. 51,52 On the other hand, the bond lengths of C31-N4 (1.283(4) Å), C31-O2 (1.317(4) Å), and Mo1-O2 (2.115 (2) Å) indicate the coordination of an imidate ligand to the molybdenum atom. These results suggest that the nucleophilic attack of the nitride ligand of 1 to the first PhNCO molecule occurs together with the deprotonation of the benzylic proton of the PNP-type pincer ligand with the formed ureate ligand, then the second PhNCO molecule is coordinated to the molyb- When the reaction of 1 with 2 equiv.…”

C–H Bond Addition across a Transient Uranium–Nitrido Moiety and Formation of a Parent Uranium Imido Complex

“…For example, while cis- uranyl complexes have remained elusive, cis- bis­(imido) complexes are common. − Recent advances in the field of uranium nitrogen multiple bonds include isolation of the first examples of a terminal, molecular uranium-nitride, − uranium tris- and tetrakis-imido moieties, and the complete scission and functionalization of N 2 with a molecular uranium cluster compound. − The single example of a uranium complex with a terminal parent imido UNH moiety, [K­(15-crown-5) 2 ]­[U IV (Tren TIPS )­(NH)] (Tren TIPS = N-(CH 2 CH 2 NSi i Pr 3 ) 3 ), has been reported by Liddle and co-workers . Even in the d-block, where M–L multiple bonding is more prevalent, crystallographically characterized examples of parent imido complexes are rare. − The small number of these complexes is surprising because this functional group has been proposed as an intermediate in dinitrogen reduction to ammonia. ,, Indeed, uranium imido complexes are relevant in this context because of the high activity of uranium toward ammonia production reported in Haber’s patent in 1909…”

Bis(acetylacetonate) Tungsten(IV) Complexes Containing a π-Basic Diazoalkane or Oxo Ligand

“…We have previously reported the formation of tungsten(IV) oxo complexes in our attempts to produce tungsten imido species. 18 Additionally, sequential diastereoselective reduction of a π-bound nitrile to an imine ligand in a tungsten(IV) oxo coordination sphere is reported.…”

“…We have described a number of tungsten­(II) bis­(acetylacetonate) complexes with two π-acids in the coordination sphere. − We now report oxidation of the metal to generate tungsten­(IV) bis­(acetylacetonate) d 2 complexes with π-basic diazoalkane or oxo ligands in the coordination sphere. We have previously reported the formation of tungsten­(IV) oxo complexes in our attempts to produce tungsten imido species . Additionally, sequential diastereoselective reduction of a π-bound nitrile to an imine ligand in a tungsten­(IV) oxo coordination sphere is reported.…”