An efficient preparative method for the synthesis of siloxanols based on aerobic Co(OAc) ₂ or Cu(OAc) ₂ /NHPI-catalyzed oxidation of hydride siloxanes has been proposed.

Recently developed non-functional derivatives of polymethylsilsesquioxane (PMSSO) dendrimers of the first to fifth generation were characterized by ¹H, ¹³C and ²⁹Si NMR spectroscopy. The self-diffusion and NMR relaxation of PMSSO dendrimers in dilute solutions of toluene and melts were investigated in a wide temperature range (−50–80 °C). The hydrodynamic radii of dendrimers were determined from the self-diffusion coefficients measured in diluted solutions according to the Stokes–Einstein equation. The hydrodynamic radius of PMSSO dendrimers as a function of molecular mass follows a power law with the scaling exponent of 0.32 ± 0.02 in the investigated temperature range. The temperature dependences of the self-diffusion coefficients of dendrimers were described by the Arrhenius-type equation. The activation energies of self-diffusion of dendrimers in diluted toluene solutions are identical for different generations while the dependence of activation energy for dendrimers in melts shows a maximum for the third generation (G3) dendrimer. Taking into account the absence of specific interactions in PMSSO dendrimer melts the observed behavior was ascribed to the manifestation of interpenetration of dendrimer molecules. For low generations (G1 and G2) the short length of the branches does not considerably affect the translational diffusion while for higher generations (G4 and G5) the densification of the structure prevents significant interpenetration.

The temperature dependence of the heat capacity of a first-generation siloxane dendrimer with terminal trimethylsilyl groups is determined for the first time via high-precision adiabatic vacuum calorimetry in the temperature range of 6 to 347 K, and by differential scanning calorimetry in the temperature range of 330 to 410 K. An anomalous change in heat capacity is detected in the range of T = 42–76 K. A transition is observed in the range of T = 137–153 K, due to devitrification of the dendrimer. The thermal stability of the compound is studied via thermogravimetric analysis. The obtained experimental data are used to calculate standard thermodynamic functions of the dendrimer in the temperature range T → 0 to T = 400 K, along with the standard entropy of its formation at T = 298.15 K.

As a convenient, stable and non-toxic substance, tetrabutylammonium difluorotriphenylsilicate (TBAT) can be used as an organocatalyst in all stages of polymer lifetime - synthesis, modification and recycling. The fluorine-containing initiator showed high activity in the polymerization of siloxanes comparing to classic organocatalytic systems. Using kinetic controlled ROP, a high molecular weight PDMS (Mn up to 820 kg/mol) was prepared at room temperature using ppm-level catalyst loadings (TON up to 53000, TOF up to 139200 h-1). The possibility of initiation of lactone polymerization by generated siloxanolates was shown. Variation of reaction conditions enables the depolymerization of synthesized, commercial and postconsumer PDMS.