Permethylated Silicon: A Structural Motif with a Critical Role in Shaping the Properties of Organic–Inorganic Compounds

Abstract The distinctive features of Si–O and Si–C bonds make the integration of silicon-organic moieties into organic structures significantly influence the architecture and properties of the resulting hybrid materials often confering conformational flexibility, hydrophobicity, surface activity, self-assembly capacity and dual character (amorphous–crystalline, flexible–rigid, mesomorphic). As a result, silicon-based structural units show considerable potential in the design of functional compounds and materials, relevant for fields such as sensor technology, optoelectronics, catalysis, energy storage and even biomedical applications. In the context of recent advances in the synthesis and functionalization of organosilicon compounds, widely reported in the specialized literature, a series of derivatives have been obtained by chemical coupling of siloxane or silane (as a bridge or tail) moieties with triazole, thiadiazole and other functionalized aromatic moieties. Some of these compounds, but also simpler α,ω-bifunctional disiloxanes, have been investigated as ligands for metal ions, leading to the formation of coordination compounds with different dimensionalities (from 0D to 3D), which can outline a distinct class in coordination chemistry. In this paper, such recently obtained representative organosilicon compounds and their metal-containing derivatives are reviewed, highlighting their defining structural and behavioral features. Although the silicon-based moiety is often perceived as chemically inert in these systems, it plays an essential role in controlling the structural and functional properties of the resulting assemblies.