Chapter 18
π-Electronic Ion-Pairing Assemblies
for Photoswitching Materials
Yohei Haketa, Ryohei Yamakado, Kazuki Urakawa, and Hiromitsu Maeda
Abstract Ion-pairing assemblies consisting of appropriately designed oppositely
charged π-electronic systems give rise to various functional supramolecular assemblies including crystals and soft materials based on the anisotropic orientation of
charged species through electrostatic and other weak noncovalent interactions. The
introduction of photo-responsive moiety to the charged species facilitated the formation of photo-responsive ion-pairing assemblies, whose assembling modes were
controlled by photoirradiation. Furthermore, pyrrole-based π-system–Pt
II complexes
were designed and exhibited unique photo-induced excited-state dynamics.
Keywords Ion-pairing assemblies · Dimension-controlled assemblies ·
Anion-responsive π-electronic molecules · Photo-responsive assemblies ·
Excited-state dynamics
18.1 Ion-Pairing Assemblies Comprising Charged
π-Electronic Systems
18.1.1 Introduction
In recent years, materials comprising ionic species based on the concept of ionic selfassembly (ISA) have attracted much attention in materials science, especially in the
fields of functional nanostructured soft materials, surface morphologies, organicinorganic hybrid materials, etc. [1, 2]. An appropriate combination of designed
organic ionic species (anions and cations) affords various ion pairs that form functional ion-pairing assemblies. Among a variety of charged species, π-electronic ions
Y. Haketa · K. Urakawa · H. Maeda (B)
Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu,
Shiga 525–8577, Japan
e-mail: maedahir@ph.ritsumei.ac.jp
R. Yamakado
Department of Organic Materials Science, Graduate School of Organic Materials Science,
Yamagata University, Yonezawa, Yamagata 992–8510, Japan
© 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_18
301
π-Electronic Ion-Pairing Assemblies
for Photoswitching Materials
Yohei Haketa, Ryohei Yamakado, Kazuki Urakawa, and Hiromitsu Maeda
Abstract Ion-pairing assemblies consisting of appropriately designed oppositely
charged π-electronic systems give rise to various functional supramolecular assemblies including crystals and soft materials based on the anisotropic orientation of
charged species through electrostatic and other weak noncovalent interactions. The
introduction of photo-responsive moiety to the charged species facilitated the formation of photo-responsive ion-pairing assemblies, whose assembling modes were
controlled by photoirradiation. Furthermore, pyrrole-based π-system–Pt
II complexes
were designed and exhibited unique photo-induced excited-state dynamics.
Keywords Ion-pairing assemblies · Dimension-controlled assemblies ·
Anion-responsive π-electronic molecules · Photo-responsive assemblies ·
Excited-state dynamics
18.1 Ion-Pairing Assemblies Comprising Charged
π-Electronic Systems
18.1.1 Introduction
In recent years, materials comprising ionic species based on the concept of ionic selfassembly (ISA) have attracted much attention in materials science, especially in the
fields of functional nanostructured soft materials, surface morphologies, organicinorganic hybrid materials, etc. [1, 2]. An appropriate combination of designed
organic ionic species (anions and cations) affords various ion pairs that form functional ion-pairing assemblies. Among a variety of charged species, π-electronic ions
Y. Haketa · K. Urakawa · H. Maeda (B)
Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu,
Shiga 525–8577, Japan
e-mail: maedahir@ph.ritsumei.ac.jp
R. Yamakado
Department of Organic Materials Science, Graduate School of Organic Materials Science,
Yamagata University, Yonezawa, Yamagata 992–8510, Japan
© 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_18
301