155019-66-2Relevant academic research and scientific papers
Synthesis of [(Me3SiNCH2CH2)3N]3- and [(C6F5NCH2CH2)3N] 3- complexes of molybdenum and tungsten that contain CO, isocyanides, or ethylene
Greco, George E.,O'Donoghue, Myra B.,Seidel, Scott W.,Davis, William M.,Schrock, Richard R.
, p. 1132 - 1145 (2008/10/08)
Paramagnetic complexes of the type [N3N]MoL ([N3N]3- = [(Me3SiNCH2CH2)3N]3-; L = CO, RNC, C2H4) have been prepared by displacing dinitrogen from [N3N]Mo(N2). [N3N]Mo-(CO) was reduced by magnesium powder in the presence of Me3SiCl to yield the diamagnetic oxycarbyne complex [N3N]Mo≡COSiMe3, while oxidation of [N3N]Mo(CN-t-Bu) with [Cp2-Fe]OTf yielded {[N3N]Mo(CN-t-Bu)}OTf. Thermolysis of [N3N]Mo(CN-t-Bu) resulted in loss of a t-Bu radical to yield [N3N]Mo(CN), which was structurally characterized. [N3NF]ML ([N3NF]3- = [(C6F5NCH2CH2)3N] 3-; M = Mo, W; L = CO, RNC) complexes have been prepared by one-electron reduction of [N3NF]M(OTf) in the presence of L. An X-ray study of [N3NF]W-(CN-t-Bu) showed it to contain a bent isocyanide ligand. Anionic CO complexes were prepared by the two-electron reduction of [N3NF]M(OTf) in the presence of CO. An X-ray study of {[N3NF]W(CO)2}Na(ether)3 revealed it to have a pseudo-octahedral structure in which sodium is bound to the CO trans to the amine donor atom. Treatment of {[N3NF]M(CO)}- complexes with Me3SiCl gave oxycarbyne complexes [N3NF]M≡COSiMe3. Reaction of [N3NF]WCO with V(Mes)3(THF) yielded [N3NF]W(CO)V(Mes)3, the structure of which was determined in an X-ray study. Cationic [N3Np]3- complexes could be prepared that contain up to 3 equiv of isocyanide. An X-ray study of {[N3NF]W(CN-t-Bu)3}BPh4 showed it to be a seven-coordinate species with one isocyanide located in the equatorial plane and the other two isocyanide ligands in the apical pocket. Reduction of [N3NF]W(OTf) under ethylene gave [N3NF]W(C2H4), which could be oxidized to yield diamagnetic {[N3NF]W(C2H4)}OTf.
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)°).
