Chapter 26
Interplay of Photoisomerization
and Phase Transition Events Provide
a Working Supramolecular Motor
Yoshiyuki Kageyama
Abstract Autonomous molecular-based microrobots have not been created despite
progress in our understanding of the chemistry of molecular motors and machines.
In the field of chemistry, the design and synthesis of molecular structures remain an
ongoing and diverse challenge. The creation of a system in which molecular structures interact represents an additional challenge. In order to functionalize a molecule
for a motor, it must be exposed to a specific reaction field. Synchronization of the
molecules involved is also required. In this chapter, we discuss our research results
on self-oscillatory flipping motions of azobenzene-containing assemblies. Briefly,
reversible photoisomerization of an azobenzene derivative occurs under steady light
irradiation. In coordination with phase transition events, a cycle modulated by the
components involved leads to repetitive structural changes. When this azobenzenebased assembly is placed in water, the assembly exhibits autonomous swimming.
This macroscopic light-powered motion is the result of the self-organization of a
large number of nanometer-scale molecules and it provides an example of the potential for mechanical work to be performed by molecular assemblies. We subsequently
describe the driving concept of far-from-equilibrium dynamics, namely a dissipative structure by which a spatial pattern maintains dynamic behavior to drive the
mechanical motion observed.
Keywords Molecular motor · Self-organized motion · Hierarchical structure ·
Azobenzene photoisomerization · Collective dynamics · Active matter ·
Limit-cycle dissipative structure
Y. Kageyama (B)
Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
e-mail: y.kageyama@sci.hokudai.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_26
449
Interplay of Photoisomerization
and Phase Transition Events Provide
a Working Supramolecular Motor
Yoshiyuki Kageyama
Abstract Autonomous molecular-based microrobots have not been created despite
progress in our understanding of the chemistry of molecular motors and machines.
In the field of chemistry, the design and synthesis of molecular structures remain an
ongoing and diverse challenge. The creation of a system in which molecular structures interact represents an additional challenge. In order to functionalize a molecule
for a motor, it must be exposed to a specific reaction field. Synchronization of the
molecules involved is also required. In this chapter, we discuss our research results
on self-oscillatory flipping motions of azobenzene-containing assemblies. Briefly,
reversible photoisomerization of an azobenzene derivative occurs under steady light
irradiation. In coordination with phase transition events, a cycle modulated by the
components involved leads to repetitive structural changes. When this azobenzenebased assembly is placed in water, the assembly exhibits autonomous swimming.
This macroscopic light-powered motion is the result of the self-organization of a
large number of nanometer-scale molecules and it provides an example of the potential for mechanical work to be performed by molecular assemblies. We subsequently
describe the driving concept of far-from-equilibrium dynamics, namely a dissipative structure by which a spatial pattern maintains dynamic behavior to drive the
mechanical motion observed.
Keywords Molecular motor · Self-organized motion · Hierarchical structure ·
Azobenzene photoisomerization · Collective dynamics · Active matter ·
Limit-cycle dissipative structure
Y. Kageyama (B)
Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
e-mail: y.kageyama@sci.hokudai.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_26
449