155019-75-3Relevant academic research and scientific papers
Synthesis, structure, and electrochemical studies of molybdenum and tungsten dinitrogen, diazenido, and hydrazido complexes that contain aryl-substituted triamidoamine ligands
Greco,Schrock
, p. 3861 - 3878 (2008/10/08)
One-electron reduction of [ArN3N]MoCl complexes (Ar = C6H5, 4-FC6H4, 4-t-BuC6H4, 3,5-Me2C6H3) yields complexes of the type [ArNr3N]Mo-N=N-Mo[ArN3N], while two-electron reduction yields {[ArN3N]Mo-N= N}- derivatives (Ar = C6H5, 4-FC6H4, 4-t-BuC6H4, 3,5-Me2C6H3, 3,5-Ph2C6H3, and 3,5-(4-t-BuC6H4) 2C6H3). Compounds that were crystallographically characterized include {[t-BuC6H4N3N]Mo}2 (N2), Na(THF)6{[PhN3N]Mo-N=N}2Na(THF)3, [t-BuC6H4N3N]Mo-N=N-Na(15-crown-5), and {[Ph2C6H3N3N]MoNN}2 Mg(DME)2. Compounds of the type [ArN3N]Mo-N=N-Mo[ArN3N] do not appear to form when Ar = 3,5-Ph2C6H3 or 3,5-(4t-BuC6H4)2C6H3, presumably for steric reasons. Treatment of diazenido complexes (eg., [ArN3N]Mo-N=NNa(THF)x) with electrophiles such as Me3SiCl or MeOTf yielded [ArN3N]Mo-N=NR complexes (R = SiMe3 or Me). These species react further to yield {[ArN3N]Mo-N=NMe2}+ species in the presence of methylating agents. Addition of anionic methyl reagents to {[ArN3N]Mo-N=NMe2}+ species yielded [ArN3N]Mo(N=NMe2)(Me) complexes. Reduction of [4-t-BuC6H4N3N]WCl under dinitrogen leads to a rare {[t-BuC6H4N3N]W}2(N2) species that can be oxidized by two electrons to give a stable dication (as its BPh4- salt). Reduction of hydrazido species leads to formation of MoN in low yields, and only dimethylamine could be identified among the many products. Electrochemical studies revealed expected trends in oxidation and reduction potentials, but also provided evidence for stable neutral dinitrogen complexes of the type. [ArN3N]Mo(N2) when Ar is a relatively bulky terphenyl substituent.
Synthesis of molybdenum and tungsten complexes that contain triamidoamine ligands of the type (C6F5NCH2CH2)3N and activation of dinitrogen by molybdenum
Kol, Moshe,Schrock, Richard R.,Kempe, Rhett,Davis, William M.
, p. 4382 - 4390 (2007/10/02)
Three new ligands of the type (ArNHCH2CH2)3N(Ar = 3,5-bis(trifluoromethyl)phenl,2-(trifluomethyl)-phenyl, and pentafluorophenyl) have been prepared. Only Mo and W complexes containing the [(C6F5NCH2CH2)3N] 3- ([N3N]3-) ligand were found to be stable. Stable complexes that have been prepared include Mo[N3N](NMe2), M[N3N]Cl (M = Mo or W), Mo[N3N](OTf) (M = Mo or W), [N3N]M≡N (M = Mo or W), and {[N3N]Mo=NMe}-(Otf). An X-ray study of Mo[N3N]Cl showed it to be a monomeric distorted trigonal bipyramidal species having a pseudo-C3 symmetry (space group P1, a = 11.265(2) ?, b = 11.371(2) ?, c = 21.805(4) ?, α = 82.40(1)°, β = 79.07(1)°, γ = 74.89(1)°, V = 2637.4 ?3, Z = 4, fw = 772.75, ρ(calcd) = 1.946 g/cm3, R = 0.032, Rw = 0.034). Reduction of Mo[N3N](OTf) with 1 equiv of sodium amalgam yields a dinuclear bridging dinitrogen species, [N3N]-Mo(μ-N2)Mo[N3N]. In the presence of 2 equiv of sodium amalgam in ether Mo[N3N](Otf) is reduced to [N3N]-Mo(N2) [Na(ether)x] (1 3N]Mo(μ-N2)Mo[N3N] can be reduced to [N3N]Mo(N2)[NaLx] by sodium amalgam under dinitrogen and the latter can be oxidized to the former by ferrocenium triflate or air. [N3N]Mo(N2)[NaLx] reacts with Mo[N3N](OTf) to give [N3N]Mo(μ-N2)Mo[N3N], with triisopropylsilyl chloride to give [N3N]MoN=NSi(i-Pr)3, and with tributyltin chloride to give [N3N]MoN=NSn(Bu)3. An X-ray study of [N3N]MoN=NSi(i-Pr)3(space group P21/n, a= 13.524-(3) ?, b = 18.016(4) ?, c = 16.248(3) ?, β = 98.74(2)°, V = 3913(1) ?3 = 4, fw = 922.67, ρ(calcd) = 1.566 g/cm3, R = 0.069 Rw = 0.072) showed it to be a trigonal bipyramidal complex containing a slightly bent diazenido ligand (Mo-Nα = 1.788(9) ?, Mo-Nα-Nβ = 171.1(8)°, Nα-Nβ-Si = 154(1)°).
