Synthetic Nitrogen Fixation with Mononuclear Molybdenum(0) Phosphine Complexes: Occupying the trans-Position of Coordinated N2

2017 ◽  
pp. 113-152 ◽  
Author(s):  
Nadja Stucke ◽  
Thomas Weyrich ◽  
Mareike Pfeil ◽  
Katharina Grund ◽  
Andrei Kindjajev ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Trans Position ◽  
Phosphine Complexes

ChemInform Abstract: New Developments in Synthetic Nitrogen Fixation with Molybdenum and Tungsten Phosphine Complexes

ChemInform ◽  
2010 ◽  
Vol 41 (51) ◽  
pp. no-no
Author(s):  
Ameli Dreher ◽  
Gerald Stephan ◽  
Felix Tuczek
Keyword(s):  
Nitrogen Fixation ◽  
New Developments ◽  
Phosphine Complexes ◽  
And Tungsten

Nitrogen Fixation Revisited on Iron(0) Dinitrogen Phosphine Complexes

2015 ◽  
Vol 54 (10) ◽  
pp. 4768-4776 ◽  
Author(s):  
Leslie D. Field ◽  
Nilay Hazari ◽  
Hsiu L. Li
Keyword(s):  
Nitrogen Fixation ◽  
Phosphine Complexes

ChemInform Abstract: Synthetic Nitrogen Fixation with Molybdenum and Tungsten Phosphine Complexes: New Developments

ChemInform ◽  
2010 ◽  
Vol 41 (50) ◽  
pp. no-no
Author(s):  
Gerald Stephan ◽  
Felix Tuczek
Keyword(s):  
Nitrogen Fixation ◽  
New Developments ◽  
Phosphine Complexes ◽  
And Tungsten

Bonding, activation, and protonation of dinitrogen on a molybdenum pentaphosphine complex — Comparison to trans-bis(dinitrogen) and -nitrile – dinitrogen complexes with tetraphosphine coordination

2005 ◽  
Vol 83 (4) ◽  
pp. 385-402 ◽  
Author(s):  
Gerald C Stephan ◽  
Gerhard Peters ◽  
Nicolai Lehnert ◽  
Carsten M Habeck ◽  
Christian Näther ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Nitrogen Fixation ◽  
Analysis Procedure ◽  
Normal Coordinate Analysis ◽  
Triflic Acid ◽  
Normal Coordinate ◽  
Phosphine Complexes ◽  
Dinitrogen Complexes ◽  
Donor Acceptor ◽  
Ir And Raman

The molybdenum-N2 pentaphosphine complex [Mo(N2)(dpepp)(dppm)] (1) containing a bi- and a tridentate phosphine ligand (dpepp = PhP(CH2CH2PPh2)2, dppm = Ph2PCH2PPh2) has been prepared and characterized. By protonation of 1 with triflic acid the NNH2 complex [Mo(NNH2)(dpepp)(dppm)](CF3SO3)2 (2) is formed without loss of the pentaphosphine coordination. The electronic properties of 1 and 2 and their 15N and (or) 2H counterparts are investigated by NMR, IR, and Raman spectroscopy coupled to DFT frequency and NMR shift calculations. Force constants are evaluated from experimental frequencies and isotope shifts by the quantum chemistry based normal coordinate analysis procedure (QCB-NCA). The results for the N2 complex 1 are compared with those obtained earlier for bis(dinitrogen) and trans-nitrile dinitrogen systems. Importantly, the N2 in the pentaphosphine complex is more strongly activated compared to corresponding bis(dinitrogen) compounds and more weakly activated compared to trans-nitrile N2 systems. The activation of the NNH2 ligand in complex 2 is similar to trans-nitrile systems and weaker compared to corresponding NNH2 complexes with coordinated anions like [MoF(NNH2)(dppe)2](BF4). These results are discussed based on the relative donor–acceptor properties of the respective trans ligands, demonstrating the influence of σ donation and π acceptance on the activation of N2 in transition metal complexes.Key words: nitrogen fixation, phosphine complexes, NMR shifts, DFT calculations, normal coordinate analysis.

scholarly journals Ammonia Formation Catalyzed by Dinitrogen-Bridged Dirhenium Complex Bearing PNP-Pincer Ligands under Mild Reaction Conditions

2020 ◽  
Author(s):  
Fanqiang Meng ◽  
Shogo Kuriyama ◽  
Hiromasa Tanaka ◽  
Akihito Egi ◽  
Kazunari Yoshizawa ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Pincer Ligands ◽  
Pincer Ligand ◽  
Reaction Conditions ◽  
Rhenium Atom ◽  
Phosphine Complexes ◽  
Proton Source ◽  
Dinitrogen Complexes ◽  
Dinitrogen Complex ◽  
Ammonia Formation

