Enthalpy of fusion of poly(3‐hexylthiophene) by differential scanning calorimetry

The enthalpy of fusion for a perfect, infinite poly(3‐hexylthiophene) (P3HT) crystal () must be known to evaluate the absolute crystallinity of P3HT. This value, however, is still ambiguous as different values have been reported using various experimental techniques. Here, we extrapolate the enthalpy of fusion for extended chain crystals of oligomeric P3HT to infinite molecular weight and obtain a value of 42.9 ± 2 J/g employing differential scanning calorimetry with a correction based on grazing incidence small angle X‐ray scattering data. Also, we define the onset of chain folding within P3HT crystallites at a chain length of 5 Kuhn segments. Knowledge of allows calculation of P3HT percent crystallinity in thin films for applications such as organic field effect transistors and solar cells. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1469–1475     

RASS-Enabled S/P−C and S−N Bond Formation for DEL Synthesis

DNA encoded libraries (DEL) have shown promise as a valuable technology for democratizing the hit discovery process. Although DEL provides relatively inexpensive access to libraries of unprecedented size, their production has been hampered by the idiosyncratic needs of the encoding DNA tag relegating DEL compatible chemistry to dilute aqueous environments. Recently reversible adsorption to solid support (RASS) has been demonstrated as a promising method to expand DEL reactivity using standard organic synthesis protocols. Here we demonstrate a suite of on-DNA chemistries to incorporate medicinally relevant and C−S, C−P and N−S linkages into DELs, which are underrepresented in the canonical methods.     

Photocatalysis of Chloroform Decomposition by Tetrachlorocuprate (II) on Dowex 2‐X8

Heterogenized on a polystyrene anion exchange resin and in the presence of oxygen, catalyzes the photodecomposition of chloroform at wavelengths above 345 nm with greater efficiency than an equivalent amount in homogeneous solution. The reaction is proposed to proceed in two stages, the first stage yielding CCl₄ and as products, the second consisting of a chain reaction resulting from the ‐catalyzed photodissociation of CCl₄, yielding phosgene with CCl₃ radicals as chain carriers. Photodecomposition is retarded by added Cl^?, CH₃CN, C₆H₁₂ or C₂H₅OH, which is ascribed to the displacement of CHCl₃ molecules from the vicinity of the copper by attraction to the polystyrene matrix or to the alkylammonium cation sites.     

TMEDA in Iron‐Catalyzed Kumada Coupling: Amine Adduct versus Homoleptic “ate” Complex Formation

The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic “ate” complex [Fe(mes)₃]^? (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)₃]^? and the related complex [Fe(Bn)₃]^? (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR₂(TMEDA)] complexes. Fe^I species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X‐ray structures of [Fe(Bn)₃]^? and [Fe(Bn)₄]^? were determined; [Fe(Bn)₄]^? is the first homoleptic σ‐hydrocarbyl Fe^III complex that has been structurally characterized.     

Green chromatographic fingerprinting: An environmentally friendly approach for the development of separation methods for fingerprinting complex matrices

A chromatographic fingerprint is a comprehensive method that reveals the distinctive pattern of peaks across the chromatogram for a given sample. It is considered an effective strategy to assess the identity and quality of herbal materials, as well as for the control of the quality of their derived products. HPLC is the most employed technique for these purposes and it is used routinely for quality control in industry. Hence, its impact on the environment should not be neglected. This work provides a rational and generic procedure to qualitatively fingerprint complex matrices. Resource‐ and time‐saving experimental designs were selected; an alternative safer organic solvent was tested and a time‐saving and innovative response entitled the green chromatographic fingerprinting response was developed and employed. This procedure was applied in the development of chromatographic fingerprints for extracts of Bauhinia forficata and Casearia sylvestris. Moreover, the response proposed here can be combined with a complementary metric available in the literature to compare methods using different solvents. According to this, the chromatographic fingerprints developed here using ethanol as the organic solvent provided a performance better than that of reference methods in which more harmful acetonitrile or methanol were employed.     

