Catalytic reduction of dinitrogen to ammonia at well-defined single metal sites
Catalytic reduction of dinitrogen to ammonia at well-defined single metal sites
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DOI：
10.1098/rsta.2004.1541
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发表时间：
2005-04-15
期刊：
影响因子：
5
通讯作者：
Schrock, RR
中科院分区：
文献类型：
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作者：
Schrock, RR
在室温和1个大气压下，用钼催化剂将二氮（N-2）还原成氨，所述钼催化剂含有在庚烷中的四齿[HIPTN 3 N]（3-）三酰胺基胺配体{[HIPTN 3 N]（3-）= [{3，5-（2，4，6-i-Pr 3C 6 H2）（2）C6 H3 NCH 2CH 2}（3）N]（3-），实例是[HIPTN 3 N]Mo（N-2）}。缓慢加入质子源（{2，6-lutinium}{BAr 4 ′}; Ar 4 ′ = 3，5-（CF 3）（2）C6 H3）和还原剂（十甲基二茂铬）确保了氨的高产率（在四次转换中为63- 65%），而不是二氢的形成。大量的X射线研究，沿着分离和表征了在所提出的催化反应中的七个中间体（在非催化条件下），表明N-2在空间保护的单个Mo中心被还原，该Mo中心在Mo（III）、Mo（IV）、Mo（V）和Mo（VI）状态之间循环。
Dinitrogen (N-2) is reduced to ammonia at room temperature and 1 atm with molybdenum catalysts that contain tetradentate [HIPTN3N](3-) triamidoamine ligands {[HIPTN3N](3-) = [{3,5-(2,4,6-i-Pr3C6H2)(2)C6H3NCH2CH2}(3)N](3-), an example being [HIPTN3N]Mo(N-2)} in heptane. Slow addition of the proton source ({2,6-lutidinium}{BAr4'}; Ar'=3,5-(CF3)(2)C6H3) 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 N-2 is being reduced at a sterically protected, single Mo centre that cycles between states Mo(III), Mo(IV), Mo(V) and Mo(VI).