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This paper presents results of a study of a new cationic oligomer that contains end groups and a chromophore affording inactivation of SARS-CoV-2 by visible light irradiation in solution or as a solid coating on paper wipes and glass fiber filtration substrates. A key finding of this study is that the cationic oligomer with a central thiophene ring and imidazolium charged groups gives outstanding performance in both the killing of E. coli bacterial cells and inactivation of the virus at very short times. Our introduction of cationic N-methyl imidazolium groups enhances the light activation process for both E. coli and SARS-CoV-2 but dampens the killing of the bacteria and eliminates the inactivation of the virus in the dark. For the studies with this oligomer in solution at a concentration of 1 μg/mL and E. coli, we obtain 3 log killing of the bacteria with 10 min of irradiation with LuzChem cool white lights (mimicking indoor illumination). With the oligomer in solution at a concentration of 10 μg/mL, we observe 4 log inactivation (99.99%) in 5 min of irradiation and total inactivation after 10 min. The oligomer is quite active against E. coli on oligomer-coated paper wipes and glass fiber filter supports. The SARS-CoV-2 is also inactivated by oligomer-coated glass fiber filter papers. This study indicates that these oligomer-coated materials may be very useful as wipes and filtration materials. © 2022 American Chemical Society. All rights reserved.

The power conversion efficiency of tandem dye-sensitized photoelectrosynthesis cells is limited by the number of p-type metal oxide semiconductors and chromophores available for the photocathode. H...

Extending the applications of Photoremovable Protecting Groups (PPGs) to "cage" phenols has generally met with unusually complex PPG byproducts. In this study, we demonstrate that thep-hydroxyphenacyl (pHP) cage for both simple and complex phenolics, including tyrosine, dispenses free phenols. With the simpler unsubstituted phenols, the reaction is governed by their Bronsted Leaving Group ability. On the other hand, the byproducts of the cage vary with these phenols. For the more acidic phenols the cage byproduct follows the Favorskii rearrangement to formp-hydroxyphenylacetic acid whereas for the weaker phenols other reactions such as reduction and hydrolysis begin to emerge. When the photolysis is conducted in octa acid (OA) containers, non-Favorskii, unrearranged fragments of the cage and other byproducts arise. Kansas University Endowment Association National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA National Science FoundationNational Science Foundation (NSF) [CHE-1807729] FCT - Foundation for Science and TechnologyPortuguese Foundation for Science and Technology [UID/Multi/04326/2019] operational program COMPETE 2020 [EMBRC.PT ALG-01-0145-FEDER-022121] info:eu-repo/semantics/publishedVersion

Infections caused by pathogenic fungi, especially Candida albicans are a growing global challenge for public health. Current antifungal drugs have been administered commonly to treat Candida infect...

Conjugated polyelectrolytes (CPEs) are a promising class of materials for photovoltaic and sensing applications due to their ability to undergo efficient photoinduced electron transfer (ET). Although water-soluble poly(p-phenylene ethynylene) (PPE) polyelectrolytes have been synthesized for various applications, no reports have clearly revealed the dynamics of the photoinduced ET process and charge transfer state of PPE-type CPE/electron acceptor systems. Herein, we investigated photoinduced ET from a water-soluble PPE based CPE functionalized with alkyl sulfonate (R–SO3−) as side groups to three cationic electron acceptors. Steady-state absorption studies showed a bathochromic shift of the absorption band for all CPE/acceptor mixtures compared to CPE as a result of the suppression of the conformational changes in the polymer caused by the ion–pair interaction. Stern–Volmer (SV) fluorescence quenching studies revealed that all of the cationic electron acceptors efficiently quenched the fluorescence of CPE with SV constants (KSV) in excess of 106 M−1. Picosecond transient absorption (TA) studies of a CPE/methyl viologen mixture revealed the absorption feature of the cation radical state (CPE˙+) of the polyelectrolyte. Kinetic measurements established that the forward electron transfer in the polyelectrolyte/acceptor mixtures occurs with rate constant kf > 1 × 1012 s−1 and the return ET occurs with kb = 3 × 1011 s−1. We also demonstrated that the electron transfer between a PPE-type polyelectrolyte and an acceptor in their assemblies could be modulated by a supramolecular approach, which revealed that the nature of the acceptor–supramolecule host–guest complexes dictates the kinetics of the electron transfer process.

This paper presents results of a study of a new cationic oligomer that contains end groups and a chromophore affording inactivation of SARS-Cov-2 by visible light irradiation in solution or as a solid coating on wipes paper and glass fiber filtration substrates. A key finding of this study is that the cationic oligomer with a central thiophene ring and imidazolium charged groups give outstanding performance in both killing of E. coli bacterial cells and inactivation of the virus at very short times. Our introduction of cationic N-Methyl Imidazolium groups enhances the light-activation process for both E. coli and SARS-Cov-2 but dampens the dark killing of the bacteria and eliminates the dark inactivation of the virus. For the studies with this oligomer in solution at concentration of 1 μg/mL and E. coli we obtain 3 log killing of the bacteria with 10 min irradiation with LuzChem cool white lights (mimicking indoor illumination). With the oligomer in solution at a concentration of 10 μg/mL, we observe 4 logs inactivation (99.99 %) in 5 minutes of irradiation and total inactivation after 10 min. The oligomer is quite active against E. coli on oligomer-coated wipes papers and glass fiber filter supports. The SARS-Cov-2 is also inactivated by the oligomer coated glass fiber filter papers. This study indicates that these oligomer-coated materials may be very useful as wipes and filtration materials.

