Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 271
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
J Am Chem Soc ; 146(25): 17084-17093, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38861619

RESUMO

Boraphenalenes, compounds in which one carbon atom in the phenalenyl skeleton is replaced with a boron atom, have attracted attention for their solid-state and electronic structures; however, the construction of boraphenalene skeletons remains challenging because of the lack of suitable methods. Through this study, we showed that the tandem borylative cyclization of C3-symmetric dehydrobenzo[12]annulenes produces a new class of fully fused boron-atom-embedded polycyclic hydrocarbons possessing a 9b-boraphenalene skeleton. The obtained compounds exhibited high electron-accepting characteristics, and their two-step redox process was reversible in the reductive region, involving interconversion of 9b-boraphenalene between Hückel aromaticity and antiaromaticity. Notably, the benzo[b]fluorene-fused derivative exhibited a stepwise single-crystal-to-single-crystal (SCSC) phase transition triggered by thermal annealing. Intermolecular electron coupling calculation of the crystal structures suggested a significant improvement of charge transporting ability associated with the SCSC phase transition. Moreover, adequate photoconductivity was observed for the single crystals before and after the SCSC phase transition through flash photolysis-time-resolved microwave conductivity.

2.
J Am Chem Soc ; 146(25): 17428-17437, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38866732

RESUMO

Synthetic challenges toward anomalous structures and electronic states often involve handling problems such as insolubility in common organic solvents and oxidative degradation under aerobic conditions. We designed benzo-annulated aza[n]helicenes, which benefit from both the suppressed elevation of highest occupied molecular orbital (HOMO) energies and high solubility due to hydrogen bonding with solvent molecules to overcome these challenges. This strategy enabled the synthesis of six new aza[n]helicenes ([n]AHs) of different lengths (n = 9-19) from acyclic precursors via one-pot intramolecular oxidative fusion reactions. The structures of all of the synthesized aza[n]helicenes were determined by X-ray diffraction (XRD) analysis, and their electrochemical potentials were measured by cyclic voltammetry. Among the synthesized aza[n]helicenes, [17]AH and [19]AH are the first heterohelicenes with a triple-layered helix. The noncovalent interaction (NCI) plots confirm the existence of an effective π-π interaction between the layers. The absorption and fluorescence spectra red-shifted as the helical lengths increased, without any distinct saturation points. The optical resolutions of N-butylated [9]AH, [11]AH, [13]AH, and [15]AH were accomplished, and their circular dichroism (CD) and circularly polarized luminescence (CPL) were measured. Thus, the structural, (chir)optical, and electrochemical properties of the aza[n]helicenes were comprehensively analyzed.

3.
Circ Rep ; 6(6): 201-208, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38860182

RESUMO

Background: Takotsubo syndrome (TTS) in male patients is under-studied, particularly in the older population. Methods and Results: From 226 patients with TTS, 44 older male patients (prevalence rate: 19.5%, age: median 77 years) were compared with 182 older female patients (prevalence rate: 80.5%, age: median 80 years). Emotional triggers of TTS were less frequent (2% vs. 19%; P=0.007), whereas physical triggers were more frequent (75% vs. 58%; P=0.040) in older men than in women. Among physical triggers, serious respiratory infection was more common in older men than in women. As initial clues to the diagnosis, ECG T-wave inversion was more frequent (48% vs. 29%; P=0.018) and chest pain and/or dyspnea were less common (23% vs. 38%; P=0.050) in older men than in women. In total, 14 patients (6%) had cardiogenic shock and 41 (18%) had severe heart failure as complications, although there were no significant differences in the frequency of these complications between older men and women. Although cardiac death occurred in 3 female patients (1%) and noncardiac death in 3 male and 5 female patients (4%), there were no significant differences in death rate between older men and women. Conclusions: Emotional triggers of TTS were extremely infrequent whereas physical triggers were common in older men. Although severe heart failure was common, there were no significant differences in the frequency of complications and in-hospital deaths between older men and women.

