A Dibismuthane with Olefin Functional Groups: Towards Tridentate Hybrid Chalcogen/Olefin Ligands

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A Dibismuthane with Olefin Functional Groups: Towards Tridentate Hybrid Chalcogen/Olefin Ligands

A dibismuthane, R2Bi−BiR2, with olefin functional groups has been isolated (top right in the graphic). Reactivity studies furnished two series of compounds with Bi-chalcogen bonds, R2Bi−EPh and R2Bi−E−BiR2 (E=O−Te). The properties of compounds R2Bi−E−BiR2 (top left in the graphic) as tridentate chalcogen/olefin ligands towards transition metals have been investigated by DFT calculations.


Abstract

Bis[dibenzobismepine], a dibismuthane composed of two bismepine units (R2Bi−BiR2), was synthesized and fully characterized (R2=(C6H4CH)2). Reactions of this dibismuthane with diphenyl dichalcogenides, dibenzoylperoxide, and elemental chalcogens have been investigated. All products of these reactions have been isolated and fully characterized, including a series of compounds R2Bi−E−BiR2 (E=O−Te). These species contain two olefin units of the bismepine moieties and a chalcogen atom as potential coordination sites. The potential of these species to act as hybrid tridentate chalcogen/olefin ligands with bismuth atoms as structure-determining elements in the backbone has been investigated by theoretical approaches, aiming at the complexation of CoI, RhI, IrI and Ni0, Pd0, Pt0. The analytical techniques applied in this work include heteronuclear and 2D NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction analysis, and DFT calculations.

Conventional understanding of SARS‐CoV‐2 Mpro and common strategies for developing its inhibitors

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The COVID-19 pandemic has brought a widespread influence on the world, especially in the face of sudden coronavirus infections, and there is still an urgent need for specific small molecule therapies to cope with possible future pandemics. The pathogen responsible for this pandemic is SARS-CoV-2, and understanding its structure and lifecycle is beneficial for designing specific drugs of treatment for COVID-19. The main protease (Mpro) which has conservative and specific advantages is essential for viral replication and transcription. It is regarded as one of the most potential targets for anti-SARS-CoV-2 drug development. This review introduces the popular knowledge of SARS-CoV-2 in drug development and lists a series of design principles and relevant activities of advanced Mpro inhibitors.

r‐BRICS – a revised BRICS module that breaks ring structures and carbon chains

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Molecular fragmentation has been frequently used for machine learning, molecular modeling, and drug discovery studies. However, the current molecular fragmentation tools often lead to large fragments that are useful to limited tasks. Specifically, long aliphatic chains, certain connected ring structures, fused rings, as well as various nitrogen-containing molecular entities often remain intact when using BRICS. With no known methods to solve this issue, we find that the fragments taken from BRICS are inflexible for tasks such as fragment-based machine learning, coarse-graining, and ligand-protein interaction assessment. In this work, we develop a revised BRICS (r-BRICS) module that allows more flexible fragmentation on a wider variety of molecules. We show that r-BRICS generates smaller fragments than BRICS, allowing localized fragment assessments. Furthermore, r-BRICS generates a fragment database with significantly more unique small fragments than BRICS, which is potentially useful for fragmentbased drug discovery.