Silver and gold are the most used plasmonic metals for surface-enhanced Raman spectroscopy (SERS), accounting for the vast majority of the published literature in this field. These two metals are preferred due to their excellent plasmonic enhancement, stability, and relative ease of synthesis and functionalization of their associated nanostructures. However, both silver and gold face earth abundance limitations, and so alternatives should be sought, particularly for large-scale plasmonic applications such as plasmon-enhanced photovoltaics or optical cloaking. In this work, a method to produce effective and scalable copper-based substrates for electrochemical SERS (EC-SERS) is introduced, utilizing commercially available carbon screen-printed electrodes (SPE) and physical vapor deposition (PVD). The carbon black particles present on the working electrode of the SPE serve as an efficient scaffold for the fabrication of copper nanostructures. Several test molecules were used to illustrate the performance of these sensors in the SERS analysis. This work also highlights the first reported formation of an electrochemically generated N-heterocyclic carbene (NHC) self-assembled monolayer (SAM) on a nanostructured copper surface under potential control in an aqueous electrolyte.

N-heterocyclic carbenes (NHCs) are a versatile class of ligands that have been widely applied in transition metal catalysis. However, NHCs are soft bases, and as such, complexes of NHCs with hard acids—such as many first-row transition metals—are typically sensitive to air and moisture, hence requiring multistep preparations. In this work, two examples of rare copper (II)-NHC complexes were prepared directly from 1,3-bis(pyridylmethyl)imidazolium chloride and 1,3-bis(2-pyridylmethyl)benzimidazolium chloride in protic conditions with no effort to exclude air or moisture. X-ray crystallographic analysis showed that both species display distorted square pyramidal geometry. A probe reaction demonstrated both complexes displayed poor catalytic activity for Chan–Evans–Lam coupling reactions.

The two-spotted lady beetle, Adalia bipunctata L., displays warning colouration that is reinforced by the production of adaline and adalinine. These alkaloids are thought to provide defense against predation throughout all life stages of A. bipunctata and may play a role in the insect immune system. Vairimorpha (Nosema) adaliae, a microsporidium described from A. bipunctata, has minimal effects on its host (delayed larval development) when reared under optimum conditions but stress factors are shown to affect the development of microsporidiosis. The objectives of this study were to determine the effects of V. adaliae on relative alkaloid content (adaline) during A. bipunctata development, and to evaluate the combined effects of physical stress and infection on adult beetles (relative alkaloid content and infection load). First-instar larvae were isolated from uninfected and V. adaliae-infected colonies. Eggs and first-instar larvae were immediately prepared for alkaloid analysis, whereas late-instar larvae, pupae and adults were systematically processed when each reached their designated developmental stage. Upon eclosion, a subsample of beetles was exposed to varying amounts of physical agitation: control (no shaking), alternate shaking (every other day), and daily shaking. Immediately following these stress trials, alkaloid samples were collected for analysis and spore loads were assessed. Overall, relative adaline proportions increased from egg to adult. Uninfected individuals had significantly higher relative proportions of adaline than did infected individuals during early development; however, adaline content was higher in infected A. bipunctata from the third-instar onwards, when compared to their uninfected counterparts. Following exposure to physical agitation on alternate days, uninfected adults had a significantly higher relative proportion of adaline than did infected adults. Interestingly, exposure to different levels of agitation had no significant effect on alkaloid production for either uninfected or infected beetles. Mean spore counts were significantly higher for adults that were exposed to daily shaking when compared to individuals from the control and alternate shaking groups. From a biological perspective, one would expect to observe differences in alkaloid production through coccinellid development, as each successive life stage faces different external pressures and risks. When infected with the microsporidium V. adaliae, however, adaline production was reduced during early development but increased significantly in late life stages.

The partition constants (p-values) of primary alcohols in solutions containing aggregates of symmetric gemini surfactants of the family N,N'-dimethyl, N-dialkyl-α,ω-alkanediammonium dibromide (m-s-m = symmetric gemini surfactants) have been computed from the measured values of their diffusion coefficients obtained from NMR-diffusion experiments. From the p-values, both mole-fraction and concentration-based partition coefficients and Gibbs energies of transfer for the alcohols from the bulk D2O phase to the gemini aggregate phase have been calculated. As expected, the Gibbs energy of transfer decreased linearly with an increase in the alcohol carbon length for each of the primary alcohol/gemini amphiphile series studied. The Gibbs transfer energy increment per CH2 for the alcohols was consistent for all the alcohol/gemini amphiphile series and was in excellent agreement with the values measured for the same primary alcohol series in conventional single-headed, single-tailed surfactants. Surprisingly, the partition coefficients of the alcohols in the symmetric gemini aggregates exhibited little, if any, dependence on the spacer length of the gemini amphiphiles and were remarkably consistent as the length of the main surfactant chain increased at constant spacer length. When these results are compared to the partition coefficients of the same alcohols in corresponding monomeric surfactants, we observe little difference in the thermodynamic driving forces governing the transfer of alcohols from water to the aggregates of either monomeric or symmetric gemini surfactants.

