Mechanically interlocked molecules (MIMs) that undergo controllable internal motions of their component parts in more than one dimension are rare entities in the molecular world. Cyclic [2]daisy chains ([c2]DCs) are a class of MIMs that have been identified as prototypes for molecular muscles. It remains, however, a challenge to synthesize [cn]DCs with n > 2 selectively and efficiently. Herein, we report the design and synthesis of [c3]DCs employing radical and anionic templates. Two mechanically interlocked [c3]DCs with 18 positive charges were obtained in >90% yields. One [c3]DC displayed good air stability in its radical cationic form, while the other underwent reversible “co-conformational” switching between open macrocyclic and closed trisarm-shaped forms under electrochemical control. These findings provide not only two-dimensional MIMs with attractive electronic and switchable properties, but also a starting point for the design of extended molecular arrays, which could become the forerunners of adjustable molecular nets and breathable molecular membranes.

机械互锁分子（MIM）在一维以上对其组成部分进行可控的内部运动是分子世界中很少见的实体。环状[2]雏菊链（[ c 2] DC）是一类MIM，已被确定为分子肌肉的原型。然而，选择性地和有效地合成n> 2的[ c n] DC仍然是一个挑战。在这里，我们报道了采用自由基和阴离子模板的[ c 3] DC的设计和合成。以> 90％的产率获得了两个带有18个正电荷的机械互锁的[ c 3] DC。一个[ c3] DC在其自由基阳离子形式下显示出良好的空气稳定性，而另一种在电化学控制下经历了可逆的“共构象”转换，在开环大环和闭环三臂形之间转换。这些发现不仅为二维MIM提供了诱人的电子和可切换特性，而且为设计扩展的分子阵列提供了起点，扩展的分子阵列可能成为可调节分子网和透气分子膜的先驱。