Ethynyl-substituted siloxysilsesquioxanes are promising building blocks for a wide range of substances based on a POSS/DDSQ core, especially for (oligo-)polymer syntheses and modifications (the formation of hybrid materials with interesting photophysical and mechanical properties). In this study, we report on a series of new mono- and diethynylsiloxysilsesquioxanes formed via an efficient and highly selective one-pot process from silsesquioxanes with reactive Si–OH groups based on sequential condensation, hydrolysis, chlorination and substitution reactions. All newly synthesized compounds were isolated and characterized by spectroscopic methods.

Herein, a facile and efficient synthetic route to unique hybrid materials containing polysiloxanes and mono(alkyl)silsesquioxanes as their pendant modifiers (T₈@PS) was demonstrated. The idea of this work was to apply the hydrosilylation reaction as a tool for the efficient and selective attachment of mono(alkenyl)substituted silsesquioxanes (differing in the alkenyl chain length, from -vinyl to -dec-9-enyl and types of inert groups iBu, Ph at the inorganic core) onto two polysiloxanes containing various amount of Si-H units. The synthetic protocol, determined and confirmed by FT-IR in situ and NMR analyses, was optimized to ensure complete Si-H consumption along with the avoidance of side-products. A series of 20 new compounds with high yields and complete β-addition selectivity was obtained and characterized by spectroscopic methods.

The new reaction of terminal alkynes with iodogermanes proceeding in the presence of an Ir^I-complex [{Ir(μ-Cl)(CO)₂}₂] (I) and NEt(ⁱPr)₂, as a hydrogen iodide acceptor, leads to the formation of functionalized alkynylgermanes. This reaction occurs via direct activation of the C_sp–H bond in the starting alkyne. Detailed stoichiometric experiments using [Ir(cod)(CCPh)(PCy₃)] (IVa) and iodogermane were performed and resulted in a proposal of a reasonable mechanism for the germylative coupling reaction between alkynes and iodogermanes.

A synthesis of a series of mono-T₈ and difunctionalized double-decker silsesquioxanes bearing substituted triazole ring(s) has been reported within this work. The catalytic protocol for their formation is based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) process. Diverse alkynes were in the scope of our interest—i.e., aryl, hetaryl, alkyl, silyl, or germyl—and the latter was shown to be the first example of terminal germane alkyne which is reactive in the applied process’ conditions. From the pallet of 15 compounds, three of them with pyridine-triazole and thiophenyl-triazole moiety attached to T₈ or DDSQ core were verified in terms of their coordinating properties towards selected transition metals, i.e., Pd(II), Pt(II), and Rh(I). The studies resulted in the formation of four SQs based coordination compounds that were obtained in high yields up to 93% and their thorough spectroscopic characterization is presented. To our knowledge, this is the first example of the DDSQ-based molecular complex possessing bidentate pyridine-triazole ligand binding two Pd(II) ions.