Spin dynamics phenomena of a cerium(III) double-decker complex induced by intramolecular electron transfer.

Switchable spin dynamic properties in single-molecule magnets (SMMs) via an applied stimulus have applications in single-molecule devices. Many SMMs containing heavy lanthanoid ions with strong uniaxial magnetic anisotropy have been reported to exhibit SMM characteristics in the absence of an external magnetic field. On the other hand, SMMs containing light lanthanoid cerium(III) (Ce3+) ions exhibit field-induced slow magnetic relaxation. We investigated the chemical conversion of a diamagnetic Ce4+ ion (4f0) to a paramagnetic Ce3+ ion (4f1) in Ce-phthalocyaninato double-decker complexes (TBA+[Ce(obPc)2]- (1) and TBA+[Ce(Pc)2]- (2)) which exhibit field-induced SMM behaviour due to a 4f1 system. The phthalocyaninato ligands with electron-donating substituents (obPc2- = 2,3,9,10,16,17,23,24-octabutoxyphthalocyaninato) in 1 have a significant effect on the valence state of the Ce ion, which is reflected in its magnetic properties due to the mixed valence state of the Ce ion. Given that Ce double-decker complexes with π-conjugated ligands undergo intramolecular electron transfer (IET) to the Ce ion mixed valence state, characterised by a mixture of 4f0 and 4f1 configurations, we examined the dynamic disorder inherent in IET influencing magnetic relaxation.

Control of the Magnetic Interaction between Single-Molecule Magnet TbPc2 and Superconductor NbSe2 Surface by an Intercalated Co Atom.

We demonstrate that an intercalated Co atom in superconductor NbSe2 could control the magnetic interaction between the adsorbed magnetic molecule of TbPc2 and the NbSe2 substrate. An intercalated Co atom enhances the magnetic interaction between the NbSe2 and the TbPc2 spin to cause Kondo resonance at the TbPc2 position, a spin-singlet state formed by the itinerary electron. By applying a surface-normal magnetic field, we change the molecule's spin direction from the initial one directed to the Co atom to the surface normal. The change appears as a split Kondo resonance at the TbPc2, one of which is enhanced at the Tb site, which disappears when the outer magnetic field normal to the surface is applied and never appears, even if we return B to 0 T. The phenomenon suggests that the intercalated magnetic atoms can control the magnetic interaction between a magnetic molecule and the superconductor NbSe2.

The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: allergen exposure, epidemiology, and diagnosis of anaphylaxis during general anaesthesia.

BACKGROUND: Diagnosis of perioperative anaphylaxis is often challenging. This study describes the utility of a newly developed tool for identifying patients with a high possibility of anaphylaxis, and aimed to investigate the frequency of anaphylaxis with each drug during the perioperative period in Japan. METHODS: This study included patients with anaphylaxis of Grade 2 or higher severity during general anaesthesia at 42 facilities across Japan in 2019 and 2020. We developed and adopted a unique objective evaluation tool yielding a composite score for diagnosing anaphylaxis, which includes the results of skin tests and basophil activation tests, and clinical scores for perioperative anaphylaxis. The number of cases using each drug and the total number of anaphylaxis cases were investigated to calculate the frequency of anaphylaxis. RESULTS: General anaesthesia was performed in 218 936 cases, which included 55 patients with suspected perioperative anaphylaxis. The developed composite score diagnosed 43 of them with a high probability of anaphylaxis. The causative agent was identified in 32 cases. Plasma histamine levels showed high diagnostic accuracy for anaphylaxis. The top causative agents were rocuronium (10 cases in 210 852 patients, 0.005%), sugammadex (7 cases in 150 629 patients, 0.005%), and cefazolin (7 cases in 106 005 patients, 0.007%). CONCLUSIONS: We developed a composite tool to diagnose anaphylaxis, and found that the combination of tryptase levels, skin testing, and basophil activation testing results and clinical score improved the certainty of anaphylaxis diagnosis. The incidence of perioperative anaphylaxis in our study was 1 in about 5000 general anaesthesia cases. CLINICAL TRIAL REGISTRATION: UMIN000035350.

