15 research outputs found
The flexibility of CuI chains and the functionality of pyrazine-2-thiocarboxamide keys to obtaining new Cu(I)-I coordination polymers with potential use as photocatalysts for organic dye degradation
This research focuses on two interesting aspects in the synthesis of new coordination polymers (CPs) taking advantage of the lability of coordination bonds. The first is the use of multifunctional and flexible building blocks, such as pyrazine-2-thiocarboxamide (Pyrtca) and CuI, and the second is the modification of the synthetic conditions to expand the amount of different crystalline phases. This means that starting from the same building blocks, we can increase the number of compounds obtained and diversify their final properties, as well as their possible applications. Furthermore, Cu(I)-halogen coordination polymers have been extensively studied for a long time due to their interesting optoelectronic properties. However, despite being usually semiconductors, research related to their possible behavior as photocatalysts is almost non-existent. In this work, we present five compounds, four coordination compounds with formulas [CuI(Pyrtca)]n (CP1), [Cu3I3(Pyrtca)7] (2) [Cu2I2(Pyrtca)]n (CP4 and CP4âČ) and a transformation of the starting ligand to a cationic imidazole derivative (compound 3) where copper iodine serves as a catalyst. All the compounds have been characterized by different techniques including single-crystal X-ray diffraction. The antibacterial behavior of CP1 against E. Coli DH5, E. Coli BL21, and C. glabrata (CECT 1448), as well as their optoelectronic properties, are also discussed in the work. The value of the band gap obtained (1.91 eV) for the two-dimensional coordination polymer of formula [Cu2I2(Pyrtca)]n (CP4) allows us to study its behavior as a photocatalyst in the degradation of persistent dyes in water with interesting results, achieving a total degradation of Methylene Blue and Rhodamine B in 40 min under UVâvisible lightThis work was supported
by the Spanish Ministerio de Ciencia e InnovaciĂłn (Agencia Estatal de
InvestigaciĂłn) (MCIN/AEI/10.13039/501100011033; PID2019-
108028GB-C22 and TED2021-131132B-C22
Structural and theoretical study of copper(ii)-5-fluoro uracil acetate coordination compounds: Single-crystal to single-crystal transformation as possible humidity sensor
This paper describes the synthesis and characterization of seven different copper(II) coordination compounds, as well as the formation of a protonated ligand involving all compounds from the same reaction. Their synthesis required hydrothermal conditions, causing the partial in situ transformation of 5-fluoro uracil-1-acetic acid (5-FUA) into an oxalate ion (ox), as well as the protonation of the 4,4âČ-bipyridine (bipy) ligand through a catalytic process resulting from the presence of Cu(II) within the reaction. These initial conditions allowed obtaining the new coordination compounds [Cu2(5-FUA)2(ox)(bipy)]n·2n H2O (CP2), [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3), as well as the ionic pair [(H2bipy)+2 2NO3â] (1). The mother liquor evolved rapidly at room temperature and atmospheric pressure, due to the change in concentration of the initial reagents and the presence of the new chemical species generated in the reaction process, yielding CPs [Cu(5-FUA)2(bipy)]n·3.5n H2O, [Cu3(ox)3(bipy)4]n and [Cu(ox)(bipy)]n. The molecular compound [Cu(5-FUA)2(H2O)4]·4H2O (more thermodynamically stable) ended up in the mother liquor after filtration at longer reaction times at 25 °C and 1 atm., cohabiting in the medium with the other crystalline solids in different proportions. In addition, the evaporation of H2O caused the single-crystal to single-crystal transformation (SCSC) of [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3) into [Cu(5-FUA)2(bipy)]n·2n H2O (CP4). A theoretical study was performed to analyze the thermodynamic stability of the phases. The observed SCSC transformation also involved a perceptible color change, highlighting this compound as a possible water sensorPID2019-108028GB-C22, TED2021-131132B-C2
A nanostructured Cu(II) coordination polymer based on alanine as a trifunctional mimic enzyme and efficient composite in the detection of Sphingobacteria
