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Journal of the American Chemical Society Feb 2021The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living...
The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living systems remains an outstanding challenge for noninvasive optical imaging. Here, we report the design, synthesis, and application of near-infrared (NIR)-absorbing and -emitting optical voltmeter based on a sulfonated, phosphine-oxide (po) rhodamine for voltage imaging in intact retinas. We find that po-rhodamine based voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at greater than 700 nm, show a range of voltage sensitivities (13 to 43% ΔF/F per 100 mV in HEK cells), and can be combined with existing optical sensors, like Ca-sensitive fluorescent proteins (GCaMP), and actuators, like light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca imaging reveals differences in activity dynamics in rat hippocampal neurons, and pairing poRhoVR with blue-light based ChR2 affords all-optical electrophysiology. In retinas isolated from a mouse model of retinal degeneration, poRhoVR, together with GCaMP-based Ca imaging and traditional multielectrode array (MEA) recording, can provide a comprehensive physiological activity profile of neuronal activity, revealing differences in voltage and Ca dynamics within hyperactive networks of the mouse retina. Taken together, these experiments establish that poRhoVR will open new horizons in optical interrogation of cellular and neuronal physiology in intact systems.
Topics: Animals; Calcium; Fluorescent Dyes; Infrared Rays; Mice; Neurons; Optical Imaging; Oxides; Phosphines; Retina; Rhodamines
PubMed: 33501825
DOI: 10.1021/jacs.0c11382 -
ACS Catalysis Mar 2022Planar chiral monodentate 1,3-disubstituted ferrocene phosphines inspired on JohnPhos-type ligands have been synthesized and applied to the enantioselective gold(I)...
Planar chiral monodentate 1,3-disubstituted ferrocene phosphines inspired on JohnPhos-type ligands have been synthesized and applied to the enantioselective gold(I) catalyzed [4 + 2] cycloaddition of 1,6-arylenynes. Computational studies rationalized the working mode of the catalyst on the folding of the substrate in the chiral environment of the ligand involving attractive noncovalent interactions.
PubMed: 35356706
DOI: 10.1021/acscatal.1c05827 -
Asian Journal of Organic Chemistry Nov 2021This Minireview provides insight into the early history of nucleophilic phosphinocatalysis. The concepts of 1,4-addition of a tertiary phosphine to an α,β-enone and of...
This Minireview provides insight into the early history of nucleophilic phosphinocatalysis. The concepts of 1,4-addition of a tertiary phosphine to an α,β-enone and of equilibrium between the resulting phosphonium zwitterion and phosphonium ylide established a fundamental basis for the development of several classical transformations, including the Rauhut-Currier, Morita, McClure-Baizer-Anderson, and Oda reactions.
PubMed: 38298937
DOI: 10.1002/ajoc.202100496 -
Scientific Reports Aug 2019The reaction of gold reagents [HAuCl•3HO], [AuCl(tht)], or cyclometalated gold(III) precursor, [C^NAuCl] with chiral ((R,R)-(-)-2,3-bis(t-butylmethylphosphino)...
The reaction of gold reagents [HAuCl•3HO], [AuCl(tht)], or cyclometalated gold(III) precursor, [C^NAuCl] with chiral ((R,R)-(-)-2,3-bis(t-butylmethylphosphino) quinoxaline) and non-chiral phosphine (1,2-Bis(diphenylphosphino)ethane, dppe) ligands lead to distorted Au(I), (1, 2, 4, 5) and novel cyclometalated Au(III) complexes (3, 6). These gold compounds were characterized by multinuclear NMR, microanalysis, mass spectrometry, and X-ray crystallography. The inherent electrochemical properties of the gold complexes were also studied by cyclic voltammetry and theoretical insight of the complexes was gained by density functional theory and TD-DFT calculations. The complexes effectively kill cancer cells with IC in the range of ~0.10-2.53 μΜ across K562, H460, and OVCAR8 cell lines. In addition, the retinal pigment epithelial cell line, RPE-Neo was used as a healthy cell line for comparison. Differential cellular uptake in cancer cells was observed for the compounds by measuring the intracellular accumulation of gold using ICP-OES. Furthermore, the compounds trigger early - late stage apoptosis through potential disruption of redox homeostasis. Complexes 1 and 3 induce predominant G1 cell cycle arrest. Results presented in this report suggest that stable gold-phosphine complexes with variable oxidation states hold promise in anticancer drug discovery and need further development.
