Anion Sensing by Novel Triarylboranes Containing Boraanthracene: DFT Functional Assessment, Selective Interactions, and Mechanism Demonstration

Structure-constraint induced increase in Lewis acidity of tris(ortho-carboranyl)borane and selective complexation with Bestmann ylides

The Lewis acidity of tris(ortho-carboranyl)borane has been slightly increased by mimicking the structural evolution from triarylborane to 9-aryl-9-borafluorene. The o-carborane-based analogue (C2B10H10)2B(C2B10H11), obtained via salt elimination between LiC2B10H11 and (C2B10H10)2BBr, has been fully characterized. Gutmann-Beckett and computational fluoride/hydride ion affinity (FIA/HIA) studies have confirmed the increase in Lewis acidity, which is attributable to structural constraint imposed by the CC-coupling between two carboranyl groups. Selective complexation of (C2B10H10)2B(C2B10H11) with Bestmann ylides R3PCCO (R = Ph, Cy) has been achieved, enabling further conversion into the zwitterionic phospholium salt through NHC-catalyzed proton transfer.

Can Duvelisib and Eganelisib work for both cancer and COVID-19? Molecular-level insights from MD simulations and enhanced samplings

SARS-CoV-2 has caused severe illness and anxiety worldwide, evolving into more dreadful variants capable of evading the host's immunity. Cytokine storms, led by PI3Kγ, are common in cancer and SARS-CoV-2. Naturally, there is a yearning to see whether any drugs could alleviate cytokine storms for both. Upon investigation, we identified two anticancer drugs, Duvelisib and Eganelisib, that could also work against SARS-CoV-2. This report is the first to decipher their synergic therapeutic effectiveness against COVID-19 and cancer with molecular insights from atomistic simulations. In addition to PI3Kγ, these drugs exhibit specificity for the main protease among all SARS-CoV-2 targets, with significant negative binding free energies and small time-dependent conformational changes of the complexes. Complexation makes active sites and secondary structures highly mechanically stiff, with barely any deformation. Replica simulations estimated large pulling forces in enhanced sampling to dissociate the drugs from Mpro's active site. Furthermore, the radial distribution function (RDF) demonstrated that the therapeutic molecules were closest to the His41 and Cys145 catalytic dyad residues. Finally, analyses implied Duvelisib and Eganelisib as promising dual-purposed anti-COVID and anticancer drugs, potentially targeting Mpro and PI3Kγ to stop virus replication and cytokine storms concomitantly. We also distinguished hotspot residues imparting significant interactions.

Applications of triarylborane materials in cell imaging and sensing of bio-relevant molecules such as DNA, RNA, and proteins

Triarylboranes have been known for more than 100 years and have found potential applications in various fields such as anion sensors and optoelectronics, for example in organic light emitting diodes (OLEDs), field effect transistors (OFETs), and organic photovoltaic devices. However, biological applications, such as bioimaging agents and biomolecule sensors have evolved much more recently. This review summarises progress in this relatively young field and highlights the potential of triarylboranes in biological applications.

Corannulene-based acenes

Synthesis of diacenes still represents a considerable challenge due to their poor stability and low solubility.

A Distorted Hybrid Corannulene-Dibenzobistetracene

We have designed and synthesized a new type of distorted nanographene by Diels-Alder and Scholl reactions that contains one dibenzobistetracene (DBT, 1) core and two end-capping corannulene units. Single-crystal X-ray diffraction analyses demonstrate that nanographene 1 contains two [5] helicene subunits with a dihedral angle of 62°, consequently leading to the distorted DBT core. In addition, the photophysical properties and (non)aromaticity of 1 were investigated by the absorption and emission spectra in combination with theoretical calculations.

Bithiophene-Cored, mono-, bis-, and tris-(Trimethylammonium)-Substituted, bis-Triarylborane Chromophores: Effect of the Number and Position of Charges on Cell Imaging and DNA/RNA Sensing

The synthesis, photophysical, and electrochemical properties of selectively mono-, bis- and tris-dimethylamino- and trimethylammonium-substituted bis-triarylborane bithiophene chromophores are presented along with the water solubility and singlet oxygen sensitizing efficiency of the cationic compounds Cat1+ , Cat2+ , Cat(i)2+ , and Cat3+ . Comparison with the mono-triarylboranes reveals the large influence of the bridging unit on the properties of the bis-triarylboranes, especially those of the cationic compounds. Based on these preliminary investigations, the interactions of Cat1+ , Cat2+ , Cat(i)2+ , and Cat3+ with DNA, RNA, and DNApore were investigated in buffered solutions. The same compounds were investigated for their ability to enter and localize within organelles of human lung carcinoma (A549) and normal lung (WI38) cells showing that not only the number of charges but also their distribution over the chromophore influences interactions and staining properties.

Capture of Toxic Oxoanions from Water Using Metal-Organic Frameworks

The effective capture of common water contaminants using metal-organic frameworks (MOFs) presents a remedy for current environmental concerns arising from the pollution of water sources. The crystalline porous nature of MOFs, their high internal surface area, and exceptional tunability make them suitable candidates for sequestration and removal of pollutants. However, the efficiency of capture depends largely on the nature of the interactions between the anions and the MOF. In this work, to elucidate the host-guest interactions involved in the capture of such pollutants, we explore three characteristically different MOFs: ZIF-8, iMOF-2c, and MOF-74. We demonstrate by ab initio electronic structure calculations the importance of exploiting qualitatively different binding modes for strong host-guest interactions available in the selected MOFs. Our simulations reveal the relative performance of neutral and cationic adsorbents while underscoring the importance of employing MOFs containing open metal sites for the efficient uptake of anions.

Synthetic Approaches to Triarylboranes from 1885 to 2020

In recent years, research in the fields of optoelectronics, anion sensors and bioimaging agents have been greatly influenced by novel compounds containing triarylborane motifs. Such compounds possess an empty p-orbital at boron which results in useful optical and electronic properties. Such a diversity of applications was not expected when the first triarylborane was reported in 1885. Synthetic approaches to triarylboranes underwent various changes over the following century, some of which are still used in the present day, such as the generally applicable routes developed by Krause et al. in 1922, or by Grisdale et al. in 1972 at Eastman Kodak. Some other developments were not pursued further after their initial reports, such as the synthesis of two triarylboranes bearing three different aromatic groups by Mikhailov et al. in 1958. This review summarizes the development of synthetic approaches to triarylboranes from their first report nearly 135 years ago to the present.

Pillar[5]arene-based supramolecular AIE hydrogel with white light emission for ultrasensitive detection and effective separation of multianalytes

A novel pillar[5]arene-based supramolecular AIE hydrogel (PDG) with white light emission was constructed. The PDG could be used for ultrasensitive detection and effective separation of multianalytes, and as fluorescent display materials.