Cyanidation has been used worldwide for over a century as the primary method for gold extraction from ore. Unfortunately, accidents have occurred that released toxic cyanide and resulted in devastation of the environment and surrounding communities. For this reason, alternatives to cyanidation have been of great interest but have yet to be implemented owing to the high costs of materials and necessary changes to infrastructure, which make these alternatives economically unfeasible. Reported herein is the use of novel ionic thiourea derivatives for the extraction of gold without the use of cyanide. A series of six pyrrolidinium and imidazolium salts have been functionalized with a thiourea group and either the anion hexafluorophosphate ([PF6]−) or dodecyl sulfate ([DS]−). Gold(iii) extraction up to 90% was achieved from an aqueous solution with a methyl imidazolium-tagged [DS] salt. Extraction experiments using gold(i) showed a decrease in extraction efficiency, suggesting the oxidation state of the gold is important for complex formation. The extraction selectivity for gold(iii) and silver(i) over copper(ii), iron(ii) and zinc(ii) was demonstrated for all ionic thiourea derivatives.

Gemini surfactants are composed of two hydrocarbon tails with corresponding polar headgroups, linked via a covalent spacer. The synthesis of these surfactants is a very active area of research due to their application as catalysts and other applied areas of study. The modification of green microwave techniques developed in our research on ionic liquids has resulted in the significant improvement of the synthesis of N,N′-bis(dimethylalkyl)-α,ω-alkanediammonium dibromide (m–s–m type) symmetrical gemini surfactants. This approach utilizes a remarkably more economical, green, and sustainable methodology for the production of symmetrical gemini surfactants that can be utilized in numerous commercial applications. The improved synthetic approach of these gemini surfactants has led to the characterization of their crystalline packing for the first time ever using X-ray crystallographic analysis.

A simple and effective method for selective liquid-liquid extraction of tetrachloroaurate anion (AuCl 4 - ) using four different alcohols was investigated. This method is based on the partitioning of tetrachloroaurate anions into an immiscible alcoholic phase out of an aqueous phase, a process which was monitored using flame atomic absorption spectroscopy (FAAS). Contributing factors including solvent volume, extraction time, and shaking frequency were examined. The extraction of Au (III) was investigated for a series of simple, low molecular weight alcohols. Specifically, 1-butanol, 1-pentanol, 1-octanol, and cyclohexanol, once optimized, showed recoveries of 98.2% ± 0.1%, 99.2% ± 0.6%, 98.2% ± 0.3%, and 99.9% ± 0.2%, respectively. The extraction efficiency and selectivity of these alcohols was also studied in the presence of other metal ions. The results reported herein present a potential green and sustainable alternative to cyanidation for gold extraction from low-grade ore samples, where iron and other metals can interfere.

Nosema adaliae, a microsporidian pathogen described from the two-spotted lady beetle, Adalia bipunctata L., delays larval development when A. bipunctata is reared under laboratory conditions at 25 degrees C. In nature, lady beetles often experience a wide range of environmental temperatures, but little is known regarding the effects of microsporidian pathogens on lady beetles when they are reared at higher and lower temperatures. In this study, the effects of elevated rearing temperatures and microsporidiosis were observed on larval development time and mortality, sex ratios, alkaloid content (adaline and adalinine), and adult morphometrics. Uninfected larvae (24 h-old) were provided either an uninfected or N. adaliae-infected conspecific egg and subsequently reared at three temperatures (25 degrees C, 27.5 degrees C or 30 degrees C). After the egg was eaten, larvae were provided a diet of green peach aphids and their development was recorded daily. Following eclosion, a subsample of adults were photographed for microscopic measurements and reflex-fluid was collected for alkaloid analysis using gas chromatography-mass spectrometry. Afterwards, all individuals were examined to determine the number that had become infected, and the same subsample was used to assess the severity of infection. Development time was delayed significantly for larvae that consumed a N. adaliae-infected egg, and infected larvae took significantly longer to develop at 25 degrees C than at 27.5 degrees C or 30 degrees C. No differences were observed for larval mortality or sex ratios. The relative proportion of adaline increased when larvae were reared at 30 degrees C, but adaline concentration was not affected by the pathogen, N. adaliae. Adults reared at 25 degrees C had larger body measurements when compared to those reared at 27.5 degrees C and 30 degrees C. Overall, adults that had eaten a N. adaliae-infected A. bipunctata egg as larvae had similar body measurements to those that ate an uninfected egg. When comparing male and female measurements, a significant interaction between infection status, temperature and sex was observed for elytra length and head capsule width only. These measurements were similar for uninfected and N. adaliae-infected females across all temperatures. However, when reared at 25 degrees C, uninfected males had significantly smaller elytra and head capsules than did infected males; but when reared at 30 degrees C, no significant difference was observed for these measurements. Both percent infection and average spore count decreased at 27.5 degrees C and 30 degrees C. These results suggest that temperatures above 25 degrees C have a mitigating effect against N. adaliae in A. bipunctata.

