Useful derivatives of tetraphenylmethane and tetraphenylsilane have been synthesized by efficient methods that give crystalline products without chromatographic purification. New compounds include tetrakis(4-hydroxyphenyl)methane (21), tetrakis(4-formylphenyl)methane (22), tetrakis[(4-hydroxymethyl)phenyl]methane (23), tetrakis(4-bromophenyl)silane (24), tetrakis(4-iodophenyl)silane (25), tetrakis(4-hydroxyphenyl)silane (26), tetrakis[(4-hydroxymethyl)phenyl]silane (27), and tetrakis[(4-chloromethyl)phenyl]silane (28). These compounds are valuable precursors for the construction of complex molecules with tetrahedral geometries.Key words: organic synthesis, molecular and supramolecular design and construction, tetraphenylmethane, tetraphenyl silane, tetrahedral building blocks.

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Incorporation of carbon nanotubes (CNTs) into textiles without sacrificing their intrinsic properties provides a promising platform in exploring wearable technology. However, manufacture of flexible, durable, and stretchable CNT/textile composites on an industrial scale is still a great challenge. We hereby report a facile way of incorporating CNTs into the traditional yarn manufacturing process by dipping and drying CNTs into cotton rovings followed by fabricating CNT/cotton/spandex composite yarn (CCSCY) in sirofil spinning. The existence of CNTs in CCSCY brings electrical conductivity to CCSCY while the mechanical properties and stretchability are preserved. We demonstrate that the CCSCY can be used as wearable strain sensors, exhibiting ultrahigh strain sensing range, excellent stability, and good washing durability. Furthermore, CCSCY can be used to accurately monitor the real-time human motions, such as leg bending, walking, finger bending, wrist activity, clenching fist, bending down, and pronouncing words. We also demonstrate that the CCSCY can be assembled into knitted fabrics as the conductors with electric heating performance. The reported manufacturing technology of CCSCY could lead to an industrial-scale development of e-textiles for wearable applications.

Flexible wearable devices for various applications have attracted research attention in recent years. To date, it is still a big challenge to fabricate strain sensors with a large workable strain range while maintaining their high sensitivity. Herein, we report the fabrication of highly sensitive wearable strain sensors from braided composite yarns (BYs) by in situ polymerization of polypyrrole (PPy) on the surface of yarns after polydopamine templating (BYs–PDA). The electromechanical performance and strain sensing properties of the fabricated braided composite yarn@polydopamine@polypyrrole (BYs–PDA–PPy) were investigated. Because of the unique braided structure of BYs, the BYs–PDA–PPy strain sensors exhibit fascinating performance, including a large workable strain range (up to 105% strain), high sensitivity (gauge factor of 51.2 in strain of 0%–40% and of 27.6 in strain of 40%–105%), long-term stability and great electrical heating performance. Furthermore, the BYs–PDA–PPy sensors can be used in real-time monitoring subtle and large human motions. The BYs–PDA-PPy strain sensors can also be woven into fabrics for large area electric heating. These results demonstrate the potential of BYs–PDA–PPy in wearable electronics.

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