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Indigo (C.I. Vat Blue 1) is a water-insoluble pigment exhibiting no affinity for fibres, and must be chemically reduced in basic solution to form the water-soluble, alkaline leucoindigo (C.I. Reduced Vat Blue 1), in order exhibit substantivity for fibres. Typical vat dyeing processes are time and resource intensive, and hazardous by-products are formed, primarily through the use of reducing agents. We describe a method for synthesizing indigo in a flow reactor that allows for application of dye precursors to fibres moments before the reaction completes. The soluble precursors soak into the cotton fabric just prior to the precipitation of the insoluble indigo, effectively providing in-situ coloration, without the need for a traditional redox dyebath. The reaction may be coupled with a propellant, an adaptation that allows for a “sprayable” form of indigo. In-situ coloration with Tyrian purple (6,6′-dibromoindigo; C.I. Natural Violet 1) was also demonstrated using the flow chemistry method. The research provides compelling proof-of-concept, but we acknowledge that the process is in its infancy and needs further development to get it to a stage where it can compete commercially with current technology.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized pathologically by amyloid beta (Aβ) deposition, microgliosis, and iron dyshomeostasis. Increased labile iron due to homeostatic dysregulation is believed to facilitate amyloidogenesis. Free iron is incorporated into aggregating amyloid peptides during Aβ plaque formation and increases potential for oxidative stress surrounding plaques. The goal of this work was to observe how brain iron levels temporally influence Aβ plaque formation, plaque iron concentration, and microgliosis. We fed humanized APPNL-F and APPNL-G-F knock-in mice lipophilic iron compound 3,5,5-trimethylhexanoyl ferrocene (TMHF) and iron deficient diets for twelve months. TMHF elevated brain iron by 22% and iron deficiency decreased brain iron 21% relative to control diet. Increasing brain iron with TMHF accelerated plaque formation, increased Aβ staining, and increased senile morphology of amyloid plaques. Increased brain iron was associated with increased plaque-iron loading and microglial iron inclusions. TMHF decreased IBA1+ microglia branch length while increasing roundness indicative of microglial activation. This body of work suggests that increasing mouse brain iron with TMHF potentiates a more human-like Alzheimer's disease phenotype with iron integration into Aβ plaques and associated microgliosis.

Generating enthusiasm among nonscience majors in a laboratory course is a difficult task. Often, students are asked to perform a precipitation reaction, only to collect and then safely dispose of the solid without detailing composition, properties, or uses. In an effort to keep the students engaged, this laboratory exercise presents an innovative way to use the product of a precipitation reaction. The reaction chosen produces basic zinc(II) chromate, a yellow pigment that can be combined with various paint binders such as beeswax, gum Arabic, egg yolk, linseed oil, and acrylic medium. The students then test their paints on a canvas and analyze their different physical properties. This exercise can be tailored to match different undergraduate levels, ranging from nonscience majors to chemistry majors and be used as a part of a STEAM (science, technology, engineering, arts, and mathematics) activity. A brief discussion on historical paint binders and their chemistry is also included.

Impaired brain iron homeostatic mechanisms, independent of pathological hallmarks, are harmful to the brain because excess free iron can cause DNA, protein, and lipid damage via oxidative stress. The goal of this study was to evaluate the longitudinal effect of chronic iron overload and deficiency in the vertebrate brain. Ten-week-old C57BL6 male mice were randomly assigned to one of four unique dietary regiments for 1 year: iron-deficient, normal iron, and two different concentrations of lipophilic iron diet containing 3,5,5-trimethylhexanoyl ferrocene (TMHF). Longitudinal MRI parametrics were used to assess the location and extent of ferric iron distribution. Tissue collected at 12 months was used to directly measure iron-load, protein alterations, and histological metrics. While the iron-deficient diet did not alter brain iron stores, 0.11% TMHF and early exposure with 0.5% TMHF elevated brain iron by roughly 40 and 100%, respectively. R 2 rate increased more in the TMHF groups within iron rich brain regions. Increased brain iron concentration was linearly correlated with an increase in L-ferritin expression, and TMHF diet was found to increase L-ferritin within the olfactory bulb, neocortex, pallidum, thalamus, corpus callosum, CA3 regions of the hippocampus, and substantia nigra. Moreover, gliosis and oxidative stress were detected in the TMHF groups in the regions associated with iron-load. Spatial memory impairment was evident in the iron-loaded mice. This work illustrates that lipophilic iron elevates brain iron in a regionally specific fashion and positions dietary TMHF administration as a model for brain iron overloading.

