New Chemistry with Anionic NNN Pincer Ligands

2015 ◽  
pp. 179-208 ◽  
Author(s):  
Rebecca L. Melen ◽  
Lutz H. Gade
Keyword(s):  
Pincer Ligands

Designed pincer ligands supported Co(II)-based catalysts for dehydrogenative activation of alcohols: Studies on N-alkylation of amines, -alkylation of ketones and synthesis of quinolines

2021 ◽  
Author(s):  
Anshu Singh ◽  
Ankur Maji ◽  
Mayank Joshi ◽  
Angshuman Roychoudhury ◽  
Kaushik Ghosh
Keyword(s):  
Base Metal ◽  
Metal Catalysts ◽  
Pincer Ligands ◽  
Activation Of Alcohols

Base-metal catalysts Co1, Co2 and Co3 were synthesized from designed pincer ligands L1, L2 and L3 having NNN donor atoms respectively. Co1, Co2 and Co3 were characterized by IR, UV–Vis....

Access to C-Stereogenic PN(sp2)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

2021 ◽  
Author(s):  
Ce Qing Foo ◽  
Abdul Sadeer ◽  
Yongxin Li ◽  
Sumod A. Pullarkat ◽  
Pak-Hing Leung
Keyword(s):  
Pincer Ligands

Mechanisms of Electrochemical N2 Splitting by a Molybdenum Pincer Complex

2021 ◽  
Author(s):  
Quinton Bruch ◽  
Santanu Malakar ◽  
Alan Goldman ◽  
Alexander Miller
Keyword(s):  
Electrode Surface ◽  
Redox Reactions ◽  
Catalytic Reduction ◽  
Reaction Pathways ◽  
Bulk Solution ◽  
Mechanistic Study ◽  
Pincer Ligands ◽  
Computational Studies ◽  
Pincer Complex ◽  
Bond Scission

Molybdenum complexes supported by tridentate pincer ligands are exceptional catalysts for dinitrogen fixation using chemical reductants, but little is known about their prospects for electrochemical reduction of dinitrogen. The viability of electrochemical N2 binding and splitting by a molybdenum(III) pincer complex, (pyPNP)MoBr3 (pyPNP = 2,6-bis(tBu2PCH2)-C5H3N)), is established in this work, providing a foundation for a detailed mechanistic study of electrode-driven formation of the nitride complex (pyPNP)Mo(N)Br. Electrochemical kinetic analysis, optical and vibrational spectroelectrochemical monitoring, and computational studies point to two reaction pathways: in the “reaction layer” pathway, the molybdenum(III) precursor is reduced by 2e– and generates a bimetallic molybdenum(I) Mo2(-N2) species capable of N–N bond scission. In the “bulk solution” pathway the precursor is reduced by 3e– at the electrode surface to generate molybdenum(0) species that undergo chemical redox reactions via comproportionation in the bulk solution away from the electrode surface to generate the same bimetallic molybdenum(I) species capable of N2 cleavage. The comproportionation reactions reveal the surprising intermediacy of dimolybdenum(0) complex trans,trans-[(pyPNP)Mo(N2)2](-N2) in N2 splitting pathways. The same “over-reduced” molybdenum(0) species was also found to cleave N2 upon addition of lutidinium, an acid frequently used in catalytic reduction of dinitrogen.

ChemInform Abstract: Pincer Ligands Based on α-Amino Acids. Part 3. New Ligands Based on 4-Substituted Phenols and Their Copper Complexes. Enantioselective Recognition of Tyrosine.

ChemInform ◽  
2009 ◽  
Vol 40 (38) ◽  
Author(s):  
N. E. Borisova ◽  
V. A. Knizhnikov ◽  
T. G. Gulevich ◽  
M. Yu. Seliverstov ◽  
E. A. Borisov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Copper Complexes ◽  
Pincer Ligands ◽  
Substituted Phenols ◽  
Enantioselective Recognition

Supramolecular structures of V(III) complexes supported by PNP pincer ligands

2017 ◽  
Vol 1149 ◽  
pp. 229-234 ◽  
Author(s):  
Rita Ruivo ◽  
Luis G. Alves ◽  
Karl Kirchner ◽  
Ana M. Martins
Keyword(s):  
Supramolecular Structures ◽  
Pincer Ligands

scholarly journals Iron Complexes of a Proton-Responsive SCS Pincer Ligand with Sensitive Electronic Structure

2021 ◽  
Author(s):  
Kazimer Skubi ◽  
Reagan Hooper ◽  
Brandon Mercado ◽  
Melissa Bollmeyer ◽  
Samantha MacMillan ◽  
...  
Keyword(s):  
Strong Field ◽  
Alkali Metal Cation ◽  
Weak Field ◽  
Pincer Ligands ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Pincer Ligand ◽  
Intermediate Spin ◽  
X Ray Absorption ◽  
Phosphine Complex

SCS pincer ligands have an interesting combination of strong-field and weak-field donors that is also present in the nitrogenase active site. Here, we explore the electronic structures of iron(II) and iron(III) complexes with such a pincer ligand, bearing a monodentate phosphine, thiolate S donor, amide N donor, ammonia, or CO. The ligand scaffold features a protonresponsive thioamide site, and the protonation state of the ligand greatly influences the reduction potential of iron in the phosphine complex. The N–H bond dissociation free energy can be quantitated as 56 ± 2 kcal/mol. EPR spectroscopy and SQUID magnetometry measurements show that the iron(III) complexes with S and N as the fourth donors have an intermediate spin (S = 3/2) ground state with large zero field splitting, and X-ray absorption spectra show high Fe–S covalency. The Mössbauer spectrum changes drastically with the position of a nearby alkali metal cation in the iron(III) amido complex, and DFT calculations explain this phenomenon through a change between having the doubly-occupied orbital as dz2 or dyz, as the former is more influenced by the nearby positive charge.

scholarly journals Construction of a (NNN)Ru-Incorporated Porous Organic Polymer with High Catalytic Activity for β-Alkylation of Secondary Alcohols with Primary Alcohols

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 231
Author(s):  
Yao Cui ◽  
Jixian Wang ◽  
Lei Yu ◽  
Ying Xu ◽  
David J. Young ◽  
...  
Keyword(s):  
Functional Group ◽  
Catalytic Efficiency ◽  
Organic Polymer ◽  
Pincer Ligands ◽  
High Catalytic Activity ◽  
Secondary Alcohols ◽  
Primary Alcohols ◽  
Solid Supports ◽  
Porous Organic Polymer ◽  
Heterogeneous And Homogeneous Catalysis

Solid supports functionalized with molecular metal catalysts combine many of the advantages of heterogeneous and homogeneous catalysis. A (NNN)Ru-incorporated porous organic polymer (POP-bp/bbpRuCl3) exhibited high catalytic efficiency and broad functional group tolerance in the C–C cross-coupling of secondary and primary alcohols to give β-alkylated secondary alcohols. This catalyst demonstrated excellent durability during successive recycling without leaching of Ru which is ascribed to the strong binding of the pincer ligands to the metal ions.

Synthesis, structure, and reactivity of fluorous phosphorus/carbon/phosphorus pincer ligands and metal complexes

2005 ◽  
pp. 2275 ◽  
Author(s):  
Róbert Tuba ◽  
Verona Tesevic ◽  
Long V. Dinh ◽  
Frank Hampel ◽  
J. A. Gladysz
Keyword(s):  
Metal Complexes ◽  
Pincer Ligands
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