Formation of novel photoadducts from irradiation of 5(S)-5-O-tert-butyldimethylsiloxymethylfuran-2(5H)-one

Irradiation of 5S-5-O-tert-butyldimethylsiloxymethylfuran-2(5H)-one 1 in acetonitrile yields the C2-symmetric bis(lactone), 1S,2S,6S,7S-[3S,10S]-bis-tert-butyldimethylsiloxymethyl-4,9-dioxatricyclo[5.3.0.02,6]deca-5,8-dione 6, and a 3-substituted intramolecular product resulting from an apparent 8-endo-trig cyclisation.

Formation of isopolyoxometallate(VI) anions in the reaction between M(CO)6 (M = W, Mo) and acetic acid: X-ray crystal structure of [W3(μ3-O)2(μ2η2-O2CCH3)6(H2O)3]2[W10O32·solvent

W(CO)6 reacts with a mixture of acetic acid/acetic anhydride to give [W3 (μ3-O)2(μ2η2-O2CCH3)6(H2O)3](CH3CO2)2 (1), which was converted by HClO4 to [W3 (μ3-O)2(μ2η2-O2CCH3)6(H2O)3](ClO4)2 (2). Addition of CH3CO2Na to the above reaction mixture, and prolonged exposure of the solution to air, results in the formation of the WIV/WVI complex salt [W3(μ3-O)2(μ2η2-O2CCH3)6(H2O)3]2[W10O32]·solvent (3). Complex 3 was also prepared by reacting 1 with Na2WO4·2H2O in acetic acid, and it has been characterized by X-ray crystallography. Addition of [CH3(CH2)3]4N(ClO4) to the reaction filtrate remaining after the preparation of [Mo2(μ-O2CCH3)4][from Mo(CO)6, CH3CO2H and (CH3CO)2O], followed by exposure to air, gives ([CH3(CH2)3]4N)2[Mo6O19] (4).

Multiple hydrogen bonds induce formation of nanoparticles with internal microemulsion structure by an amphiphilic copolymer

A particulate microemulsion is generated in a simple two-component system comprising an amphiphilic copolymer (Pluronic P123) in mixtures with tannic acid. This is correlated to complexation between the poly(ethylene oxide) in the Pluronic copolymer and the multiple hydrogen bonding units in tannic acid which leads to the breakup of the ordered structure formed in gels of Pluronic copolymers, and the formation of dispersed nanospheres containing a bicontinuous internal structure. These novel nanoparticles termed ‘‘emulsomes’’ are self-stabilized by a coating layer of Pluronic copolymer. The microemulsion exhibits a pearlescent appearance due to selective light scattering from the emulsion droplets. This simple formulation based on a commercial copolymer and a biofunctional and biodegradable additive is expected to find applications in the fast moving consumer goods sector.

Substituent and counterion effects on the formation of p-dimer dications of end-capped heptathienoacenes

We have investigated the impact of the functionalization and the chemical nature of counterions on the p-dimer dications formation in two end-capped heptathienoacenes. Radical cations of an a-substituted heptathienoacene with triisopropylsilyl groups do not p-dimerize, while those of an a,b-substituted heptathienoacene with four n-decyl side chains show a high propensity toward p-dimerization, increased by PF6 ÿ counterions.

A novel study of the polymerisation process involved in the formation of the network component of polymer-stabilised liquid crystals within electro-optic cells using high performance liquid chromatography

Polymer-stabilised liquid crystals are systems in which a small amount of monomer is dissolved within a liquid crystalline host, and then polymerised in situ to produce a network. The progress of the polymerisation, performed within electro-optic cells, was studied by establishing an analytical method novel to these systems. Samples were prepared by photopolymerisation of the monomer under well-defined reaction conditions; subsequent immersion in acetone caused the host and any unreacted monomer to dissolve. High performance liquid chromatography was used to separate and detect the various solutes in the resulting solutions, enabling the amount of unreacted monomer for a given set of conditions to be quantified. Longer irradiations cause a decrease in the proportion of unreacted monomer since more network is formed, while a more uniform LC director alignment (achieved by decreasing the sample thickness) or a higher level of order (achieved by decreasing the polymerisation temperature) promotes faster reactions.

In vitro fermentation of a red wine extract by human gut microbiota: changes in microbial groups and formation of phenolic metabolites

An in vitro batch culture fermentation experiment was conducted with fecal inocula from three healthy volunteers in the presence and absence of a red wine extract. Changes in main bacterial groups were determined by FISH during a 48 h fermentation period. The catabolism of main flavonoids (i.e., flavan-3-ols and anthocyanins) and the formation of a wide a range of phenolic microbial metabolites were determined by a targeted UPLC-PAD-ESI-TQ MS method. Statistical analysis revealed that catechol/pyrocatechol, as well as 4-hydroxy-5-(phenyl)-valeric, 3- and 4-hydroxyphenylacetic, phenylacetic, phenylpropionic, and benzoic acids, showed the greatest increases in concentration during fermentation, whereas 5-(3′-hydroxyphenyl)-γ-valerolactone, its open form 4-hydroxy-5-(3′-hydroxyphenyl)-valeric acid, and 3,4-dihydroxyphenylacetic acid represented the largest interindividual variations in the catabolism of red wine polyphenols. Despite these changes, microbial catabolism did not produce significant changes in the main bacterial groups detected, although a slight inhibition of the Clostridium histolyticum group was observed.

