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Six-membered heterocycles containing one phosphorus and one nitrogen atom, known as azaphosphinines, have existed in the shadows of their single heteroatom-containing analogues for almost 150 years. Despite this, recent chemistry has seen a rapid increase in publications concerning this uncommon scaffold. Azaphosphinines exist in one of six isomers—there are three possible orientations of the pnictogen atoms and in each of these, the phosphorus is in one of two valences (PIII vs. PV). This review aims to outline and inform on the synthesis and applications of all six isomers. PV–oxo azaphosphinines are of particular interest to this review as many of the discussed heterocycles either form as the pentavalent species directly or oxidize to this over time. In very recent years the published applications of azaphosphinines have blossomed into subjects spanning several fields of chemistry such as asymmetric catalysis, supramolecular association, cellular imaging, and medicinal chemistry. 

Ocean acidification (OA) presents a unique challenge to early life stages of marine species. Developing organisms must balance the need to grow rapidly with the energetic demands of maintaining homeostasis. The small sizes of early life stages can make them highly sensitive to changes in environmental CO₂levels, but studies have found wide variation in responses to OA. Thus far most OA studies have manipulated CO₂only, and modifying factors need to be considered in greater detail. We investigated the effects of high pCO₂and food ration on rates of growth and mortality of a coastal fish, the California Grunion (Leuresthes tenuis). We also examined how CO₂and food levels affected feeding success, metabolic rate, and swimming activity – processes reflective of energy acquisition and expenditure. In general, exposure to high CO₂decreased energy intake by reducing feeding success, and increased energy expenditure by increasing metabolic rate and routine swimming speed, though the magnitudes of these effects varied somewhat with age. Despite these changes in energetics, growth of biomass was not affected significantly by pCO₂level but was reduced by low ration level, and we did not detect an interactive effect of food ration and pCO₂on growth. However, under OA conditions, larvae were in poorer condition (as evaluated by the mass to length ratio) by the end of the experiment and our analysis of mortality revealed a significant interaction in which the effects of OA were more lethal when food energy was limited. These results are consistent with the idea that although energy can be reallocated to preserve biomass growth, increased energetic demand under ocean acidification may draw energy away from maintenance, including those processes that foster homeostasis during development. Overall, these results highlight both the need to consider the availability of food energy as a force governing species’ responses to ocean acidification and the need to explicitly consider the energy allocated to both growth and maintenance as climate changes.

 

New routes to the formation of macrocyclic molecules are of high interest to the supramolecular chemistry community and the chemistry community at large. Here we describe the incorporation of heterocyclic core units into discrete macrocycles via the utilization of a pnictogen-assisted self-assembly technique. This method allows for the rapid and efficient formation of discreet macrocyclic units from simple dithiol precursors in high yields with good control over macrocycle size. Up to this point, this technique has been reported on primarily benzylic thiol systems with very little incorporation of endohedral heteroatoms in the resulting assemblies. This study demonstrates the effective incorporation of heterocyclic core molecules allowing for the formation of a more functional cavity, resulting in the formation and crystallization of novel furan- and thiophene-based disulfide dimer and trimer macrocycles, respectively, that are isolated from a range of other larger discrete macrocycles that assemble as well. These disulfide macrocycles can be trapped as their more kinetically stable thioether congeners upon sulfur extrusion.

 

Several phosphaquinolinone derivatives have been synthesized and characterized to explore their usefulness in the realm of cell imaging. Solution-state photophysical properties in both aqueous and organic solutions were collected for these derivatives. Additionally, CCK-8 cell viability assays and fluorescent imaging in HeLa cells incubated with the new heterocyclic derivatives show evidence of favorable cell permeability, cell viability, and moderate intracellular localization when appended with the well-known morpholine targeting motif. 

Bambusuril-containing ChemFET sensor membranes show excellent selectivity for HS⁻and inform on its placement in the Hofmeister series. 

This work reports the synthesis and self‐assembly of perylene diimide (PDI)‐containing macrocycles designed for facile and high‐throughput production of shape‐persistent, macrocyclic organic electronic materials. Specifically, utilizing dynamic covalent chemistry (DCvC), this work showcases ditopic thiols can be utilized as building blocks toward 3D materials with defined porosity, low‐lying unoccupied molecular orbitals, and intrinsic fluorescence. The PDI disulfide‐linked macrocycles are generated in a single step from the thiolic building block to yield dimeric through pentameric assemblies in overall 95% combined yield; moreover, following self‐assembly, the disulfide ensemble is sulfur extruded to the more kinetically stable thioether in 79% combined yield. The modular design suggests these methods can be used to easily self‐assemble other electronically active precursors for utility in porous macrocyclic materials where stepwise pathways may be laborious and/or low yielding.

 

Abstract Cyclophanes are an admirable class of macrocyclic and cage compounds that often display unusual properties due to their high strain and unusual conformations. However, the exploration of new, complex cyclophanes has been encumbered by syntheses that can be low yielding, require harsh reaction conditions, and arduous purification steps. Herein, we discuss our work using metalloid-directed self-assembly and dynamic covalent chemistry to form cryptands. These were then subjected to mild conditions to produce discrete disulfide, thioether and hydrocarbon macrocycles in high yields. ‘Design of Experiments’ was then used to selectively synthesize targeted macrocycles from complex mixtures. 1 Introduction 2 Cryptands to Cyclophanes 3 Functionalizable Macrocycles 4 ‘Design of Experiments’ Targeted Synthesis 5 Conclusions and Outlook 

The short C–H⋯S contacts found in available structural data for both small molecules and larger biomolecular systems suggest that such contacts are an often overlooked yet important stabilizing interaction. Moreover, many of these short C–H⋯S contacts meet the definition of a hydrogen bonding interaction. Using available structural data from the Cambridge Structural Database (CSD), as well as selected examples from the literature in which important C–H⋯S contacts may have been overlooked, we highlight the generality of C–H⋯S hydrogen bonding as an important stabilizing interaction. To uncover and establish the generality of these interactions, we compare C–H⋯S contacts with other traditional hydrogen bond donors and acceptors as well as investigate how coordination number and metal bonding affect the preferred geometry of interactions in the solid state. This work establishes that the C–H⋯S bond meets the definition of a hydrogen bond and serves as a guide to identify C–H⋯S hydrogen bonds in diverse systems.