Spatially Resolving Electron Spin Resonance of π-Radical in Single-molecule Magnet.

The spintronic properties of magnetic molecules have attracted significant scientific attention. Special emphasis has been placed on the qubit for quantum information processing. The single-molecule magnet bis(phthalocyaninato (Pc)) Tb(III) (TbPc2) is one of the best examined cases in which the delocalized π-radical electron spin of the Pc ligand plays the key role in reading and intermediating the localized Tb spin qubits. We utilized the electron spin resonance (ESR) technique implemented on a scanning tunneling microscope (STM) and use it to measure local the ESR of a single TbPc2 molecule decoupled from the Cu(100) substrate by a two-monolayer NaCl film to identify the π-radical spin. We detected the ESR signal at the ligand positions under the resonance condition expected for an S = 1/2 spin. The results reveal that the π-radical electron is delocalized within the ligands and exhibits intramolecular coupling susceptible to the chemical environment.

Rare-earth based tetrapyrrolic sandwiches: chemistry, materials and applications.

The unique properties of natural tetrapyrrolic compounds have inspired the rapid growth of research interest in the design and synthesis of artificial porphyrinoids and their metal complexes as a basis of modern functional materials. A special role in the design of such materials is played by sandwich complexes formed by tetrapyrrolic macrocycles with rare earth elements, especially lanthanides. The development of synthetic approaches to the functionalization of tetrapyrrolic compounds and their rare earth complexes has facilitated the intensive development of new applications over the last decade. As a way of expanding the functionalities of rare earth complexes, sophisticated examples have been obtained, including mixed-ligand complexes, π-extended analogues, covalently linked and fused sandwiches, complexes with less-common tetrapyrrols, sandwiches with non-tetrapyrrolic macrocycles and even complexes containing up to six stacked ligands. This review intends to offer a general overview of the preparation of such sophisticated REE tetrapyrrolic sandwiches over the last decade as well as emphasizes the current challenges and perspectives of their application in areas such as single-molecule magnetism (SMM), organic field-effect transistors (OFET), conductive materials and nonlinear optics (NLO).

Observation of Yu-Shiba-Rusinov States and Inelastic Tunneling Spectroscopy for Intramolecule Magnetic Exchange Interaction Energy of Terbium Phthalocyanine (TbPc) Species Adsorbed on Superconductor NbSe2.

We investigated the spin properties of the terbium phthalocyanine (TbPc) species adsorbed on the superconductor NbSe2 surface using scanning tunneling microscopy and spectroscopy. TbPc2 is a molecule in a class of single-molecule magnets (SMMs), and the use of superconductor electrodes attracts attention for the application to the devices using the spin degree of freedom. TbPc is a building block of TbPc2 and can reveal the spin component's behavior. In the experiment, TbPc species were placed on the surface of the superconductor NbSe2. We measured Yu-Shiba-Rusinov (YSR) states caused by the interaction between the superconducting state and magnetic impurity and inelastic tunneling spectroscopy (IETS) for the spin excitation, below 1 K. We also measured the Kondo state formed by the magnetic singlet formation. We detected the radical spin at the ligand position of the TbPc by the presence of the Kondo peak and demonstrated that the radical spin forms the YSR feature. In addition, the exchange interaction energy (Eex) between the spins of the radical ligand (Pc) and the center 4f metal atom (Tb3+) is determined by using the IETS technique. Eex is a critical parameter that determines the blocking temperature, below which the sample behaves as an SMM. IETS results show that the statistical distribution of Eex has peaked at 1.3, 1.6, and 1.9 meV. The energy range is comparable to the recent theoretical calculation result. In addition, we show that the energy variation is correlated with the bonding configuration of TbPc.

Comparison between DySc2N@C80 and Dy2ScN@C80 single-molecule magnetic metallofullerenes encapsulated in single-wall carbon nanotubes.

Encapsulation of a metallofullerene single-molecule magnet, Dy2ScN@C80, into single-wall carbon nanotubes (SWCNTs) accelerates magnetic relaxation processes. In contrast, encapsulation of DySc2N@C80 suppresses them. The effects of the encapsulation are discussed in terms of intermolecular magnetic interactions and charge transfer among metallofullerenes and SWCNTs.

