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We report here the first chiral barbiturate to act as a single-component LMOG capable of gelating a variety of chlorinated and aromatic solvents. Solution-based DOSY NMR experiments, solid-state VP-SEM, and X-ray crystallography techniques were used to characterize chloroform-based gels at a variety of size domains. This scaffold provides a simple system to study the dynamics of gelation and self-assembly.

Ring-opening metathesis polymerization (ROMP), which is derived from transition-metal-based olefin metathesis, has evolved into one of the most prevalent technologies for making functional polymeric materials in academia and in industry. The initial discovery of and advances in ROMP used ill-defined mixtures of metal salts to initiate polymerization. The initiators most commonly used today, developed with tremendous efforts, are well-defined metal-alkylidene complexes that have enabled a good mechanistic understanding of the polymerization as well as improvement of the initiators' activity, stability, and functional group tolerance.The evolution of ROMP has been decidedly metal-centric, with the path to accolades being paved primarily in ruthenium-, molybdenum-, and tungsten-based systems. Our departure from the ROMP trailhead was inspired in part by recent breakthroughs in radical-mediated polymerizations, whereby their mechanisms were leveraged to develop metal-free reaction conditions. Inventing a metal-free complement to traditional ROMP would essentially involve stepping away from decades of inorganic and organometallic developments, but with the promise of crossing new synthetic capabilities and curiosities.Driven by this motivation, as well as a community-inspired desire to develop "greener" controlled polymerizations, our team pioneered the search for, and discovery of, a wholly organic alternative to traditional metal-mediated ROMP. In this Account, we review our recent efforts to develop metal-free ring-opening metathesis polymerization (MF-ROMP), which is inspired by previous reports in electro- and photo-mediated organic transformations.This work began with an exploration of the direct oxidation of enol ethers and the propensity of the ensuing radical cations to initiate ROMP. To overcome limitations of the electrochemical conditions, a photoredox-mediated method was investigated next, using photoexcited pyrylium salts to oxidize the enol ethers. With this system, we demonstrated the ability to produce ROMP products and temporally control the polymerization.Further investigations into different aspects of the reaction included monomer scope, functional group tolerance, the impact of changing photocatalyst properties, and the ability to control molecular weight. The unique mechanism of MF-ROMP, along with the relative ease of synthesizing enol ether initiators, enabled the preparation of numerous polymeric materials that are hard to access through traditional metal-mediated pathways. At the end of this Account, we provide a perspective on future opportunities in this emerging area.

A new method for the synthesis of heteroleptic alkylphosphine oxides (R2R1P═O, where R ≠ R1) from secondary phosphine oxides (or SPOs, R2HP═O) is presented. These reactions were fast at room temperature, sterically selective, high yielding, and >95% pure after an aqueous wash. Deprotonation of an SPO generates a phosphinite anion ([R2P–O]−) that was found to be highly selective for nucleophilic P–C bond formation (as opposed to O–C bond formation) with alkyl halides. Surprisingly, most strong organometallic bases failed to deprotonate SPOs to their respective phosphinite anions (pKas for most SPOs are

Potentiometric sensing devices were prepared based on ion-selective membranes (ISM) containing Hamilton-type receptors incorporated into polymer membranes. Measurement capabilities of these devices were evaluated and exhibit near-Nernstian sensitivities in several different aqueous matrices, demonstrating the utility of Hamilton receptors within polymer membranes for potentiometric detection of a barbiturates in water. This work also investigates the effects of receptor preorganization on sensor performance and compares these effects to those observed for similar receptor systems in solution.

A new method for ozonolysis of alkenes using a continuous flow film-shear reactor was developed. The reactor uses a shearing microfluidic mixing chamber to provide biphasic mixing of an organic phase and aqueous phase with ozone gas. The H2O acts as an in situ reducing agent for the carbonyl oxide intermediate, providing ketones and aldehydes directly from the reaction mixture. Flow rates of up to 1.0 mmol/min (alkene) with an ozone reaction efficiency of >70% were achieved. Aryl conjugated olefins reacted to form carbonyl species in good yields on a multi-gram scale; however, alkyl olefins reacted with ozone to predominantly form secondary ozonides. The discrepancy in product distributions between alkyl and aryl olefins likely originates from the electronic stability of the carbonyl oxide intermediate, which is longer lived for aryl derivatives due to conjugation.

Benzo[1,2-b:4,5-b']dithiophenes were oxidized under mild conditions with m-CPBA to yield the corresponding bis-sulfones (or tetraoxides). These sulfones possess red-shifted absorption and emission spectra relative to the parent molecules. Electrochemical analyses reveal that the benzodithiophene molecules are transformed from electron donors to electron acceptors.

There is constant demand for new ligand archictectures on which inorganic and organometallic structures can be leveraged. An important, but often synthetically challenging, class of ligands is bidentate phosphines. Here we report self-assembling, supramolecular bidentate ligand scaffolds based on deconstructed Hamilton receptors with binding affinities up to 800 ± 100 M−1.

A new method for ozonolysis of alkenes using a continuous flow film-shear reactor was developed. The reactor uses a shearing microfluidic mixing chamber to provide biphasic mixing of an organic phase and aqueous phase with ozone gas. The H2O acts as an in situ reducing agent for the carbonyl oxide intermediate, providing ketones and aldehydes directly from the reaction mixture. Flow rates of up to 1.0 mmol/min (alkene) with an ozone reaction efficiency of >70% were achieved. Aryl conjugated olefins reacted to form carbonyl species in good yields on a multi-gram scale; however, alkyl olefins reacted with ozone to predominantly form secondary ozonides. The discrepancy in product distributions between alkyl and aryl olefins likely originates from the electronic stability of the carbonyl oxide intermediate, which is longer lived for aryl derivatives due to conjugation.

A simple two-step procedure is elaborated for the preparation of dialkylated benzodithiophenes (III) and (V) from dione (I).

A simple two-step procedure is elaborated for the preparation of dialkylated benzodithiophenes (III) and (V) from dione (I).