4.
Cardiovasc Intervent Radiol ; 47(6): 730-740, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38816504

RESUMO

PURPOSE: In the present trial, the 24-month safety and effectiveness of the TCD-17187 drug-coated balloon (DCB) for the treatment of atherosclerotic lesions in the superficial femoral artery (SFA) and proximal popliteal artery (PA) were evaluated in Japanese patients. METHODS: This was a prospective, multicenter, core laboratory-adjudicated, single-arm trial. From 2019 to 2020, 121 patients with symptomatic peripheral artery disease were enrolled. The primary effectiveness outcome measure was primary patency. The safety outcome measure was the major adverse event (MAE) rate. RESULTS: Age was 74.5 ± 7.3 years, and diabetes mellitus was present in 67.5%. Lesion length and reference vessel diameter (RVD) were 106.0 ± 52.6 mm and 5.2 ± 0.8 mm, respectively. Chronic total occlusion (CTO) and bilateral calcification rate (Grade 3 and 4 by peripheral arterial calcium scoring system (PACSS)) were 17.5% and 50.8%, respectively. The 24-month primary patency rate by duplex ultrasound was 71.3%, while freedom from clinically driven target lesion revascularization (CD-TLR) was 87.0%. The MAE rate was 13.2% and all events consisted of CD-TLR. There were no instances of device- or procedure-related deaths major amputations throughout the 24 months. Multivariate Cox proportional hazards regression analysis revealed significant differences associated with loss of primary patency in the following characteristics: CTO, restenotic lesion and RVD. CONCLUSION: This trial confirmed the safety and effectiveness of TCD-17187 DCB for atherosclerotic lesions of the SFA and/or proximal PA for up to 24 months. LEVEL OF EVIDENCE: Level 3, Cohort study. CLINICAL TRIAL REGISTRATION: URL: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&recptno=R000038612&type=summary&language=J:Registration ID: UMIN000034122. Registration Date: September 13, 2018.


Assuntos
Angioplastia com Balão , Materiais Revestidos Biocompatíveis , Artéria Femoral , Doença Arterial Periférica , Artéria Poplítea , Grau de Desobstrução Vascular , Humanos , Masculino , Artéria Poplítea/diagnóstico por imagem , Feminino , Idoso , Artéria Femoral/diagnóstico por imagem , Estudos Prospectivos , Doença Arterial Periférica/terapia , Doença Arterial Periférica/diagnóstico por imagem , Angioplastia com Balão/métodos , Idoso de 80 Anos ou mais , Resultado do Tratamento , Japão
5.
Chem Sci ; 15(20): 7603-7609, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38784757

RESUMO

Norcorrole derivatives with 3,4,5-trialkoxyphenyl moieties at the meso positions were synthesized to form various stacking assemblies in single crystals and thermotropic liquid crystals (LCs) depending on aliphatic chain lengths. Triple-decker stacking structures were formed via the interactions between the antiaromatic systems formed for the butoxy and dodecyloxy derivatives in the single-crystal and LC states, respectively. In particular, the LC state exhibited discotic columnar structures comprising triple deckers to exhibit high electric conductivity, as supported by molecular dynamics simulations.

6.
Chem Commun (Camb) ; 60(31): 4190-4193, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38506762

RESUMO

Metal complexation and peripheral modifications of thiaporphyrins have been investigated for preparing polarized π-electronic cations with anion-dependent ion-pairing assembling modes, including charge-segregated structures exhibiting electric conductive properties.

7.
J Am Chem Soc ; 146(12): 8557-8566, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38484118

RESUMO

Alkylamide-substituted [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivative of BTBT-NHCOC14H29 (1), which has ferroelectric N-H···O= hydrogen-bonding network of alkylamide group and two-dimensional (2D) electric structure of BTBT π-cores, was prepared to design the external electric field-responsive organic semiconductors. The short-chain derivative of BTBT-NHCOC3H7 (1') revealed the coexistence of a 2D electronic band structure based on the herringbone BTBT arrangement and the one-dimensional (1D) hydrogen-bonding chain. 1 formed a smectic E (SmE) liquid crystal phase above 412 K and showed ferroelectric hysteresis in the electric field-polarization (P-E) curves at 403-433 K. The remanent polarization (Pr) and coercive electric field (Ec) of 1 at 408 K, 0.1 Hz were 24.0 µC cm-2 and 5.54 V µm-1, respectively. By thermal annealing of thin-film 1 at 443 K, the molecular assembly structure of 1 changed from a monolayer to a bilayer structure with high crystallinity, resulting in conducting layers of BTBT parallel to the substrate surface. The organic field-effect transistor (OFET) device with thermally annealed thin-film 1 showed p-type semiconducting behavior with the hole mobility of 1.0 × 10-3 cm2 V-1 s-1. Furthermore, device 1 showed switching behavior of semiconducting properties by electric field poling and thermal annealing cycle. The electric field response of ferroelectrics modulated the molecular orientation and conduction properties of organic semiconductors, resulting in external electric field control of carrier transport properties.

