Coordination Programming: Science of Molecular Superstructures for Chemical Devices

金沢大学理工学域物質科学系本研究では、新規なハイブリッド型金属錯体ナノチューブの構成要素となり得る円筒型化合物とその関連化合物の構築を目指した研究を行った。構成要素としてペンタセンキノンを用いた系では、クラウンエーテルとアルカリ金属イオンとの錯形成を利用した大環状自己集合錯体の構築を行った。ペンタセンキノンに二つの15-クラウン-5部位を導入した分子を合成し、これとカリウムイオン、ルビジウムイオン、セシウムイオンを錯形成させたところ、大環状の2:2型錯体が定量的に生成した。すなわち、扁平なチューブの構成要素となる大環状構造を簡単な手法で効率的に得ることに成功した。さらに、チューブの三つ又分岐部に相当する構造の構成要素となり得るカゴ型メタロホスト分子の合成を行い、その特異なゲスト認識能を明らかにした。研究課題/領域番号:24108707, 研究期間(年度):2012-04-01 – 2014-03-3

Response speed control of helicity inversion based on a “regulatory enzyme”-like strategy

In biological systems, there are many signal transduction cascades in which a chemical signal is transferred as a series of chemical events. Such successive reaction systems are advantageous because the efficiency of the functions can be finely controlled by regulatory enzymes at an earlier stage. However, most of artificial responsive molecules developed so far rely on single-step conversion, whose response speeds have been difficult to be controlled by external stimuli. In this context, developing artificial conversion systems that have a regulation step similar to the regulatory enzymes has been anticipated. Here we report a novel artificial two-step structural conversion system in which the response speed can be controlled based on a regulatory enzyme-like strategy. In this system, addition of fluoride ion caused desilylation of the siloxycarboxylate ion attached to a helical complex, resulting in the subsequent helicity inversion. The response speeds of the helicity inversion depended on the reactivity of the siloxycarboxylate ions; when a less-reactive siloxycarboxylate ion was used, the helicity inversion rate was governed by the desilylation rate. This is the first artificial responsive molecule in which the overall response speed can be controlled at the regulation step separated from the function step

State- and water repellency-controllable molecular glass of pillar[5]arenes with fluoroalkyl groups by guest vapors

Molecular glasses are low-molecular-weight organic compounds that are stable in the amorphous state at room temperature. Herein, we report a state- and water repellency-controllable molecular glass by n-alkane guest vapors. We observed that a macrocyclic host compound pillar[5]arene with the C₂F₅ fluoroalkyl groups changes from the crystalline to the amorphous state (molecular glass) by heating above its melting point and then cooling to room temperature. The pillar[5]arene molecular glass shows reversible transitions between amorphous and crystalline states by uptake and release of the n-alkane guest vapors, respectively. Furthermore, the n-alkane guest vapor-induced reversible changes in the water contact angle were also observed: water contact angles increased and then reverted back to the original state by the uptake and release of the n-alkane guest vapors, respectively, along with the changes in the chemical structure and roughness on the surface of the molecular glass. The water repellency of the molecular glass could be controlled by tuning the uptake ratio of the n-alkane guest vapor

Real-time chirality transfer monitoring from statistically random to discrete homochiral nanotubes

Real time monitoring of chirality transfer processes is necessary to better understand their kinetic properties. Herein, we monitor an ideal chirality transfer process from a statistically random distribution to a diastereomerically pure assembly in real time. The chirality transfer is based on discrete trimeric tubular assemblies of planar chiral pillar[5]arenes, achieving the construction of diastereomerically pure trimers of pillar[5]arenes through synergistic effect of ion pairing between a racemic rim-differentiated pillar[5]arene pentaacid bearing five benzoic acids on one rim and five alkyl chains on the other, and an optically resolved pillar[5]arene decaamine bearing ten amines. When the decaamine is mixed with the pentaacid, the decaamine is sandwiched by two pentaacids through ten ion pairs, initially producing a statistically random mixture of a homochiral trimer and two heterochiral trimers. The heterochiral trimers gradually dissociate and reassemble into the homochiral trimers after unit flipping of the pentaacid, leading to chirality transfer from the decaamine and producing diastereomerically pure trimers

Syntheses,Structures,and Applications of the Conformationally Frozen Isomers of Novel Bridged Calix[6]arenes