A new method involving rapid flow of ligand solutions through a cartridge loaded with crystalline sodium diethylzinc hydride and subsequent isolation of three Zn—hydroxyquinoline complexes is described. The rapid-flow approach allowed the pyrophoric starting material to be used outside of the glovebox atmosphere and enabled fast mixing with ligand solutions for zinc complexation in seconds. The identity of all complexes was established by proton (1H) and carbon (13C) nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction.

Inspired in part by Chemistry Collaborations, Workshops, and Community of Scholars workshops, the Chemistry and Art course offered at Ithaca College is team-taught by a chemist and an art historian, underscoring the complementary nature of the two disciplines. The course, populated primarily by nonscience majors, highlights the importance of using both historical knowledge and empirical measurements to address particular questions about a work of art. The course culminates in a collaborative student research project in which students must select a nonaccessioned art object, generate a series of questions about the object, and subsequently use available scientific tools to attempt to address these questions. Undergraduates are exposed to a variety of techniques used in the analysis of art objects, including visible and infrared spectroscopy, gas chromatography and mass spectrometry, X-ray fluorescence spectroscopy, and microscopy. The Chemistry and Art course at Ithaca College will be discussed, and two case studies from the collaborative student research projects will be summarized.

Writing is an essential part of a successful career in science. As such, many undergraduate science courses have begun to implement writing assignments that reflect “real-world” applications and focus on a critical analysis of current literature; these assignments are often in the form of a review or a research proposal. The semester-long project described herein is a unique marriage of these two ideas: students first select a topic and conduct a literature review, and then choose an area of that same topic to investigate further in a peer-reviewed grant proposal. A modified version of this project, which incorporates peer-reviewed oral presentations, is also discussed. This project is designed for an upper-level undergraduate course, typically having 15–20 students, and the approach (or parts of the approach) has been successfully incorporated in an advanced organic chemistry course, a biochemistry capstone course, and courses in endocrinology, as well as ecophysiology.

The synthesis and characterization of a series of bis(8-quinolinato)aluminum ethyl complexes, substituted at the 2-, 5-, and 7- positions on the 8-quinolinol ligand, are presented. These complexes are viable initiators for the ring-opening polymerization of rac-lactide in the presence of 1 equiv of isopropyl alcohol. The polymerization control is good, it shows a linear evolution of molecular weight as the polymerization progresses, the polylactide molecular weights are in close agreement with those determined on the basis of the reaction stoichiometry, and the polydispersity indices are narrow. The polymerization kinetics have been monitored, and the influence of the site of ligand substitution has been related to the rates. Some of the initiators show stereocontrol, producing PLA with a good probability of isotactic enchainment (Pi = 0.76).

Inflammatory processes play a key role in the pathogenesis of a number of common neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Abnormal iron accumulation is frequently noted in these diseases and compelling evidence exists that iron is involved in inflammatory reactions. Histochemical stains for iron repeatedly demonstrate that oligodendrocytes, under normal conditions, stain more prominently than any other cell type in the brain. Therefore, we examined the hypothesis that cytokine toxicity to oligodendrocytes is iron mediated. Oligodendrocytes in culture were exposed to interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). Toxicity was observed in a dose-dependent manner for IFN-gamma and TNF-alpha. IL-1beta was not toxic in the concentrations used in this study. The toxic concentration of IFN-gamma, and TNF-alpha was lower if the cells were iron loaded, but iron loading had no effect on the toxicity of IL-1beta. These data provide insight into the controversy regarding the toxicity of cytokines to oligodendrocytes by revealing that iron status of these cells will significantly impact the outcome of cytokine treatment. The exposure of oligodendrocytes to cytokines plus iron decreased mitochondrial membrane potential but activation of caspase 3 is limited. The antioxidant, TPPB, which targets mitochondria, protected the oligodendrocytes from the iron-mediated cytotoxicity, providing further support that mitochondrial dysfunction may underlie the iron-mediated cytokine toxicity. Therapeutic strategies involving anti-inflammatory agents have met with limited success in the treatment of demyelinating disorders. A better understanding of these agents and the contribution of cellular iron status to cytokine toxicity may help develop a more consistent intervention strategy.

