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Perchlorate-induced structural diversity in thiosemicarbazone copper(ii) complexes provides insights to understand the reactivity in acidic and basic media
Get PDFThe use of perchlorate ancillary ligands with relatively low coordination ability nicely illustrates a rich structural diversity in thiosemicarbazone copper(II) (TSC-Cu(II)) systems. Five compounds with the formulae {[CuL(OH2)][CuL(OClO3)]}n·nClO4·2nH2O (1), [{CuL(OClO3)}2] (2), [Cu(HL)(OClO3)2(OH2)] H2O (3), [Cu2L3](ClO4)·2H2O (4) and [Cu(HL)(NCS)](ClO4) (5) are studied, where HL = pyridine-2-carbaldehyde thiosemicarbazone. The crystal structures show the presence of polynuclear species in the compounds containing an anionic L− thiosemicarbazone ligand: 1D chains (1) and dinuclear (2 and 4) arrangements. Meanwhile, complexes with a neutral HL ligand give rise to mononuclear entities (3 and 5). The chemical and structural parallelism of these complexes with the analogous TSC–Cu(II)–nitrate system is discussed. The thiocyanate ligand in compound 5 comes from partial desulfurization of the thiosemicarbazone in acid medium and results in an incommensurate modulated structure. On the other hand, it is proposed that [Cu2L3]+ species present in 4 could play a possible role in desulfurization reactions. Experimental evidence and theoretical calculations support a proposed mechanism for the partial desulfurization of preformed TSC-Cu(II) entities in basic and physiological media to yield the [CuL(LCN)] (HLCN = pyridine-2-ylmethylene(hydrazine carbonitrile)) and [{CuL(SH)}2)] compounds.This work was supported by the European Union H2020-LC-SC3-2020-NZE-RES-CC, NMBP-16- 2020-GA 953152 and DT-NMBP-04-2020 Projects, together with Ministerio de Ciencia, Innovación, for the project PID2021- 127531NB-I00 (AEI/10.13039/501100011033/FEDER, UE), PDC2022-133955-I00 and Ministerio de Ciencia, Innovación y Universidades CTQ(QMC) RED2018-102471-T MultiMetDrugs Network (Spain), Consejería de Educación of Junta de Castilla y León and FEDER BU049P20, Fundacion Bancaria Caixa D. Estalvis i Pensions de Barcelona 001 and Ministerio de Ciencia e Innovación PID2019-106644GB-I00 and Gobierno Vasco IT1458-22. R. G.-G. and A. J.-P. wish to thank the Junta de Castilla y León for their Doctoral Fellowships
Direct synthesis of haloaromatics from nitroarenes via a sequential one-pot Mo-catalyzed reduction/Sandmeyer reaction
Get PDFHerein, we report the direct synthesis of a wide variety of functionalized aromatic bromides, chlorides, iodides, and fluorides from nitroarenes in a sequential one-pot operation. This protocol is based on an air- and moisture-tolerant dioxomolybdenum-catalyzed reduction of nitroaromatics, employing pinacol as a reducing agent, which enables subsequent diazotization and halogenation steps. This methodology represents a step-economical, practical, and alternative procedure for synthesizing haloaromatics directly from nitroaromatics.We gratefully acknowledge the Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033 (PID2020-115789GB-C21) and the Junta de Castilla y León and FEDER (BU049P20) for financial support. R. H.-R. and S. G.-G. thank the Ministerio de Educación for FPU predoctoral contracts. S. S.-P. thanks the Ministerio de Ciencia e Innovación and the “NextGenerationEU”/PRTR EU for a Ramón y Cajal contract (RYC2021-031533-I)
Broadening Applicability of the Poor Academic's Method for Reversing Polarity in Redox Flow Cell Cycling
Get PDFThe use of symmetrical cells is becoming popular for the search of new electroactive materials in redox flow batteries. Unfortunately, low-cost battery cyclers, commonly used for electrochemical battery testing, are not compatible with symmetrical cells since they usually cannot apply negative bias voltages needed for symmetrical cells. The insertion of a Ni−Cd battery in the voltage sensing path is a simple and effective methodology to overcome this limitation for certain battery cyclers. Herein, the validity of this useful method is evaluated for other battery cyclers, realizing that the strategy is not universal. A modified methodology is developed for a battery cycler in which the previous method is not valid. The new strategy is based on inserting a Ni-MH battery in the current path, and enables using a low-cost Neware CT-4008T-5V6A-S1 cycler for ferro- /ferricyanide symmetrical cells demonstrating proper operation for >19 days. This new method possesses advantages, e. g. direct reading of the cell voltage, and disadvantages, e. g. the Ni-MH battery is charged/discharged during