Dinuclear Complexes of Flexidentate Pyridine‐Substituted Formazanate Ligands

Dinuclear Complexes of Flexidentate Pyridine‐Substituted Formazanate Ligands

Coordination modes: Flexidentate pyridine‐substituted ligand designs allow facile and modular assembly of dinuclear coordination compounds scaffolded with redox‐active formazanate bridging ligands. A series of dinuclear complexes of platinum and iridium are described, with a variety of ligand binding modes observed (see figure).

Abstract

The utility of flexidentate pyridyl‐substituted formazanate ligands for assembling dinuclear coordination complexes with iridium(III) and/or platinum(II) building blocks is demonstrated herein. The dinuclear complexes are prepared either via a stepwise strategy, adding one metal unit at a time, or via one‐pot self‐assembly. Eight of the new complexes, including both mononuclear precursors and dinuclear products, are structurally characterized by single‐crystal X‐ray diffraction and NMR spectroscopy, revealing several distinct binding modes of the formazanates. All complexes are characterized by UV/Vis absorption spectroscopy and cyclic voltammetry. The frontier orbitals are primarily localized on the formazanate ligand, and a characteristic, intense formazanate‐centered π→π* absorption band is observed in the absorption spectra.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Ge Mu, Chenggang Jiang, Thomas S. Teets
doi.org/10.1002/chem.202002351

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A Lamellar MWW Zeolite With Silicon and Niobium Oxide Pillars: A Catalyst for the Oxidation of Volatile Organic Compounds

A Lamellar MWW Zeolite With Silicon and Niobium Oxide Pillars: A Catalyst for the Oxidation of Volatile Organic Compounds

Pillars are not only used as structural elements in architecture or civil engineering but also on a nanoscale to obtain 2D vertical zeolitic architectures with improved interlamellar accessibility. This work aims to use pillars containing silicon and niobium oxides, with the latter as an active phase for the catalytic oxidation of volatile organic compounds such as benzene, toluene, and xylene (BTX), which is an important reaction for environmentally clean technology. More information can be found in the Full Paper by A. J. Schwanke et al. (DOI: doi.org/10.1002/chem.20200086210.1002/chem.202000862).

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Anderson Joel Schwanke, Rosana Balzer, Christian Wittee Lopes, Débora Motta Meira, Urbano Díaz, Avelino Corma, Sibele Pergher
doi.org/10.1002/chem.202002771

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Controlled Self‐Assembly of Metallacycle‐Bridged Gold Nanoparticles for Surface‐Enhanced Raman Scattering

Controlled Self‐Assembly of Metallacycle‐Bridged Gold Nanoparticles for Surface‐Enhanced Raman Scattering

Perfectly distanced: Taking advantage of the inherent features of 2D metallacycles, the first example of well‐controlled self‐assembly of gold nanoparticles into discrete clusters such as dimers, trimers, tetramers, pentamers and even hexamers has been successfully realized at the liquid–liquid interface.

Abstract

In this work, well‐defined two‐dimensional metallacycles have been successfully employed for the well‐controlled self‐assembly of gold nanoparticles (AuNPs) into discrete clusters such as dimers, trimers, tetramers, pentamers and even hexamers at the water–oil interface for the first time. Furthermore, the modular construction of metallacycle molecules allows precise control of spacing between the gold nanoparticles. Interestingly, it was found that interparticle spacing below 5 nm created by molecular metallacycles in the resultant discrete gold nanoparticle clusters led to a strong plasmon coupling, thus inducing great field enhancement inside the gap between the NPs. More importantly, different discrete clusters with precise interparticle spacing provide a well‐defined system for studying the hot‐spot phenomenon in surface‐enhanced Raman scattering (SERS); this revealed that the SERS effects were closely related to the interparticle spacing.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Wei Zheng, Xiao‐Lei Yang, Gui‐Yuan Wu, Lin Cheng
doi.org/10.1002/chem.202002248

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Bicyclohexene-peri-naphthalenes: Scalable Synthesis, Diverse Functionalization, Efficient Polymerization, and Facile Mechanoactivation of Their Polymers

