In this work, we were the first to show the possibility of synthesizing polydimethylsiloxanes (PDMSs) with azidopropyl-functional groups at the silicon atom by the classical methods for PDMS synthesis, that is, ring-opening polymerization (ROP) and catalytic rearrangement of siloxanes in the presence of a strong acid (CF3SO3H). The suggested method was used to obtain PDMSs containing azidopropyl-functional groups at both ends of the polymer chain (telechelics) as well as PDMSs with irregular structures containing different fractions (5–50%) of azidopropyl-functional groups in the main polymer chain. The suggested method also proved to be efficient for synthesizing PDMSs containing both azidopropyl- and hydridosilyl-functional groups simultaneously. As a result, PDMSs with different mutual arrangements of two types of functional groups along the PDMS chain were obtained. The method for the catalytic rearrangement of low-molecular-weight siloxanes that we used made it possible to obtain azidopropyl-functional PDMSs in a wide range of molecular weights from 2000 to 88,000 according to gel permeation chromatography (GPC) data. The possibility of further modification of the resulting azidopropyl-functional PDMS, as well as multifunctional PDMSs containing azidopropyl- and hydridosilyl-functional groups simultaneously, by azide-alkyne cycloaddition reactions was demonstrated. The polymers obtained were characterized by 1H and 29Si NMR spectroscopy and by GPC.

Despite the presence of many methods, which were created to date for the preparation, functionalization, and vulcanization of polysiloxanes, the development of materials based on silicones remains relevant and requires the introduction of new approaches that combine such modern strategies as atom-economical reactions, refusal to use harmful and dangerous organochlorosilanes, and using the principles of green chemistry and minimizing the use of solvents. In this work, we develop modern approaches to the preparation of both linear and branched polyorganosiloxanes containing azidopropyl functions at the silicon atom. In the first part of the work, it was shown that the proposed method for introducing these groups by catalytic rearrangement with the opening of cyclosiloxane is effective and makes it possible to obtain polysiloxanes with different contents of azidopropyl groups and different molecular weights. The second part of the work demonstrated the possibility of postpolymerization functionalization of such polymers by the mechanism of azide–alkyne cycloaddition under “green” conditions, without using solvents and amines. All of the most important functional fragments were introduced into the structures of organosilicon polymers by a single mechanism, under simple conditions, without the use of expensive catalysts, exposure to irradiation, and hazardous solvents. The combination of simplicity and versatility in the preparation of polysiloxanes with azidopropyl groups with the possibility of performing a click reaction makes it possible to directionally obtain the required materials based on universal raw materials and, as a result, can open up broad prospects for serious development and rethinking of the chemistry of silicones.

PDMS telechelics are important both in industry and in academic research. They are used both in the free state and as part of copolymers and cross-linked materials. At present, the most important, practically used, and well-studied method for the preparation of such PDMS is diorganosiloxane ring-opening polymerization (ROP) in the presence of nucleophilic or electrophilic initiators. In our brief review, we reviewed the current advances in the field of obtaining polydiorganosiloxane telechelics and monofunctional PDMS, as well as well-organized branching centers by the ROP mechanism and catalytic rearrangement, one of the first and most important reactions in the polymer chemistry of silicones, which remains so at the present time.