This research raises the potential use of coordination polymers as new useful materials in two essential research fields, allowing the obtaining of a new multiartificial enzyme with the capacity to inhibit the growth of bacteria resistance. The fine selection of the ligands allows the design of a new 2D coordination polymer (CP), with the formula [Cu2(IBA)2(OH2)4]n·6nH2O, by the combination of Cu (II) as the metal center with a pseudoamino acid (H2IBA = isophthaloyl bis ÎČ-alanine). Quantitative total X-ray fluorescence (TXRF) analyses show that the obtained CP can gradually release Cu (II) ions. Additionally, this CP can be nanoprocessed and transformed into a metal-organic gel (MOG) by using different Cu (II) salt concentrations and the application of ultrasounds. Considering its nanometric dimensions, the slow Cu (II) release and its simple processability, its performance as an artificial enzyme, and its antibacterial ability were explored. The results obtained show the first nanocoordination polymer acting as an artificial multienzyme (peroxidase, catalase, and superoxodismutase) exhibiting antibacterial activity in the presence of hydrogen peroxide, with selective behavior for three bacterium strains (S. spiritovirum, A. faecales, and B. cereus). Indeed, this CP shows a more robust inhibition capacity for Sphingobacterium. Going beyond that, as there are no comfortable and practically clinical tests capable of detecting the presence of Sphingobacteria, the compound can be easily embedded to form moldable gelatin that will facilitate the handling and low-cost commercial kit
Cunning defects: Emission control by structural point defects on Cu(i)I double chain coordination polymers
The following version is an accepted manuscript in Journal of Materials Chemistry C 8.4 (2020): 1448-1458 and may be found at ttps://doi.org/10.1039/C9TC05185FThe direct reaction between CuI and 3,5-dichloropyridine, in acetonitrile at room temperature, gives rise to [Cu(Cl2-py)I]n (Cl2-py = 3,5-dichloropyridine), which consists of a Cu(i)-I double chain based coordination polymer (CP) grafted with 3,5-dichloropyridine. In this simple one-pot process, the modulation of the reaction conditions, i.e. slight variations in the CuI and Cl2-py ratio caused by in situ disproportion, can, however, produce significant changes in the physical properties of the materials. For instance, the reaction carried out in a 1â:â1 ratio under ambient conditions leads to compound 1, while compound 1âČ is obtained upon a solvothermal process of stoichiometric reaction mixture, Cl2-py and CuI, which produces partial disproportion (<0.5% in weight) of the initial Cu(i). Interestingly, compounds 1 and 1âČ show an identical chemical composition and structure as determined by both single crystal and powder X-ray diffraction. However, they display remarkable differences in the luminescence behavior, featuring broad emission bands centered at 515 and 670 nm and associated to photoluminescence quantum yields of 12 and 5% for 1 and 1âČ, respectively. Density functional theory (DFT) calculations allowed us to rationalize the nature of this rare behavior. This is attributed to structural defects related to the weaker coordination bond present in these structures that provoke the strong red-shifted emissionThe authors thank financial support from the Spanish Ministerio de Economıa y Competitividad (MAT2016-77608-C3-1-P,
MAT2016-75883-C2-2-P, MAT2010-20843-C02-01, CTQ2016-75816-
C2-1P, MAT2016-75586-C4-4-P) and by EU-FEDER funds. JGP
thanks to Servicios Generales de Apoyo a la Investigacion (SEGAI)
at La Laguna University. J. I. M. acknowledges the financial support
by the ââRamoÂŽn y Cajalââ Program of MINECO (Grant RYC-2015-
17730) and the EU via the ERC-Synergy Program (Grant ERC-2013-
SYG-610256 NANOCOSMOS). J. C. E. acknowledges the financialsupport by the ââFPI-MINECOââ Program of MINECO (Grant BES2015-071534). R. D. C. acknowledges the program ââAyudas para la
atraccioÂŽn de talento investigadorâModalidad 1 of the ConsejerıŽa de EducacioÂŽn, Juventud y DeporteâComunidad de
Madrid with the Reference No. 2016-T1/IND-1463.ââ, Spanish
MINECO for the RamoÂŽn y Cajal program (RYC-2016-20891), the
Europa Excelencia program (ERC2019-092825), and HYNANOSC (RTI2018-099504-A-C22). R. D. C. also acknowledges the
2018 Leonardo Grant for Researchers and Cultural Creators
from BBVA Foundation and the FOTOART-CM project funded
by Madrid region under programm P2018/NMT-4367. J. F.-C.