8.
Chem Asian J ; 19(9): e202400134, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38421377

RESUMO

A benzannulated double aza[9]helicene 1 was successfully synthesized via a one-pot oxidative fusion reaction. 1 was derivatized to N-alkylated double aza[9]helicene 1-Et and 1-Bu, whose structures were determined by X-ray diffraction analysis. 1-Et and 1-Bu exhibited red-shifted absorption and fluorescence spectra compared to single aza[9]helicene. The double aza[9]helicenes were expected to have two different conformers. Consistent with solid-state structure, the chiral-isomer was estimated to be more stable by 16 kcal/mol relative to meso-isomer. Indeed, enantiomers of 1-Et and 1-Bu were optically resolved by HPLC and showed mirror-imaged CD and CPL spectra with the CPL brightness up to 19.2 M-1cm-1 for 1-Bu.

9.
Chemistry ; 30(25): e202400392, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38391395

RESUMO

Supramolecular electronics exploits the distinctive features stemming from noncovalent interactions, guiding the self-assembly of molecules to craft materials endowed with customized electronic functionalities. Hydrogen-bonded materials, characterized by their capacity to establish dynamic and stable networks, introduce an extra dimension to the development of supramolecular electronic systems. This study presents a comparative analysis of two remarkably small semiconductors utilizing diketopyrrolopyrrole functionalized with urea units as hydrogen-bonding motifs, strategically positioned at opposing ends of the conjugated core. We show how the subtle distinction in functionalization not only influences morphology and self-assembly dynamics via hydrogen-bonding and π-π stacking formation, but also holds significant consequences for ultimate charge transport properties. Our observations into the interplay of noncovalent interactions provide valuable insights and strategic pathways for the design of novel materials with enhanced electronic characteristics.

10.
Faraday Discuss ; 250(0): 271-280, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-37994087

RESUMO

Amplified spontaneous emission (ASE) is considered to be a primary indication of optical gain in active media without an external resonator. Molecular materials with ASE are expected to be one of the suitable light sources for specific applications such as optical coherent tomography owing to their low coherence and flexible tunability. Concentration quenching of emissive excited states has been a critical issue to boost the quantum efficiency of molecular materials in their condensed phases. The rod-like design of molecules with excited state intramolecular proton transfer (ESIPT) has been demonstrated to overcome this issue in highly-concentrated molecularly-doped systems, as represented by C4alkyne-HBT (2-(4-(1-hexynyl)-2-hydroxyphenyl)-benzothiazole). We designed an ESIPT molecule-doped liquid crystalline (LC) system for optical amplification via the ASE regime with its wide tunability of emission intensity. Detailed ASE behaviour and optical gain of a LC blend of C4alkyne-HBT and 4-pentyl-4'-cyano biphenyl (5CB) was evaluated to afford a maximum optical gain of 16.5 cm-1 with an estimated ASE threshold of optical pumping at 0.6-0.7 mJ cm-2. Although most ASE studies focus on homogeneous solutions, solids, or crystalline states, ASE from a soft-flexible LC phase is quite limited and advantageous for the design of an external optical resonator/cavity structure. Optical excitation parallel and perpendicular to the director resulted in the strong modulation of the ASE. By using the benefits of a LC phase, the ASE was actively modulated under the external electric field by the reorientation of the molecular dipole moment.

11.
ACS Appl Mater Interfaces ; 15(50): 58711-58722, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38055344

RESUMO

An alkylamide-substituted [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivative of BTBT-CONHC14H29 (1) and C8H17-BTBT-CONHC14H29 (2) were prepared to design the multifunctional organic materials, which can show both ferroelectric and semiconducting properties. Single-crystal X-ray structural analyses of short-chain (-CONHC3H7) derivatives revealed the coexistence of two-dimensional (2D) electronic band structures brought from a herringbone arrangement of the BTBT π core and the one-dimensional (1D) hydrogen-bonding chains of -CONHC3H7 chains. The thin films of 1 and 2 fabricated on the Si/SiO2 substrate surface have monolayer and bilayer structures, respectively, resulting in conducting layers parallel to the substrate surface, which is suitable for a channel layer of organic field-effect transistors (OFETs). The thin film of 1 indicated a hole mobility µFET = 2.4 × 10-5 cm2 V-1 s-1 and threshold voltage VTh = - 29 V, whereas that of 2 showed a µFET = 2.1 × 10-2 cm2 V-1 s-1 and threshold voltage VTh = -9.7 V. Both 1 and 2 formed the smectic E (SmE) phase above 410 and 369 K, respectively, where the existence of a hole transport pathway was confirmed in the SmE phase. The ferroelectric hysteresis behavior was observed in bulk 1 and 2 in the polarization-electric field (P-E) curves at the SmE phase. 1 showed the remanent polarization Pr = 2.3 µC cm-2 and coercive electric field Ec = 5.2 V µm-1, whereas the Pr and Ec of 2 were 3.4 µC cm-2 and 7.0 V µm-1 at the conditions of 453 K and 1 Hz. Introduction of alkylamide units into the BTBT π core has the potential to develop the external stimulus-responsive organic semiconductors brought from both ferroelectricity and semiconducting properties.

