scholarly journals H2 Formation Holds the Key to Opening the Fe Coordination Sites of Nitrogenase FeMo-cofactor for Dinitrogen Activation

2020 ◽  
Author(s):  
Yong Li ◽  
Wan-Lu Li ◽  
Jin-Cheng Liu ◽  
Jun-Bo Lu ◽  
W. H. Eugen Schwarz ◽  
...  
Keyword(s):  
Double Bond ◽  
Binding Site ◽  
Energy Release ◽  
Triple Bond ◽  
Quantum Mechanical ◽  
Essential Step ◽  
Coordination Sites ◽  
Femo Cofactor ◽  
H2 Formation ◽  
Electron Transfers

The present quantum-mechanical and molecular-mechanics study reveals the crucial roles of H<sub>2</sub> formation, of H<sub>2</sub>S shift and of N<sub>2</sub> bond expansion in the nitrogenase process of the reduction of N<sub>2</sub> to <a href="https://en.wikipedia.org/wiki/Ammonia">NH<sub>3</sub></a>. Proton and electron transfers to the Fe(C@Fe<sub>6</sub>S<sub>9</sub>)Mo unit of the FeMo-co complex weaken the Fe-S and Fe-H bonds and expose the <b>Fe</b> coordination sites, coupled with energy release due to H<sub>2</sub> generation. Thereby the two sites <b>Fe2</b> and <b>Fe6</b> become prepared for stronger N<sub>2</sub> adsorption, expanding and attenuating the ǀN≡Nǀ bond. After subsequent detachment of H<sub>2</sub>S from its Fe binding site into a holding site of the rearranged protein residue, the <b>Fe6</b> site becomes completely unfolded, and the N<sub>2</sub> triple bond becomes completely activated to an ‑<u>N</u>=<u>N</u>- double bond for easy subsequent hydrogenation to NH<sub>3</sub>. We explain in particular, why the obligatory H<sub>2</sub> formation is an essential step in N<sub>2</sub> adsorption and activation

scholarly journals H2 Formation Holds the Key to Opening the Fe Coordination Sites of Nitrogenase FeMo-cofactor for Dinitrogen Activation

2020 ◽  
Author(s):  
Yong Li ◽  
Wan-Lu Li ◽  
Jin-Cheng Liu ◽  
Jun-Bo Lu ◽  
W. H. Eugen Schwarz ◽  
...  
Keyword(s):  
Double Bond ◽  
Binding Site ◽  
Energy Release ◽  
Triple Bond ◽  
Quantum Mechanical ◽  
Essential Step ◽  
Coordination Sites ◽  
Femo Cofactor ◽  
H2 Formation ◽  
Electron Transfers

The present quantum-mechanical and molecular-mechanics study reveals the crucial roles of H<sub>2</sub> formation, of H<sub>2</sub>S shift and of N<sub>2</sub> bond expansion in the nitrogenase process of the reduction of N<sub>2</sub> to <a href="https://en.wikipedia.org/wiki/Ammonia">NH<sub>3</sub></a>. Proton and electron transfers to the Fe(C@Fe<sub>6</sub>S<sub>9</sub>)Mo unit of the FeMo-co complex weaken the Fe-S and Fe-H bonds and expose the <b>Fe</b> coordination sites, coupled with energy release due to H<sub>2</sub> generation. Thereby the two sites <b>Fe2</b> and <b>Fe6</b> become prepared for stronger N<sub>2</sub> adsorption, expanding and attenuating the ǀN≡Nǀ bond. After subsequent detachment of H<sub>2</sub>S from its Fe binding site into a holding site of the rearranged protein residue, the <b>Fe6</b> site becomes completely unfolded, and the N<sub>2</sub> triple bond becomes completely activated to an ‑<u>N</u>=<u>N</u>- double bond for easy subsequent hydrogenation to NH<sub>3</sub>. We explain in particular, why the obligatory H<sub>2</sub> formation is an essential step in N<sub>2</sub> adsorption and activation

Nature of the carbon-phosphorus double bond and the carbon-phosphorus triple bond as studied by solid-state NMR

1990 ◽  
Vol 112 (19) ◽  
pp. 6803-6809 ◽  
Author(s):  
James C. Duchamp ◽  
Marek Pakulski ◽  
Alan H. Cowley ◽  
Kurt W. Zilm
Keyword(s):  
Double Bond ◽  
Solid State ◽  
Solid State Nmr ◽  
Triple Bond

scholarly journals 3-Phenyl-N,N,N′,N′-tetramethyl-1-ethyne-1-carboximidamidium bromide

2012 ◽  
Vol 68 (6) ◽  
pp. o1812-o1812 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Triple Bond ◽  
Positive Charge ◽  
Bond Distance ◽  
Double Bond Character ◽  
Acetylenic Bond ◽  
Compound C ◽  
Bond Character

The reaction of 3,3,3-tris(dimethylamino)-1-phenylprop-1-yne with bromine in pentane yields the title compound, C13H17N2 +·Br−. The acetylenic bond distance [1.197 (2) Å] is consistent with a C[triple-bond]C triple bond. The amidinium C=N bonds [1.325 (2) and 1.330 (2) Å] have double-bond character and the positive charge is delocalized between the two dimethylamino groups.

Pharmacological effects of introducing a double bond into a binding site of oxytocin. Analogs with L-3,4-dehydroproline in position 7

1977 ◽  
Vol 20 (4) ◽  
pp. 495-500 ◽  
Author(s):  
Stanley Moore ◽  
Arthur M. Felix ◽  
Johannes Meienhofer ◽  
Clark W. Smith ◽  
Roderich Walter
Keyword(s):  
Double Bond ◽  
Binding Site ◽  
Pharmacological Effects

Novel Finding of the Effect of Triple Bond on the Photochemicalcis–transIsomerization of C=C Double Bond

2001 ◽  
Vol 30 (10) ◽  
pp. 1050-1051 ◽  
Author(s):  
Hirokazu Sakakibara ◽  
Masashi Ikegami ◽  
Kakuzo Isagawa ◽  
Sachiko Tojo ◽  
Tetsuro Majima ◽  
...  
Keyword(s):  
Double Bond ◽  
Triple Bond

Chemical Bonding Specifics of Hybrid Metal-Polymer Nanocomposites Based on Cobalt Nanoparticles and Polyacrylonitrile: X-Ray Spectroscopy Investigation

2016 ◽  
Vol 257 ◽  
pp. 175-178 ◽  
Author(s):  
Galina Yalovega ◽  
Tatiana Semenistaya
Keyword(s):  
Double Bond ◽  
Porous Structure ◽  
Polymer Nanocomposites ◽  
Chemical Bonding ◽  
Triple Bond ◽  
Cobalt Nanoparticles ◽  
Polymer Backbone ◽  
X Ray ◽  
Ir Pyrolysis ◽  
Metal Polymer

The cobalt-containing polyacrylonitrile (PAN) films were fabricated using IR-pyrolysis under low vacuum conditions. It was found that Co/PAN films have a porous structure and cobalt nanoparticles with size 0.1-0.2 μm embedded into PAN matrix. Besides, as a result of interaction between PAN matrix and Co ions unsaturation in the polymer backbone is observed caused by the transformation of the C≡N triple bond to a C=N double bond. At the same time formation of Co-N bond is observed.

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