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Jinghui Yang, Matias Horst, Sabrina H. Werby, Lynette Cegelski, Noah Z. Burns, and Yan Xia*
feedproxy.google.com/~r/acs/jacsat/~3/d8Gp55iz4Kg/jacs.0c06454

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Identification and Optimization of a Series of 8-Hydroxy Naphthyridines with Potent In Vitro Antileishmanial Activity: Initial SAR and Assessment of In Vivo Activity

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Michael G. Thomas*†, Manu De Rycker†, Richard J. Wall†, Daniel Spinks†, Ola Epemolu†, Sujatha Manthri†, Suzanne Norval†, Maria Osuna-Cabello†, Stephen Patterson†, Jennifer Riley†, Frederick R. C. Simeons†, Laste Stojanovski†, John Thomas†, Stephen Thompson†, Claire Naylor†, Jose M. Fiandor‡, Paul G. Wyatt†, Maria Marco‡, Susan Wyllie†, Kevin D. Read†, Timothy J. Miles*‡, and Ian H. Gilbert*†
feedproxy.google.com/~r/acs/jmcmar/~3/717LENuQUPQ/acs.jmedchem.0c00705

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Niobium Oxides as Heterogeneous Catalysts for Biginelli Multicomponent Reaction

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The Journal of Organic Chemistry

The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Letícia Gomes do Nascimento†, Isabela Milhomem Dias†, Guilherme Botelho Meireles de Souza†, Isabela Dancini-Pontes‡, Nádia Regina Camargo Fernandes‡, Paulo Sérgio de Souza†, Guilherme Roberto de Oliveira†, and Christian Gonçalves Alonso*†
feedproxy.google.com/~r/acs/joceah/~3/f-KPzOY-0gw/acs.joc.0c01167

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Synthesis and Basicity Studies of Quinolino[7,8-h]quinoline Derivatives

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The Journal of Organic Chemistry

The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Gareth J. Rowlands†, Rebecca J. Severinsen†, Jenna K. Buchanan†, Karl J. Shaffer†, Heather T. Jameson†, Nishani Thennakoon†, Ivo Leito‡, Märt Lõkov‡, Agnes Kütt‡, Robert Vianello§, Ines Despotović§, Nena Radić§, and Paul G. Plieger*†
feedproxy.google.com/~r/acs/joceah/~3/ZBq1uBOFx0I/acs.joc.0c01428

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Palladium-Catalyzed [2 + 2 + 1] Annulation of Alkyne-Tethered Aryl Iodides with Diaziridinone: Synthesis of 3,4-Fused Tricyclic Indoles

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The Journal of Organic Chemistry

The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Lei Zhang, Junyu Chen, Tianshuo Zhong, Xiangyun Zheng, Jian Zhou, Xinpeng Jiang*, and Chuanming Yu*
feedproxy.google.com/~r/acs/joceah/~3/CvedZZC4YfE/acs.joc.0c01365

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Self-Assembly of N-Phenyl-2,5-dimethylpyrrole from Acetylene and Aniline in KOH/DMSO and KOBut/DMSO Superbase Systems: A Quantum-Chemical Insight

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The Journal of Organic Chemistry

The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Nadezhda M. Vitkovskaya*†, Vladimir B. Orel†, Damir Z. Absalyamov†‡, and Boris A. Trofimov‡
feedproxy.google.com/~r/acs/joceah/~3/LLt2yEmYYco/acs.joc.0c01185

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Copper/DTBP-Promoted Oxyselenation of Propargylic Amines with Diselenides and CO2: Synthesis of Selenyl 2-Oxazolidinones

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The Journal of Organic Chemistry

The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Jia-Min Chen†, Lin Qi†, Linlin Zhang†, Li-Jun Li†, Cong-Ying Hou†, Wei Li*†‡, and Li-Jing Wang*†‡
feedproxy.google.com/~r/acs/joceah/~3/IVruhe2Dp30/acs.joc.0c01519

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Bivalent Inhibitors of Prostate-Specific Membrane Antigen Conjugated to Desferrioxamine B Squaramide Labeled with Zirconium-89 or Gallium-68 for Diagnostic Imaging of Prostate Cancer

