916042-47-2Relevant academic research and scientific papers
Synthesis of molybdenum complexes that contain hybrid triamidoamine ligands, [(hexaisopropylterphenyl-NCH2CH 2)2NCH2CH2N-aryl]3-, and studies relevant to catalytic reduction of dinitrogen
Weare, Walter W.,Schrock, Richard R.,Hock, Adam S.,Mueller, Peter
, p. 9185 - 9196 (2008/10/09)
In the Buchwald-Hartwig reaction between HIPTBr (HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C 6H3 = hexaisopropylterphenyl) and (H2NCH 2CH2)3N, it is possible to obtain a 65% isolated yield of (HIPTNHCH2CH2)2NCH 2CH2NH2. A second coupling then can be carried out to yield a variety of hybrid ligands, (HIPTNHCH 2CH2)2NCH2CH2NHAr, where Ar = 3,5-Me2C6H3, 3,5-(CF3) 2C6H3, 3,5-(MeO)2C6H 3, 3,5-Me2NC5H3, 3,5-Ph 2NC5H3, 2,4,6-i-Pr3C 6H2, or 2,4,6-Me3C6H2. The hybrid ligands may be attached to Mo to yield [hybrid]MoCl species. From the monochloride species, a variety of other species such as [hybrid]MoN, {[hybrid]MoN2}Na, and {[hybrid]Mo(NH3)}+ can be prepared. [Hybrid]MoN2 species were prepared through oxidation of {[hybrid]MoN2}Na species with ZnCl2, but they could not be isolated. [Hybrid]Mo=N-NH species could be observed as a consequence of the protonation of {[hybrid]MoN2}- species, but they too could not be isolated as a consequence of a facile decomposition to yield dihydrogen and [hybrid]MoN2 species. Attempts to reduce dinitrogen catalytically led to little or no ammonia being formed from dinitrogen. The fact that no ammonia was formed from dinitrogen in the case of Ar = 3,5-Me2C 6H3, 3,5-(CF3)2C6H 3, or 3,5-(MeO)2C6H3 could be attributed to a rapid decomposition of intermediate [hybrid]Mo=N-NH species in the catalytic reaction, a decomposition that was shown in separate studies to be accelerated dramatically by 2,6-lutidine, the conjugate base of the acid employed in the attempted catalytic reduction. X-ray structures of [(HIPTNHCH2CH2)NCH2CH2N{3,5-(CF 3)2C6H3}]MoCl and [(HIPTNHCH 2CH2)2NCH2CH2N(3,5- Me2C6H3)]MoN2}Na(THF)2 are reported.
