Comparative Studies of Mechanochemically Synthesized Insoluble Beta-Cyclodextrin Polymers

: Cyclodextrin (CD) polymers are covalently linked hollow structures that are a network of less flexible macrocycles. They can be divided into two main groups: a) soluble (CDPS); and b) insoluble (CDPIS) polymers. These two types are generally prepared in a similar reaction, and the CD/reagent ratio determines the final properties of the reaction product. Changing this ratio of the generally bifunctionalized crosslinking agent and reaction conditions can lead to CDPS or CDPIS. The classical synthetic way in solution often leads to partial reagent(s) degradation, which frequently results in poorly reproducible products. At the same CD/reagent ratio, the reaction in solution yielded soluble CD polymers, whereas the reaction under mechanochemical conditions produced insoluble CD polymers. Usually, further derivatization of CDPIS or polymerization of derivatized CDs can be difficult or even impossible. The reactivity of hydroxyl groups in methylated CDs is limited so that reactions generally require high-boiling solvents and/or a large excess of reagent. This paper presents an economical, reproducible, and well-scalable synthetic method for producing some insoluble CD polymers. The physicochemical and adsorption properties of CDPIS prepared in a planetary ball mill are also compared.

Reaction-diffusion hydrogels from urease enzyme particles for patterned coatings

The reaction and diffusion of small molecules is used to initiate the formation of protective polymeric layers, or biofilms, that attach cells to surfaces. Here, inspired by biofilm formation, we present a general method for the growth of hydrogels from urease enzyme-particles by combining production of ammonia with a pH-regulated polymerization reaction in solution. We show through experiments and simulations how the propagating basic front and thiol-acrylate polymerization were continuously maintained by the localized urease reaction in the presence of urea, resulting in hydrogel layers around the enzyme particles at surfaces, interfaces or in motion. The hydrogels adhere the enzyme-particles to surfaces and have a tunable growth rate of the order of 10 µm min−1 that depends on the size and spatial distribution of particles. This approach can be exploited to create enzyme-hydrogels or chemically patterned coatings for applications in biocatalytic flow reactors.

Synthesis, structures and properties of Cd(II) supramolecular compound based on nitrogen heterocyclic cation

A novel supramolecular compound {(L1) [CdI4]} (L1 = 1-(3-(((1 s,3R,5S)-1,3,5,7,tetraazaadamantan-1-ium-1-yl)methyl)benzyl)-1,3,5,7,-tetraazaadamantan-1-ium) was synthesized from CdI2 and L1 by self-assembly reaction in solution. Its structure was analyzed by X-ray diffraction, and X-ray crystallography showed that the crystal was mononuclear. The compound was characterized by UV, TG, photocatalysis and adsorption.

Synthesis and Luminescence Properties of Rare Earth (Eu, Tb) Complexes of Octanoylphenylalanine

Tb (oct-phe)3·H2O and Eu (oct-phe)3·H2O were prepared by chemical reaction in solution. The molecular formula of the complex was determined by elemental analysis and FT-IR. The optical properties of rare earth complexes were further tested by ultraviolet-visible-infrared absorption measurements. The results show that the optical absorption performance is better in the wavelength range of 200-300 nm. The luminescent properties of the rare earth complexes in the wavelength range of 450-750 nm were tested. It was found that the rare earth (Eu, Tb) complexes of octylphenylalanine have good luminescent properties.

Poly(ε-Caprolactone)/Poly(Lactic Acid) Blends Compatibilized by Peroxide Initiators: Comparison of Two Strategies

Poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) blends were compatibilized by reactive blending and by copolymers formed during reaction in the solution. The reactive blending of PCL/PLA was performed using di-(2-tert-butyl-peroxyisopropyl)benzene (BIB) or dicumyl peroxide (DCP) as radical initiator. PCL-g-PLA copolymers were prepared using 1.0 wt. % of DCP or BIB via reaction in solution, which was investigated through a Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance (NMR) in order to better understand the occurring mechanisms. The effect of different additions such as PCL-g-PLA copolymers, DCP, or BIB on the properties of PCL/PLA blends was studied. The unmodified PCL/PLA blends showed a sea-island morphology typical of incompatible blends, where PLA droplets were dispersed in the PCL matrix. Application of organic peroxides improved miscibility between PCL and PLA phases. A similar effect was observed for PCL/PLA blend compatibilized by PCL-g-PLA copolymer, where BIB was used as initiator. However, in case of application of the peroxides, the PCL/PLA blends were cross-linked, and it has been confirmed by the gel fraction and melt flow index measurements. The thermal and mechanical properties of the blends were also investigated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and tensile strength.

A copper(i) bromide organic–inorganic zwitterionic coordination compound with a new type of core: structure, luminescence properties, and DFT calculations

A new organic–inorganic Cu(i) bromide complex based on protonated tris(2-pyridyl)phosphine, [(HPy)3PCu2Br5], has been synthesized by a straightforward reaction in solution or by modification of the [Cu2Br2(Py3P)2] complex using hydrobromic acid.