Since emerging in China in December 2019, COVID-19 has spread globally, wreaked havoc for public health and economies worldwide and, given the high infectivity and unexpectedly rapid spread of the virus responsible—that is, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)—urged the World Health Organization to declare it a pandemic. In response, reducing the virus’s adverse effects requires developing methods of early diagnosis that are reliable, are inexpensive and offer rapid response. As demonstrated in this article, the colorimetric and electrochemical detection of SARS-CoV-2 spike antigens with gold nanoparticle-based biosensors may be one such method. In the presence of the SARS-CoV-2 antigen, gold nanoparticles aggregated rapidly and irreversibly due to antibody–antigen interaction and consequently changed in colour from red to purple, as easily observable with the naked eye or UV-Vis spectrometry by way of spectral redshifting with a detection limit of 48 ng/mL. Moreover, electrochemical detection was achieved by dropping developed probe solution onto the commercially available and disposable screen-printed gold electrode without requiring any electrode preparation and modification. The method identified 1 pg/mL of the SARS-CoV-2 spike antigen and showed a linear response to the SARS-CoV-2 spike antigen ranging from 1 pg/mL to 10 ng/mL. Both methods were highly specific to detecting the SARS-CoV-2 antigen but not other antigens, including influenza A (i.e. H1N1), MERS-CoV and Streptococcus pneumoniae , even at high concentrations.

A BODIPY-based fluorescent probe integrated with an aldoxime unit shows a remarkable fluorescence "turn-on" response to hypochlorous acid (HOCl). The oxidative dehydrogenation of BODIPY aldoxime by HOCl results in a distinct fluorescence enhancement as well as a change in color from red to orange.Izmir Institute of Technology (IZTECH

Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties. Supporting Information Available. Detailed experimental procedures, and compound characterization data. This material is available free of charge via the Internet at http://pubs.acs.org.

We described the design and synthesis of a molecular sensor based on a rhodamine/BODIPY platform that displayed differential fluorescence responses towards Hg 2+ and Au 3+ and demonstrated its utility in intracellular ion imaging.In recent years, the construction of fluorescent molecular sensors for the detection of metal ion species has received a great deal of attention. 1 To date a large number of molecular sensors have been designed and developed, the majority of which are single-ion responsive and present no great challenge to researchers. Compared to single-ion responsive molecular sensors, however, the construction of multi-ion responsive molecular sensors with multiple emission modes are extremely challenging. 2 Molecular sensors displaying differential responses towards multiple ions are indispensable for designing molecular logic gates and molecular keypad lock devices. 3,4The challenge of multiple analyte recognition presents several detection strategies. Incorporating multiple binding motifs onto a single sensing molecule, or alternatively, combining different transducing units (chromophores/fluorophores), allows for rapid access to molecular sensors with multiple emission modes. 2 We envisaged that incorporating both a chemosensor and a chemodosimeter onto a single molecule could provide a suitable sensing platform for the differential detection of metal species. On the basis of this hypothesis, we constructed a molecular sensor possessing two different fluorophore units chemically integrated with each other. Both fluorophore units were elegantly designed to be non-emissive (i.e., ''off'') in their initial states and are expected to turn on respectively in response to the metal species of interest. To the best of our knowledge, molecular sensors based on this novel approach have not been covered in the literature.Ionic species of mercury (Hg 2+ ) and gold (Au 3+) share several similarities in terms of coordination properties. As both metal species show high affinities to thiols, they have the potential to interact with sulfur bearing biomolecules such as enzymes, proteins, and DNA. As a result, these metal species can disturb a series of cellular processes that lead to toxicity in humans. . This fluorescent probe, reported by Dong et al., operates through a single emission mode and the differentiation is highly dependent on the sensing conditions. Obviously, there is a high demand for the development of molecular sensors that can differentiate multiple analytes of a similar chemical nature (e.g. Hg 2+ and Au 3+ ). In addition, smallmolecule fluorescent sensors allowing the intracellular monitoring of multiple ions via differential responses are of high necessity for real-time cell imaging studies. Herein, we present the design, synthesis, spectral properties, and cell imaging studies of RhS-BOD, a new ''turn-on'' multifluorescent probe that allows the Hg 2+ and Au 3+ species to be differentiated on the basis of distinct fluorescence responses. RhS-BOD constitutes a boron-dipyrromethene (BODIPY...