Topics: Animals; Apoptosis; Cattle; Cell Cycle; Cell Death; Cell Line, Tumor; Cell Proliferation; Crystallography, X-Ray; Density Functional Theory; Electrochemistry; Electrodes; Endocytosis; Gold; Humans; Inhibitory Concentration 50; Magnetic Resonance Spectroscopy; Models, Molecular; Phosphines; Serum Albumin, Bovine; Serum Albumin, Human; Spectrophotometry, Ultraviolet; Temperature
PubMed: 31451718
DOI: 10.1038/s41598-019-48584-5 -
International Journal of Molecular... Sep 2022Quantum dots (QDs) have outstanding optical properties such as strong fluorescence, excellent photostability, broad absorption spectra, and narrow emission bands, which...
Quantum dots (QDs) have outstanding optical properties such as strong fluorescence, excellent photostability, broad absorption spectra, and narrow emission bands, which make them useful for bioimaging. However, cadmium (Cd)-based QDs, which have been widely studied, have potential toxicity problems. Cd-free QDs have also been studied, but their weak photoluminescence (PL) intensity makes their practical use in bioimaging challenging. In this study, Cd-free QD nanoprobes for bioimaging were fabricated by densely embedding multiple indium phosphide/zinc sulfide (InP/ZnS) QDs onto silica templates and coating them with a silica shell. The fabricated silica-coated InP/ZnS QD-embedded silica nanoparticles (SiO@InP QDs@SiO NPs) exhibited hydrophilic properties because of the surface silica shell. The quantum yield (QY), maximum emission peak wavelength, and full-width half-maximum (FWHM) of the final fabricated SiO@InP QDs@SiO NPs were 6.61%, 527.01 nm, and 44.62 nm, respectively. Moreover, the brightness of the particles could be easily controlled by adjusting the amount of InP/ZnS QDs in the SiO@InP QDs@SiO NPs. When SiO@InP QDs@SiO NPs were administered to tumor syngeneic mice, the fluorescence signal was prominently detected in the tumor because of the preferential distribution of the SiO@InP QDs@SiO NPs, demonstrating their applicability in bioimaging with NPs. Thus, SiO@InP QDs@SiO NPs have the potential to successfully replace Cd-based QDs as highly bright and biocompatible fluorescent nanoprobes.
Topics: Animals; Cadmium; Indium; Mice; Nanoparticles; Neoplasms; Phosphines; Quantum Dots; Silicon Dioxide; Sulfides; Zinc Compounds
PubMed: 36142888
DOI: 10.3390/ijms231810977 -
Nature Aug 2021The substitution of an alkyl electrophile by a nucleophile is a foundational reaction in organic chemistry that enables the efficient and convergent synthesis of organic...
The substitution of an alkyl electrophile by a nucleophile is a foundational reaction in organic chemistry that enables the efficient and convergent synthesis of organic molecules. Although there has been substantial recent progress in exploiting transition-metal catalysis to expand the scope of nucleophilic substitution reactions to include carbon nucleophiles, there has been limited progress in corresponding reactions with nitrogen nucleophiles. For many substitution reactions, the bond construction itself is not the only challenge, as there is a need to control stereochemistry at the same time. Here we describe a method for the enantioconvergent substitution of unactivated racemic alkyl electrophiles by a ubiquitous nitrogen-containing functional group, an amide. Our method uses a photoinduced catalyst system based on copper, an Earth-abundant metal. This process for asymmetric N-alkylation relies on three distinct ligands-a bisphosphine, a phenoxide and a chiral diamine. The ligands assemble in situ to form two distinct catalysts that act cooperatively: a copper/bisphosphine/phenoxide complex that serves as a photocatalyst, and a chiral copper/diamine complex that catalyses enantioselective C-N bond formation. Our study thus expands enantioselective N-substitution by alkyl electrophiles beyond activated electrophiles (those bearing at least one sp- or sp-hybridized substituent on the carbon undergoing substitution) to include unactivated electrophiles.