Social networks and occupational choice: the endogenous formation of attitudes and beliefs about tax compliance

The paper analyses the emergence of group-specific attitudes and beliefs about tax compliance when individuals interact in a social network. It develops a model in which taxpayers possess a range of individual characteristics – including attitude to risk, potential for success in self-employment, and the weight attached to the social custom for honesty – and make an occupational choice based on these characteristics. Occupations differ in the possibility for evading tax. The social network determines which taxpayers are linked, and information about auditing and compliance is transmitted at meetings between linked taxpayers. Using agent-based simulations, the analysis demonstrates how attitudes and beliefs endogenously emerge that differ across sub-groups of the population. Compliance behaviour is different across occupational groups, and this is reinforced by the development of group-specific attitudes and beliefs. Taxpayers self-select into occupations according to the degree of risk aversion, the subjective probability of audit is sustained above the objective probability, and the weight attached to the social custom differs across occupations. These factors combine to lead to compliance levels that differ across occupations.

Formation of vesicles through solvent assisted self-assembly of hydrophobic pentapeptides: encapsulation and pH responsive release of dyes by the vesicles

In the biomimetic design two hydrophobic pentapetides Boc-Ile-Aib-Leu-Phe-Ala-OMe ( I) and Boc-Gly-Ile-Aib-Leu-Phe-OMe (II) (Aib: alpha-aminoisobutyric acid) containing one Aib each are found to undergo solvent assisted self-assembly in methanol/water to form vesicular structures, which can be disrupted by simple addition of acid. The nanovesicles are found to encapsulate dye molecules that can be released by the addition of acid as confirmed by fluorescence microscopy and UV studies. The influence of solvent polarity on the morphology of the materials generated from the peptides has been examined systematically, and shows that fibrillar structures are formed in less polar chloroform/petroleum ether mixture and vesicular structures are formed in more polar methanol/water. Single crystal X-ray diffraction studies reveal that while beta-sheet mediated self-assembly leads to the formation of fibrillar structures, the solvated beta-sheet structure leads to the formation of vesicular structures. The results demonstrate that even hydrophobic peptides can generate vesicular structures from polar solvent which may be employed in model studies of complex biological phenomena.

Epoxide ring opening in a zinc(II) complex in water without any Lewis acid catalyst: formation of only one diastereomer out of 2

The epoxide ring in 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) opens up in its reaction with 4-methylaniline and 4-methoxyaniline in water in equimolar proportion at room temperature without any Lewis acid catalyst to give a monohydrate of 6-(4-methyl-phenylamino)-5,6-dihydro-1,10-phenanthrolin-5-ol (L′·H2O) and 6-(4-methoxyphenyl-amino)-5,6-dihydro-1,10-phenanthrolin-5-ol (L″) respectively. Reaction time decreases from 72 to 14 h in boiling water. But the yields become less. Reaction of L with Zn(ClO4)2·6H2O in methanol in 3:1 molar ratio at room temperature affords white [ZnL3](ClO4)2·H2O. The X-ray crystal structure of the acetonitrile solvate [ZnL3](ClO4)2·MeCN has been determined which shows that the metal has a distorted octahedral N6 coordination sphere. [ZnL3](ClO4)2·2H2O reacts with 4-methylaniline and 4-methoxyaniline in boiling water in 1:3 molar proportion in the absence of any Lewis acid catalyst to produce [ZnL′3](ClO4)2·4H2O and [ZnL″3](ClO4)2·H2O, respectively in 1–4 h time in somewhat low yield. In the 1H NMR spectra of [ZnL′3](ClO4)2·4H2O and [ZnL″3](ClO4)2·H2O, only one sharp methyl signal is observed implicating that only one diastereomer out of the 23 possibilities is formed. The same diastereomers are obtained when L′·H2O and L″ are reacted directly with Zn(ClO4)2·6H2O in tetrahydrofuran at room temperature in very good yields. Reactions of L′·H2O and L″ with Ru(phen)2Cl2·2H2O (phen = 1,10-phenanthroline) in equimolar proportion in methanol–water mixture under refluxing condition lead to the isolation of two diastereomers of [Ru(phen)2L′](ClO4)2·2H2O and [Ru(phen)2L″](ClO4)2·2H2O.

Reading is now 'cool': a study of English teachers' perspectives on e-reading devices as a challenge and an opportunity

E-reading devices such as The Kindle have rapidly secured a significant place in a number of societies as at least one major platform for reading. To some extent they are part of the overarching move towards a fully digitised world but they have a distinctiveness in being deliberately “book-like”. Teachers generally have some suspicion towards “New Media”, especially when it challenges their established practice and nothing dominates the school more than the physical book. What may be the challenges but also the benefits of e-readers to teachers and students? What may be the particular challenges to those teachers who are, traditionally, the guardians of the book, that is the teachers of mother tongue literature? This article reports on a survey of English teachers in England to gauge their reactions to e-readers, both personally and professionally and describes their speculations about the place of e-readers in schools in the future. There is a mixed reaction with some teachers concerned about the demise of the book and the potential negative impact on reading. However, the majority welcome e-readers as a dynamic element within the reading environment with particular potential to enthuse reluctant readers and those with special or linguistic needs. They also, some grudgingly, view the fact that reading using this form of technology appeals to the “e-generation” and may succeed in making reading “cool”. This form of technology is, ironically (given that it appears to threaten traditional books) likely to be rapidly adopted in classrooms.