The effects of food availability and infection with the microsporidium Nosema adaliae on alkaloid production in the two-spotted lady beetle, Adalia bipunctata L., was examined. Alkaloid production (relative percent adaline in reflex-fluid) and pathogen load (spore counts) were quantified for both uninfected and N. adaliae-infected A. bipunctata. Alkaloid content was significantly higher for beetles fed irregularly than for those fed daily. For beetles infected with N. adaliae, spore counts were significantly higher for those fed irregularly compared to those fed daily. These results suggest that adaline content in reflex-fluid is influenced by infection and that irregular food supply increases pathogen load.

A mechanochemical approach has been demonstrated for the selective cleavage of nitrogen-carbon bonds in the N-demethylation of various alkaloids relevant in the pharmaceutical industry. This methodology employs a range of so-called "liquid additives" used in microliter quantities in liquid assisted grinding rather than "solvents" used in solution phase reactions. Green liquid additives such as alcohols, water, PEG and ionic liquids as well as a nonchemical, mechanical approach for the generation of nanoscale Fe dust significantly improve the green attributes of the N-demethylation process.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Copper N-heterocyclic carbene complexes (Cu-NHCs) are prevalent in the literature, and their stability and catalytic activity have been well characterized and established. In an overwhelming majority of the reported examples, copper is present as Cu(I), owing to the favorable soft-soft interaction. In contrast, there are very few reports of Cu-NHCs containing Cu(II). This can be explained by the unfavorable intermediate/hard soft interaction between carbon and Cu(II). The syntheses of examples reported thus far require the exclusion of air and moisture and involve the use of NHC transfer reagents or the use of free NHCs. This results in tedious, multistep procedures, making their preparation more time consuming and costly. Herein we report the synthesis and characterization of two air- and moisture-stable Cu(II)-NHC complexes by direct combination Of 1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride with copper(II) hexafluorosilicate. Analysis by single-crystal X-ray diffraction revealed that the species could be isolated in both distorted-octahedral and distorted square-pyramidal geometries.

N-Demethylation of selected N-methylalkaloids using a modified Polonovski reaction can be accomplished employing nanoscale zero-valent iron, nZVI, in isopropanol.

An ionic thiourea based organocatalyst has been shown to promote a 1,4-diazabicyclo[2.2.2]octane, (DABCO) catalysed Morita-Baylis-Hillman reaction between benzaldehyde and cyclohex-2-en-1-one. The ionic thiourea catalyst was easily prepared from a pyrrolidinium salt containing an arylamine moiety and 3,5-di(trifluoromethyl)phenylisothiocyanate. X-ray crystallographic analysis of the ionic thiourea catalyst shows an acetone molecule doubly hydrogen bonded to the Lewis acidic thiourea N-H protons. Entrainment of the ionic thiourea co-catalyst in the ionic liquid N-butyl-N-methylpyrrolidinium bistriflimide, [BMPyr][N(Tf)(2)], facilitates catalyst recycling and affords very good yields with reaction times reduced through use of microwave heating.

