The base-free benzoborirene 1,2-BR-1,2-C6H4 (7) and its three-dimensional inorganic analogue 1,2-BR-1,2-C2B10H10 (13) have been successfully synthesized by Cp2ZrBr2 and LiCl elimination, respectively. The Cl analogue of the key intermediate for the formation of benzoborirene 7 has been isolated and structurally characterized, thus suggesting the reaction pathway via benzyne Zr complex formation, B–Br/Cbenzyne–Zr σ-bond metathesis, and a Cp2ZrBr2 elimination/ring-closing process. The rationality of the reaction pathway has been confirmed by DFT calculations. In addition, the title compounds shared the same reactivity pattern (i.e., 1,3-silyl migration) toward MeIiPr (8), thus allowing for the synthetic approach to the first carborane-substituted iminoborane 14.

Coarsening of barium titanate (BaTiO3) particles under hydrothermal conditions was investigated theoretically and experimentally. A detailed model, in which coarsening is assumed to be controlled by a reversible interface reaction, is presented and discussed. The model predicts a linear growth law R − R 0 = Kt in the early stage of coarsening. This result is supported by the experimental data collected for conventional and microwave-assisted hydrothermal syntheses at two different temperatures. The growth constant K corresponds to a nonlinear combination of thermodynamic and kinetic parameters. Under microwave irradiation, the growth rate was found to be 1 order of magnitude larger than in a conventional hydrothermal process. The predicted variation of the growth kinetics, from linear to parabolic, was observed experimentally at long reaction times.

The size effect in barium titanate (BaTiO3) was investigated both experimentally and theoretically. Tetragonal BaTiO3 powders with average sizes from 80to420nm were directly prepared by different hydrothermal methods. The tetragonality of the hydrothermal BaTiO3 decreased with decreasing particle size, which exhibited a dependence on the synthesis method. A phenomenological model for the size effect was proposed to interpret the experimental observations. The influence of the defects, mainly the lattice hydroxyl, on the size effect was investigated to understand the correlation between the size effect and synthesis condition. The permittivities of BaTiO3 powder at different particle sizes were calculated, which predicted a maximum permittivity of over 16 000 around the room-temperature critical size of ∼70nm. The prediction was in good accordance with the experimental data reported recently.

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The iminoboryl o-carboranes (Me3Si)–Cb–BN–R (Cb = B10C2H10, 3a, R = SiMe3; 3b, R = t Bu) have been successfully synthesized by tetrahydrofuran (THF)-promoted isomerization from the corresponding o-carborane-fused aminoboriranes Cb­{BN­(SiMe3)­R} (2). The synthetic protocol of the previously reported borirane 2a was optimized. The borirane Cb­{BN­(SiMe3) t Bu} (2b) and the iminoboranes 3a and 3b were fully characterized by NMR, IR, and single-crystal X-ray diffraction analyses. The borirane 2a isomerizes more readily than 2b. The kinetics study revealed a bimolecular mechanism between borirane and THF, which is in good agreement with the computationally proposed reaction pathway. The title compounds are thermally robust, but compound 3a dimerized in the presence of a catalytic amount of t BuNC to give the cyclodimer 4. Quick equilibrium between 4 and the isonitrile adduct 4· t BuNC was observed in solution.