A series of rhenium complexes bearing a pyridine-based PNP-type pincer ligand are synthesized from rhenium phosphine complexes as precursors. A dinitrogen-bridged dirhenium complex bearing the PNP-type pincer ligands catalytically converts dinitrogen into ammonia in the reaction with KC<sub>8</sub> as a reductant and [HPCy<sub>3</sub>]BAr<sup>F</sup><sub>4</sub> (Cy = cyclohexyl, Ar<sup>F</sup> = 3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>) as a proton source at –78 °C to afford 8.4 equiv of ammonia based on the rhenium atom of the catalyst. The rhenium-dinitrogen complex also catalyzes silylation of dinitrogen in the reaction with KC<sub>8</sub> as a reductant and Me<sub>3</sub>SiCl as a silylating reagent under ambient reaction conditions to afford 11.3 equiv of tris(trimethylsilyl)amine based on the rhenium atom of the catalyst. These results demonstrate the first successful example of catalytic nitrogen fixation under mild reaction conditions by using rhenium-dinitrogen complexes as catalysts.

New developments in synthetic nitrogen fixation with molybdenum and tungsten phosphine complexes

2009 ◽  
pp. 367-405 ◽  
Author(s):  
Ameli Dreher ◽  
Gerald Stephan ◽  
Felix Tuczek
Keyword(s):  
Nitrogen Fixation ◽  
New Developments ◽  
Phosphine Complexes ◽  
And Tungsten

scholarly journals Ammonia Formation Catalyzed by Dinitrogen-Bridged Dirhenium Complex Bearing PNP-Pincer Ligands under Mild Reaction Conditions

2020 ◽  
Author(s):  
Fanqiang Meng ◽  
Shogo Kuriyama ◽  
Hiromasa Tanaka ◽  
Akihito Egi ◽  
Kazunari Yoshizawa ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Pincer Ligands ◽  
Pincer Ligand ◽  
Reaction Conditions ◽  
Rhenium Atom ◽  
Phosphine Complexes ◽  
Proton Source ◽  
Dinitrogen Complexes ◽  
Dinitrogen Complex ◽  
Ammonia Formation

A series of rhenium complexes bearing a pyridine-based PNP-type pincer ligand are synthesized from rhenium phosphine complexes as precursors. A dinitrogen-bridged dirhenium complex bearing the PNP-type pincer ligands catalytically converts dinitrogen into ammonia in the reaction with KC<sub>8</sub> as a reductant and [HPCy<sub>3</sub>]BAr<sup>F</sup><sub>4</sub> (Cy = cyclohexyl, Ar<sup>F</sup> = 3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>) as a proton source at –78 °C to afford 8.4 equiv of ammonia based on the rhenium atom of the catalyst. The rhenium-dinitrogen complex also catalyzes silylation of dinitrogen in the reaction with KC<sub>8</sub> as a reductant and Me<sub>3</sub>SiCl as a silylating reagent under ambient reaction conditions to afford 11.3 equiv of tris(trimethylsilyl)amine based on the rhenium atom of the catalyst. These results demonstrate the first successful example of catalytic nitrogen fixation under mild reaction conditions by using rhenium-dinitrogen complexes as catalysts.

Factors controlling nitrogen fixation in temperate seagrass beds

2015 ◽  
Vol 525 ◽  
pp. 41-51 ◽  
Author(s):  
PLM Cook ◽  
V Evrard ◽  
RJ Woodland
Keyword(s):  
Nitrogen Fixation ◽  
Seagrass Beds

NEW CLOVER CULTIVARS FOR WAIKATO DAIRY PASTURE: ESTABLISHMENT, PRODUCTION AND NITROGEN FIXATION DURING THE FIRST YEAR

1988 ◽  
pp. 207-211
Author(s):  
S.F. Ledgard ◽  
G.J. Brier ◽  
R.N. Watson
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Dairy Cow ◽  
Red Clover ◽  
First Year ◽  
Buried Seed

Clover cultivars grown with ryegrass were compared in an establishment year under dairy cow grazing. There was no difference in total annual productton but summer production was greater with Pawera red clover and with Kopu or Pitau white clovers. Clovers differed little in the proportion of nitrogen fixed, except during summer when values were highest for Pawera. Pawera was less prone to nematode attack than white clover cultivars but was more susceptible to clover rot. Resident clovers and high buried seed levels (e.g., 11-91 kg/ha) made introduction of new clover cultivars difficult. Sown clovers established best (50-70% of total clover plants) when drilled into soil treated with dicamba and glyphosate. Keywords: white clover, red clover, nematodes. nitrogen fixation, pasture renovation

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