Cyclometalation of Substrates Containing Imine and Pyridyl Anchoring Groups by Iron and Cobalt Complexes

2005 ◽  
Vol 44 (6) ◽  
pp. 975-977 ◽  
Author(s):  
Hans-Friedrich Klein ◽  
Sebnem Camadanli ◽  
Robert Beck ◽  
Diana Leukel ◽  
Ulrich Flörke
Keyword(s):  
Cobalt Complexes ◽  
Anchoring Groups

Cobaloxime-Based Double Complex Salts as Efficient and Versatile Catalysts for the Light-Driven Hydrogen Evolution Reaction

2020 ◽  
Author(s):  
Elisabeth Hofmeister ◽  
Jisoo Woo ◽  
Tobias Ullrich ◽  
Lydia Petermann ◽  
Kevin Hanus ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Systematic Study ◽  
Cobalt Complexes ◽  
Spectroscopic Studies ◽  
Double Complex ◽  
Double Complex Salts ◽  
Noble Metal Catalysts ◽  
Reduction Potentials ◽  
Complex Salts

Cobaloximes and their BF<sub>2</sub>-bridged analogues have emerged as promising non-noble metal catalysts for the photocatalytic hydrogen evolution reaction (HER). Herein we report the serendipitous discovery that double complex salts such as [Co(dmgh)<sub>2</sub>py<sub>2</sub>]<sup>+</sup>[Co(dmgBPh<sub>2</sub>)<sub>2</sub>Cl<sub>2</sub>]<sup>-</sup> can be obtained in good yields by treatment of commercially available [Co(dmgh)<sub>2</sub>pyCl] with triarylboranes. A systematic study on the use of such double complex salts and their single salts with simple counterions as photocatalysts revealed HER activities comparable or superior to existing cobaloxime catalysts and suggests ample opportunities for this compound class in catalyst/photosensitizer dyads and immobilized architectures. Preliminary electrochemical and spectroscopic studies indicate that one key advantage of these charged cobalt complexes is that the reduction potentials as well as the electrostatic interaction with charged photosensitizers can be tuned.

scholarly journals Paramagnetic solid-state NMR assignment and novel chemical conversion of the aldehyde group to dihydrogen ortho ester and hemiacetal moieties in copper(ii)- and cobalt(ii)-pyridinecarboxaldehyde complexes

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20216-20231
Author(s):  
Ayelén F. Crespi ◽  
Verónica M. Sánchez ◽  
Daniel Vega ◽  
Ana L. Pérez ◽  
Carlos D. Brondino ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Assignment ◽  
Cobalt Complexes ◽  
Chemical Conversion ◽  
Aldehyde Group ◽  
Ortho Ester ◽  
Complex Chemical ◽  
Chemical Functionalization

The complex chemical functionalization of the aldehyde group was elucidated in copper and cobalt complexes for 4- and 3-pyridinecarboxaldehyde ligands.

scholarly journals Structural, Magnetic, and Electrochemical Characterization of Iron(III) and Cobalt Complexes with Penta‐N 3 O 2 ‐dentate Ligands

2021 ◽  
Vol 2021 (15) ◽  
pp. 1498-1504
Author(s):  
Dominik Natke ◽  
Annika Preiss ◽  
Stephen Klimke ◽  
Takuya Shiga ◽  
Roman Boca ◽  
...  
Keyword(s):  
Cobalt Complexes ◽  
Electrochemical Characterization

scholarly journals Mechanical single-molecule potentiometers with large switching factors from ortho-pentaphenylene foldamers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jinshi Li ◽  
Pingchuan Shen ◽  
Shijie Zhen ◽  
Chun Tang ◽  
Yiling Ye ◽  
...  
Keyword(s):  
Charge Transport ◽  
Single Molecule ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Helical Structures ◽  
Anchoring Groups ◽  
Molecular Conductance ◽  
And Control ◽  
Helical Molecules ◽  
Shed Light

