Double‐Pillaring Strategy for Silacyclophanes: Synthesis and Structures of Disilanyl Double‐Pillared Bisanthracenes

A new series of silacyclophanes with two disilanyl pillars has been synthesized using a straightforward method. A silylation reaction of 1,8‐dilithioanthracenes allowed the connection of two anthracene rings with two SiSi bonds to afford disilanyl double‐pillared bisanthracenes ( Si DPBAs). The major product had an anti geometry of the anthracene rings, and a unique steplike structure favorable for σ–π conjugations was revealed by X‐ray crystallographic analysis. Upon introducing a substituent at the 10‐position of anthracene, we obtained a U‐shaped isomer with syn geometry that yielded an excimer upon excitation and can decompose without steric protection .