12.
Angew Chem Int Ed Engl ; 62(50): e202314968, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-37883214

RESUMO

Oxidative fusion reaction of cyclic heteroaromatic pentads consisting of pyrrole and thiophene gave closed-heterohelicene monomers and dimers depending on the oxidation conditions. Specifically, oxidation with [bis(trifluoroacetoxy)iodo]benzene (PIFA) gave closed-[7]helicene dimers connected at the ß-position of one of the pyrrole units with remarkably elongated C-C bonds of about 1.60 Å. Although this bond was intact against thermal and physical activations, homolytic bond dissociation took place in DMSO upon irradiation with UV light to give the corresponding monomers. Thus, interconversion between the closed-helicene monomer and dimer was achieved. The optically pure dimer was photo-dissociated into the monomers associated with a turn-on of circularly polarized luminescence (CPL).

13.
Adv Mater ; 35(48): e2306061, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37695880

RESUMO

The emergence of the chiral-induced spin-selectivity (CISS) effect offers a new avenue for chiral organic molecules to autonomously manipulate spin configurations, thereby opening up possibilities in spintronics and spin-dependent electrochemical applications. Despite extensive exploration of various chiral systems as spin filters, one often encounters challenges in achieving simultaneously high conductivity and high spin polarization (SP). In this study, a promising chiral van der Waals superlattice, specifically the chiral TiS2 crystal, is synthesized via electrochemical intercalation of chiral molecules into a metallic TiS2 single crystal. Multiple tunneling processes within the highly ordered chiral layered structure of chiral TiS2 superlattices result in an exceptionally high SP exceeding 90%. This remarkable observation of significantly high SP within the linear transport regime is unprecedented. Furthermore, the chiral TiS2 electrode exhibits enhanced catalytic activity for oxygen evolution reaction (OER) due to its remarkable spin-selectivity for triplet oxygen evolution. The OER performance of chiral TiS2 superlattice crystals presented here exhibits superior characteristics to previously reported chiral MoS2 catalysts, with an approximately tenfold increase in current density. The combination of metallic conductivity and high SP sets the stage for the development of a new generation of CISS materials, enabling a wide range of electron spin-based applications.

15.
Nat Mater ; 22(7): 807-808, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37337070
16.
Respirol Case Rep ; 11(7): e01179, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37303310

RESUMO

We present a 41-year-old man with idiopathic interstitial pneumonia and pulmonary hypertension (PH) in the setting of a non-autoimmune background whose clinical presentation masqueraded pulmonary veno-occlusive disease (PVOD). Because of no histological evidence of venous occlusion in his previous lung biopsy, phosphodiesterase type-5 inhibitor was given, resulting in sudden onset of pulmonary edema. At autopsy, there were histological features of interstitial fibrosis with occlusion of the lobular septal veins and venules. Clinical presentations of PH due to interstitial fibrosis with pulmonary venous lesions may simulate those of PVOD and careful diagnostic and therapeutic approaches are required.

17.
Nat Commun ; 14(1): 2741, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37188690

RESUMO

Fullerenes are compelling molecular materials owing to their exceptional robustness toward multi-electron reduction. Although scientists have attempted to address this feature by synthesizing various fragment molecules, the origin of this electron affinity remains unclear. Several structural factors have been suggested, including high symmetry, pyramidalized carbon atoms, and five-membered ring substructures. To elucidate the role of the five-membered ring substructures without the influence of high symmetry and pyramidalized carbon atoms, we herein report the synthesis and electron-accepting properties of oligo(biindenylidene)s, a flattened one-dimensional fragment of fullerene C60. Electrochemical studies corroborated that oligo(biindenylidene)s can accept electrons up to equal to the number of five-membered rings in their main chains. Moreover, ultraviolet/visible/near-infrared absorption spectroscopy revealed that oligo(biindenylidene)s exhibit enhanced absorption covering the entire visible region relative to C60. These results highlight the significance of the pentagonal substructure for attaining stability toward multi-electron reduction and provide a strategy for the molecular design of electron-accepting π-conjugated hydrocarbons even without electron-withdrawing groups.