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Asif Noor†, Jessica K. Van Zuylekom‡, Stacey E. Rudd†, Kelly Waldeck‡, Peter D. Roselt‡, Mohammad B. Haskali‡, Michael P. Wheatcroft§, Eddie Yan§, Rodney J. Hicks‡∥, Carleen Cullinane‡∥, and Paul S. Donnelly*†
feedproxy.google.com/~r/acs/jmcmar/~3/Ybmh4i__hZU/acs.jmedchem.0c00291

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Structure–Activity Relationship Studies of α-Ketoamides as Inhibitors of the Phospholipase A and Acyltransferase Enzyme Family

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Juan Zhou†∥, Elliot D. Mock†∥, Karol Al Ayed†, Xinyu Di‡, Vasudev Kantae‡, Lindsey Burggraaff§, Anna F. Stevens†, Andrea Martella†, Florian Mohr†, Ming Jiang†, Tom van der Wel†, Tiemen J. Wendel†, Tim P. Ofman†, Yvonne Tran†, Nicky de Koster†, Gerard J.P. van Westen§, Thomas Hankemeier‡, and Mario van der Stelt*†
feedproxy.google.com/~r/acs/jmcmar/~3/7SShcpk9uao/acs.jmedchem.0c00522

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One‐Pot Two‐Step Synthesis of Isochromene‐Fused CF3‐Substituted Pyrazoles

One‐Pot Two‐Step Synthesis of Isochromene‐Fused CF3‐Substituted Pyrazoles

An efficient one‐pot, two step method for fusing two biologically active motifs, CF3‐substituted pyrazoles and isochromenes, was developed. Selective O‐benzylation of CF3‐substituted pyrazolones and subsequent Pd‐catalyzed direct C–H arylation generate a fused tricycle.

An efficient one‐pot, two step method for fusing two biologically active motifs, CF3‐substituted pyrazoles and isochromenes, was developed. Selective O‐benzylation of CF3‐substituted pyrazolones and subsequent Pd‐catalyzed direct C–H arylation generate a fused tricycle. For the synthesized compounds through‐space 13C–19F spin–spin coupling was revealed. In addition, the synthesis of three thioisochromene analogues, and one isocoumarin derivative, was accomplished.

Wiley: European Journal of Organic Chemistry: Table of Contents
Authors: Andrea M. Nikolić, Filip Živković, Života Selaković, Peter Wipf, Igor M. Opsenica
doi.org/10.1002/ejoc.202000942

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Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN

Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN

TMSCl associated with NaI was used to deprotect various dithioacetals in CH3CN with good to excellent yields. This metal‐free process can also be applied with success for the regeneration of carbonyl of O,O‐acetals, O,S‐oxathianes, S,N‐acetals, ketimines, and hydrazones.

A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3‐dioxanes, 1,3‐dioxolanes and 1,3‐oxathianes quantitatively. As a possible extension of this method, it was also shown that nitrogenated substrates such as hydrazones, N‐tosylhydrazones, and ketimines reacted well under these conditions to give the expected ketones in high yields. The methodology proposed herein is a good alternative to the existing methods since it does not use metals, oxidants, reducing agents, acidic or basic media, and keto‐products were obtained in high to excellent yields.

Wiley: European Journal of Organic Chemistry: Table of Contents
Authors: Yunxin Yao, Guangkuan Zhao, Abdallah Hamze, Mouad Alami, Olivier Provot
doi.org/10.1002/ejoc.202000979

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Helicates with Ether‐Substituted Catechol Esters as Ligands

Helicates with Ether‐Substituted Catechol Esters as Ligands

A series of ether (and thioether) substituted helicate‐type complexes are presented which act as cation dependent molecular switches and in the cases of covalently linked systems show a counterion and length dependent “spring”‐type expansion/compression behaviour.