Herein, we report the aerobic oxidation of several bio-oils (pyrolysis and microwave) derived from Kraft lignin using oxovanadium complex catalyst, (HQ)2Vv(O)(OiPr) (HQ=8-oxyquinoline) (2), ionic liquid (IL)-tagged oxovanadium complex, PF6-IL-salen-VIV(O) (3) (PF6=hexafluorophosphate) and copper catalyst CuX/TEMPO/2,6-lutidine (4) [X=OTf, trifluoro-methanesulfonate), Cl; TEMPO=2,2,6,6-tetramethylpiperidine-1-oxyl]. Cleavage of some lignin linkages and reduced phenolic content were observed by multinuclear NMR spectroscopy, FT-IR and 1D/2D GC/MS analysis. Catalyst 2 oxidized chloroform extracts of the microwave bio-oil more extensively than those from the pyrolysis bio-oil although reactivity trends were similar. With catalyst 3 in [MMIM][MeOSO3], the phenolic conversion was modest compared with the increase in carboxyl and decrease in aliphatic OH groups. IR spectra were consistent with phenol oxidation to quinone-type structures. In contrast, copper catalyst 4 showed formation of high molecular weight compounds after oxidation, likely resulting from radical recombination. Comparison of reactivity between the different types of lignin-derived bio-oils is also discussed.

Fazit Eine leptomeningeale Kollateralisierung steht auch bei nicht asiatischen Patienten mit Moyamoya-Erkrankung mit deren Schweregrad in Zusammenhang, so die Autoren. Im Gegensatz aber zu asiatischen Patienten fand sich in der hier untersuchten Population kein Zusammenhang von Dilatationen der A. chorioidea anterior mit dem Auftreten von Blutungen – möglicherweise liegt das aber auch an der sehr geringen Anzahl von Hämorrhagien: In asiatischen Populationen liegt die Häufigkeit bei bis zu 65 %, während in der hier untersuchten Gruppe Ischämien deutlich überwogen.

Several ionic liquids (ILs) were prepared in order to study the susceptibility of various cores and substituents to biodegradability using the ‘CO2 headspace’ test (ISO 14593). Several of the ILs contained tertiary amine substituents and were tested as solvents and reagents for several base mediated processes including Suzuki–Miyaura, Sonogashira, Knoevenagel, and Morita–Baylis–Hilman reactions. It was found that although these ILs contain basic functionality, they do not promote base mediated reactions. Density functional theory molecular calculations confirmed that the protonation of these ILs is energetically unfavourable.

Ionic liquid tagged salen ligands containing two proximal 1,3-disubstituted imidazolium ionic liquid cores form cobalt(III) complexes capable of selectively oxidizing veratryl alcohol, a lignin model compound, to veratraldehyde using air or pure oxygen as the source of oxygen. Entrainment of these catalysts in either 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], or 1-butyl-3-methylimidazolium bistriflimide, [bmim][NTf2], hydrophobic ionic liquid solvents, results in biphasic reactions when water is used as the second solvent allowing the catalyst/ionic liquid phase to be recycled.

Electrochemical SERS (E-SERS) was used for the first time to study the interfacial behavior of a class of pyridinium-based biodegradable ionic liquids at a silver nanoparticle (AgNP) electrode surface. An isomeric series of ionic liquids (IL) based on 3-butoxycarbonyl-1-methylpyridinium bis(trifluoromethanesulfonyl)imide were prepared, which have demonstrable biodegradability. It was found that all four of the isomeric ionic liquids studied exhibited excellent electrochemical stability as binary mixtures combined with methanol, with the absence of any specific redox processes occurring over nearly 3.0 V of applied potential. Normal Raman measurements of the neat isobutyl IL showed a signal rich in vibrational features, with strong contributions from both the anion and the bulky organic cation. E-SERS of the neat isobutyl IL was shown to exhibit excellent potential stability, with no potential-induced orientational change at the metal surface. When the ionic liquids were prepared as methanolic binary mixtures, dissociation of the IL ions was observed, and only the organic cation was shown to adsorb at the Ag/solution interface. The nature of the substituent on the ester group of the IL series was observed to have a significant effect on the orientation of the cation on the metal surface, based on the application of the metal surface selection rules combined with computational data. Notably, the isobutyl and sec-butyl isomers were observed to have an orientation wherein the pyridinium ring was oriented perpendicular to the surface, while the tert-butyl and n-butyl isomers were observed to have an orientation wherein the pyridinium ring was lying flat on the metal surface.

Ionic ligands derived from a salen ligand containing two proximal 1,3-disubstituted imidazolium ionic liquid cores form cobalt(III) complexes capable of selectively oxidizing veratryl alcohol, a lignin model compound, to veratraldehyde using air as the source of oxygen. These complexes are easy to prepare, inexpensive, water stable, and soluble in ionic liquids, making them viable candidates for use as oxidation catalysts.