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Tetraamminecadmium(II)] bis(permanganate) (1) was prepared and its crystal structure was elucidated with XRD-Rietveld refinement and vibrational spectroscopic methods. Compound 1 has a cubic lattice consisting of a 3D hydrogen-bonded network built as four by four distorted tetrahedral blocks of [Cd(NH 3 ) 4 ] 2+ cations and MnO 4 anions, respectively. The other four permanganate ions are located in a crystallographically different environment, placed in the cavities formed by the attachment of the building blocks. A low-temperature (≈100°C) solid phase quasi-intramolecular redox reaction producing ammonium nitrate and amorphous CdMn 2 O 4 could be established. Neither solid phase nor aqueous solution phase thermal deammoniation of compound

Magnetically controlled enzymatic composites have received much attention for both therapeutic and industrial applications. Until now, such materials have been composed of at least four components: the enzyme, magnetic nanoparticles, their stabilizing components, and an organic or inorganic (or hybrid) matrix as a carrier. However, such compositions affect the magnetic response and the enzymatic activity, and also pose obstacles for intravenous administration, because of regulatory restrictions. Here, we present a methodology for the creation of magnetic bioactive nanocomposites composed of only two biocompatible components: an enzyme and magnetite nanoparticles. A series of magnetic biocomposites with a full set of therapeutical and industrial proteins (carbonic anhydrase, ovalbumin, horseradish peroxidase, acid phosphatase, proteinase, and xylanase) were successfully created by the direct entrapment of the proteins within a sol–gel magnetite matrix specially developed for these aims. The activity of the entrapped enzymes was studied at different temperatures and concentrations, and it was found that they showed remarkable thermal stabilization induced by the ferria matrix. For instance, entrapped carbonic anhydrase catalyzed the decomposition of p-nitrophenylacetate at a temperature of 90 °C, while free enzyme completely loses activity and denaturates already at 70 °C. Magnetic characterization of the obtained biomaterials is provided.

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A magnetite-only hydrogel was prepared for the first time by weak base mediated gelation of stable magnetite hydrosols at room temperature. The hydrogel consists of 10 nm magnetite nanoparticles linked by interparticle Fe-O-Fe bonds and has the appearance of a dark-brown viscous thixotropic material. The water content in the hydrogel could be up to 93.6% by mass while volume fraction reaches 99%. The material shows excellent biocompatibility and minor cytotoxic effects at concentrations up to 207 μg mL. The gel shows excellent sorption capacity for heavy metal adsorption such as chrome and lead ions, which is 225% more than the adsorption capacity of magnetite nanoparticles. Due to thixotropic nature, the gel demonstrates mechanical stimuli-responsive release behavior with up to 98% release triggered by ultrasound irradiation. The material shows superparamagnetic behavior with a coercivity of 65 emu g at 6000 Oe. The magnetite gels prepared could be used for the production of magnetite aerogels, magnetic drug delivery systems with controlled release and highly efficient sorbents for hydrometallurgy.