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Template condensation of dibromoglyoxime with n-butylboronic acid on the corresponding metal ion as a matrix under vigorous reaction conditions afforded iron and cobalt(ii) hexabromoclathrochelates. The paramagnetic cobalt clathrochelate was found to be a low-spin complex at temperatures below 100 K, with a gradual increase in the effective magnetic moment at higher temperatures due to the temperature 1/2↔3/2 spin crossover and a gap caused by the structure phase transition. The multitemperature X-ray and DSC studies of this complex and its iron(ii)-containing analog also showed temperature structural transitions. The variation of an encapsulated metal ion's radius, electronic structure and spin state caused substantial differences in the geometry of its coordination polyhedron; these differences increase with the decrease in temperature due to Jahn-Teller distortion of the encapsulated cobalt(ii) ion with an electronic configuration d(7). As follows from CV and GC data, these cage iron and cobalt complexes undergo both oxidation and reduction quasireversibly, and showed an electrocatalytic activity for hydrogen production in different producing systems.

The synthesis of two novel bithiophenesilane-based dendronized polymers by a chain growth Kumada polymerization, their molecular properties in dilute solutions and thermal properties in the bulk are described and compared with those of bithiophenesilane dendrimers. GPC equipped with a dual light scattering detector has shown that the polymers exhibit narrow polydispersity indices (PDI = 1.22–1.23) and have a weight-average polymerization degree of 44 for P1 and 30 for P2, which correspond to 88 and 120 bithiophenesilane fragments, respectively. Spectral-luminescent investigations showed that both polymers among with the bithiophenesilanes contain from 1 to 4 terthiophenesilane fragments in every macromolecule, which leads to the so-called “dendritic molecular antenna” effect. The intramolecular energy transfer efficiency was measured to be 50 and 70% for polymers P1 and P2 respectively, which, alongside with the results of viscometric studies, points out to the compact conformation of these macromolecules in solution, which is close to those of bithiophenesilane dendrimers.

Magnetorheological fluids (MFs) based on hyperbranched polycarbosilanes as a carrier medium and micron-sized carbonyl iron particles as filler have been synthesized for the first time. Their magnetorheological (MR) behavior has been studied in steady-state flow regime and under dynamic torsion oscillations on a commercial rheometer. At zero magnetic field, in spite of a rather high molecular mass, the hyperbranched polymers as well as their magnetic compositions with up to 72 mass% of magnetic filler demonstrate Newtonian behavior, and their viscosity considerably increases with magnetic filler content. In magnetic fields MFs show a huge MR response. Namely, in steady-state flow experiments a five orders of magnitude increase in viscosity was observed accompanied by magnetic-field-induced well-pronounced non-Newtonian behavior and a non-zero yield stress. Dynamic experiments demonstrate the transition from liquid-like to solid-like behavior of MFs with a large increase in both the storage and loss moduli under application of a magnetic field. In magnetic fields, the rheological behavior of the obtained MF resembles that of soft MR elastomers being mainly determined by the magnetic particle network formed due to magnetic interactions. In particular, like MR elastomers the MFs exhibit the Payne effect, i.e. dependence of the dynamic modulus on the strain amplitude.

Hyperbranched polyvinyl‐ and polymethylethoxysiloxanes were obtained for the first time by heterofunctional polycondensation of the corresponding organoethoxysilanols derived from relevant monosodium organodiethoxysilanolates. Synthesized structures were characterized using 29Si NMR, 1H NMR and infrared spectroscopies, gel permeation chromatography and elemental analysis. On the basis of the obtained hyperbranched polyorganoethoxysiloxanes, new ‘core–shell’ structured polyvinyl‐ and polymethylsilsesquioxanes with adjustable sizes, different crosslinking densities and variable chemical natures of the core–shell surroundings were prepared, investigated and characterized using 1H NMR and infrared spectroscopies, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry and elemental analysis. © 2015 Society of Chemical Industry

Summary: Synthesis of the six generations of polyallylcarbosilane dendrimers with tetrafunctional branching center and tetrafunctional base reagent is reported. Obtained dendrimers are compared to carbosilane dendrimers with less dense molecular structure synthesized before. Densification of the dendrimer structure alters some basic dendrimer properties as well as their dependence on generation.