18.
Int Heart J ; 64(3): 491-495, 2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-37197918

RESUMO

Intracardiac thrombosis formation in patients in sinus rhythm is a rare phenomenon. An 84-year-old woman was admitted because of worsening dyspnea on exertion. An electrocardiogram showed sinus rhythm, left atrial overload, marked left axis deviation, low voltage, and poor r-wave progression in leads V1-4. An echocardiogram showed relatively preserved left ventricular ejection fraction with minimal wall thickening. Her serum level of B-type natriuretic peptide (931 pg/mL) was markedly elevated and a diagnosis of worsening heart failure was made. During the course of treatment for heart failure, she was complicated by acute abdominal aortic thromboembolism together with left atrial thrombus. An emergency abdominal aortic thrombectomy was followed by the removal of a left atrial thrombus 2 days later. Left ventricular biopsy performed during the surgery revealed amyloid deposits in the myocardial interstitium. Immunohistochemical study confirmed the diagnosis of transthyretin cardiac amyloidosis. It is postulated that the risk of intracardiac thrombosis and systemic embolism is increased even in sinus rhythm in patients with cardiac amyloidosis.


Assuntos
Amiloidose , Fibrilação Atrial , Embolia , Cardiopatias , Insuficiência Cardíaca , Trombose , Humanos , Feminino , Idoso de 80 Anos ou mais , Fibrilação Atrial/complicações , Volume Sistólico , Função Ventricular Esquerda , Cardiopatias/complicações , Cardiopatias/diagnóstico , Trombose/complicações , Trombose/diagnóstico , Embolia/complicações , Amiloidose/complicações , Amiloidose/diagnóstico
19.
J Cardiol Cases ; 27(5): 233-236, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37180214

RESUMO

A 63-year-old man with hypertrophic cardiomyopathy (HCM), mid-ventricular obstruction, and an apical aneurysm had an episode of cardiac arrest due to sustained ventricular tachycardia (VT). He was resuscitated and an implantable cardioverter-defibrillator (ICD) was implanted. In the following years, several episodes of VT and ventricular fibrillation were successfully terminated by antitachycardia pacing or ICD shocks. Three years after ICD implantation, he was re-admitted because of refractory electrical storm (ES). Since aggressive pharmacological treatments, direct current cardioversions, and deep sedation were not effective, he underwent epicardial catheter ablation which was successful to terminate ES. However, because of the recurrence of refractory ES after one year, he proceeded to surgical left ventricular myectomy with apical aneurysmectomy which provided him a relatively stable clinical course for six years. Although epicardial catheter ablation may be an acceptable option, surgical resection of apical aneurysm seems to be most efficacious for ES in patients with HCM and an apical aneurysm. Learning objectives: In patients with hypertrophic cardiomyopathy (HCM), implantable cardioverter-defibrillators (ICDs) are the gold standard of therapy for prophylaxis against sudden death. Electrical storm (ES) caused by recurrent episodes of ventricular tachycardia can cause sudden death even in patients with ICDs. Although epicardial catheter ablation may be an acceptable option, surgical resection of apical aneurysm is most efficacious for ES in patients with HCM, mid-ventricular obstruction, and an apical aneurysm.

20.
Small ; 19(34): e2301769, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37093207

RESUMO

Pentagon-heptagon embedded polycyclic aromatic hydrocarbons (PAHs) have aroused increasing attention in recent years due to their unique physicochemical properties. Here, for the first time, this report demonstrates a facile method for the synthesis of a novel B2 N2 -doped PAH (BN-2) containing two pairs of pentagonal and heptagonal rings in only two steps. In the solid state of BN-2, two different conformations, including saddle-shaped and up-down geometries, are observed. Through a combined spectroscopic and calculation study, the excited-state dynamics of BN-2 is well-investigated in this current work. The resultant pentagon-heptagon embedded B2 N2 -doped BN-2 displays both prompt fluorescence and long-lived delayed fluorescence components at room temperature, with the triplet excited-state lifetime in the microsecond time region (τ = 19 µs). The triplet-triplet annihilation is assigned as the mechanism for the observed long-lived delayed fluorescence. Computational analyses attributed this observation to the small energy separation between the singlet and triplet excited states, facilitating the intersystem crossing (ISC) process which is further validated by the ultrafast spectroscopic measurements.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA