A5089770104- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Porphyrin and Phthalocyanine Chemistry
- Metal-Catalyzed Oxygenation Mechanisms
- Luminescence and Fluorescent Materials
- Radioactive element chemistry and processing
- Catalytic Cross-Coupling Reactions
- Surface Chemistry and Catalysis
- Chemical Synthesis and Reactions
- Alzheimer's disease research and treatments
- Molecular Sensors and Ion Detection
- Electrochemical Analysis and Applications
- Magnetism in coordination complexes
- Lanthanide and Transition Metal Complexes
- Mesoporous Materials and Catalysis
- Chemical synthesis and alkaloids
- Carbon dioxide utilization in catalysis
- Photochromic and Fluorescence Chemistry
- Oxidative Organic Chemistry Reactions
- Metal complexes synthesis and properties
- Advanced Proteomics Techniques and Applications
- Synthetic Organic Chemistry Methods
- Analytical Chemistry and Sensors
- Radical Photochemical Reactions
- Supramolecular Self-Assembly in Materials
Massachusetts Institute of Technology
2023-2024
The University of Texas at Austin
2017-2020
Convenient strategies for the deconstruction and reprocessing of thermosets could improve circularity these materials, but most approaches developed to date do not involve established, high-performance engineering materials. Here, we show that bifunctional silyl ether, i.e., R'O-SiR2-OR'', (BSE)-based comonomers generate covalent adaptable network analogues industrial thermoset polydicyclopentadiene (pDCPD) through a novel BSE exchange process facilitated by low-cost food-safe catalyst...
Here we report the first series of in-plane thorium(IV), uranium(IV), and neptunium(IV) expanded porphyrin complexes. These actinide (An) complexes were synthesized using a hexa-aza analogue, termed dipyriamethyrin, nonaqueous An(IV) precursors, ThCl4(DME)2, UCl4, NpCl4(DME)2. The molecular electronic structures ligand, each complex, corresponding uranyl(VI) complex characterized nuclear magnetic resonance (NMR) UV-vis spectroscopies as well single-crystal X-ray diffraction analysis....
Porphyrin and related pyrrole-containing macrocycles, collectively porphyrinoids, are versatile ligands that allow access to a multitude of coordination modes. Judicious modification the porphyrin core as well pendant substituents has extended chemistry porphyrinoids include systems able stabilize f-block element complexes with possible utility. This review focuses on our group's efforts prepare expanded porphyrinogen can serve tools study apply f-element metal chemistry: it covers...
The complex etiology of neurodegeneration continues to stifle efforts develop effective therapeutics. New agents elucidating key pathways causing might serve increase our understanding and potentially lead improved treatments. Here, we demonstrate that a water-soluble manganese(II) texaphyrin (MMn) is suitable magnetic resonance imaging (MRI) contrast agent for detecting larger amyloid beta constructs. potential MMn was inferred on the basis
The concentrations of reactive oxygen species (ROS), e.g., H2O2, are often elevated in diseased tissue microenvironments. Therefore, the selective detection ROS could enable new diagnostic methods or tools for chemical biology. Here, we report synthesis boronic ester-bis-norbornene core-cross-linked brush-arm star polymers (BASPs) with polyethylene glycol (PEG) PEG-branch-spirocyclohexyl nitroxide (chex) shells. Size exclusion chromatography (SEC) and dynamic light scattering (DLS) showed...
A new mixed hexaphyrin, pyrihexaphyrin (0.1.0.0.1.0) (1), was prepared via an acid catalyzed cyclization between 5,5'-(pyridine-2,6-diyl)bis(pyrrole-2-carbaldehyde) (2) and terpyrrole (3). This expanded porphyrin undergoes a ring contraction upon metallation with uranyl silylamide [UO2[N(SiMe3)2]2] under anaerobic conditions followed by purification over basic aluminum oxide exposed to air. The uranyl-contracted (0.0.0.0.1.0) complex (4) produced as result contains unique structural...
The use of protonation to switch nonaromatic expanded porphyrins their corresponding anti-aromatic forms has not been widely explored. Here, we show that free-base pyriamethyrin and dipyriamethyrin display character, as inferred from NMR spectroscopic analyses, optical properties, theoretical calculations. Addition two protons extends the π - conjugation these amethyrin analogues yields formally systems.
The reaction between a naphthylbipyrrole-containing hexaphyrin-type expanded porphyrin and copper acetate affords bench-stable dicopper(II) complex. UV–vis spectroscopy, cyclic voltammetry, X-ray crystallographic analysis measurements provide support for the conclusion that this complex displays aromatic features. A weak antiferromagnetic exchange interaction binuclear copper(II) ions is evidenced by variable-temperature electron paramagnetic resonance fitting of bulk magnetic susceptibility...
Using naphthobipyrrole as a functional building block, new expanded porphyrin, naphthoisoamethyrin, was prepared in 85% yield under acid-catalyzed [4 + 2] MacDonald coupling conditions. Treatment of naphthoisoamethyrin with the nonaqueous uranyl silylamide salt [UO2[N(SiMe3)2]2·2THF] yielded corresponding complex. Upon metalation, undergoes two-electron oxidation to formal 22 π-electron aromatic species, inferred from 1H NMR and UV-vis spectroscopy, well cyclic voltammetry.
While Si-containing polymers can often be deconstructed using chemical triggers such as fluoride, acids, and bases, they are resistant to cleavage by mild reagents biological nucleophiles, thus limiting their end-of-life options potential environmental degradability. Here, ring-opening metathesis polymerization, we synthesize terpolymers of (1) a "functional" monomer (e.g., polyethylene glycol macromonomer or dicyclopentadiene); (2) containing an electrophilic pentafluorophenyl (PFP)...
The reaction between amethyrin and non-aqueous uranyl silylamide (UO2[N(SiMe3)2]2) under anaerobic conditions affords a bench-stable complex. UV–vis spectroscopy, cyclic voltammetry, as well proton NMR spectroscopic analyses provide support for the conclusion that all six pyrrole subunits participate in coordination of dication that, upon complexation, amethyrin-core undergoes 2-electron oxidation to yield formal 22 π-electron aromatic species.
The controlled preparation of higher order oligopyrrolic species holds broad utility across the chemical and material sciences. Here, we describe gram-scale synthesis a bench-stable 5,5″-unsubstituted terpyrrole in excellent yield via tandem Suzuki cross-coupling with situ deprotection. solution solid-state stability as well UV–vis, fluorescence, single crystal X-ray diffraction structure are also detailed.
The reaction between dipyriamethyrin and copper(II) acetate [Cu(OAc)2] afforded what is, to our knowledge, the first transition metal-dipyriamethyrin complex. Molecular electronic characterization of this binuclear Cu(II) complex via EPR, UV-vis, single crystal X-ray diffraction analysis revealed marked differences present constructs previously reported hexaphyrin species. UV-vis titration analyses provided evidence for a homotropic positive allosteric effect, wherein species is formed...
The controlled synthesis of oligoaromatics can provide materials wide utility. Here, we describe the preparation higher order oligoheterocycles via a tandem Suzuki cross-coupling protocol. This method has allowed for iterative construction fluorescent [Formula: see text],[Formula: text]-linked penta- and septaheterocyclic systems with modification terminal moiety allowing fine-tuning emission features.