The topotactic dehydration of monoclinic {[Co(pht)(bpy)(H2O)2]·2H2O}n into orthorhombic [Co(pht)(bpy)(H2O)2]n (pht is phthalate and bpy is 4,4′‐bipyridine)

Controlled heating of single crystals of the previously reported [Köferstein & Robl (2007). Z. Anorg. Allg. Chem. 633 , 1127–1130] dihydrate {[Co(pht)(bpy)(H₂O)₂]·2H₂O}_n, (II) [where pht is phthalate (C₈H₄O₄) and bpy is 4,4′‐bipyridine (C₁₀H₈N₂)], produced a topotactic transformation into an unreported diaqua anhydrate, namely poly[diaqua(μ₂‐benzene‐1,2‐dicarboxylato‐κ²O¹:O²)(μ₂‐4,4′‐bipyridine‐κ²N:N′)cobalt(II)], [Co(C₈H₄O₄)(C₁₀H₈N₂)(H₂O)₂]_n, (IIa). The structural change consists of the loss of the two solvent water molecules linking the original two‐dimensional covalent substructures which are the `main frame' of the monoclinic P2/n hydrate (strictly preserved during the transformation), with further reaccommodation of the latter. The anhydrate organizes itself in the orthorhombic system (space group Pmn2<sub>1</sub>) in a disordered fashion, where the space‐group‐symmetry restrictions are achieved only in a statistical sense, with mirror‐related two‐dimensional planar substructures, mirrored in a plane perpendicular to [100]. Thus, the asymmetric unit in the refined model is composed of two superimposed mirror‐related `ghosts' of half‐occupancy each. Similarities and differences with the parent dihydrate and some other related structures in the literature are discussed.     

Investigating the acoustics of a sample of open plan and enclosed Kindergarten classrooms in Australia

Open plan classrooms, where several class bases share the same space, have recently re-emerged in Australian primary schools. This study compared the acoustics of four different Kindergarten classrooms: an enclosed classroom with 25 students, a double classroom with 44 students, a linear fully open plan triple classroom with 91 students, and a semi-open plan K-6 classroom with 205 students. Ambient noise levels, intrusive noise levels, occupied background noise levels, and teacher’s speech levels were recorded during different activities. Room impulse responses using logarithmic sweeps were also recorded for different teaching scenarios. From these recordings, signal-to-noise ratios, speech transmission index scores, and reverberation times were calculated. The results revealed much higher intrusive noise levels in the two largest open plan classrooms, resulting in signal-to-noise ratios and speech transmission index scores to be well below those recommended in classrooms with students of this age. Additionally, occupied background noise levels in all classrooms were well above recommended levels. These results suggest noise in classrooms needs to be better controlled, and open plan classrooms are unlikely to be appropriate learning environments for young children due to their high intrusive noise levels. The impact of noise on children’s learning and teacher’s vocal health are discussed.     

An indium tin oxide electrode modified with gold nanorods for use in potential-controlled surface plasmon resonance studies

The modification of electrodes with gold nanoparticles results in an increased electrode surface area, enhanced mass transport, and improved catalytic properties. We have extended this approach to indium tin oxide (ITO) electrodes to obtain optically transparent gold nanorod-modified electrodes which display enhanced electrochemical capabilities and have the additional advantage of showing a tunable surface plasmon resonance. The procedures for attaining high surface coverage (15 gold nanorods per square µm) of such electrodes were optimized, and the potential-dependent surface plasmon resonance was studied under controlled electrical potential. In an exemplary sensor application, we demonstrate the detection of mercury via potential-dependent formation of an Au-Hg amalgam.

Synthesis of diastereomeric,deoxy and ring-expanded sulfone analogues of aigialomycin D

Several analogues of the fungal natural product aigialomycin D (AmD) have been synthesised. These include the stereoisomer 5′R,6′S-AmD, 2,4-di-deoxyAmD, 1′,2′,7′,8′-tetrahydroAmD and a 15-membered macrocyclic sulfone. Growth inhibitory activities of these compounds against the HL-60 leukaemic cell line were measured. The ring-expanded sulfone and tetrahydro-analogue were found to have similar IC₅₀ values to the natural product, whereas the 5′R,6′S-stereoisomer was inactive. Energy minimisation of AmD and the synthesised analogues resulted in a range of lowest energy conformers, from planar, open arrangements of the macrocycle in AmD and tetrahydroAmD to bent, L-shaped structures for the sulfone. The synthesis of methyl orsellinate was investigated and optimised as part of this work. A stereodivergent route to both enantiomers of the diol fragment from d-ribose was also achieved.     

Use of Formax High-Throughput Platform to Create a Specific Emulsion

The Formax high-throughput platform is capable of rapidly mapping out the formulation and process parameters required to produce an array of emulsions with a range of particle sizes. The specific emulsion in this instance is a stable emulsion with a small droplet size, preferably submicron. Using a combination of design of experimental software and high-throughput experimentation, the factors required to produce the emulsion with smallest droplet size were identified. Additionally, this work produced a template which allows the quick and efficient mapping of process and formulation space to determine for new systems which variables have the greatest impact upon the emulsion produced. (Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Dispersion Science and Technology to view the free supplemental file.)