Protonation of the dinitrogen-reduction catalyst [HIPTN3N]Mo(III) investigated by ENDOR spectroscopy.

ABSTRACT: Dinitrogen is reduced to ammonia by the molybdenum complex of L = [HIPTN3N](3-) [Mo; HIPT = 3,5-(2,4,6-iPr3C6H2)2C6H3]. The mechanism by which this occurs involves the stepwise addition of proton/electron pairs, but how the first pair converts MoN2 to MoN ═ NH remains uncertain. The first proton of reduction might bind either at Nβ of N2 or at one of the three amido nitrogen (N(am)) ligands. Treatment of MoCO with [2,4,6-Me3C5H3N]BAr'4 [Ar' = 2,3-(CF3)2C6H3] in the absence of reductant generates HMoCO(+), whose electron paramagnetic resonance spectrum has greatly reduced g anisotropy relative to MoCO. (2)H Mims pulsed electron nuclear double-resonance spectroscopy of (2)HMoCO(+) shows a signal that simulations show to have a hyperfine tensor with an isotropic coupling, aiso((2)H) = -0.22 M

SUBMITTER: Kinney RA 

PROVIDER: S-EPMC3139016 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature