54 research outputs found

    Polarized supramolecular aggregates based on luminescent perhalogenated gold derivatives

    Get PDF
    Reaction of [Au(C6F5)(tht)] (tht = tetrahydrothiophene) with 1,3,5-triaza-7-phosphaadamantane (PTA) and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]-nonane (DAPTA) leads to the formation of [Au(C6F5)(phosph)] (phosph = PTA, 1; phosph = DAPTA, 2). The compounds are slightly soluble in water and aggregate at higher concentrations giving rise to the formation of needle- and rod-like structures (1) and well-organized spherical aggregates (2). Compounds 1 and 2 were reacted with AgPF6 giving rise to the formation in all cases of luminescent water soluble 1:1 Au·Ag heterometallic complexes, as evidenced by X-ray crystal structure determination. The use of different silver salts that differ on the counterion induces changes on the resulting luminescence and aggregation morphology

    Electrical sensing of the thermal and light induced spin transition in robust contactless spin-crossover/graphene hybrid devices

    Get PDF
    Hybrid devices based on spin-crossover (SCO)/2D heterostructures grant a highly sensitive platform to detect the spin transition in the molecular SCO component and tune the properties of the 2D material. However, the fragility of the SCO materials upon thermal treatment, light irradiation or contact with surfaces and the methodologies used for their processing have limited their applicability. Here, we report an easily processable and robust SCO/2D hybrid device with outstanding performance based on the sublimable SCO [Fe(Pyrz)2] molecule deposited over CVD-graphene, which is fully compatible with electronics industry protocols. Thus, a novel methodology based on growing an elusive polymorph of [Fe(Pyrz)2] (tetragonal phase) over graphene is developed that allows us to electrically detect a fast and effective light-induced spin transition in the devices (~50% yield in 5 minutes). Such performance can be enhanced even more when a flexible polymeric layer of PMMA is inserted in between the two active components in a contactless configuration, reaching a ~100 % yield in 5 minutes.Comment: 25 pages, 5 figure

    Electrical sensing of the thermal and light induced spin transition in robust contactless spin-crossover/graphene hybrid devices

    Get PDF
    Hybrid devices based on spin-crossover (SCO)/2D heterostructures grant a highly sensitive platform to detect the spin transition in the molecular SCO component and tune the properties of the 2D material. However, the fragility of the SCO materials upon thermal treatment, light irradiation or contact with surfaces and the methodologies used for their processing have limited their applicability. Here, we report an easily processable and robust SCO/2D hybrid device with outstanding performance based on the sublimable SCO [Fe(Pyrz)2] molecule deposited over CVD-graphene, which is fully compatible with electronics industry protocols. Thus, a novel methodology based on growing an elusive polymorph of [Fe(Pyrz)2] (tetragonal phase) over graphene is developed that allows us to electrically detect a fast and effective light-induced spin transition in the devices (~50% yield in 5 minutes). Such performance can be enhanced even more when a flexible polymeric layer of PMMA is inserted in between the two active components in a contactless configuration, reaching a ~100 % yield in 5 minutes

    Sublimable complexes with spin switching: Chemical design, processing as thin films and integration in graphene-based devices

    Full text link
    Among the different types of switchable molecular compounds, sublimable Fe(II) SCO molecules provide a suitable platform to develop smart devices that respond to external stimuli. Here we report the synthesis, crystallographic structure and magnetic properties of three new neutral Fe(II) SCO molecules belonging to the {Fe[H2B(pz)2]2(L)} family with bidentate-alpha-diimine ligands L = 3-(pyridin-2-yl)-[1,2,3]triazolo[1,5-a]pyridine (tzpy), 5,5,6,6-tetrahydro-4H,4H-2,2-bi(1,3-thiazine) (btz) and 4,4,5,5-tetrahydro-2,2-bithiazole (bt) (1, 2 and 3, respectively), as well as two solvated forms of 1 and 3. All three desolvated compounds present thermal- and light-induced SCO transitions with different degrees of cooperativity and effectiveness. Furthermore, 1 and 2 are demonstrated to be sublimable under HV conditions affording homogeneous thin films 200 nm thick (TF1 and TF2) that retain the chemical integrity of the original molecules regardless the deposition surface. The SCO behaviour of the films is characterized by XAS technique revealing the partial retainment of both thermal- and light-induced spin transitions, yet losing the cooperativity. Finally, SCO/2D horizontal hybrid devices based on CVD-graphene are produced using these films. Being the first ones of this type utilizing molecules of {Fe[H2B(pz)2]2(L)} family, with L = tzpy and btz, the devices have allowed the successful detection of the thermal SCO transition through the electric properties of the CVD-graphene.Comment: 20 pages, 8 figure

    Confined Sandwichlike Microenvironments Tune Myogenic Differentiation.

    Get PDF
    Sandwichlike (SW) cultures are engineered as a multilayer technology to simultaneously stimulate dorsal and ventral cell receptors, seeking to mimic cell adhesion in three-dimensional (3D) environments in a reductionist manner. The effect of this environment on cell differentiation was investigated for several cell types cultured in standard growth media, which promotes proliferation on two-dimensional (2D) surfaces and avoids any preferential differentiation. First, murine C2C12 myoblasts showed specific myogenic differentiation. Human mesenchymal stem cells (hMSCs) of adipose and bone marrow origin, which can differentiate toward a wider variety of lineages, showed again myodifferentiation. Overall, this study shows myogenic differentiation in normal growth media for several cell types under SW conditions, avoiding the use of growth factors and cytokines, i.e., solely by culturing cells within the SW environment. Mechanistically, it provides further insights into the balance between integrin adhesion to the dorsal substrate and the confinement imposed by the SW system

    The optimal age for performing surgery on patients with MEN 2B syndrome

    Get PDF
    Multiple endocrine neoplasia (MEN) syndromes are characterized by the association of various endocrine neoplasias. Prophylactic thyroidectomy is the treatment of choice for patients with RET gene mutations. The age at which patients undergo prophylactic thyroidectomy may vary depending on the position of the RET gene codon. In cases of MEN 2B, when the mutation is carried in codons 883, 918 or 922, prophylactic thyroidectomy is performed prior to 6 months of age, due to the increased aggressiveness of these heterozygosities, which are capable of determining the onset of medullary cancer during the first months of life. We present two heterozygous twin patients with MEN 2B syndrome who were born 32 weeks premature, and who underwent prophylactic thyroidectomy at 7 months of age. The patients were carriers of the mutation at codon 918. We suggested the early surgery at 7 months as, due to their prematurity, the patients were required to gain weight to improve their condition prior to surgery. The two patients had medullary thyroid carcinoma without lymph node involvement. In conclusion, for a truly prophylactic thyroidectomy, such patients should undergo surgery within the first month of life, particularly if these patients are carriers of the mutation in codons 883, 918 or 922

    Predictive Value of Cardiac Magnetic Resonance Feature Tracking after Acute Myocardial Infarction: A Comparison with Dobutamine Stress Echocardiography

    Full text link
    [EN] In acute ST-segment elevation myocardial infarction (STEMI) late gadolinium enhancement (LGE) may underestimate segmental functional recovery. We evaluated the predictive value of cardiac magnetic resonance (CMR) feature-tracking (FT) for functional recovery and whether it incremented the value of LGE compared to low-dose dobutamine stress echocardiography (LDDSE) and speckle-tracking echocardiography (STE). Eighty patients underwent LDDSE and CMR within 5-7 days after STEMI and segmental functional recovery was defined as improvement in wall-motion at 6-months CMR. Optimal conventional and FT parameters were analyzed and then also applied to an external validation cohort of 222 STEMI patients. Circumferential strain (CS) was the strongest CMR-FT predictor and addition to LGE increased the overall accuracy to 74% and was especially relevant in segments with 50-74% LGE (AUC 0.60 vs. 0.75, p = 0.001). LDDSE increased the overall accuracy to 71%, and in the 50-74% LGE subgroup improved the AUC from 0.60 to 0.69 (p = 0.039). LGE + CS showed similar value as LGE + LDDSE. In the validation cohort, CS was also the strongest CMR-FT predictor of recovery and addition of CS to LGE improved overall accuracy to 73% although this difference was not significant (AUC 0.69, p = 0.44). Conclusion: CS is the strongest CMR-FT predictor of segmental functional recovery after STEMI. Its incremental value to LGE is comparable to that of LDDSE whilst avoiding an inotropic stress agent. CS is especially relevant in segments with 50-74% LGE where accuracy is lower and further testing is frequently required to clarify the potential for recovery.This research was supported by the Instituto de Salud Carlos III and co-funded by Fondo Europeo de Desarrollo Regional (FEDER) (grant numbers PI17/01836 and CIBERCV16/11/00486). JG and DM acknowledge financial support from the "Agencia Valenciana de la Innovacion, Generalitat Valenciana" (grant) and from the "Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana" (grant number AEST/2019/037).Valente, FX.; Gavara-Doñate, J.; Gutiérrez, L.; Rios-Navarro, C.; Rello, P.; Maymi, M.; Fernandez-Galera, R.... (2021). Predictive Value of Cardiac Magnetic Resonance Feature Tracking after Acute Myocardial Infarction: A Comparison with Dobutamine Stress Echocardiography. Journal of Clinical Medicine. 10(22):1-12. https://doi.org/10.3390/jcm10225261S112102

    Design and processing as ultrathin films of a sublimable Iron(II) spin crossover material exhibiting efficient and fast light-induced spin transition

    Full text link
    Materials based on spin crossover (SCO) molecules have centred the attention in Molecular Magnetism for more than forty years as they provide unique examples of multifunctional and stimuli-responsive materials, which can be then integrated into electronic devices to exploit their molecular bistability. This process often requires the preparation of thermally stable SCO molecules that can sublime and remain intact in contact with surfaces. However, the number of robust sublimable SCO molecules is still very scarce. Here we report a novel example of this kind. It is based on a neutral iron (II) coordination complex formulated as [FeII(neoim)2], where neoimH is the ionogenic ligand 2-(1H-imidazol-2-yl)-9-methyl-1,10-phenanthroline. In the first part a comprehensive study, which covers the synthesis and magneto-structural characterization of the [FeII(neoim)2] complex as a bulk microcrystalline material, is reported. Then, in the second part we investigate the suitability of this material to form thin films through high vacuum (HV) sublimation. Finally, the retainment of all present SCO capabilities in the bulk when the material is processed is thoroughly studied by means of X-ray absorption spectroscopy. In particular, a very efficient and fast light-induced spin transition (LIESST effect) has been observed, even for ultrathin films of 15 nm.Comment: 27 pages, 2 schemes, 5 figures, 1 tabl

    MRI Investigation of the Differential Impact of Left Ventricular Ejection Fraction After Myocardial Infarction in Elderly vs. Nonelderly Patients to Predict Readmission for Heart Failure

    Get PDF
    Acute heart failure; Acute myocardial infarction; ElderlyInsuficiència cardíaca aguda; Infart agut de miocardi; Gent granInsuficiencia cardíaca aguda; Infarto agudo de miocardio; AncianoBackground Patients with ST-segment elevation myocardial infarction (STEMI), especially elderly individuals, have an increased risk of readmission for acute heart failure (AHF). Purpose To study the impact of left ventricular ejection fraction (LVEF) by MRI to predict AHF in elderly (>70 years) and nonelderly patients after STEMI. Study Type Prospective. Population Multicenter registry of 759 reperfused STEMI patients (23.3% elderly). Field Strength/Sequence 1.5-T. Balanced steady-state free precession (cine imaging) and segmented inversion recovery steady-state free precession (late gadolinium enhancement) sequences. Assessment One-week MRI-derived LVEF (%) was quantified. Sequential MRI data were recorded in 579 patients. Patients were categorized according to their MRI-derived LVEF as preserved (p-LVEF, ≥50%), mildly reduced (mr-LVEF, 41%–49%), or reduced (r-LVEF, ≤40%). Median follow-up was 5 [2.33–7.54] years. Statistical Tests Univariable (Student's t, Mann–Whitney U, chi-square, and Fisher's exact tests) and multivariable (Cox proportional hazard regression) comparisons and continuous-time multistate Markov model to analyze transitions between LVEF categories and to AHF. Hazard ratios (HR) with 95% confidence intervals (CIs) were computed. P < 0.05 was considered statistically significant. Results Over the follow-up period, 79 (10.4%) patients presented AHF. MRI-LVEF was the most robust predictor in nonelderly (HR 0.94 [0.91–0.98]) and elderly patients (HR 0.94 [0.91–0.97]). Elderly patients had an increased AHF risk across the LVEF spectrum. An excess of risk (compared to p-LVEF) was noted in patients with r-LVEF both in nonelderly (HR 11.25 [5.67–22.32]) and elderly patients (HR 7.55 [3.29–17.34]). However, the mr-LVEF category was associated with increased AHF risk only in elderly patients (HR 3.66 [1.54–8.68]). Less transitions to higher LVEF states (n = 19, 30.2% vs. n = 98, 53%) and more transitions to AHF state (n = 34, 53.9% vs. n = 45, 24.3%) were observed in elderly than nonelderly patients. Data Conclusion MRI-derived p-LVEF confers a favorable prognosis and r-LVEF identifies individuals at the highest risk of AHF in both elderly and nonelderly patients. Nevertheless, an excess of risk was also found in the mr-LVEF category in the elderly group. Evidence Level 2. Technical Efficacy Stage 2.Grant sponsor: This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (grant numbers PI20/00637, PI15/00531, and CIBERCV16/11/00486, CIBERCV16/11/00420, CIBERCV16/11/00479, and CM21/00175 to V.M.-G.), Fundació La Marató TV3 (grant 20153030-31-32), La Caixa Banking Foundation (HR17-00527) and by Conselleria de Educación – Generalitat Valenciana (PROMETEO/2021/008). J.G. acknowledges financial support from the “Agencia Estatal de Investigación” (grant FJC2020-043981-I/AEI/10.13039/501100011033)

    Sublimable complexes with spin switching: chemical design, processing as thin films and integration in graphene-based devices

    Get PDF
    Entre los diferentes tipos de compuestos moleculares conmutables, las moléculas SCO de Fe( II ) sublimables proporcionan una plataforma adecuada para desarrollar dispositivos inteligentes que respondan a estímulos externos. En este documento, presentamos la síntesis, la estructura cristalográfica y las propiedades magnéticas de tres nuevas moléculas neutras de Fe( II ) SCO pertenecientes a la familia {Fe[H 2 B(pz) 2 ] 2 (L)} con ligandos bidentado-α-diimina L = 3-(piridin-2-il)-[1,2,3]triazolo[1,5- a ]piridina (tzpy), 5,5′,6,6′-tetrahidro-4 H ,4′ H - 2,2′-bi(1,3-tiazina) (btz) y 4,4′,5,5′-tetrahidro-2,2′-bitiazol (bt) ( 1 , 2 y 3, respectivamente), así como dos formas solvatadas de 1 y 3 . Los tres compuestos desolvatados presentan transiciones de SCO inducidas por calor y luz con diferentes grados de cooperatividad y efectividad. Además, se ha demostrado que 1 y 2 son sublimables en condiciones HV, lo que proporciona películas delgadas homogéneas de 200 nm de espesor ( TF1 y TF2) que conservan la integridad química de las moléculas originales independientemente de la superficie de depósito. El comportamiento SCO de las películas se caracteriza por la técnica XAS que revela la retención parcial de las transiciones de espín inducidas por la luz y el calor, pero pierde la cooperatividad. Finalmente, los dispositivos híbridos horizontales SCO/2D basados ​​en CVD-grafeno se producen utilizando estas películas. Siendo los primeros de este tipo utilizando moléculas de la familia {Fe[H 2 B(pz) 2 ] 2 (L)}, con L = tzpy y btz, los dispositivos han permitido la detección exitosa de la transición térmica SCO a través de la Propiedades eléctricas del CVD-grafeno.Among the different types of switchable molecular compounds, sublimable Fe(II) SCO molecules provide a suitable platform to develop smart devices that respond to external stimuli. Herein, we report the synthesis, crystallographic structure and magnetic properties of three new neutral Fe(II) SCO molecules belonging to the {Fe[H2B(pz)2]2(L)} family with bidentate-α-diimine ligands L = 3-(pyridin-2-yl)-[1,2,3]triazolo[1,5-a]pyridine (tzpy), 5,5′,6,6′-tetrahydro-4H,4′H-2,2′-bi(1,3-thiazine) (btz) and 4,4′,5,5′-tetrahydro-2,2′-bithiazole (bt) (1, 2 and 3, respectively), as well as two solvated forms of 1 and 3. All three desolvated compounds present thermal- and light-induced SCO transitions with different degrees of cooperativity and effectiveness. Furthermore, 1 and 2 are demonstrated to be sublimable under HV conditions, affording homogeneous thin films 200 nm thick (TF1 and TF2) that retain the chemical integrity of the original molecules regardless of the deposition surface. The SCO behaviour of the films is characterized by the XAS technique revealing the partial retainment of both thermal- and light-induced spin transitions, yet losing the cooperativity. Finally, SCO/2D horizontal hybrid devices based on CVD-graphene are produced using these films. Being the first ones of this type utilizing molecules of the {Fe[H2B(pz)2]2(L)} family, with L = tzpy and btz, the devices have allowed the successful detection of the thermal SCO transition through the electric properties of CVD-graphene
    corecore