Metal-Ligand Cooperation at Phosphine-Based Acceptor Pincer Ligands

2020 ◽  
Author(s):  
Martine R. Tiddens ◽  
Marc-Etienne Moret
Keyword(s):  
Pincer Ligands ◽  
Metal Ligand

scholarly journals Iron(II) Complexes Featuring a Redox-Active Dihydrazonopyrrole Ligand

2021 ◽  
Author(s):  
Kate Jesse ◽  
Mu-Chieh Chang ◽  
Alexander S. Filatov ◽  
John Anderson
Keyword(s):  
Redox State ◽  
Oxidation States ◽  
Pincer Ligands ◽  
Detailed Characterization ◽  
Metal Centers ◽  
Redox Couples ◽  
Redox Active ◽  
Secondary Coordination Sphere ◽  
Powerful Strategy ◽  
Metal Ligand

<div>Nature uses control of the secondary coordination sphere</div><div>to facilitate an astounding variety of transformations. Similarly, synthetic chemists have found metal-ligand cooperativity to be a powerful strategy for designing complexes that can mediate challenging reactivity. In particular, this strategy has been used to facilitate two electron reactions with first row transition metals that</div><div>more typically engage in one electron redox processes. While NNN pincer ligands feature prominently in this area, examples which can potentially engage in both proton and electron transfer are less common. Dihydrazonopyrrole (DHP) ligands have been isolated in a variety of redox and protonation states when complexed to Ni. However, the redox-state of this ligand scaffold is less obvious when</div><div>complexed to metal centers with more accessible redox couples. Here, we synthesize a new series of Fe-DHP complexes in two distinct oxidation states. Detailed characterization supports that the redox chemistry</div><div>in this set is still primarily ligand based. Finally, these</div><div>complexes exist as 5-coordinate species with an open coordination site offering the possibility of enhanced reactivity.</div>

ChemInform Abstract: A New Class of PN3-Pincer Ligands for Metal-Ligand Cooperative Catalysis

ChemInform ◽  
2015 ◽  
Vol 46 (47) ◽  
pp. no-no
Author(s):  
Huaifeng Li ◽  
Bin Zheng ◽  
Kuo-Wei Huang
Keyword(s):  
Pincer Ligands ◽  
New Class ◽  
Cooperative Catalysis ◽  
Metal Ligand

scholarly journals Iron(II) Complexes Featuring a Redox-Active Dihydrazonopyrrole Ligand

2021 ◽  
Author(s):  
Kate Jesse ◽  
Mu-Chieh Chang ◽  
Alexander S. Filatov ◽  
John Anderson
Keyword(s):  
Redox State ◽  
Oxidation States ◽  
Pincer Ligands ◽  
Detailed Characterization ◽  
Metal Centers ◽  
Redox Couples ◽  
Redox Active ◽  
Secondary Coordination Sphere ◽  
Powerful Strategy ◽  
Metal Ligand

<div>Nature uses control of the secondary coordination sphere</div><div>to facilitate an astounding variety of transformations. Similarly, synthetic chemists have found metal-ligand cooperativity to be a powerful strategy for designing complexes that can mediate challenging reactivity. In particular, this strategy has been used to facilitate two electron reactions with first row transition metals that</div><div>more typically engage in one electron redox processes. While NNN pincer ligands feature prominently in this area, examples which can potentially engage in both proton and electron transfer are less common. Dihydrazonopyrrole (DHP) ligands have been isolated in a variety of redox and protonation states when complexed to Ni. However, the redox-state of this ligand scaffold is less obvious when</div><div>complexed to metal centers with more accessible redox couples. Here, we synthesize a new series of Fe-DHP complexes in two distinct oxidation states. Detailed characterization supports that the redox chemistry</div><div>in this set is still primarily ligand based. Finally, these</div><div>complexes exist as 5-coordinate species with an open coordination site offering the possibility of enhanced reactivity.</div>

scholarly journals A new class of PN3-pincer ligands for metal–ligand cooperative catalysis

2015 ◽  
Vol 293-294 ◽  
pp. 116-138 ◽  
Author(s):  
Huaifeng Li ◽  
Bin Zheng ◽  
Kuo-Wei Huang
Keyword(s):  
Pincer Ligands ◽  
New Class ◽  
Cooperative Catalysis ◽  
Metal Ligand

ESTIMATING THE STABILITY OF METAL–LIGAND BONDING IN CARBOXYL-CONTAINING POLYMER COMPLEXES BY IR SPECTROSCOPY

2020 ◽  
Vol 61 (12) ◽  
pp. 1876-1887
Author(s):  
T. V. Berestova ◽  
K. N. Nosenko ◽  
O. V. Lusina ◽  
L. G. Kuzina ◽  
E. I. Kulish ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Polymer Complexes ◽  
The Stability ◽  
Metal Ligand

A Solvent-Dependent and Electrochemically Controlled Self-Assembling/Disassembling System