Tertiary amines are utilized extensively as non-nucleophilic proton scavengers for a number of organic transformations. Herein we report the efficient syntheses of tertiary alkyl amines from their corresponding alkyl nitriles in the presence of a heterogeneous palladium catalyst and a source of dihydrogen in aprotic solvents. The reaction is atom economic, the conditions are mild, and the isolated yields are virtually quantitative. The degree of amine alkylation shows some solvent dependency; in polar protic solvents such as ethanol or methanol, the reaction affords a mixture of products with the secondary alkyl amine as the major product.

Reaction of [(dcypb)ClRu(μ-Cl)3Ru(dcypb)(N2)] (1) with 4 equiv of the stable silylene 1,3-di-tert-butyl-1,3,2-diazasilol-2-ylidene (SiLN2) yields coordinatively unsaturated RuCl(η3-dcypb)(SiLN2) (2...

The synthesis and several reactions of the stable silylene 1 (N,N'-di-tert-butyl-1,3-diaza-2-sila-2-ylidene) are reported. Overreduction of 1 with alkali metals results in the formation of a dimeric dianion, which can be trapped with a proton source to give the dihydride derivative 9. In the solid state or in concentrated solutions, 1 undergoes a reversible conversion into the novel tetrameric disilene, 10. 1 reacts with ethanol, phenol, and water via insertion into the O—H bond, and with iodomethane by insertion into the C—I bond. A reaction of 1 with the diene 2,3-dimethyl-1,3-butadiene affords the silacyclopentene, 15. This reaction is markedly different from the one found for the unsaturated analog of the silylene, 2, which catalyzes the conversion of this diene into a highly cross-linked polymer.Key words: silylene, carbene analog, disilene, divalent compounds, N-heterocycles.

The Raman, IR and UV spectra of the silylene ( t BuNCH CHN t Bu)Si: ( 1 ) as well as the Raman spectra of related compounds with tetravalent silicon ( t BuNCH CHN t Bu) 2 Si ( 2 ) and ( t BuNCH CHN t Bu)SiCl 2 ( 3 ) and of the heterocycle ( t BuNCH CHN t Bu)C O ( 4 ) are reported. Comparison of the spectra obtained for 1 – 3 reveals a lowered frequency and greatly enhanced intensity of the Raman band corresponding to the C C stretching vibration in the spectrum of 1 which is in accord with the aromatic character of the silylene.

The synthesis and several reactions of the stable silylene 1 (1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazasilol-2-ylidene) are described. X-ray crystal structures are given for two intermediates in the synthesis of 1, the diimine 7 and its dilithium salt 8, and for a byproduct, the spiro compound 10. 1 reacts with ethanol and water by inserting into the O−H bond, and with iodomethane by insertion into the C−I bond. The silanol from reaction of 1 with water condenses to a disiloxane, 13. From 1 and sulfur and selenium, cyclic compounds containing Si2E2 rings are obtained (E = S or Se). Crystal structures are presented for disiloxane 13 and for the sulfur and selenium cycloadducts, 15 and 17.

The process affords the desired amines, required as non-nucleophilic proton scavengers, exclusively from nitriles (I) in THF, hexanes or pentane.

Two homoleptic Ni(silylene)3 complexes, 1a and 2a, have been synthesized and characterized by X-ray crystallography. Due to steric constraints only three silylenes coordinate to the nickel, generating novel complexes that are trigonal planar at the nickel center.