AbstractMolecular potentiometers that can indicate displacement-conductance relationship, and predict and control molecular conductance are of significant importance but rarely developed. Herein, single-molecule potentiometers are designed based on ortho-pentaphenylene. The ortho-pentaphenylene derivatives with anchoring groups adopt multiple folded conformers and undergo conformational interconversion in solutions. Solvent-sensitive multiple conductance originating from different conformers is recorded by scanning tunneling microscopy break junction technique. These pseudo-elastic folded molecules can be stretched and compressed by mechanical force along with a variable conductance by up to two orders of magnitude, providing an impressively higher switching factor (114) than the reported values (ca. 1~25). The multichannel conductance governed by through-space and through-bond conducting pathways is rationalized as the charge transport mechanism for the folded ortho-pentaphenylene derivatives. These findings shed light on exploring robust single-molecule potentiometers based on helical structures, and are conducive to fundamental understanding of charge transport in higher-order helical molecules.

Molecular engineering of anchoring groups for designing efficient triazatruxene-based organic dye-sensitized solar cells

2019 ◽  
Vol 43 (17) ◽  
pp. 6480-6491 ◽  
Author(s):  
Narendra Nath Ghosh ◽  
Md. Habib ◽  
Anup Pramanik ◽  
Pranab Sarkar ◽  
Sougata Pal
Keyword(s):  
Solar Cells ◽  
Dye Sensitized Solar Cells ◽  
Organic Dye ◽  
Molecular Engineering ◽  
Dye Sensitized ◽  
Anchoring Groups ◽  
Sensitized Solar Cells

Triazatruxene with designed anchoring groups provides better photovoltaic activities.

scholarly journals Design of Molecular Water Oxidation Catalysts Stabilized by Ultrathin Inorganic Overlayers—Is Active Site Protection Necessary?

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 105 ◽  
Author(s):  
Laurent Sévery ◽  
Sebastian Siol ◽  
S. Tilley
Keyword(s):  
Water Oxidation ◽  
Atomic Layer ◽  
Deposition Process ◽  
Operating Conditions ◽  
Molecular Water ◽  
Side Reactions ◽  
Aqueous Environment ◽  
Oxidation Catalysts ◽  
Initial Onset ◽  
Anchoring Groups

Anchored molecular catalysts provide a good step towards bridging the gap between homogeneous and heterogeneous catalysis. However, applications in an aqueous environment pose a serious challenge to anchoring groups in terms of stability. Ultrathin overlayers embedding these catalysts on the surface using atomic layer deposition (ALD) are an elegant solution to tackle the anchoring group instability. The propensity of ALD precursors to react with water leads to the question whether molecules containing aqua ligands, such as most water oxidation complexes, can be protected without side reactions and deactivation during the deposition process. We synthesized two iridium and two ruthenium-based water oxidation catalysts, which contained an aqua ligand (Ir–OH2 and Ru–OH2) or a chloride (Ir–Cl and Ru–Cl) that served as a protecting group for the former. Using a ligand exchange reaction on the anchored and partially embedded Ru–Cl, the optimal overlayer thickness was determined to be 1.6 nm. An electrochemical test of the protected catalysts on meso-ITO showed different behaviors for the Ru and the Ir catalysts. The former showed no onset difference between protected and non-protected versions, but limited stability. Ir–Cl displayed excellent stability, whilst the unprotected catalyst Ir–OH2 showed a later initial onset. Self-regeneration of the catalytic activity of Ir–OH2 under operating conditions was observed. We propose chloride ligands as generally applicable protecting groups for catalysts that are to be stabilized on surfaces using ALD.

One-pot synthesis of cobalt complexes with 2,6-bis(arylimino)phenoxyl/phenthioxyl ligands and catalysis on isoprene polymerization

2021 ◽  
Vol 50 (15) ◽  
pp. 5218-5225
Author(s):  
Xue-Meng Chen ◽  
Li-Cheng Huang ◽  
Wei Gao
Keyword(s):  
Mixed Valence ◽  
Cobalt Complexes ◽  
One Pot ◽  
One Pot Synthesis ◽  
Isoprene Polymerization

Several cobalt complexes supported by 2,6-bis(arylimino)phenoxyl/phenthioxyl ligands κ2N,X-Ar[NXN]CoCl(THF) were synthesized by direct oxygen(sulfur) insertion into the C–Co bond of the mixed-valence cobalt complexes {κ2C,N,η6-Ar[NCN]Co-κN-CoCl(μ-Cl)}2.

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