posted on 2020-12-29, 02:30authored byZhao-Tao Shi, Yi-Xiong Hu, Zhubin Hu, Qi Zhang, Shao-Yu Chen, Meng Chen, Jing-Jing Yu, Guang-Qiang Yin, Haitao Sun, Lin Xu, Xiaopeng Li, Ben L. Feringa, Hai-Bo Yang, He Tian, Da-Hui Qu
The organization of molecular motors
in supramolecular assemblies
to allow the amplification and transmission of motion and collective
action is an important step toward future responsive systems. Metal-coordination-driven
directional self-assembly into supramolecular metallacycles
provides a powerful strategy to position several motor units in larger
structures with well-defined geometries. Herein, we present a pyridyl-modified
molecular motor ligand (MPY) which upon coordination
with geometrically distinct di-Pt(II) acceptors assembles into discrete
metallacycles of different sizes and shapes. This coordination
leads to a red-shift of the absorption bands of molecular motors,
making these motorized metallacycles responsive to visible light.
Photochemical and thermal isomerization experiments demonstrated that
the light-driven rotation of the motors in the metallacycles
is similar to that in free MPY in solution. CD studies
show that the helicity inversions associated with each isomerization
step in the rotary cycle are preserved. To explore collective motion,
the trimeric motor-containing metallacycle was aggregated with
heparin through multiple electrostatic interactions, to construct
a multi-component hierarchical system. SEM, TEM, and DLS measurements
revealed that the photo- and thermal-responsive molecular motor units
enabled selective manipulation of the secondary supramolecular
aggregation process without dissociating the primary metallacycle
structures. These visible-light-responsive metallacycles, with
intrinsic multiple rotary motors, offer prospects for cooperative
operations, dynamic hierarchical self-assembled systems, and adaptive
materials.