We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic–inorganic halides (R)ZnBr 3 (DMSO), (R) 2 CdBr 4 ·DMSO, and (R)CdI 3 (DMSO) (where (R) = C 6 (CH 3 ) 5 CH 2 N(CH 3 ) 3 , and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO–methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations. The presence of discrete molecular building blocks in the 0D structures results in localized charges and tunable room-temperature light emission, including white light for (R)ZnBr 3 (DMSO), bluish-white light for (R) 2 CdBr 4 ·DMSO, and green for (R)CdI 3 (DMSO). The highest photoluminescence quantum yield (PLQY) value of 3.07% was measured for (R)ZnBr 3 (DMSO), which emits cold white light based on the calculated correlated color temperature (CCT) of 11,044 K. All compounds exhibit fast photoluminescence lifetimes on the timescale of tens of nanoseconds, consistent with the fast luminescence decay observed in π-conjugated organic molecules. Temperature dependence photoluminescence study showed the appearance of additional peaks around 550 nm, resulting from the organic salt emission. Density functional theory calculations show that the incorporation of both the low-gap aromatic molecule R and the relatively electropositive Zn and Cd metals can lead to exciton localization at the aromatic molecular cations, which act as luminescence centers.

Bacterial biofilms, often impenetrable to antibiotic medications, are a leading cause of poor wound healing. The prognosis is worse for wounds with biofilms of antimicrobial-resistant (AMR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and multi-drug resistant Pseudomonas aeruginosa (MDR-PA). Resistance hinders initial treatment of standard-of-care antibiotics. The persistence of MRSA, MRSE, and/or MDR-PA often allows acute infections to become chronic wound infections. The water-soluble hydrophilic properties of low-molecular-weight (600 Da) branched polyethylenimine (600 Da BPEI) enable easy drug delivery to directly attack AMR and biofilms in the wound environment as a topical agent for wound treatment. To mitigate toxicity issues, we have modified 600 Da BPEI with polyethylene glycol (PEG) in a straightforward one-step reaction. The PEG–BPEI molecules disable β-lactam resistance in MRSA, MRSE, and MDR-PA while also having the ability to dissolve established biofilms. PEG-BPEI accomplishes these tasks independently, resulting in a multifunction potentiation agent. We envision wound treatment with antibiotics given topically, orally, or intravenously in which external application of PEG–BPEIs disables biofilms and resistance mechanisms. In the absence of a robust pipeline of new drugs, existing drugs and regimens must be re-evaluated as combination(s) with potentiators. The PEGylation of 600 Da BPEI provides new opportunities to meet this goal with a single compound whose multifunction properties are retained while lowering acute toxicity.

Pentafluoropyridine, a potentially useful precursor in organofluorine methodology, undergoes selective substitution of a fluorine with a phenoxide at the site para to the nitrogen. Subsequent aryloxide substitutions can be accomplished at the ortho-positions with aryloxide groups containing various functional groups para to the phenoxide oxygen. During this phase of the reaction, “reverse reactions” involving substitutions of the original para substituent with a free fluoride or with another aryloxide moiety are observed with a frequency that depends on the functional group para to the oxygen on the aryloxide. Herein, we provide a theoretical explanation of these observations through use of density functional theory.

Polymer functionality greatly determines many of the key properties of these materials, such as glass-transition temperature, electrical and thermal conductivity, thermal stability, mechanical strength, and processability. Despite the importance of polymer functionality in determining material properties, the synthesis of functional polymers, with well-defined molecular weights and compositions, can still present a significant challenge, with many of the methods related to pre- or postpolymerization modification lacking synthetic scope, or requiring harsh functionalization conditions or transition-metal coupling reactions to install the desired functionality. Perfluoroaromatic systems are promising for the preparation of novel polymer architectures given that they can be readily functionalized using simple nucleophilic chemistries under very mild basic conditions. While promising, these systems have displayed some drawbacks. Previous work has shown that perfluoroaromatics, such as perfluoropyridine, can demonstrate a high degree of chemical reversibility with heteroatom nucleophiles. If the synthetic potential of these systems is to be realized, then a strategy for the rational design of stable monomers must be developed. Herein, we report the design, synthesis, and characterization of a series of unexplored heteroatom-based ring-opening metathesis polymerization (ROMP)-active monomers containing a reactive perfluoropyridine pendent group, which can be used to readily prepare a wide variety of aryl ether-functionalized polymers, using both pre- and postpolymerization modification strategies. We also establish a direct connection between the dihedral angle of the monomer and its propensity to undergo reversible addition reactions, establishing functional criteria for the design of pre- and postmodifiable systems.

Fluorinated molecules containing reactive functionalities are of great interest to the materials community as these compounds can be used to prepare fluorinated polymers with desirable physical and electronic properties. Despite their potential, many of these compounds are limited by their synthesis which generally requires transition-metal-catalyzed coupling reactions or harsh fluorinating conditions. Perfluoroheteroaromatic compounds provide a unique solution to this problem as compounds such as perfluoropyridine can undergo SNAr reactions with a wide range of simple nucleophiles in a controlled and regioselective manner. Herein we report the transition-metal-free synthesis of a pool of highly soluble high aromatic content (HAC) perfluoropyridine-based thermosetting precursors and compounds of interest which can be easily obtained from readily available chemical precursors using simple nucleophilic chemistries. These thermally active monomers cure readily, in 350–400 °C temperature ranges, into highly densified polyaryelene networks and demonstrate decomposition temperatures well above 400 °C and high char yields at 900 °C, making these promising materials for high-temperature applications as well as templates for carbon-based nanomaterials.

The addition of fluorine atoms to an aromatic ring brings about an additional set of π-bonding and antibonding orbitals culminating after the addition of the sixth fluorine with a new set of π-aromatic-like orbitals that affect the molecule in a way that we will refer to hereafter as "fluoromaticity". Depending on the number and position of the fluorine atoms, the contributed πorbitals can even further stabilize the ring leading to smaller bond lengths within the ring and higher resistance to addition reactions. This added ring stability partially explains the high thermostability and chemical resistance found in polymers containing fluorinated aromatics in their architecture. A similar molecular orbital effect is seen with the addition of other halogen atoms to aromatic rings, though to a much smaller degree and not resulting in the additional ring stability.

This report details the syntheses of five new 2,6bis(pyrazol-1-yl)pyridine ligands carried out by a unique strategy of utilizing pentafluoropyridine for the pyridine core. Formation of each ligand is accomplished under mild conditions utilizing carbonate bases. Each ligand reacts readily with copper(II) triflate to form the corresponding salt in high yield. Ligands and complexes were characterized by a combination of multi-nuclear NMR, FTIR, UV/Vis, and single-crystal X-ray diffrac- [a] Scheme 1. Synthetic strategies for bis(pyrazol-1-yl)pyridine ligands.

The Cover Feature shows 2,6‐bis(pyrazol‐1‐yl)pyridine ligands prepared by a unique strategy of utilizing pentafluoropyridine for the pyridine core to synthesize a ligand that reacts readily with copper(II) triflate to form the corresponding salts. Similar to skiers on a lift choosing their preferred routes, pentafluoropyridine allows one also to regioselectively access tailorable ligands for custom Cu complexes without the use of conventional Pd‐based aryl–aryl coupling. More information can be found in the Full Paper by S. T. Iacono, W. T. Pennington et al.