Topics: Amides; Bromides; Carbon; Catalysis; Copper; Cyclization; Diamines; Ligands; Nitrogen; Phosphines; Photochemistry
PubMed: 34182570
DOI: 10.1038/s41586-021-03730-w -
Nanomaterials (Basel, Switzerland) Sep 2022Nickel and nickel phosphide nanoparticles are highly useful in various fields, owing to their catalytic and magnetic properties. Although several synthetic protocols to...
Nickel and nickel phosphide nanoparticles are highly useful in various fields, owing to their catalytic and magnetic properties. Although several synthetic protocols to produce nickel and nickel phosphide nanoparticles have been previously proposed, controllable synthesis of nanoparticles using these methods is challenging. Herein, we synthesized highly monodisperse nickel and nickel phosphide nanoparticles via thermal decomposition of nickel-oleylamine-phosphine complexes in organic solvents. The size and composition of the nickel and nickel phosphide nanoparticles were easily controlled by changing the aging temperature, precursor concentration, and phosphine surfactant type. Large-sized monodisperse nickel nanoparticles obtained using our method were successfully applied for the purification of histidine-tagged proteins.
PubMed: 36144985
DOI: 10.3390/nano12183198 -
Polymers Apr 2022Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and...
Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and flame-retardant separator in high-performance and safe lithium-ion batteries (LIBs). ADEP is phosphorus-rich, thermally stable, and flame retardant, and it can effectively suppress the combustibility of PAN nanofibers. Nanofibrous membranes were obtained by electrospinning, and the content of ADEP varied from 0 to 20 wt%. From the vertical burning test, it was demonstrated that the flame retardancy of the composite membranes was enhanced when more than 5 wt% of ADEP was added to PAN, potentially increasing the safety level of LIBs. Moreover, the composite membrane showed higher ionic conductivity and electrolyte uptake (0.83 mS/cm and 137%) compared to those of commercial polypropylene (PP) membranes (Celgard 2400: 0.65 mS/cm and 63%), resulting from interconnected pores and the polar chemical composition in the composite membranes. In terms of battery performance, the composite membrane showed highly stable electrochemical and heat-resistant properties, including superior discharge capacity when compared to Celgard 2400, indicating that the PAN/ADEP composite membrane has the potential to be used as a heat-resistant and flame-retardant separator for safe and high-power LIBs.
PubMed: 35566819
DOI: 10.3390/polym14091649 -
Journal of Labelled Compounds &... Nov 2022The synthesis of deuteriated tri-tert-butyl phosphine is reported. This synthesis is an adaptation of the known procedure for tri-tert-butyl phosphine via a Grignard...
The synthesis of deuteriated tri-tert-butyl phosphine is reported. This synthesis is an adaptation of the known procedure for tri-tert-butyl phosphine via a Grignard intermediate.
Topics: Molecular Structure; Phosphines
PubMed: 36041885
DOI: 10.1002/jlcr.4001 -
Chemical Science Aug 2023Phosphines and phosphites are critical tools for non-metal desulfurative methodologies due to the strength of the P[double bond, length as m-dash]S bond. An overarching...
Phosphines and phosphites are critical tools for non-metal desulfurative methodologies due to the strength of the P[double bond, length as m-dash]S bond. An overarching premise in these methods has been that stoichiometric (or excess) P(iii) reagent is required for reactivity. Despite decades of research, a desulfurative process that is catalytic in phosphine/phosphite has not been reported. Here, we report the successful merging of two thermal radical processes: the desulfurization of unactivated and activated alkyl thiols and the reduction of P(v) = S to P(iii) by reaction with a silyl radical species. We employ catalytic trimethyl phosphite, catalytic azo-bis(cyclohexyl)nitrile, and two equivalents of tris(trimethylsilyl)silane as the stoichiometric reductant and sulfur atom scavenger. This method is tolerant of common organic functional groups and affords products in good to excellent yields.
PubMed: 37655042
DOI: 10.1039/d3sc00045a