Supramolecular Control of Spin Crossover Phenomena Using Various Amphiphiles

Keita Kuroiwa

doi:10.3390/inorganics5030045

Abstract

An aspect of nanochemistry that has attracted significant attention is the formation of nanoarchitectures from the self-assembly of metal complexes, based on the design of compounds having cooperative functionalities. This technique is currently seen as important within the field of nanomaterials. In the present review, we describe the methods that allow tuning of the intermolecular interactions between spin crossover (SCO) complexes in various media. These approaches include the use of lipophilic derivatives, lipids, and diblock copolypeptide amphiphiles. The resulting supramolecular assemblies can enhance the solubility of various SCO complexes in both organic and aqueous media. In addition, amphiphilic modifications of coordination systems can result in metastable structures and dynamic structural transformations leading to unique solution properties, including spin state switching. The supramolecular chemistry of metal complexes is unprecedented in its scope and potential applications, and it is hoped that the studies presented herein will promote further investigation of dynamic supramolecular devices.

Highlights

The self-assembly and integration of functional metal complexes has attracted significant attention due to the potential for the development of useful molecular systems [1]
We briefly describe the chemical structures and properties that result in flexible supramolecular systems, focusing on the use of lipophilic amphiphiles [27], lipid amphiphiles (Figure 1b) [29], and diblock copolypeptide amphiphiles (Figure 1c) [36,37]
Flexible metal complexes such asa these undergo a variety of organic interactions with organic media, organic molecules, as these undergo variety of interactions with media, organic molecules, and liquid crystals, complexes such as these undergo a variety of interactions with organic media, organic molecules, and liquid crystals, the present review examines coordination structures, magnetic and present reviewand examines the coordination structures,the magnetic properties, and morphological and the liquid crystals, and the present review examines the coordination structures, magnetic properties, and morphological dynamism of these complexes

Summary

Introduction

The self-assembly and integration of functional metal complexes has attracted significant attention due to the potential for the development of useful molecular systems [1]. To date, almost all supramolecular systems based on low-dimensional compounds have relied on strong interactions such as covalent bonding and coordination, and the properties of the resulting supramolecules have been similar to those of the original metal complexes in the solid state (Figure 1a). Our group developed a flexible supramolecular system composed of metal complexes, using both lipophilic and amphiphilic compounds [24,25,26,27,28,29,30,31,32,33,34,35] (Figure 1b,c) This system exhibited tunable, metastable properties, such as the formation of heat-set gel-like networks [25,26] and supramolecular SCO via adaptive molecular clefts [27], that are not observed in the solid state. AndLipid nm are assigned completely reversible upon temperature cycling

Acomplex

20 K compared toKthat of the solid value

Self-Assembly of Metal Complexes with Diblock Copolypeptide Amphiphiles

Co-Terpyridine

Fe-Complexes with Diblock Copolypeptide Amphiphiles

Conclusions