Schrock Richard R
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Philos Trans A Math Phys Eng Sci. 2005 Apr 15;363(1829):959-69; discussion 1035-40. doi: 10.1098/rsta.2004.1541.
Dinitrogen (N2) is reduced to ammonia at room temperature and 1atm with molybdenum catalysts that contain tetradentate [HIPTN3N]3- triamidoamine ligands {[HIPTN3N]3-=[{3,5-(2,4,6-i-Pr3C6H2)2C6H3NCH2CH2}3N]3-, an example being [HIPTN3N]Mo(N2)} in heptane. Slow addition of the proton source ({2,6-lutidinium}{BAr'4}; Ar'=3,5-(CF3)2C6H3) and reductant (decamethyl chromocene) assure a high yield of ammonia (63-65% in four turnovers) versus dihydrogen formation. Numerous X-ray studies, along with isolation and characterization of seven intermediates in the proposed catalytic reaction (under noncatalytic conditions), suggest that N2 is being reduced at a sterically protected, single Mo centre that cycles between states Mo(III), Mo(IV), Mo(V) and Mo(VI).
在室温及1个大气压下，使用含有四齿[HIPTN3N]3-三酰胺基胺配体（{[HIPTN3N]3- = [{3,5-(2,4,6-异丙基-3-苯基)2-苯基}3-氮丙啶]3-，例如[HIPTN3N]Mo(N2)}）的钼催化剂，在庚烷中将氮气（N2）还原为氨。缓慢加入质子源（{2,6-二甲基吡啶鎓}{BAr'4}；Ar' = 3,5-(三氟甲基)2-苯基）和还原剂（十甲基二茂铬）可确保与生成氢气相比，氨的产率较高（四个循环中为63 - 65%）。大量的X射线研究，以及对所提出的催化反应中七种中间体的分离和表征（在非催化条件下）表明，N2在一个空间位阻保护的单一钼中心被还原，该中心在Mo(III)、Mo(IV)、Mo(V)和Mo(VI)状态之间循环。
