Research inspired by the chemistry of nitrogenase — Novel metal complexes and their reactivity toward dinitrogen, nitriles, and alkynes

2005 ◽  
Vol 83 (4) ◽  
pp. 358-374 ◽  
Author(s):  
Masanobu Hidai ◽  
Yasushi Mizobe

Summarized here are our continuous studies of the last three decades concerning syntheses of new types of complexes learned from nitrogenase and their reactivites toward dinitrogen, nitriles, and alkynes. For Mo and W dinitrogen complexes with tertiary phosphine coligands, a variety of their intriguing reactivities have been demonstrated, and novel transformations of the N2 ligands into numerous nitrogen-containing ligands and compounds have been developed. The C≡N bond cleavage of certain nitriles also proceeds on the Mo site surrounded by tertiary phosphines. Stimulated by the sophisticated structure of the active site of nitrogenase, multinuclear metal–sulfur complexes have been synthesized in rational ways. New types of stoichiometric and catalytic reactions of alkynes have been found by using the thiolato-bridged diruthenium complexes and some cubane-type sulfido clusters containing a noble metal.Key words: nitrogen fixation, molybdenum and tungsten dinitrogen complexes, ruthenium thiolato complexes, metal sulfido clusters, nitriles, alkynes.


2001 ◽  
Vol 73 (2) ◽  
pp. 261-263 ◽  
Author(s):  
Masanobu Hidai ◽  
Yasushi Mizobe

Dinitrogen complex cis-[W (N2) 2 (PMe2Ph) 4] reacts with an excess of acidic dihydrogen complexes such as trans-[RuCl (h2-H2) (dppe) 2]BF4 (dppe = 1,2-bis (diphenylphosphino) ethane) at 55 °C under 1 atm of H2 to form ammonia in moderate yield. The reaction is presumed to proceed through nucleophilic attack of the remote nitrogen of the coordinated dinitrogen on the dihydrogen ligand. The coordinated dinitrogen is also protonated by treatment with hydrosulfido-bridged dinuclear complexes such as [Cp*Ir (m-SH) 3IrCp*]Cl (Cp* = h5-C5Me5) to afford ammonia. On the other hand, the synthetic cycle for the formation of pyrrole and N-aminopyrrole from dinitrogen and 2,5-dimethoxytetrahydrofuran has been established starting from dinitrogen complexes of the type trans-[M (N2) 2 (dppe) 2 ] (M = Mo, W).



1980 ◽  
Vol 34a ◽  
pp. 483-494 ◽  
Author(s):  
Abdul Malek ◽  
Börje Folkesson ◽  
Ragnar Larsson ◽  
E. Tørneng ◽  
T. Woldbæk ◽  
...  


1983 ◽  
Vol 105 (6) ◽  
pp. 1680-1682 ◽  
Author(s):  
Tamotsu Takahashi ◽  
Teruyuki Kodama ◽  
Atsushi Watakabe ◽  
Yasuzo Uchida ◽  
Masanobu Hidai


2015 ◽  
Vol 6 (7) ◽  
pp. 3940-3951 ◽  
Author(s):  
Shogo Kuriyama ◽  
Kazuya Arashiba ◽  
Kazunari Nakajima ◽  
Hiromasa Tanaka ◽  
Kazunari Yoshizawa ◽  
...  

Mo–N2complex bearing ferrocenes as redox-active units efficiently catalyses the formation of ammonia from molecular dinitrogen under ambient conditions.





2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Riley B. Peacock ◽  
Taylor McGrann ◽  
Marco Tonelli ◽  
Elizabeth A. Komives

AbstractSerine proteases catalyze a multi-step covalent catalytic mechanism of peptide bond cleavage. It has long been assumed that serine proteases including thrombin carry-out catalysis without significant conformational rearrangement of their stable two-β-barrel structure. We present nuclear magnetic resonance (NMR) and hydrogen deuterium exchange mass spectrometry (HDX-MS) experiments on the thrombin-thrombomodulin (TM) complex. Thrombin promotes procoagulative fibrinogen cleavage when fibrinogen engages both the anion binding exosite 1 (ABE1) and the active site. It is thought that TM promotes cleavage of protein C by engaging ABE1 in a similar manner as fibrinogen. Thus, the thrombin-TM complex may represent the catalytically active, ABE1-engaged thrombin. Compared to apo- and active site inhibited-thrombin, we show that thrombin-TM has reduced μs-ms dynamics in the substrate binding (S1) pocket consistent with its known acceleration of protein C binding. Thrombin-TM has increased μs-ms dynamics in a β-strand connecting the TM binding site to the catalytic aspartate. Finally, thrombin-TM had doublet peaks indicative of dynamics that are slow on the NMR timescale in residues along the interface between the two β-barrels. Such dynamics may be responsible for facilitating the N-terminal product release and water molecule entry that are required for hydrolysis of the acyl-enzyme intermediate.



Sign in / Sign up

Export Citation Format

Share Document