Synthesis of a xanthene-based macrocyclic imine ligand and two-step planarization by metalation with Ni and Na.

A xanthene-based macrocyclic π-containing imine ligand, HL, was newly designed and synthesized in order to obtain a series of metal-containing planar structures. Due to the xanthene framework with the methylene bridge, the macrocyclic molecule, HL, had a more planar structure than the corresponding diaryl-ether-type analogue, HL. This macrocyclic molecule, HL, was converted into the dinuclear nickel(II) complex, LNi, which was characterized by spectroscopic techniques as well as crystallography.

Older adults' autobiographical memories of their youth return when interviewed by children: Applications to reminiscence therapy and dementia prevention.

Previous studies found that older adults recall autobiographical memories from their 20s and 30s. Sakata (2023) reported that child interviewers increased older adults' childhood memories using a between-participant design. This study confirms the effect's validity in a within-participant design and suggests its application in reminiscence therapy and dementia prevention.

Novel Helical Metallocryptand for Size-Selective Recognition of Amino Acid Derivatives with Aliphatic Side Chains.

The novel tris(salen)-type metallocryptand, LNi, was designed and synthesized. Its crystallographic analysis revealed the presence as a helical enantiomeric pair, right-handed (P) and left-handed (M) forms, rather than the meso form, which was energetically supported by density functional theory (DFT) calculations. This LNi host was capable of recognizing amino acid derivatives by several non-covalent interactions, showing a selectivity to those bearing an aliphatic side chain.

Tuning of Guest Uptake/Release Kinetics of a Dinuclear Cobalt(III) Metallohost by Auxiliary Amine Ligands.

A series of dicobalt(III) metallohosts, [LCoA](OTf), which have different auxiliary amine ligands A (=EtNH, PhCHNH, PhCHNH, PhCHNH), were synthesized in order to investigate the tuning of the guest uptake/release kinetics without significantly affecting the guest binding affinity. The metallohosts were characterized by spectroscopic methods and X-ray crystallography. All the metallohosts showed a Na selectivity among the investigated alkali meal ions with a clear selectivity trend of Na>K>Rb>Cs.

Preferential Formation of Three-layered Host-Guest Complexes of a Planar Dinuclear Metallohost with Alkali Metal Ions.

We synthesized a planar macrocyclic dinuclear nickel(II) metallohost from the corresponding macrocyclic imine ligand containing two NO chelate coordination sites and an O cation binding site like 18-crown-6 as well as peripheral hexyl groups. Due to the lipophilic nature of the hexyl groups, the metallohost was soluble in less polar media where its interaction with alkali metal ions was enhanced. The binding studies by NMR spectroscopy clearly showed its strong tendency to form multi-layered structures.

Non-threaded and rotaxane-type threaded wheel-axle assemblies consisting of dinickel(II) metallomacrocycle and dibenzylammonium axle.

Rotaxanes are typically prepared using covalent bonds to trap a wheel component onto an axle molecule, and rotaxane-type wheel-axle assembly using only noncovalent interactions has been far less explored. Here we show that a dinickel(II) metallomacrocycle forms two different types of wheel-axle assemblies with a dibenzylammonium axle molecule based only on noncovalent interactions. The non-threaded assembly was obtained by introduction of Ni into the macrocycle before the complexation with the axle molecule (metal-first method).

Induced chirality at the surface: fixation of a dynamic / invertible helical Co complex on SiO.

Dynamic / invertible helicity was successfully induced at a SiO surface immobilized with a dynamic helical trinuclear cobalt complex, [LCo(NHMe)](OTf), using chiral (() or ())-1-phenylethylamine. Solid-state CD spectra and theoretical calculations suggested that the fixation of the / helical complex on the surface coordination interactions was the key factor of the induced chirality at the surface.

Effects of Interviewer Age on the Reminiscence Bump in Older adults' Autobiographical Memories.

Introduction: This study aims to investigate whether the reminiscence bump in older adults' autobiographical memory is influenced by the interviewer's age. Methods: I arranged four interviewer.

Conditions: child, university student, middle-aged adult, and older adult.

Speed Tuning of the Formation/Dissociation of a Metallorotaxane.

