Triamidoamine complexes of molybdenum and tungsten that contain metal-E (E = N, P, and As) single, double, or triple bonds

Addition of two or more equivalents of LiPPhH to [N3N]MCl ([N3N](3-) = [(Me3SiNCH2CH2)(3)N](3-); M = Mo or W) produced [N3N]M=P complexes via intermediate [N3N]M(PPhH) complexes. The reaction between [N3N]MoCl and 2 equiv of LiAsPhH in the absence of light gave a mixture of [N3N]Mo=As (similar to 30% yield) and [N3N] MoPh. [N3N]Mo=N and [N3N]W=N were both prepared via decomposition of intermediate azide complexes. Tungsten nitrido, phosphido, or arsenide complexes react readily with methyl triflate in toluene to give the cationic methyl imido, methyl phosphinidene, and methyl arsinidene complexes, respectively. Addition of methyl triflate or trimethylsilyl triflate to [N3N]Mo=N yields the cationic imido complexes {[N3N]Mo=NMe)OTf and {[N3N]-Mo=NSiMe3}OTf, respectively, but {[N3N]Mo=PMe}OTf is not stable in solution at room temperature for more than 1-2 h. The reaction between ''[Rh(CO)(2)(CH3CN)(2)]PF6'' and 2 equiv of [N3N]Mo=P or [N3N]W=P gave red, crystalline adducts that contain two [N3N]M=P ''ligands'', e.g., [Rh{[N3N]W=P}(2)(CP)(CH3CN)](+), while red, crystalline [Rh{[N3N]W=As}(2)(CO)(CH3CN)]PF6 could be prepared by an analogous route. {[N3N]Mo=NSiMe3}OTf could be reduced to ''19-electron'' [N3N]Mo=NSiMe3, while addition of MeMgCl to {[N3N]Mo=NSiMe3}OTf or {[N3N]Mo=NMe}OTf yielded complexes of the type [N3N]Mo(NR)(Me). The complex in which R = Me was unstable with respect to loss of methane and formation of the iminato complex, [N3N]Mo(N=CH2). Both [N3NF]W-(PPhH) and [N3NF]Mo(PPhH) ([N3NF](3-) = [(C6F5NCH2CH2)(3)N](3-)) could be prepared readily, but all attempts to prepare [N3NF]W=P failed. X-ray studies of [N3N]W=P, [N3N]Mo(PPhH), [N3N]Mo=As, {[N3N]W=AsMe}OTf, [Rh{[N3N]W=P}(2)(CO)(CH3CN)](+), and [N3N]Mo=NSiMe3 are presented and discussed.