報告番号: 甲15014 ; 学位授与年月日: 2000-03-29 ; 学位の種別: 課程博士 ; 学位の種類: 博士(理学) ; 学位記番号: 博理第3778号 ; 研究科・専攻: 理学系研究科化学専

Dynamic Helicity Control of Oligo(salamo)-Based Metal Helicates

Much attention has recently focused on helical structures that can change their helicity in response to external stimuli. The requirements for the invertible helical structures are a dynamic feature and well-defined structures. In this context, helical metal complexes with a labile coordination sphere have a great advantage. There are several types of dynamic helicity controls, including the responsive helicity inversion. In this review article, dynamic helical structures based on oligo(salamo) metal complexes are described as one of the possible designs. The introduction of chiral carboxylate ions into Zn3La tetranuclear structures as an additive is effective to control the P/M ratio of the helix. The dynamic helicity inversion can be achieved by chemical modification, such as protonation/deprotonation or desilylation with fluoride ion. When (S)-2-hydroxypropyl groups are introduced into the oligo(salamo) ligand, the helicity of the resultant complexes is sensitively influenced by the metal ions. The replacement of the metal ions based on the affinity trend resulted in a sequential multistep helicity inversion. Chiral salen derivatives are also effective to bias the helicity; by incorporating the gauche/anti transformation of a 1,2-disubstituted ethylene unit, a fully predictable helicity inversion system was achieved, in which the helicity can be controlled by the molecular lengths of the diammonium guests

開閉機構をもつ新規なカゴ型錯体の合成と応答型物質捕捉・放出制御への応用

金沢大学新学術創成研究機構ナノ生命科学研究所本研究では、物質の取り込みと放出の速度を自在にコントロールできるような、新規な開閉型ホストの開発を行った。カゴ型トリス(saloph)および大環状ビス(saloph)配位子を独自に設計し、その配位サイトにコバルトを二つ導入した。カゴ型錯体については、開口部にヘキサンジアミン配位子を導入することで効果的にゲスト取り込み速度をコントロールできた。また、大環状錯体については、コバルト上のメチルアミン配位子が対アニオンとの結合部位として働き、そのキャッピング効果によって効果的にゲストが閉じ込められることがわかった。これを利用することで、オンデマンド型のゲスト交換を初めて実現できた。We aimed to develop new open/close mechanisms of host structures that can be used to control the guest uptake/release rates. We introduced cobalt(III) ions into the newly designed tris(saloph) cage and bis(saloph) macrocyclic host molecules. The introduction of hexanediamine ligands at the cage apertures efficiently suppressed the guest uptake into the cage cavity. In the case of the macrocyclic system, the counteranions at the capping sites efficiently reduced the guest uptake and exchange rates. By taking advantage of the slow guest uptake behavior, we developed a new on-demand type guest exchange system, in which the guest exchange can be accelerated by counteranion.研究課題/領域番号:26288022, 研究期間(年度):2014-04-01 - 2018-03-3

多環芳香族パネリングによるπ電子系多面体の合成と新規巨大フラーレンの探索

金沢大学新学術創成研究機構ナノ生命科学研究所分子全体が一つのパイ電子系となっているケージ状分子フラーレンと並ぶ新しいケージ状分子ファミリーの創出をめざして、多環芳香族炭化水素を正多面体型に組み合わせていく「多環芳香族パネリング」の手法を提案し、研究を行った。オール炭素骨格の多環芳香族炭化水素配位子に導入する配位部位としてビニル基やアリル基を用い、10族金属への配位を駆動力として自己集合を試みたが、多くの場合で複雑な混合物が生成した。エチニル基を導入した化合物との錯形成では各種サイズのオリゴマーが生成することがわかった。さらに、10族金属としてニッケルを含む各種環状構造の構築にも成功した。In this research, we proposed a new method "polycyclic aromatic paneling" in which self-assembly of polycyclic aromatic hydrocarbons are assembled into polyhedral structures. This would be useful to create a family of cage-like molecules that show electronic properties similar to those of conventional fullerenes. In order to make all-carbon framework, we designed aromatic compounds having vinyl or allyl groups as a coordination site and attempted the self-assembly driven by coordination to Group 10 metal. In many cases, however, the complexation gave complicated mixtures. In contrast, the complexation of compounds having ethynyl groups gave oligomers of various sizes. In addition, we succeeded in synthesizing various kinds of cyclic structures containing nickel(II) as Group 10 metal.研究課題/領域番号:15K13638, 研究期間(年度):2015-04-01 - 2017-03-3