A boron-dipyrromethene (BODIPY)-based fluorescent probe with a phosgene-specific reactive motif shows remarkable selectivity toward phosgene, in the presence of which the nonfluorescent dye rapidly transforms into a new structure and induces a fluorescent response clearly observable to the naked eye under ultraviolet light. Given that dynamic, a prototypical handheld phosgene detector with a promising sensing capability that expedites the detection of gaseous phosgene without sophisticated instrumentation was developed. The proposed method using the handheld detector involves a rapid response period suitable for issuing early warnings during emergency situations.

An ESIPT-based fluorescent dye, 3-hydroxyflavone, is chemically masked with an electrophilic cyanate motif in order to construct a fluorescent probe for cellular sulfur species. This novel probe structure, displays an extremely fast, highly sensitive and selective "turn-on" type fluorescent response toward H 2 S. We have also documented its utility for imaging of H 2 S in the living cells. H ydrogen sulfide (H 2 S), the smallest member among cellular sulfur species, plays critical roles in the functioning of living organisms. The compound is produced in biological systems from various sulfur-containing biomolecules and through a range of particular enzymatic pathways. The assessment of H 2 S levels in the cellular milieu is clearly vital to investigations of cell function and the early diagnosis of some diseases. Understanding the diverse contributions of H 2 S to physiology and pathology therefore first requires the development of efficient methods of visualizing H 2 S production and distribution in living systems. In related research, sustained attention has been paid to the development of molecular tools for probing cellular sulfur species.23−30 Among known analytical tools; fluorescence-based assays are particularly attractive, for they allow the real-time visualization of target species in cellular milieus. During the last several decades, numerous types of fluorescent H 2 S probes have appeared in scientific literature on the topic, most of them involving the use of specific chemical reactions to exploit the reactive and reductive nature of H 2 S. 31−41In general, the construction of any reaction-based H 2 S probe relies on modifying a fluorescent reporter with a reactive masking moiety, which splits away by interacting with H 2 S. To attain high selectivity over other relevant sulfur species, these masking moieties are necessarily highly specific to H 2 S ( Figure 1). 42−48 There are several important issues that have to be taken into account when designing a H 2 S recognition system. At the heart of the matter lies the discrimination of H 2 S over other biological sulfur species such as cysteine and glutathione. Low sensitivity and prolonged response times are other significant stumbling blocks that require attention. Moreover, most masking groups used in probe structures are relatively large

A hypercrosslinked ultramicroporous and ordered organic polymer network was synthesized from a planar trimer indole building block called triazatruxene (TAT) through anhydrous FeCl3 catalyzed Friedel–Crafts alkylation using methylal as a crosslinker. The polymer network is stable in a variety of chemicals and thermally durable. The hypercrosslinked network TATHCP shows a high BET (Brunauer–Emmet–Teller) specific surface area of 997 m2 g–1 with CO2 uptake capacity of 12.55 wt % at 273 K, 1.1 bar. Gas selectivities of 38.4 for CO2/N2, 7.8 for CO2/CH4, 40.6 for CO2/O2, and 32.1 for CO2/CO were achieved through IAST calculation. The PXRD analysis has revealed that TATHCP has a fully eclipsed structure in full agreement with Pawley refinement. The ordered 2D layers provide anisotropy that could be used in catalysis and thermoelectric measurements. After loading with Pd­(II), TATHCP-Pd showed high catalytic activity in Suzuki–Miyaura cross coupling reaction with a wide range of reagents and excellent reaction yields of 90–98% with good recyclability. The structure of TATHCP-Pd was found to have two independent molecules of Pd­(OAc)2 in the asymmetric unit cell which are arranged between two TATHCP layers. Thermoelectric properties of TATHCP showed a high Seebeck coefficient and ZT, a first and promising example in HCPs with applications in all-organic thermal energy recovery devices.

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