Heterobimetallic complexes from addition of molybdo- or tungstophosphine ligands to metal halides and by oxidative addition of molybdo- or tungsto-aryl iodides to low-oxidation state metal species

1986 ◽  
Vol 11 (4) ◽  
pp. 138-142 ◽  
Author(s):  
Christopher J. Jones ◽  
Jon A. McCleverty ◽  
Sarah J. Reynolds
Keyword(s):  
Oxidation State ◽  
Oxidative Addition ◽  
Metal Species ◽  
Metal Halides ◽  
Heterobimetallic Complexes ◽  
Aryl Iodides ◽  
Low Oxidation State

Piperazine as an Inexpensive and Efficient Ligand for Pd-Catalyzed Homocoupling Reactions to Synthesize Bipyridines and Their Analogues

2019 ◽  
Vol 16 (1) ◽  
pp. 173-180
Author(s):  
Mingwei Chen ◽  
Jinyu Hu ◽  
Xiaoli Tang ◽  
Qiming Zhu
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Metal Species ◽  
Good Substrate ◽  
Active Metal ◽  
Homocoupling Reaction ◽  
Catalytic Cycles ◽  
Reductive Homocoupling

Aim and Objective: The synthesis of bipyridines, especially 2, 2’-bipyridines, remains challenging because the catalytic cycle can be inhibited due to coordination of bipyridine to transition metal. Thus, the development of efficient methods for the synthesis of bipyridines is highly desirable. In the present work, we presented a promising approach for preparation of bipyridines via a Pd-catalyzed reductive homocoupling reaction with simple piperazine as a ligand. Materials and Methods: Simple and inexpensive piperazine was used as a ligand for Pd-catalyzed homocoupling reaction. The combination of Pd(OAc)2 and piperazine in dimethylformamide (DMF) was observed to form an excellent catalyst and efficiently catalyzed the homocoupling of azaarenyl halides, in which DMF was used as the solvent without excess reductants although stoichiometric reductant was generally required to generate the low-oxidation-state active metal species in the catalytic cycles. </P><P> Results: In this case, good to excellent yields of bipyridines and their (hetero) aromatic analogues were obtained in the presence of 2.5 mol% of Pd(OAc)2 and 5 mol% of piperazine, using K3PO4 as a base in DMF at 140°C. Conclusion: According to the results, piperazine as an inexpensive and efficient ligand was used in the Pd(OAc)2-catalyzed homocoupling reaction of heteroaryl and aryl halides. The coupling reaction was operationally simple and displayed good substrate compatibility.

scholarly journals Synthesis and Characterization of Super Bulky β-Diketiminato Group 1 Metal Complexes

Inorganics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 72
Author(s):  
Dafydd D. L. Jones ◽  
Samuel Watts ◽  
Cameron Jones
Keyword(s):  
Nmr Spectroscopy ◽  
Alkali Metal ◽  
Metal Complexes ◽  
Oxidation State ◽  
Synthesis And Characterization ◽  
X Ray Crystallography ◽  
Low Oxidation State ◽  
Bulky Ligand ◽  
Group 1

Sterically bulky β-diketiminate (or Nacnac) ligand systems have recently shown the ability to kinetically stabilize highly reactive low-oxidation state main group complexes. Metal halide precursors to such systems can be formed via salt metathesis reactions involving alkali metal complexes of these large ligand frameworks. Herein, we report the synthesis and characterization of lithium and potassium complexes of the super bulky anionic β-diketiminate ligands, known [TCHPNacnac]− and new [TCHP/DipNacnac]− (ArNacnac = [(ArNCMe)2CH]−) (Ar = 2,4,6-tricyclohexylphenyl (TCHP) or 2,6-diisopropylphenyl (Dip)). The reaction of the proteo-ligands, ArNacnacH, with nBuLi give the lithium etherate compounds, [(TCHPNacnac)Li(OEt2)] and [(TCHP/DipNacnac)Li(OEt2)], which were isolated and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The unsolvated potassium salts, [{K(TCHPNacnac)}2] and [{K(TCHP/DipNacnac)}∞], were also synthesized and characterized in solution by NMR spectroscopy. In the solid state, these highly reactive potassium complexes exhibit differing alkali metal coordination modes, depending on the ligand involved. These group 1 complexes have potential as reagents for the transfer of the bulky ligand fragments to metal halides, and for the subsequent stabilization of low-oxidation state metal complexes.

Amido Silicon Chalcogenide Compounds with Unprecedented Cluster Cores and Low Oxidation State Silicon Atoms

2019 ◽  
Vol 2019 (44) ◽  
pp. 4719-4726 ◽  
Author(s):  
Kevin Schwedtmann ◽  
Alexander Hepp ◽  
Kai Schwedtmann ◽  
Jan J. Weigand ◽  
Felicitas Lips
Keyword(s):  
Oxidation State ◽  
Low Oxidation State ◽  
Cluster Cores

N-Heterocyclic Carbene Adducts of High-Oxidation-State Metal Halides: An Unexpected Instance of Lewis Acidic Carbene Character

ChemInform ◽  
2006 ◽  
Vol 37 (40) ◽  
Author(s):  
Mark D. Spicer ◽  
Christopher A. Dodds ◽  
John P. Culver ◽  
Colin D. Abernethy
Keyword(s):  
Oxidation State ◽  
Metal Halides ◽  
High Oxidation State ◽  
High Oxidation
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