Structural, magnetic and theoretical analyses of anionic and cationic phthalocyaninato-terbium(III) double-decker complexes: magnetic relaxation via higher ligand-field sublevels enhanced by oxidation.

Crystal structural and magnetic analyses were performed for the anionic (1-) and cationic (1+) forms of phthalocyaninato-Tb3+ double-decker single-molecule magnets (SMMs). Both charged species showed slow magnetic relaxations and magnetic hysteresis characteristics for SMMs. 1+ showed longer magnetic relaxation times (τ) and higher activation energy for spin reversal (ΔE) than 1- did. Ligand field (LF) splitting calculated using ab initio methods revealed that the experimental ΔE values in 1- and 1+ were considerably larger than the first excited LF levels but rather close to the higher excited ones, indicating the magnetic relaxation via higher excited states.

Electro-Conductive Single-Molecule Magnet Composed of a Dysprosium(III)-Phthalocyaninato Double-Decker Complex with Magnetoresistance.

A one-dimensional (1D) arrangement of an unsubstituted partially oxidized Dy3+ double-decker complex, [DyPc2 ]Ix (Pc=phthalocyaninato, I=iodide; 1.93

Survey on Specialty Preference and Work-Life Balance among Residents of Japanese Red Cross Hospitals.

INTRODUCTION: The paucity and maldistribution of physicians among various specialties are key issues facing the Japanese health care system. Studies have shown that young physicians place more emphasis on work-life balance while selecting their specialty and that they prefer controllable lifestyle (CL) specialties over noncontrollable lifestyle (NCL) specialties. As this may be a cause of maldistribution, we investigated the relationship between views on work-life balance and specialty selection among young physicians in Japan. METHODS: An online questionnaire was sent to 1451 residents (postgraduate years 1-5) at 60 Japanese Red Cross hospitals across Japan. RESULTS: In all, 226 physicians responded (response rate: 15%), with 21% in CL and 74% in NCL specialties. When compared with NCL specialties, CL specialties had less overtime (43% vs. 16%, p = 0.001), considered life to be more important than work (26% vs. 15%, p = 0.018), and were more likely to give precedence to work-life balance over medical interest while choosing their specialty (49% vs. 30%, p < 0.001). Furthermore, physicians were more likely to change their choice of specialty, contrary to their professional interest, because of social reasons (49% vs. 26%, p = 0.007). CONCLUSIONS: Our study suggests that young physicians in CL specialties have better working hours and place more emphasis on work-life balance while choosing their specialty compared with those in NCL specialties. The increase in the number of physicians in CL specialties is likely attributable to the growing preference for an optimal work-life balance among young physicians; this seems to have increased the maldistribution of physicians among various specialties. Institutional mechanisms to support the lifestyle of physicians (especially in NCL specialties) are required to provide a balanced medical service in Japan.

Cocrystals of Li+ encapsulated fullerenes and Tb(iii) double-decker single molecule magnet in a quasi-kagome lattice.

Cocrystallization of a lithium ion encapsulated fullerene Li+@C60 with a terbium(iii) phthalocyaninato porphyrinato double-decker single-molecule magnet [Tb(Pc)(OEP)] is reported. The cocrystal, containing PF6- as a counter anion, packs in a quasi-kagome lattice, which leads to intermolecular ferromagnetic interactions as well as the modulation of the single-molecule magnet (SMM) properties.

Highly Oxidized States of Phthalocyaninato Terbium(III) Multiple-Decker Complexes Showing Structural Deformations, Biradical Properties and Decreases in Magnetic Anisotropy.

Presented here is a comprehensive study of highly oxidized multiple-decker complexes composed of TbIII and CdII ions and two to five phthalocyaninato ligands, which are stabilized by electron-donating n-butoxy groups. From X-ray structural analyses, all the complexes become axially compressed upon ligand oxidation, resulting in bowl-shaped distortions of the ligands. In addition, unusual coexistence of square antiprism and square prism geometries around metal ions was observed in +4e charged species. From paramagnetic 1 H NMR studies on the resulting series of triple, quadruple and quintuple-decker complexes, ligand oxidation leads to a decrease in the magnetic anisotropy, as predicted from theoretical calculations. Unusual paramagnetic shifts were observed in the spectra of the +2e charged quadruple and quintuple-decker complexes, indicating that those two species are actually unexpected triplet biradicals. Magnetic measurements revealed that the series of complexes show single-molecule magnet properties, which are controlled by the multi-step redox induced structural changes.

Coexistence of Spin-Lattice Relaxation and Phonon-Bottleneck Processes in GdIII -Phthlocyaninato Triple-Decker Complexes under Highly Diluted Conditions.

Gd3+ complexes have been shown to undergo unusual slow magnetic relaxation processes similar to those of single-molecule magnets (SMMs), even though Gd3+ does not exhibit strong magnetic anisotropy. To reveal the origin of the slow magnetic relaxation of Gd3+ complexes, we have investigated the magnetic properties and heat capacities of two Gd3+ -phthalocyaninato triple-decker complexes, one of which has intramolecular Gd3+ -Gd3+ interactions and the other does not. It was found that the Gd3+ -Gd3+ interactions accelerate the magnetic relaxation processes. In addition, magnetically diluted samples, prepared by doping a small amount of the Gd3+ complexes into a large amount of diamagnetic Y3+ complexes, underwent dual magnetic relaxation processes. A detailed dynamic magnetic analysis revealed that the coexistence of spin-lattice relaxation and phonon-bottleneck processes is the origin of the dual magnetic relaxation processes.

Manipulation of the Coordination Geometry along the C4 Rotation Axis in a Dinuclear Tb3+ Triple-Decker Complex via a Supramolecular Approach.

A supramolecular complex (1⋅C60 ) was prepared by assembling (C60-Ih)[5,6]fullerene (C60 ) with the dinuclear Tb3+ triple-decker complex [(TPP)Tb(Pc)Tb(TPP)] (1: Tb3+ =trivalent terbium ion, Pc2- =phthalocyaninato, TPP2- =tetraphenylporphyrinato) with quasi-D4h symmetry to investigate the relationship between the coordination symmetry and single-molecule magnet (SMM) properties. Tb3+ -Pc triple-decker complexes (Tb2 Pc3 ) have an important advantage over Tb3+ -Pc double-decker complexes (TbPc2 ) since the magnetic relaxation processes correspond to the Zeeman splitting when there are two 4f spin systems. The two Tb3+ sites of 1 are equivalent, and the twist angle (φ) was determined to be 3.62°. On the other hand, the two Tb3+ sites of 1⋅C60 are not equivalent. The φ values for sites Tb1 and Tb2 were determined to be 3.67° and 33.8°, respectively, due to a change in the coordination symmetry of 1 upon association with C60 . At 1.8 K, 1 and 1⋅C60 undergo different magnetic relaxations, and the changes in the ground state affect the spin dynamics. Although 1 and 1⋅C60 relax via QTM in a zero applied magnetic field (H), H dependencies of the magnetic relaxation times (τ) for H>1500 Oe are similar. On the other hand, for H<1500 Oe, the τ values have different behaviors since the off-diagonal terms ( B k q ; q ≠ 0 ) affect the magnetic relaxation mechanism. From temperature (T) and H dependences of τ, spin-phonon interactions along with direct and Raman mechanisms explain the spin dynamics. We believe that a supramolecular method can be used to control the magnetic anisotropy along the C4 rotation axis and the spin dynamic properties in dinuclear Ln3+ -Pc multiple-decker complexes.

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7',8,8'-Tetracyano-p-quinodimethane.

Invited for the cover of this issue are Ryuta Ishikawa and Satoshi Kawata at Fukuoka University and co-workers at Osaka University, Tohoku University, and Kumamoto University, Japan, collaborating within the research project "SOFT CRYSTALS". The image depicts the thermally induced simultaneous switching of magnetism and electrical conductivity in a two-dimensional supramolecular architecture composed of dinuclear FeII spin-crossover complexes and partially charged 7,7',8,8'-tetracyano-p-quinodimethanide radicals. 10.1002/chem.201903934.