2003 ◽  
Vol 68 (9) ◽  
pp. 1647-1662 ◽  
Author(s):  
Valeria Amendola ◽  
Massimo Boiocchi ◽  
Yuri Diaz Fernandez ◽  
Carlo Mangano ◽  
Piersandro Pallavicini
Keyword(s):  
Equilibrium Mixture ◽  
Bidentate Ligand ◽  
Molecular Structures ◽  
The Self ◽  
Molar Ratio ◽  
Crystal And Molecular Structures ◽  
Self Assembling ◽  
Irreversible Oxidation ◽  
Irreversible Reduction ◽  
Metal Ligand

The bis-bidentate ligand R,S-1,2-diphenyl-N,N'-bis(2-quinolinemethylidene)ethane-1,2-diamine (ligand 4), containing two (iminomethyl)quinoline moieties separated by a cis-1,2-diphenylethylene spacer, forms stable complexes with both CuI and CuII. With CuII, the monomeric 1:1 complex [CuII(4)]2+ is obtained both in CH3CN and CH2Cl2. With CuI and overall 1:1 metal/ligand molar ratio, an equilibrium mixture is obtained in CH3CN, consisting of [CuI(4)2]+, [CuI2(4)2]2+ and [CuI2(4)(CH3CN)4]2+. The preponderant species is the two-metal one-ligand "open" complex [CuI2(4)(CH3CN)4]2+, in which each Cu+ cation is coordinated in a tetrahedral fashion by one (iminomethyl)quinoline unit and by two CH3CN molecules. Precipitation from the equilibrium mixture yields only crystals of [CuI2(4)(CH3CN)4](ClO4)2·2CH3CN, whose crystal and molecular structures have been determined. On the other hand, in the poorly coordinating CH2Cl2 solvent, only the dimeric helical [CuI2(4)2]2+ complex is obtained, when the overall metal/ligand 1:1 molar ratio is chosen. Addition of large quantities of acetonitrile to solutions of [CuI2(4)2]2+ in dichlorometane results in the formation of [CuI2(4)(CH3CN)4]2+, i.e. in the solvent-driven disassembling of the CuI helicate. While electrochemistry in CH3CN is poorly defined due to the presence of more than one CuI species, cyclic voltammetry experiments carried out in CH2Cl2 revealed a well defined behavior, with irreversible oxidation of [CuI2(4)2]2+ and irreversible reduction of [CuII(4)]2+ taking place at separate potentials (∆E ≈ 700 mV). Irreversibility and separation of the redox events are due to the self-assembling and disassembling processes following the reduction and oxidation, respectively.

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....

scholarly journals Self-Assembled Nanomaterials Based on Complementary Sn(IV) and Zn(II)-Porphyrins, and Their Photocatalytic Degradation for Rhodamine B Dye

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3598
Author(s):  
Nirmal K. Shee ◽  
Hee-Joon Kim
Keyword(s):  
Aqueous Solution ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Self Assembly ◽  
The Self ◽  
Assembly Process ◽  
Absorption Bands ◽  
Ligand Coordination ◽  
Rhodamine B Dye ◽  
Metal Ligand

A series of porphyrin triads (1–6), based on the reaction of trans-dihydroxo-[5,15-bis(3-pyridyl)-10,20-bis(phenyl)porphyrinato]tin(IV) (SnP) with six different phenoxy Zn(II)-porphyrins (ZnLn), was synthesized. The cooperative metal–ligand coordination of 3-pyridyl nitrogens in the SnP with the phenoxy Zn(II)-porphyrins, followed by the self-assembly process, leads to the formation of nanostructures. The red-shifts and remarkable broadening of the absorption bands in the UV–vis spectra for the triads in CHCl3 indicate that nanoaggregates may be produced in the self-assembly process of these triads. The emission intensities of the triads were also significantly reduced due to the aggregation. Microscopic analyses of the nanostructures of the triads reveal differences due to the different substituents on the axial Zn(II)-porphyrin moieties. All these nanomaterials exhibited efficient photocatalytic performances in the degradation of rhodamine B (RhB) dye under visible light irradiation, and the degradation efficiencies of RhB in aqueous solution were observed to be 72~95% within 4 h. In addition, the efficiency of the catalyst was not impaired, showing excellent recyclability even after being applied for the degradation of RhB in up to five cycles.

Mechanistic Study of Metal–Ligand Cooperativity in Mn(II)-Catalyzed Hydroborations: Hemilabile SNS Ligand Enables Metal Hydride-Free Reaction Pathway

ACS Catalysis ◽  
2021 ◽  
pp. 9043-9051
Author(s):  
Matthew R. Elsby ◽  
Mina Son ◽  
Changjin Oh ◽  
Jessica Martin ◽  
Mu-Hyun Baik ◽  
...  
Keyword(s):  
Metal Hydride ◽  
Reaction Pathway ◽  
Mechanistic Study ◽  
Sns Ligand ◽  
Metal Ligand
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