Switching between the formation/dissociation of rotaxanes is important to control the function of various types of rotaxane-based materials. We have developed a convenient and simple strategy, the so-called "accelerator addition", to make a static rotaxane dynamic without apparently affecting the chemical structure. As an interlocked molecule that enables tuning of the formation/dissociation speed, a metallorotaxane was quantitatively generated by the complexation of a triptycene-based dumbbell-shaped mononuclear complex, [PdL ] (L=2,3-diaminotriptycene), with 27C9.

Synthesis of amphiphilic chiral salen complexes and their conformational manipulation at the air-water interface.

A series of amphiphilic salen complexes, [L1a,bM] and [L2a,bM], were designed and synthesized. These complexes consist of two or four hydrophilic triethylene glycol (TEG) chains and a hydrophobic π-extended metallosalen core based on naphthalene or phenanthrene. The obtained amphiphilic complexes, [L1bM] (M = Ni, Cu, Zn), formed a monolayer at the air-water interface, while the monocationic [L1bCo(MeNH)](OTf) did not form a well-defined monolayer.

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 -alkane guest vapors. We observed that a macrocyclic host compound pillar[5]arene with the CF fluoroalkyl groups changes from the crystalline to the amorphous state (molecular glass) by heating above its melting point and then cooling to room temperature.

Transient chirality inversion during racemization of a helical cobalt(III) complex.

SignificanceWe first observed a transient chirality inversion on a simple unimolecular platform during the racemization of a chiral helical complex [LCo], i.e., the helicity changed from -rich (right-handed) to -rich (left-handed), which then racemized to a / equimolar mixture in spite of the absence of a reagent that could induce the helix.

Metal-dependent selective formation of calix[4]arene assemblies based on dynamic covalent chemistry.

The reaction of calix[4]arene derivatives 1a and 1b bearing four salicylaldehyde moieties with 1,3-propanediamine gave macrocyclic trimers 5a and 5b, respectively, which have intramolecular bridges formed the conformation. In contrast, a capsular-shaped dimeric cage [7a·2Na] was selectively formed when the conformation of the calix[4]arene moiety of 1a was fixed in the conformation by complexation with Na at the lower-rim amide groups.

Rhodium(I) Complexes Bearing an Aryl-Substituted 1,3,5-Hexatriene Chain: Catalysts for Living Polymerization of Phenylacetylene and Potential Helical Chirality of 1,3,5-Hexatrienes.

Unique bench-stable rhodium(I) complexes bearing an aryl-substituted 1,3,5-hexatriene chain have been synthesized by reactions of (bicyclo[2.2.1]hepta-2,5-diene)rhodium(I) chloride dimer ([Rh(nbd)Cl] ) with aryl boronic acids and diphenylacetylenes in the presence of a 50 % aqueous solution of KOH.

A chiral spirobifluorene-based bis(salen) zinc(ii) receptor towards highly enantioselective binding of chiral carboxylates.

We have designed a new chiral receptor based on two salen zinc(ii) complex units connected with a spirobifluorene framework. The chiral receptor is proven to enantioselectively bind chiral carboxylate guests and the differences between the binding constants of enantiomeric guests were up to more than one order of magnitude.

Guest Recognition Control Accompanied by Stepwise Gate Closing and Opening of a Macrocyclic Metallohost.

Host-guest binding behavior of macrocyclic hosts is significantly influenced by the shapes and sizes of the hosts. In particular, closing/opening the apertures of the hosts controls the guest uptake/release. A post-metalation modification method was used to achieve the open/close conversions.

Efficient formation of [3]pseudorotaxane based on cooperative complexation of dibenzo-24-crown-8 with diphenylviologen axle.

A novel cooperative [3]pseudorotaxane system consisting of dibenzo-24-crown-8 (DB24C8) and diphenylviologen axle has been developed. The two-step formation of the [3]pseudorotaxane occurred in a positive-cooperative manner. The corresponding [3]rotaxane was successfully obtained from just a stoichiometric mixture of each component by end-capping without dissociation.

Post-Metalation Modification of a Macrocyclic Dicobalt(III) Metallohost by Site-Selective Ligand Exchange for Guest Recognition Control.