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7',8,8'-Tetracyano-p-quinodimethane.

The reaction of Fe(OAc)2 and Hbpypz with neutral TCNQ results in the formation of [Fe2 (bpypz)2 (TCNQ)2 ](TCNQ)2 (1), in which Hbpypz=3,5-bis(2-pyridyl)pyrazole and TCNQ=7,7',8,8'-tetracyano-p-quinodimethane. Crystal packing of 1 with uncoordinated TCNQ and π-π stacking of bpypz- ligands produces an extended two-dimensional supramolecular coordination assembly. Temperature dependence of the dc magnetic susceptibility and heat capacity measurements indicate that 1 undergoes an abrupt spin crossover (SCO) with thermal spin transition temperatures of 339 and 337 K for the heating and cooling modes, respectively, resulting in a thermal hysteresis of 2 K. Remarkably, the temperature dependence of dc electrical transport exhibits a transition that coincides with thermal SCO, demonstrating the thermally induced magnetic and electrical bistability of 1, strongly correlating magnetism with electrical conductivity. This outstanding feature leads to thermally induced simultaneous switching of magnetism and electrical conductivity and a magnetoresistance effect.

Detailed Analysis of the Crystal Structures and Magnetic Properties of a Dysprosium(III) Phthalocyaninato Sextuple-Decker Complex: Weak f-f Interactions Suppress Magnetic Relaxation.

In the research field of single-molecule magnets (SMMs), lanthanoid-lanthanoid interactions, so-called f-f interactions, are known to affect the SMM properties, although their magnitudes are small. In this article, an SMM with very weak f-f interactions is reported, and the effects of the interactions on the SMM properties are discussed. X-ray structural analysis of the DyIII -CdII -phthalocyaninato sextuple-decker complex (Dy2 Cd3 ) reveals that the intramolecular Dy-Dy length in Dy2 Cd3 is more than 13 Å, which is longer than the intermolecular Dy-Dy length. Even though the two DyIII ions are far apart, intermolecular ferromagnetic dipole-dipole interactions are observed in Dy2 Cd3 . From detailed analysis of ac magnetic susceptibilities, quantum tunneling of the magnetization (QTM) in Dy2 Cd3 is partially suppressed owing to the existence of very weak Dy-Dy interactions. Our results show that even very weak Dy-Dy interactions act as a dipolar bias, suppressing QTM.

Tetranuclear Dysprosium(III) Quintuple-Decker Single-Molecule Magnet Prepared Using a π-Extended Phthalocyaninato Ligand with Two Coordination Sites.

The magnetic properties and spin relaxation processes of a tetranuclear dysprosium(III) fused phthalocyaninato (Pc4- ) quintuple-decker single-molecule magnet (SMM) (1) with non-equivalent octa-coordination geometries are reported. The structure of 1 is regarded as a dimer of Dy3+ -Pc triple-decker SMMs with different magnetic relaxation characteristics, corresponding to the octa-coordination geometry sites Dy1 with C4 symmetry (ϕ1 =23°) and Dy2 with D4d symmetry (ϕ2 =45°). In an Hdc of 1750 Oe and T range of 1.8-3.75 K, the quantum tunnelling of the magnetization was suppressed, and the direct process was enhanced. The effects of the coordination geometry on the spin relaxation phenomena are examined.

DySc2N@C80 Single-Molecule Magnetic Metallofullerene Encapsulated in a Single-Walled Carbon Nanotube.

DySc2N@C80 is an endohedral metallofullerene showing single-molecule magnet (SMM) behavior. In this work, we encapsulated DySc2N@C80-SMMs into the internal one-dimensional nanospace of single-walled carbon nanotubes (SWCNTs). Using transmission electron microscopy, "peapod" structures were clearly observed. From magnetic field dependent measurements, DySc2N@C80 showed stepwise hysteresis characteristic of SMMs even inside the SWCNTs, and the coercivity increased from 0.5 to 4 kOe. In addition, it showed slow relaxation of the magnetization without an applied external magnetic field. This system is the first example where SMMs have been encapsulated in SWCNTs, and this system could be used in future molecular-spintronics devices.