An improved method for the synthesis of F-BODIPYs from dipyrrins and bis(dipyrrin)s

An improved methodology for the synthesis of F-BODIPYs from dipyrrins and bis(dipyrrin)s is reported. This strategy employs lithium salts of dipyrrins as intermediates that are then treated with only 1 equiv of boron trifluoride diethyletherate to obtain the corresponding F-BODIPYs. This scalable route to F-BODIPYs renders high yields with a facile purification process involving merely filtration of the reaction mixture through Celite in many cases.     

A small molecule sensor for fluoride based on an autoinductive, colorimetric signal amplification reaction

This article describes a small molecule reagent that is capable of detecting fluoride down to 0.12 mM (2.3 ppm) in water. The reagent reveals this level of fluoride through a novel autoinductive signal amplification reaction that produces an unambiguous colorimetric readout.     

New reactivity of the uranyl ion: ring opening polymerisation of epoxides

The uranyl aryloxide, [UO(2)(OAr)(2)(THF)(2)], and uranyl chloride, [UO(2)Cl(2)(THF)(3)] or [UO(2)Cl(2)(THF)(2)](2) act as pre-catalysts for the ring opening polymerization of propylene oxide and cyclohexene oxide. Coordination of the monomers has been investigated using (1)H EXSY spectroscopy and kinetic and thermodynamic parameters reported. NMR analyses of the polymers suggest a bimetallic mechanism for the polymerization.     

Magnetically gated microelectrodes

Microelectrodes fabricated in the center of single-coil microelectromagnetic traps are described. Magnetic particles are then used to reversibly gate transport of an electroactive species to the surface of the electrode or as a means to produce an ON/OFF bioelectrocatalytic glucose sensor.     

Graphs with the n‐e.c. adjacency property constructed from resolvable designs

Only recently have techniques been introduced that apply design theory to construct graphs with the n‐e.c. adjacency property. We supply a new random construction for generating infinite families of finite regular n‐e.c. graphs derived from certain resolvable Steiner 2‐designs. We supply an extension of our construction to the infinite case, and thereby give a new representation of the infinite random graph. We describe a family of deterministic graphs in infinite affine planes which satisfy the 3‐e.c. property. © 2009 Wiley Periodicals, Inc. J Combin Designs 17: 294–306, 2009     

Benzothiazines in organic synthesis. Synthesis of fluorescent 7-amino-2,1-benzothiazines

Fluorescent 7-amino-2,1-benzothiazines were prepared in high yields using the palladium-catalyzed reaction of 4-amino-2-chlorobenzaldehydes with a sulfoximine or the reaction of 7-fluoro-2,1-benzothiazines with amines.     

Microscopic Diffusion Dynamics of Silver Complex‐Based Room‐Temperature Ionic Liquids Probed by Quasielastic Neutron Scattering

Quasielastic neutron scattering is used to probe the microscopic diffusion dynamics of the hydrogen‐bearing cations of two different silver complex‐derived room‐temperature ionic liquids, [Ag(propylamine)₂⁺][Tf₂N^?] (Tf=trifluoromethanesulfonyl) and [Ag(1‐pentene)⁺][Tf₂N^?]. In the temperature range from 300 to 340 K, analysis of the scattering momentum transfer dependence of the data provides evidence for three distinct diffusion components. The slowest component describes the long‐range cationic translational diffusion. A possible link between the microscopic diffusion parameters and the structural features of the cations comprising these two ionic liquids is discussed.     

The mystery of gold's chemical activity: local bonding, morphology and reactivity of atomic oxygen

Recently, gold has been intensely studied as a catalyst for key synthetic reactions. Gold is an attractive catalyst because, surprisingly, it is highly active and very selective for partial oxidation processes suggesting promise for energy-efficient "green" chemistry. The underlying origin of the high activity of Au is a controversial subject since metallic gold is commonly thought to be inert. Herein, we establish that one origin of the high activity for gold catalysis is the extremely reactive nature of atomic oxygen bound in 3-fold coordination sites on metallic gold. This is the predominant form of O at low concentrations on the surface, which is a strong indication that it is most relevant to catalytic conditions. Atomic oxygen bound to metallic Au in 3-fold sites has high activity for CO oxidation, oxidation of olefins, and oxidative transformations of alcohols and amines. Among the factors identified as important in Au-O interaction are the morphology of the surface, the local binding site of oxygen, and the degree of order of the oxygen overlayer. In this Perspective, we present an overview of both theory and experiments that identify the reactive forms of O and their associated charge density distributions and bond strengths. We also analyze and model the release of Au atoms induced by O binding to the surface. This rough surface also has the potential for O(2) dissociation, which is a critical step if Au is to be activated catalytically. We further show the strong parallels between product distributions and reactivity for O-covered Au at low pressure (ultrahigh vacuum) and for nanoporous Au catalysts operating at atmospheric pressure as evidence that atomic O is the active species under working catalytic conditions when metallic Au is present. We briefly discuss the possible contributions of oxidants that may contain intact O-O bonds and of the Au-metal oxide support interface in Au catalysis. Finally, the challenges and future directions for fully understanding the activity of gold are considered.     

Chromium chains as polydentate fluoride ligands for lanthanides

Hexametallic chromium(III) chains can act as fluoride donor ligands to lanthanide ions giving {(Cr(6))Ln(x)}(n) complexes; preliminary spectroscopic studies are reported.     

Exploring the Responses of Underrepresented Students in Science to an Elementary Classroom Outreach Program

This paper describes a subset of results from a large‐scale two‐year independent evaluation study conducted with the Scientists in School (SiS) outreach program and two large school boards in Ontario, Canada. Specifically, it explores the responses of elementary students (n= 811) from typically underrepresented groups in science (English language learners [ELL], girls, and students at low‐achieving schools) to the SiS outreach program. It explores responses related to enjoyment, interest, perceptions of role modeling, and future career choice in science. Compared to other students, findings suggest that girls and students from low‐achieving schools found the program more enjoyable and reported that it provided positive science role models. Students at schools with high ELL populations also reported higher levels of enjoyment and reported that the program helped get them excited about science.