New Calix[4]arene—Fluoresceine Conjugate by Click Approach—Synthesis and Preparation of Photocatalytically Active Solid Lipid Nanoparticles

New fluorescent systems for photocatalysis, sensors, labeling, etc., are in great demand. Amphiphilic ones are of special interest since they can form functional colloidal systems that can be used in aqueous solutions. A new macrocycle platform for click chemistry and its adduct with o-propargylfluoresceine was synthesized and characterized using modern physical techniques. Nanosized solid lipid nanoparticles (SLNs) from the calixarene—fluoresceine adduct were synthesized through the solvent injection technique and well-characterized in the solution and in solid state using light-scattering and microscopy methods. The maximum fluorescence intensity of the SLNs was found to be in the pH range from 7 to 10. The Förster resonance energy transfer (FRET) efficiency from SLNs to rhodamine 6g was found to be 97.8%. Finally, pure SLNs and the FRET system SLNs—Rh6G were tested in model photocatalytic ipso oxidative hydroxylation of phenylboronic acid under blue LED light. The SLNs—Rh6G system was found to be the best, giving an almost qualitative phenol yield, which was shown by HPLC-UV analysis.     

Synthesis of O-Alkylbenzohydroximoyl Iodides and a Comparison of their Structures to other Oxime Derivatives

Abstract  The first general synthesis of (Z)-O-alkylbenzohydroximidoyl iodides [ArC(I)=NOR] is reported. X-ray crystallographic structures of two of these compounds confirm that they are in the Z-configuration: p-NO₂ArC(I)=NOCH₃ crystallizes in space group Pnma with lattice constants a = 12.682(2) ?, b = 6.5217(15) ?, and c = 11.755(2) ?, and p-ClArC(I)=NOCH₃ crystallizes in space group P2₁/n with lattice constants a = 15.670(4) ?, b = 5.742(4) ?, and c = 27.156(7) ? and beta angle 102.71(2). Their structures are compared to other O-alkylbenzohydroximoyl halides including p-NO₂ArC(F)=NOCH₃ which crystallizes in space group P2₁/c with lattice constants a = 3.8475(10) ?, b = 22.501(5) ?, and c = 10.088(2) ? and beta angle 91.130(11). The synthesis of two additional compounds containing the N-alkoxyimine moiety {methyl (Z)-O-methyl-4-nitrobenzothiohydroximate [p-NO₂ArC(SCH₃)=NOCH₃] which crystallizes in space group P2₁/n with lattice constants a = 11.8046(15) ?, b = 7.0774(10) ?, and c = 12.2741(15) ? and beta angle 100.401(9) and (Z)-O-methyl-4-nitrobenzohydroximoyl azide [p-NO₂ArC(N₃)=NOCH₃] which crystallizes in space group P2₁/c with lattice constants a = 11.753(2) ?, b = 11.310(3) ?, and c = 7.351(2) ? and beta angle 103.805(15) are also reported. Their structures are compared to (Z)-ethyl benzohydroximate [PhC(OEt)=NOH] and (Z)-O-methyl-4-nitrobenzohydroximoyl cyanide [p-NO₂ArC(CN)=NOCH₃] respectively. Characterizations include spectrometric identifications employing IR, ¹H-NMR, ¹³C-NMR and mass spectrometry. Index Abstract  X-ray structures of several N-alkoxyimines, including the newly synthesized N-alkoxyimidoyl iodides and azide, have been performed, and these structures unambiguously show the geometric configuration (E vs. Z) of these compounds.

Bulk High‐Impact Polystyrene Process, 1

In relation to the bulk high‐impact polystyrene process, this work investigates the partition between phases of styrene and an initiator: tert‐butyl peroctoate. A Flory‐Huggins model was applied for predicting the phase separation point and the partitions of styrene and tert‐butyl peroctoate. For blends of styrene, polystyrene, and a styrene‐butadiene diblock copolymer, the model provides reasonable predictions of a ternary equilibrium diagram. For blends of styrene, polystyrene, polybutadiene, and tert‐butyl peroctoate, the partition of tert‐butyl peroctoate was measured at 25 °C. At emulated conversions of 13% or lower, equilibrium was reached after 1 h of mixing time. For the higher molar masses and conversion of 16%, equilibrium was not reached after 24 h of mixing time. To fit the equilibrium measurements, the solubility parameter of tert‐butyl peroctoate was adjusted.

     

Supersymmetries and Constants of Motion in Taub-NUT Spinning Space

We review the geodesic motion of pseudo-classical spinning particles in curved spaces. Investigating the generalized Killing equations for spinning spaces, we express the constants of motion in terms of Killing-Yano tensors. The general results are applied to the case of the four-dimensional Euclidean Taub-NUT spinning space. A simple exact solution, corresponding to trajectories lying on a cone, is given.     

Unravelling free volume in branched-cation ionic liquids based on silicon

The branching of ionic liquid cation sidechains utilizing silicon as the backbone was explored and it was found that this structural feature leads to fluids with remarkably low density and viscosity. The relatively low liquid densities suggest a large free volume in these liquids. Argon solubility was measured using a precise saturation method to probe the relative free volumes. Argon molar solubilities were slightly higher in ionic liquids with alkylsilane and siloxane groups within the cation, compared to carbon-based branched groups. The anion size, however, showed by far the dominant effect on argon solubility. Thermodynamic solvation parameters were derived from the solubility data and the argon solvation environment was modelled utilizing the polarizable CL&Pol force field. Semiquantitative analysis was in agreement with trends established from the experimental data. The results of this investigation demonstrate design principles for targeted ionic liquids when optimisation for the free volume is required, and demonstrate the utility of argon as a simple, noninteracting probe. As more ionic liquids find their way into industrial processes of scale, these findings are important for their utilisation in the capture of any gaseous solute, gas separation, or in processes involving the transformation of gases or small molecules.

The branching of ionic liquid cation sidechains utilizing silicon as the backbone was explored and it was found that this structural feature leads to fluids with remarkably low density and viscosity.     

Selective Integrin α5β1 Targeting through Spatially Constrained Multivalent DNA-Based Nanoparticles

Targeting cells specifically based on receptor expression levels remains an area of active research to date. Selective binding of receptors cannot be achieved by increasing the individual binding strength, as this does not account for differing distributions of receptor density across healthy and diseased cells. Engaging receptors above a threshold concentration would be desirable in devising selective diagnostics. Integrins are prime target candidates as they are readily available on the cell surface and have been reported to be overexpressed in diseases. Insights into their spatial organization would therefore be advantageous to design selective targeting agents. Here, we investigated the effect of activation method on integrin α₅β₁ clustering by immunofluorescence and modeled the global neighbor distances with input from an immuno-staining assay and image processing of microscopy images. This data was used to engineer spatially-controlled DNA-scaffolded bivalent ligands, which we used to compare trends in spatial-selective binding observed across HUVEC, CHO and HeLa in resting versus activated conditions in confocal microscopy images. For HUVEC and CHO, the data demonstrated an improved selectivity and localisation of binding for smaller spacings ~7 nm and ~24 nm, in good agreement with the model. A deviation from the mode predictions for HeLa was observed, indicative of a clustered, instead of homogeneous, integrin organization. Our findings demonstrate how low-technology imaging methods can guide the design of spatially controlled ligands to selectively differentiate between cell type and integrin activation state.