We propose post-metalation modification as a useful strategy to control the guest recognition behavior of a metal-containing macrocyclic host. This is based on the ligand exchange of the axial ligands of a cobalt(III) dinuclear macrocyclic host, [LCo X ] (X=axial amine ligand). Four piperidine ligands in [LCo (pip) ] (pip=piperidine) were site-selectively replaced with primary amines.

Non-Covalent Interactions Enable the Length-Controlled Generation of Discrete Tubes Capable of Guest Exchange.

Supramolecular chemistry in confined spaces constructed from macrocyclic molecules has attracted much attention because it can utilize the specific binding properties of macrocyclic cavities. Herein we report the preparation of length-controlled discrete tubular structures by homo-/co-assembly of rim-differentiated and peralkylamino-substituted pillar[5]arenes via hydrogen bonds and salt bridges. By dimerization and trimerization, the expanded tubes show a fivefold helical structure and stepwise binding, respectively.

ON/OFF Control of the Flipping Motion of Diuranyl Bis(Salophen) Macrocycle by Extremely Strong Binding with Fluoride Ion.

Diuranyl bis(salophen) complex features a relatively slow conformational motion, induced by an intramolecular O═U═O···UO binding motif, which interconverts the two nonsymmetric halves of the ligand. This flipping motion, which constitutes one of the fundamental molecular motions, can be completely halted by addition of fluoride anion, which is bound to , reaching one of the highest affinities reported to date. This system represents a model to study flipping dynamics in light of the possibility of developing novel types of molecular machines based on it.

Switching of and Mechanisms in Host-Guest Binding Associated with Chemical Reactions.

Host-guest binding sometimes triggers the subsequent chemical reactions of the host framework as well as changes in the physical properties. Since the host-guest binding generally occurs very quickly, it is sometimes difficult to differentiate the mechanism from the alternative one in which the guest binding occurs after the reaction. However, it is important to differentiate the two mechanisms when we develop new molecules based on time-dependent functions.

Molecular weight fractionation by confinement of polymer in one-dimensional pillar[5]arene channels.

Confinement of polymers in nano-spaces can induce unique molecular dynamics and properties. Here we show molecular weight fractionation by the confinement of single polymer chains of poly(ethylene oxide) (PEO) in the one-dimensional (1D) channels of crystalline pillar[5]arene. Pillar[5]arene crystals are activated by heating under reduced pressure.

Ligand Exchange Strategy for Tuning of Helicity Inversion Speeds of Dynamic Helical Tri(saloph) Metallocryptands.

We developed a new strategy, ligand exchange strategy, for tuning the response speeds of helicity inversion of a metal-containing helical structure. This is based on the exchange of the two axial amine ligands of the octahedral Co centers in the metallocryptands [LCo X ] (X=axial amine ligand). The response speeds of the helicity induction were controlled by using different combinations of achiral and chiral amines as the starting and entering ligands, respectively.

Host-Guest Complexation Using Pillar[5]arene Crystals: Crystal-Structure Dependent Uptake, Release, and Molecular Dynamics of an Alkane Guest.

Host-guest complexation has been mainly investigated in solution, and it is unclear how guest molecules access the assembled structures of host and dynamics of guest molecules in the crystal state. In this study, we studied the uptake, release, and molecular dynamics of n-hexane vapor in the crystal state of pillar[5]arenes bearing different substituents. Pillar[5]arene bearing 10 ethyl groups yielded a crystal structure of herringbone-type 1:1 complexes with n-hexane, whereas pillar[5]arene with 10 allyl groups formed 1:1 complexes featuring a one-dimensional (1D) channel structure.

Metallonanobelt: A Kinetically Stable Shape-Persistent Molecular Belt Prepared by Reversible Self-Assembly Processes.

A triptycene-based shape-persistent belt-shaped macrocycle, metallonanobelt, was synthesized by the self-assembly of 2,3,6,7-tetraaminotriptycene L and square planar Pd. The pentamer was selectively formed by the complexation of L with Pd in the presence of the pillar[6]arene derivative P6 having triethylene glycol pendant as a template, whereas a mixture of a trimer, tetramer, and pentamer was obtained in the absence of the template. The pentamer was successfully isolated based on the solubility difference between the metallonanobelt and the template.