Metal‐Mediated Production of Isocyanates, R₃ENCO from Dinitrogen, Carbon Dioxide, and R₃ECl

Abstract

A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N2 , CO2 and R3 ECl (E=C, Si, and Ge). Key steps include a 'one-pot' photolytic N-N bond cleavage of a Group 6 dinuclear dinitrogen complex with in situ trapping by R3 ECl to provide a metal terminal imido complex that can engage in simultaneous nitrene-group transfer and oxygen-atom transfer to generate an intermediate metal terminal oxo complex with release of the isocyanate product. Reaction of the oxo complex with additional equivalents of R3 ECl regenerates a metal dichloride that is the precursor for dinuclear dinitrogen starting material.

Direct Transformation of Molecular Dinitrogen into Ammonia Catalyzed by Cobalt Dinitrogen Complexes Bearing Anionic PNP Pincer Ligands

“…[1] To elucidate the reaction mechanism of nitrogen fixation catalyzed by nitrogenases,t he synthesis and reactivity of various transition-metal dinitrogen complexes have been extensively studied. [2,3] As ar esult, nitrogen fixation with molybdenum dinitrogen complexes as the catalysts under ambient reaction conditions was achieved by Schrock and Yandulov in 2003 [4] and by our groups in 2010. [5] Recently,Peters and co-workers developed an iron-catalyzed reduction of molecular dinitrogen into ammonia using iron dinitrogen complexes as catalysts under mild reaction conditions.…”

“…[6] However,t he transformation of molecular dinitrogen into ammonia under mild reaction conditions using other transition-metal dinitrogen complexes as the catalysts has not yet been achieved. [2,3] Thef irst cobalt dinitrogen complex, [Co(H)(N 2 )(PPh 3 ) 3 ], was reported by Yamamoto and co-workers as the successful example of the synthesis of at ransition-metal dinitrogen complex directly from dinitrogen gas. [7] Since the discovery of this complex, detailed studies on the stoichiometric reactivity of avariety of cobalt dinitrogen complexes have been carried out by several research groups.…”

“…[7] Since the discovery of this complex, detailed studies on the stoichiometric reactivity of avariety of cobalt dinitrogen complexes have been carried out by several research groups. [2c,d, 8, 9] In 2015, our group and Lu and co-workers independently found that some cobalt complexes are effective catalysts for the reduction of dinitrogen gas into silylamine (N(SiMe 3 ) 3 ), which is regarded as an ammonia equivalent, under ambient reaction conditions. [10,11] In sharp contrast to the catalytic formation of N(SiMe 3 ) 3 ,the cobalt-catalyzed direct formation of ammonia from molecular dinitrogen has not been reported to date.I n 2015, Peters and co-workers reported the "superstoichiometric" direct formation of ammonia by using acobalt dinitrogen complex bearing at ris(phosphine)borane ligand, but the amount of formed ammonia (2.4 equiv) based on the amount of catalyst used was not sufficient for the reaction to be considered catalytic.…”

Remarkable catalytic activity of dinitrogen-bridged dimolybdenum complexes bearing NHC-based PCP-pincer ligands toward nitrogen fixation

“…Despite intensive efforts for the transformation of dinitrogen gas using transition metal–dinitrogen complexes as catalysts under mild reaction conditions910111213141516, only a few systems have succeeded in the catalytic formation of ammonia from dinitrogen gas171819202122232425262728. In 2003, Yandulov and Schrock29303132 reported the first successful example of the catalytic conversion of dinitrogen gas into ammonia using a molybdenum–dinitrogen complex as a catalyst and in 2013 Peters and co-workers33343536373839 reported the iron-catalysed transformation using an iron–dinitrogen complex as a catalyst.…”

Alkali-Controlled C–H Cleavage or N–C Bond Formation by N2-Derived Iron Nitrides and Imides

“…6 In other cases, the nucleophilicity of coordinated N 2 has been utilized in order to bring about reactions with electrophiles by Hidai, Fryzuk, Chirik, Sita, Schrock, Nishibayashi, and Pe-ters. 7,8 …”