Mono‐ or biscatechol esters with ether‐type substituents or spacers form either triple lithium bridged dimeric helicates or triple stranded helicates with the ability to bind three lithium cations in their interior. Hierarchical helicates with ether or thioether substituents show in solution a monomer‐dimer equilibrium which is independent of the heteroatom in the ester substituent. However, dimerization constants are significantly lower than for corresponding alkyl derivatives. Dinuclear helicates with oligoether spacers are well obtained in the presence of lithium cations. Upon removal of the cations the helicates expand and successive addition of LiCl results in compression again.

Wiley: European Journal of Organic Chemistry: Table of Contents
Authors: Christian Mevissen, A. Carel N. Kwamen, Leonard Himmel, Xiaofei Chen, Matthias Brückner, Saskia Huda, Christian Göb, Judith Jenniches, Iris Oppel, Jas S. Ward, Kari Rissanen, Markus Albrecht
doi.org/10.1002/ejoc.202000843

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Successive Pd‐Catalyzed Decarboxylative Cross‐Couplings for the Modular Synthesis of Non‐Symmetric Di‐Aryl‐Substituted Thiophenes

Successive Pd‐Catalyzed Decarboxylative Cross‐Couplings for the Modular Synthesis of Non‐Symmetric Di‐Aryl‐Substituted Thiophenes

A thiophene building block, with opposing bromide and ester‐protected acid moieties, is utilized as a starting material for the efficient synthesis of an array of non‐symmetric, di‐aryl‐substituted thiophene through successive decarboxylative palladium‐catalyzed couplings, with an intermediate saponification step.

Oligothiophenes are important organic molecules in a number of burgeoning industries as semi‐conducting materials due to their extensive π‐conjugation and charge transport properties. Typically, non‐symmetric, di‐aryl‐substituted thiophenes are prepared by the successive formation of Grignards, organotin, and/or boronic acid intermediates that can be subsequently employed in cross‐coupling reactions. While reliable, these approaches present synthetic difficulties due to the reactivity of organo‐metallic/pseudo‐metallic species, and produce considerable amounts of waste due to necessary pre‐functionalization. We have developed a decarboxylative cross‐coupling route as an effective strategy for the modular and less wasteful synthesis of a wide range of non‐symmetric, di‐arylthiophenes. This method uses a thiophene ester building block for successive decarboxylative palladium‐catalyzed couplings that allows for the efficient synthesis and evaluation of the opto‐electronic properties of a library of candidate semi‐conductors with functional groups that could be challenging to access using previous routes.

Wiley: European Journal of Organic Chemistry: Table of Contents
Authors: Cynthia Messina, Liam Z. Douglas, Jiang Tian Liu, Pat Forgione
doi.org/10.1002/ejoc.202000780

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Prebiotically Plausible Organocatalysts Enabling a Selective Photoredox α‐Alkylation of Aldehydes on the Early Earth

Prebiotically Plausible Organocatalysts Enabling a Selective Photoredox α‐Alkylation of Aldehydes on the Early Earth

Kick‐start for the origin of life : A class of imidazolidine‐4‐thione organocatalysts has been identified enabling enantioselective α‐alkylation of aldehydes under prebiotic conditions. These catalysts are easily accessible from simple molecules available on an Early Earth under highly plausible prebiotic reaction conditions. Remarkably, they crystallize as conglomerate facilitating the process of spontaneous symmetry breaking.

Abstract

Organocatalysis is a powerful approach to extend and (enantio‐) selectively modify molecular structures. Adapting this concept to the Early Earth scenario offers a promising solution to explain their evolution into a complex homochiral world. Herein, we present a class of imidazolidine‐4‐thione organocatalysts, easily accessible from simple molecules available on an Early Earth under highly plausible prebiotic reaction conditions. These imidazolidine‐4‐thiones are readily formed from mixtures of aldehydes or ketones in presence of ammonia, cyanides and hydrogen sulfide in high selectivity and distinct preference for individual compounds of the resulting catalyst library. These organocatalysts enable the enantioselective α‐alkylation of aldehydes under prebiotic conditions and show activities that correlate with the selectivity of their formation. Furthermore, the crystallization of single catalysts as conglomerates opens the pathway for symmetry breaking.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Anna C. Closs, Elina Fuks, Maximilian Bechtel, Oliver Trapp
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202001514

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