scholarly journals Directly probing the effect of the solvent on a catalyst electronic environment using X-ray photoelectron spectroscopy

RSC Advances ◽  
2015 ◽  
Vol 5 (45) ◽  
pp. 35958-35965 ◽  
Author(s):  
Shuang Men ◽  
Kevin R. J. Lovelock ◽  
Peter Licence

The anion of an ionic liquid can significantly influence the electronic environment of a metal centre, and thus impact upon reaction performance in a model Suzuki cross coupling reaction.

Science ◽  
2018 ◽  
Vol 362 (6416) ◽  
pp. eaat8603 ◽  
Author(s):  
Kangway V. Chuang ◽  
Michael J. Keiser

Ahneman et al. (Reports, 13 April 2018) applied machine learning models to predict C–N cross-coupling reaction yields. The models use atomic, electronic, and vibrational descriptors as input features. However, the experimental design is insufficient to distinguish models trained on chemical features from those trained solely on random-valued features in retrospective and prospective test scenarios, thus failing classical controls in machine learning.


Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5627
Author(s):  
Monika Olesiejuk ◽  
Agnieszka Kudelko ◽  
Marcin Świątkowski

An alternative approach to the Suzuki cross-coupling reaction is used to synthesize a series of new luminophores based on 4-alkyl-4H-1,2,4-triazole cores conjugated via 1,4-phenylene linker to fused-bicyclic and tricyclic aromatic, or heteroaromatic arrangements. The described methodology allows one to conduct the coupling reaction with the use of commercially available boronic acids in the presence of conventional solvents or ionic liquids and produced excellent yields. It was found that the use of ultrasounds or microwaves significantly accelerates the reaction. The obtained compounds exhibited high luminescent properties and a large quantum yield of emitted photons. The X-ray molecular structures of three highly conjugated 4H-1,2,4-triazole representatives are also presented.


2021 ◽  
Author(s):  
Kimia Hoseinzade ◽  
Seyed Ali Mousavi-Mashhadi ◽  
Ali Shiri

Abstract Immobility of copper on magnetic nanoparticles was performed using surface rectification of Fe3O4 with Agar. The magnetic Fe3O4@Agar-Cu nanocatalyst was prepared and entirely characterized by different analyses such as Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), energy dispersive X-ray (EDX), thermogravimetric (TGA), and inductively coupled plasma (ICP). The nanocatalyst was applied in C-N bond formation through the cross-coupling reaction of aryl halides with primary or secondary amines in water as a green medium known as the Buchwald-Hartwig reaction. The results of the Buchwald-Hartwig reaction by Fe3O4@Agar-Cu magnetic nanoparticles as catalyst demonstrate excellent activity and stability in water. Moreover, this catalyst can be recycled several times without considerable loss in its activity.


Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 770
Author(s):  
Igor Zayakin ◽  
Irina Bagryanskaya ◽  
Dmitri Stass ◽  
Maxim Kazantsev ◽  
Evgeny Tretyakov

We synthesized two new organogold derivatives of a nitronyl nitroxide (NN) with phosphine ligands, namely NN-Au-PtBuPh2 and NN-Au-PtBu2Ph. They were characterized by X-ray diffraction analysis, cyclic voltammetry, and ESR, IR, and UV/Vis spectroscopy. The X-ray structural analysis revealed a tendency of the NN moiety to form a large number of short intermolecular contacts. This phenomenon is related to the anionic nature of the paramagnetic group NN, as evidenced by a significantly lower oxidation potential in comparison with purely organic derivatives of NN radicals. The cross-coupling reaction of NN-Au-PPh3, NN-Au-PtBuPh2, or NN-Au-PtBu2Ph with an activated bromoarene, namely, p-BrC6H4NO2, was investigated. It was shown that regardless of the presence of the bulky tert-butyl substituent, all gold derivatives have similar activities in the cross-coupling reaction and give a cross-coupling product, NN-C6H4NO2, with comparable yields.


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