This study examines the use of Pd(0)-catalyzed chain-growth Sonogashira coupling to prepare a series of poly(phenylene ethynylene) (PPE)-type conjugated polyelectrolytes that feature alkyl sulfonat...

The current Covid-19 Pandemic caused by the highly contagious SARS-CoV-2 virus has proven extremely difficult to prevent or control. Currently there are few treatment options and very few long-lasting disinfectants available to prevent the spread. While masks and protective clothing and “social distancing” may offer some protection, their use has not always halted or slowed the spread. Several vaccines are currently undergoing testing; however there is still a critical need to provide new methods for inactivating the virus before it can spread and infect humans. In the present study we examined the inactivation of SARS-CoV-2 by synthetic conjugated polymers and oligomers developed in our laboratories as antimicrobials for bacteria, fungi and non-enveloped viruses. Our results show that we can obtain highly effective light induced inactivation with several of these oligomers and polymers including irradiation with near-UV and visible light. With both the oligomers and polymers, we can reach several logs of inactivation with relatively short irradiation times. Our results suggest several applications involving the incorporation of these materials in wipes, sprays, masks and clothing and other Personal Protection Equipment (PPE) that can be useful in preventing infections and the spreading of this deadly virus and future outbreaks from similar viruses.

The two-photon absorption properties of anionic poly(phenylene ethynylene)-type conjugated oligo- and polyelectrolytes are studied in molecularly dissolved and aggregated forms in aqueous solution. Several different polyvalent cations are used to induce aggregation. It is found that both materials in the aggregated form exhibit enhanced two-photon excited fluorescence (2PEF) and two-photon cross section (σ2) compared with the molecularly dissolved structures. The 2PEF and σ2 are unaffected by the nature of the polyvalent cation that is used to induce aggregation. The two-photon absorption cross section enhancement arises because of the increase in the difference dipole moment (Δμ) in the aggregates of the conjugated materials, an effect that is attributed to the introduction of charge transfer character into the aggregate excited state.

The reactions of cis-[PtCl2{P(C6H4CH3-p)3}2] with HC C-C6H4R-p (R = NO2, CH3, OCH3), in the presence of CuCl catalyst, lead to the formation of mono-acetylide complexes trans-[PtCl{P(C6H4CH3-p)3}2(C C-C6H4R-p)] (R = NO2 1; R = CH3 2; R = OCH3, 3). These monochloro-acetylide complexes were further employed for the synthesis of symmetrical dinuclear platinum complexes. Thus, the reactions of HC C-C6H2(2,5-OC4H9)2-C CH with two molar equivalents of 1, 2 and 3, in the presence of CuCl catalyst, affords dinuclear complexes trans-trans-[Pt2{P(C6H4CH3-p)3}4(C C-C6H4R-p)2(C C-C6H2(OC4H9)2-C C)](R = NO2 4; R = CH3 5; R = OCH3; 6). All these mono- and dinuclear platinum complexes have been characterized by IR, 1H NMR, 31P NMR spectroscopy, and the molecular structures of 2 and 5 were unequivocally established by single crystal X-ray diffraction analyses. The thermal stability of these complexes has been studied by thermogravimetric analysis (TGA). The photophysical properties of these materials have been probed using electronic absorption and emission spectroscopy, and z-scan techniques.

We report the synthesis and excited-state intramolecular proton transfer (ESIPT) properties of three tris(N-salicylideneaniline)-based (TSA) imine-linked porous organic polymers (POPs) containing C3-symmetric 1,3,5-triarylbenzene (TAB), -tristyrylbenzene (TSB), and -tris(arylethynyl)benzene (TAE) monomer units. The TSA–POPs are fluorescent in the solid-state and responsive to Cu2+ and Pd2+.

This chapter begins with a discussion on various types of Conjugated polyelectrolytes (CPE) that have been reported, with several examples, that will be followed by the fluorescence properties of CPEs. It analyses the biological applications of CPEs, in which biosensing, biocidal, and cell imaging properties will be described with specific examples. The chapter provides some useful examples that provide the reader with an overview of the field. It reviews research applying CPEs as sensors to detect important biological species such as protein, DNA, and bacteria. The chapter provides an overview of the structure, properties, and biological applications of conjugated polyelectrolytes. It is clear that since the initial report of biosensing avidin with a CPE, the diversity of polyelectrolyte structures and applications have become broad. The chapter also provides a reader with a general introduction to the field of conjugated polyelectrolytes. Conjugated polyelectrolytes have emerged as an important class of materials with a wide range of applications due their structural diversity.

