Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Preparation of metal organic frameworks (MOFs) via microwave heating is becoming increasingly popular due to reduced reaction times and enhanced control of MOF particle size. However, there is little understanding about the detailed interaction of the electric field portion of the wave with reactants during the synthesis of MOFs. In order to overcome this lack of fundamental understanding, information about the dielectric properties of the reactants is required. In this work the dielectric constants (ε′) and loss factors (ε′′) of benzene-1,4-dicarboxylic acid (H2BDC; also known as terephthalic acid) and a number of M(III) (M = metal) salts dissolved in deionized water were measured as a function of frequency, temperature and concentration and with varying anions and cations. Dielectric data confirm the aqueous M(III) salts to be strong microwave absorbers, particularly at 915 MHz. M(III) salts with mono-anionic ligands (for example chlorides and nitrates) exhibit higher losses than di-anionic salts (sulfates) demonstrating that the former are heated more effectively in an applied microwave field. Of the M(III) salts containing either singly- or doubly-charged anions, those containing Fe(III) have the highest loss indicating that they will heat more efficiently than other M(III) salts such as Cr(III) and Al(III). Interestingly, H2BDC exhibits little interaction with the electric field at microwave frequencies

Engineered expression of the invertebrate‐specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella

Background: Previous Genetic Pest Management (GPM) systems in diamondback moth (DBM) have relied on expressing lethal proteins (‘effectors’) that are ‘cell‐autonomous’ i.e. do not leave the cell they are expressed in. To increase the flexibility of future GPM systems in DBM, we aimed to assess the use of a non cell‐autonomous, invertebrate‐specific, neurotoxic effector – the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions. Results: Expression of AaHIT caused a ‘shaking/quivering’ phenotype which could be repressed by provision of an antidote (tetracycline); a phenotype consistent with the AaHIT mode‐of‐action. This effect was more pronounced when AaHIT expression was driven by the Hr5/ie1 promoter (82.44% of males, 65.14% of females) rather than Op/ie2 (57.35% of males, 48.39% of females). Contrary to expectations, the shaking phenotype and observed fitness costs were limited to adults where they caused severe reductions in mean longevity (‐81%) and median female fecundity (‐93%). qPCR of AaHIT expression patterns and analysis of piggyBac‐mediated transgene insertion sites suggest that restriction of observed effects to the adult stages may be due to influence of local genomic environment on the tetO‐AaHIT transgene. Conclusion: We have demonstrated the feasibility of using non cell‐autonomous effectors within a GPM context for the first time in the Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors

Benzene-1,2-diaminium bis(hydrogen phosphonate)

The asymmetric unit of the title molecular salt, C6H10N22+·2H2PO3−, contains half of a benzene-1,2-diaminium cation and a phosphite anion, the complete cation being generated by a crystallographic mirror plane. In the crystal, N—H...O hydrogen bonds generate R22(9) and R22(8) ring motifs and O—H...O hydrogen bonds generate an R22(8) ring motif. Overall, these generate a three-dimensional framework. The crystal structure also features π–π interactions [centroid-to-centroid distance = 3.8642 (7) Å]

Ion association and hydration in aqueous solutions of copper(II) Sulfate from 5 to 65 °C by dielectric spectroscopy

Aqueous solutions of copper(II) sulfate have been studied by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 ≲ v/ GHz ≤ 89), concentrations (0.02 ≤ m/mol kg-1 ≲ 1.4), and temperatures (5 ≤ t/°C ≤ 65). The spectra show clear evidence for the simultaneous existence of double-solvent-separated, solvent-shared, and contact ion pairs at all temperatures, with increasing formation especially of contact ion pairs with increasing temperature. The overall ion association constant KA0 corresponding to the equilibrium: Cu2+(aq) + SO42-(aq) ⇌ CuSO40(aq) was found to be in excellent agreement with literature data over the investigated temperature range. However, the precision of the spectra and other difficulties did not allow a thermodynamic analysis of the formation of the individual ion-pair types. Effective hydration numbers derived from the DRS spectra were high but consistent with simulation and diffraction data from the literature. They indicate that both ions influence solvent water molecules beyond the first hydration sphere. The implications of the present findings for previous observations on copper sulfate solutions are briefly discussed

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4-Methylanilinium 3-carboxy-4-hydroxybenzenesulfonate

In the title molecular salt, C7H10N+·C7H5O6S−, the anion is deprotonated at the hydroxy O atom of the sulfonate group. In the anion, an intra-ionic O—H...O hydrogen bond generates an S(6) graph-set motif. In the crystal, the inter-ionic N—H...O and O—H...O hydrogen bonds generate an R24(12) ring-set motif, linking the anions and cations into an infinite three-dimensional framework. The crystal structure also features C—H...π and π–π [centroid-to-centroid distance = 3.5946 (11) Å] interactions

4-Methylanilinium 2-carboxyacetate

In the crystal of the title salt, C7H10N+·C3H3O4−, the cations are linked to the anions via N—H...O and trifurcated N—H...(O,O,O) hydrogen bonds. The anions are linked into [010] chains by O—H...O hydrogen bonds. Taken together, these interactions generate (100) sheets