Synthesis of Tetrachloro, Tetraiodo, and Tetraazido Double-Decker Siloxanes

Abstract

A convenient and scalable (gram-scale) route to unprecedented T8D2-DDSQs bearing four chloro-(3b) or four azido (5b) groups is reported. Both compounds were characterized and proved to undergo successfully nucleophilic substitution for 3b (with iodide or azide) and coppercatalyzed azide-alkyne [3+2] cycloaddition for 5b. All these transformations occurred under mild conditions and the corresponding DDSQs were prepared in very high yields. Beyond the enhanced multivalency as compared to the previously described di-substituted D2T8 structures, the reported tetra-functional DDSQs are formed as a single isomer and readily isolated in very high yields.Moreover, the tetra-azido DDSQ 5b constitutes a multipurpose nano-building block for the further preparation of new inorganic-organic hybrid materials where the covalent incorporation of a DDSQ moiety brings valuable properties.

Synthesis, Characterization, and Reaction of Divinyl‐substituted Laddersiloxanes

“…Along these lines, we recently reported the preparation of tricyclic ladder silsesquioxanes with 6-8-6 fused rings bearing four reactive vinyl or allyl substituents on the D-group silicon atoms. The latter ones could be easily transformed into the corresponding tetrachloro- [27] or tetramercapto- [28] laddersiloxanes through hydrosilylation or thiol-ene reactions, respectively. Some of us also reported the functionalization of phenyl-substituted 8-8-8-laddersiloxanes through Friedel-Crafts acylation to prepare nanoporous materials for water-treatment, which shows the potential of hybrid materials based on laddersiloxanes [26].…”

Synthesis and characterization of tetrathiol-substituted double-decker or ladder silsesquioxane nano-cores

“…68 In addition, in 3, the Si-O-Si bond angles vary from 136.44 to 176.62° which corresponds to the range encountered for 1 (138.8(8)°-166.3(7)°) and previously reported DDSQ resulting from the hydrosilylation of the C=C bond. [64][65] The large deviation of the bond angles as compared to most of T 8scaffolds (standard deviation < 15 °) indicates the flexible structure of the frameworks. 1 In the case of the octathiol-T 8cage, adjacent molecules were found to be associated in onedimensional supramolecular chains due to intermolecular S-H…S hydrogen bonds.…”

“…S3). In an endeavour to access tetramercapto-DDSQ with longer arms and increased flexibility, previously described DDSQ 4 decorated with four chloro substituents and obtained quantitatively from 1 in one step 65 was allowed to react with potassium thioacetate. The resulting tetra-thioacetate DDSQ 5 was isolated in 91% yield after 16h at 22 °C (Scheme 2).…”

The Use of the Thiol-Ene Addition Click Reaction in the Chemistry of Organosilicon Compounds: An Alternative or a Supplement to the Classical Hydrosilylation?

“…Currently, compounds with various framework structures and functionality can be obtained on their basis. A great contribution to the development of this approach was made by the Unno team [ 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 ]. They synthesized compounds with diverse structures and functionality, in particular, Double-Decker siloxanes [ 85 , 87 , 91 ].…”

“…A great contribution to the development of this approach was made by the Unno team [ 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 ]. They synthesized compounds with diverse structures and functionality, in particular, Double-Decker siloxanes [ 85 , 87 , 91 ]. It appears that the following structures are most interesting in terms of hydrothiolation usage (see Figure 21 ).…”