Diazirine reagents allow for the ready generation of carbenes upon photochemical, thermal, or electrical stimulation. Because carbenes formed in this way can undergo rapid insertion into any nearby C–H, O–H...

Motivated by a desire to develop flexible covalent adhesives that afford some of the same malleability in the adhesive layer as traditional polymer-based adhesives, we designed and synthesized two flexible,...

Electronically optimized bis-diazirine crosslinkers allow aliphatic polymers to be crosslinked with up to 10-fold improved efficacy, relative to earlier designs. Activation is achieved using modest temperatures or through UV or visible light.

The SARS-CoV-2 pandemic has highlighted the weaknesses of relying on single-use mask and respirator personal protective equipment (PPE) and the global supply chain that supports this market. There have been no major innovations in filter technology for PPE in the past two decades. Non-woven textiles used for filtering PPE are single-use products in the healthcare environment; use and protection is focused on preventing infection from airborne or aerosolized pathogens such as Influenza A virus or SARS-CoV-2. Recently, C–H bond activation under mild and controllable conditions was reported for crosslinking commodity aliphatic polymers such as polyethylene and polypropylene. Significantly, these are the same types of polymers used in PPE filtration systems. In this report, we take advantage of this C–H insertion method to covalently attach a photosensitizing zinc-porphyrin to the surface of a melt-blow non-woven textile filter material. With the photosensitizer covalently attached to the surface of the textile, illumination with visible light was expected to produce oxidizing 1O2/ROS at the surface of the material that would result in pathogen inactivation. The filter was tested for its ability to inactivate Influenza A virus, an enveloped RNA virus similar to SARS-CoV-2, over a period of four hours with illumination of high intensity visible light. The photosensitizer-functionalized polypropylene filter inactivated our model virus by 99.99% in comparison to a control.

Antimicrobial photodynamic inactivation represents a promising and potentially greener alternative to conventional antimicrobials, and a solution for multidrug-resistant strains. The current study reports the development and characterization of tetra-substituted diazirine porphyrin covalently bonded to polyethylene terephthalate (PET) and its use as an antimicrobial surface. The diazirine moiety on the porphyrin was activated using a temperature of 120 °C, which initiated a C–H insertion mechanism that irreversibly functionalized the PET surface. Activation of the surface with white LED light in phosphate-buffered saline (PBS) led to singlet oxygen generation, which was detected via the degradation of 9,10-anthracenediylbis(methylene)dimalonic acid (ADMA) over time. The bactericidal effect of the 1 O 2 -producing surface against Staphylococcus aureus was determined qualitatively and quantitatively. The growth of the pathogen beneath porphyrin-functionalized PET coupons was reduced; moreover, the PET coupons resulted in a 1.76-log reduction in cell counts after exposure to white LED light for 6 h. This is a promising material and platform for the development of safer antimicrobial surfaces, with applications in healthcare, food packaging, marine surfaces, and other surfaces in the environment.

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The non-enzymatic acylative kineticr esolutiono f challenging aryl-alkenyl (sp 2 vs. sp 2 )s ubstituted secondary alcohols is described,w ith effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of aw ide range of aryl-alkenyls ubstituted alcohols has been evaluated, with either electron-rich or naphthyl aryl substituents in combination with an unsubstituted vinyl substituent providing the highests electivity( S = 2-1980). The use of this protocolf or the gram-scale (2.5 g) kinetic resolution of am odel aryl-vinyl (sp 2 vs. sp 2 )s ubstituted secondary alcohol is demonstrated, giving access to > 1gof each of the product enantiomers both in 99:1 e.r.

Ultra-high-molecular weight polyethylene (UHMWPE) fibers show promise for use in fiber-reinforced polymer composites but have poor interfacial adhesion to the epoxy resin that would serve as the polymer matrix. Here, we describe the development of a diazirine-grafted polyamine that can be used as a topically applied primer for UHMWPE fibers. Activation of the diazirine groups on the primer initiates C−H bond insertion on the polyethylene fiber, leading to strong covalent bonds between the fiber and the polyamine coating. The covalently functionalized surface can then engage in nucleophilic addition reactions with epoxy resinresulting in increased bonding to the epoxy matrix (demonstrated through lap-shear experiments) and increased performance for fiber-reinforced composite materials (demonstrated through lamination rates and short-beam stress measurements).