acknowledges the Marie SkĆodowska-Curie Individual Fellowships (H2020-MSCA-IF-2017). This paper is dedicated to Dmitri
MendeleÂŽyev in honour of the 150th anniversary of the discovery
of the periodic tabl
2D Cu(I)âI Coordination Polymer with Smart Optoelectronic Properties and Photocatalytic Activity as a Versatile Multifunctional Material
This work presents two isostructural Cu(I)-I 2-fluoropyrazine (Fpyz) luminescent
and semiconducting 2D coordination polymers (CPs). Hydrothermal synthesis allows the growth
of P-1 space group single crystals, whereas solvent-free synthesis produces polycrystals. Via
recrystallization in acetonitrile, P21 space group single crystals are obtained. Both show a reversible
luminescent response to temperature and pressure. Structure determination by single-crystal X-ray
diffraction at 200 and 100 K allows us to understand their response as a function of temperature.
Applying hydrostatic/uniaxial pressure or grinding also generates significant variations in their
emission. The high structural flexibility of the Cu(I)-I chain is significantly linked to the
corresponding alterations in structure. Remarkably, pressure can increase the conductivity by up to 3 orders of magnitude. Variations
in resistivity are consistent with changes in the band gap energy. The experimental results are in agreement with the DFT
calculations. These properties may allow the use of these CPs as optical pressure or temperature sensors. In addition, their behavior
as a heterogeneous photocatalyst of persistent organic dyes has also been investigatedThanks to Micro and Nanotechnology Institute CNM-CSIC
for SEM images. Thanks to the SCXRD laboratory of the
Interdepartmental Research Service and to Servicios Generales
de Apoyo a la InvestigaciĂłn (SEGAI) at La Laguna University.
This work has been supported by MCINN/AEI/ 10.13039/
5011000011033 under the National Program of Sciences and
Technological Materials, PID2019-108028GB-C22, PID2019-
106383GB-C41/C44, and TED2021-131132B-C22. Thanks to
Gobierno d e Canarias and EU-FEDER (grant:
ProID2020010067). This study forms part of the Advanced
Materials program and was supported by MCIN with funding
from European Union Next Generation EU (PRTR-C17.I1)
and by Generalitat Valenciana (grant MFA/2022/007 and
PROMETEO CIPROM/2021/075-GREENMAT). A.L.
(R.T.) and D.E. thank the Generalitat Valenciana for the
Ph.D. (Postdoctoral) Fellowship No. GRISOLIAP/2019/025
(CIAPOS/2021/20). J.C.G. and R. W. acknowledge the
support from the Spanish Ministry of Science and Innovation
(RTI2018-097508-B-I00, PID2021-128313OB-I00, TED2021-
131018B-C22) and the Regional Government of Madrid
through projects NMAT2D-CM (S2018/NMT-4511). J.C.G.