We report the clean, efficient photorelease of a series of carboxylic acids embedded in octa acid (OA) host and protected by a p-hydroxyphenacyl cage. A key role is played by the cage by providing hydrophobicity for entry into the OA enclosure and yet readily removable as a photoactivated protecting group for release from the host. The rapid photo-Favorskii rearrangement of the departing chromophore does not react with the host OA but diminishes hydrophobicity of the OA contents, leading to their facile release into the solvent.

Water-soluble gold nanoparticles (AuNP) stabilized with cavitands having carboxylic acid groups have been synthesized and characterized by a variety of techniques. Apparently, the COOH groups similar to thiol are able to prevent aggregation of AuNP. These AuNP were stable either as solids or in aqueous solution. Most importantly, these cavitand functionalized AuNP were able to include organic guest molecules in their cavities in aqueous solution. Just like free cavitands (e.g., octa acid), cavitand functionalized AuNP includes guests such as 4,4'-dimethylbenzil and coumarin-1 through capsule formation. The exact structure of the capsular assembly is not known at this stage. Upon excitation there is communication between the excited guest present in the capsule and gold atoms and this results in quenching of phosphorescence from 4,4'-dimethylbenzil and fluorescence from coumarin-1.

The synthesis and photophysical properties of three tris(N-salicylideneaniline) (TSA) compounds containing 1,3,5-triarylbenzene, -tristyrylbenzene, and -tris(arylethynyl)benzene core units are reported. The TSA compounds underwent efficient excited-state intramolecular proton transfer (ESIPT) in solution and in solid state due to the preformed C=N⋅⋅⋅H-O hydrogen-bonded motifs of the structures. Steady-state fluorescence emission spectra of the TSA molecules revealed dual bands only in DMSO, and large Stokes shifts in other polar aprotic and protic solvents. Femtosecond transient absorption spectroscopic measurements in THF revealed lifetime values in the range of 14-16 ps for the excited-state keto-tautomer. The TSA compounds are also responsive to metal ions (Cu2+ and Zn2+ ) in DMSO, exhibit enhanced aggregate-induced emission (AIE) properties in DMSO/water mixtures, and are highly luminescent in the solid state.

Two new cavitands substituted with acid and alcohol groups (tetra-acid tetra-alcohol [TATA] and inverted TATA [iTATA]) bearing the same molecular skeleton as octa acid (OA) have been synthesized and their use as photochemical reaction containers explored. Isothermal calorimetric titration experiments suggest that the inclusion of organic molecules within these cavitands is driven both by favorable ΔH and ΔS and the substituents at the portals have little role to play. Comparison of the 2 new cavitands with the previous results on OA reveals that the presence of benzoate anion at the top periphery is essential for the cavitand to be a triplet sensitizer. Polarity within the water-soluble capsules, resulting from TATA and iTATA, was found to be close to that of ethylacetate and hydrocarbons, similar to that of OA. Photophysical studies with anthracene and camphorthione as guests disclose that the capsules made of 2 molecules of cavitands do not disassemble in the time scale of the excited states of the above guests (S1 in the case of anthracene and T1 in the case of camphorthione). Capsules ability to confine guests and the resulting photochemical intermediates has been tested by examining the photochemistry of 1-phenyl-3-para-tolyl-2-propanone. The radicals resulting from the Norrish type 1 cleavage of 1-phenyl-3-para-tolyl-2-propanone did not escape the cage and gave products, resulting from 100% cage effect. Availability of TATA and iTATA along with already reported similar cavitands expands the list of water-soluble capsule forming cavitands that could be used as molecular containers.

Examples of release of organic acids from encapsulated p-methoxyphenacyl esters provided here demonstrate the value of a phototrigger strategy to release chemicals of interest in water from hydrophobic precursors. In this study, a photochemical beta-cleavage process centered on the p-methoxyphenacyl group is exploited to release the acid of interest from a water-soluble capsule made up of octa acid.

Two deep cavity cavitands, octa acid and resorcinol-capped octa acid, have been established to be good triplet energy donors in the excited state and electron donors in the ground state to excited acceptors. This property endows them the capacity to be “active” reaction containers. The above recognition provides opportunities to investigate the excited state chemistry of host-encapsulated guests without the use of secondary triplet energy and electron donors.

In this report, we present methods of functionalization of AuNP's with deep-cavity cavitands that can include organic molecules. Two types of deep-cavity cavitand-functionalized AuNP's have been synthesized and characterized, one soluble in organic solvents and the other in water. Functionalized AuNP soluble in organic solvents forms a 1:1 host–guest complex where the guest is exposed to the exterior solvents. The one soluble in water forms a 2:1 host–guest complex where the guest is protected from solvent water. Phosphorescence from thiones and benzil included within heterocapsules attached to AuNP was quenched by gold atoms present closer to the guests included within deep-cavity cavitands. During this investigation, we have synthesized four new deep-cavity cavitands. Of these, two thiol-functionalized hosts allowed us to make stable AuNP's. However, AuNP's protected with two amine-functionalized cavitands tended to aggregate within a day.