operation, which are discussed. The four battery cyclers evaluated show that, despite neither method is universal, both methods are complementary to each other. Thus, the decision of using either one method or the other must be reached on a case-by-case basis.The authors acknowledge financial support by the Spanish Government (Ministerio de Ciencia e Innovacion, Grants PID2021-124974OB-C22 and TED2021-131651B-C21) and Ramon y Cajal award (RYC2018-026086-I) as well as the MeBattery project. MeBattery has received funding from the European Innovation Council of the European Union under Grant Agreement no. 101046742. This work was supported by the Regional Government of Castilla y Leon (Junta de Castilla y Leon), the Basque Government (GV-ELKARTEK-2022 KK-2022/00043) and by the Ministry of Science and Innovation MICIN and the European Union NextGeneration EU/PRTR (C17. I1). Gimena Marin is supported by a grant from the Regional Government of Castilla y León (Junta de Castilla y León), which is partially supported by the European Social Fund
GBNN algorithm enhanced by movement planner for UV‐C disinfection
Get PDFIn order to maintain adequate levels of cleanliness and sanitation in public facilities, prevent the buildup of viruses and other harmful pathogens, and ensure health and safety, health and labor authorities have repeatedly warned of the need to adhere to proper disinfection protocols in the workplace. This is particularly important in public places where food is handled, where there are more vulnerable people, including hospitals and health care centers, or where there is a large concentration of people. One promising approach is the combination of ultraviolet-C (UV-C) light and mobile robots to automate disinfection processes. Being this technology effective for disinfection, an excessive dose of UV can damage the materials, limiting its applicability. Therefore, a major challenge for automatic disinfection is to find a route that covers the entire surface, ensures cleanliness, and provides the correct radiation dose while preventing environmental materials from being damaged. To achieve this, in this paper a novel intelligent control approach is proposed. A bio-inspired Glasius neural network with a motion planner, an UV estimation module, a speed regulator, and pure pursuit controller are combined into one intelligent system. The motion planner proposes a sequence of movements to go through the space in the most efficient way possible, avoiding obstacles of the environment. The speed controller adjusts the dose of UV-C radiation and the pure pursuit regulator ensures the following of the path. This approach has been tested in various simulation scenarios of increasing complexity and in four different areas of dosing requirements. In simulation, a 44% reduction of the maximum dose is achieved, 17% less distance travelled by the robot and, what is more important, 229% more locations with the appropriate dose
The effect of plastic deformation on hydrogen diffusion in nickel Alloy 625
No full textRecently, several hydrogen-assisted failures have been reported on different nickel alloys used in the subsea oil
and gas industries. It is thus essential to correlate hydrogen uptake and diffusion behavior with stress conditions
for an in-depth understanding of the failures. This study reports the first-hand finding on hydrogen diffusion
behavior in a nickel Alloy 625 under different pre-strain levels by combining the electrochemical permeation test
and diffusion model, with a particular focus on the effect of grain boundary carbide. As the multiplication of
dislocations was claimed to trap hydrogen atoms and reduce the diffusivity by increasing the strain levels from
0.05 to 0.2, an acceleration in hydrogen diffusivity was however observed when the strain was higher than 0.1.
This phenomenon was deduced to be caused by the diffusion highways by the hydrogen-enhanced strain-induced
vacancy formation at the grain boundaries and reduced hydrogen trapping by the fractured carbides.The authors acknowledge the financial support from the Research Council of Norway through the project M-HEAT (294689) and the industry companies in the project. The Research Council of Norway is acknowledged for the support to the Norwegian Micro- and Nano-Fabrication Facility, NorFab, project number 295864. A. Díaz gratefully acknowledges the financial support from the Junta of Castile and Leon through grant BU-002-P20, co-financed by FEDER funds, and wishes to thank the Nanomechanical Lab of NTNU for providing hospitality during his research stay