acknowledges support from the Regional Government of
Madrid through âProyectos SinĂ©rgicos de I + Dâ (grant
Y2018/NMT-5028 FULMATEN-CM) and NANOCOV-CM
(REACT-UE). IMDEA Nanociencia acknowledges support
from the Severo Ochoa Programme for Centres of Excellence
in R&D (MINECO, grant CEX2020-001039-S
Rational design of copper(II)-uracil nanoprocessed coordination polymers to improve their cytotoxic activity in biological media
This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ê-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the partial release of its building blocks and the formation of new species, such as [Cu(UAcO)2(H2O)4]·2H2O (Cu(II)-complex), and species corresponding to the partial reduction of the Cu(II) centers. The cytotoxic studies of CP1n versus human pancreatic adenocarcinoma and human uveal melanoma cells show that CP1n produces a decrease in the cell viability, while their UAcOH and Cu(II)-complex are not cytotoxic under similar conditions. The copper reduction species detected in the hydrolysis of CP1n are closely related to the formation of the reactive oxygen species (ROS) detected in the cytotoxic studies. These results prompted us to prepare CP2n that was designed to improve the cytotoxicity by the substitution of UAcO by 5-FUAcO, taking into account the anticancer activity of the 5-fluorouracil moiety. The new CP2n has a similar behavior to CP1n both in water and in biological media. However, its subtle structural differences are vital in improving its cytotoxic activity. Indeed, the release during the hydrolysis of species containing the 5-fluorouracil moiety provokes a remarkable increase in cellular toxicity and a significant increase in ROS species formationThe authors thank the financial support from the Spanish
Ministerio de EconomĂa y Competitividad (PID2019-
108028GB-C22, PID2019-108028GB-C21, MAT2016-77608-
C3-1-P, MAT2016-75883-C2-1-P, MAT2016-75883-C2-2-P,
MAT2016-75586-C4-4-P, and CTQ2017-87201-PAEI/
FEDER, UE) and the Generalidad Valenciana (Prometeo/
2019/076
Epidemiologic Features and Control Measures during Monkeypox Outbreak, Spain, June 2022
During June 2022, Spain was one of the countries most affected worldwide by a multicountry monkeypox outbreak with chains of transmission without identified links to disease-endemic countries. We provide epidemiologic features of cases reported in Spain and the coordinated measures taken to respond to this outbreak.S
Using Interpretable Machine Learning to Identify Baseline Predictive Factors of Remission and Drug Durability in Crohnâs Disease Patients on Ustekinumab
Ustekinumab has shown efficacy in Crohn's Disease (CD) patients. To identify patient profiles of those who benefit the most from this treatment would help to position this drug in the therapeutic paradigm of CD and generate hypotheses for future trials. The objective of this analysis was to determine whether baseline patient characteristics are predictive of remission and the drug durability of ustekinumab, and whether its positioning with respect to prior use of biologics has a significant effect after correcting for disease severity and phenotype at baseline using interpretable machine learning. Patients' data from SUSTAIN, a retrospective multicenter single-arm cohort study, were used. Disease phenotype, baseline laboratory data, and prior treatment characteristics were documented. Clinical remission was defined as the Harvey Bradshaw Index <= 4 and was tracked longitudinally. Drug durability was defined as the time until a patient discontinued treatment. A total of 439 participants from 60 centers were included and a total of 20 baseline covariates considered. Less exposure to previous biologics had a positive effect on remission, even after controlling for baseline disease severity using a non-linear, additive, multivariable model. Additionally, age, body mass index, and fecal calprotectin at baseline were found to be statistically significant as independent negative risk factors for both remission and drug survival, with further risk factors identified for remission
Long-Term Real-World Effectiveness and Safety of Ustekinumab in Crohnâs Disease Patients: The SUSTAIN Study
Background
Large real-world-evidence studies are required to confirm the durability of response, effectiveness, and safety of ustekinumab in Crohnâs disease (CD) patients in real-world clinical practice.
Methods
A retrospective, multicentre study was conducted in Spain in patients with active CD who had received â„1 intravenous dose of ustekinumab for â„6 months. Primary outcome was ustekinumab retention rate; secondary outcomes were to identify predictive factors for drug retention, short-term remission (week 16), loss of response and predictive factors for short-term efficacy and loss of response, and ustekinumab safety.
Results
A total of 463 patients were included. Mean baseline Harvey-Bradshaw Index was 8.4. A total of 447 (96.5%) patients had received prior biologic therapy, 141 (30.5%) of whom had received â„3 agents. In addition, 35.2% received concomitant immunosuppressants, and 47.1% had â„1 abdominal surgery. At week 16, 56% had remission, 70% had response, and 26.1% required dose escalation or intensification; of these, 24.8% did not subsequently reduce dose. After a median follow-up of 15 months, 356 (77%) patients continued treatment. The incidence rate of ustekinumab discontinuation was 18% per patient-year of follow-up. Previous intestinal surgery and concomitant steroid treatment were associated with higher risk of ustekinumab discontinuation, while a maintenance schedule every 12 weeks had a lower risk; neither concomitant immunosuppressants nor the number of previous biologics were associated with ustekinumab discontinuation risk. Fifty adverse events were reported in 39 (8.4%) patients; 4 of them were severe (2 infections, 1 malignancy, and 1 fever).
Conclusions
Ustekinumab is effective and safe as short- and long-term treatment in a refractory cohort of CD patients in real-world clinical practice