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  1. Article ; Online: Field-Induced Slow Magnetization Relaxation of a Tetrahedral S=2 FeIIS4-Containing Complex.

    Pissas, Michael / Ferentinos, Eleftherios / Kyritsis, Panayotis / Sanakis, Yiannis

    ChemPlusChem

    2024  , Page(s) e202400109

    Abstract: In the work described herein, the spin relaxation properties of the mononuclear tetrahedral S = 2 [Fe{(SPiPr2)2N}2] complex (1) were studied by employing static and dynamic magnetic measurements al liquid helium temperatures. In the absence of an ... ...

    Abstract In the work described herein, the spin relaxation properties of the mononuclear tetrahedral S = 2 [Fe{(SPiPr2)2N}2] complex (1) were studied by employing static and dynamic magnetic measurements al liquid helium temperatures. In the absence of an external direct current (DC) magnetic field, 1 exhibits fast magnetization relaxation. However, in the presence of external magnetic fields of a few kOe, slow relaxation is induced as monitored by alternating current (AC) magnetic susceptibility measurements up to 10 kHz, in the temperature range 2-5 K. Analysis of the temperature dependence of the corresponding relaxation time reveals contributions by Quantum Tunnelling of Magnetization, and the Direct and Orbach processes in the magnetization relaxation mechanism of 1. The energy barrier, Ueff, of the Orbach process, as determined by this analysis, is compared with that related to the zero field splitting parameters of 1 which were previously determined by high- frequency and -field electron paramagnetic resonance and Mössbauer spectroscopies.
    Language English
    Publishing date 2024-05-10
    Publishing country Germany
    Document type Journal Article
    ISSN 2192-6506
    ISSN (online) 2192-6506
    DOI 10.1002/cplu.202400109
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  2. Article ; Online: Chiral Heterometallic Cu

    Dermitzaki, Despina / Panagiotopoulou, Angeliki / Pissas, Michael / Psycharis, Vassilis / Raptopoulou, Catherine P

    ChemPlusChem

    2024  , Page(s) e202400123

    Abstract: The enantiomerically pure Schiff base ligands ... ...

    Abstract The enantiomerically pure Schiff base ligands H
    Language English
    Publishing date 2024-04-09
    Publishing country Germany
    Document type Journal Article
    ISSN 2192-6506
    ISSN (online) 2192-6506
    DOI 10.1002/cplu.202400123
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  3. Article: Exploring the Magnetic and Electrocatalytic Properties of Amorphous MnB Nanoflakes.

    Fu, Boxiao / Tzitzios, Vasileios / Zhang, Qiancheng / Rodriguez, Brian / Pissas, Michael / Sofianos, Maria Veronica

    Nanomaterials (Basel, Switzerland)

    2023  Volume 13, Issue 2

    Abstract: Two-dimensional (2D) metal borides are a class of ceramic materials with diverse structural and topological properties. These diverse material properties of metal borides are what forms the basis of their interdisciplinarity and their applicability in ... ...

    Abstract Two-dimensional (2D) metal borides are a class of ceramic materials with diverse structural and topological properties. These diverse material properties of metal borides are what forms the basis of their interdisciplinarity and their applicability in various research fields. In this study, we highlight which fundamental and practical parameters need to be taken into consideration when designing nanomaterials for specific applications. A simple one-pot chemical reduction method was applied for the synthesis of manganese mono-boride nanoflakes at room temperature. How the specific surface area and boron-content of the as-synthesized manganese mono-boride nanoflakes influence their magnetic and electrocatalytic properties is reported. The sample with the highest specific surface area and boron content demonstrated the best magnetic and electrocatalytic properties in the HER. Whereas the sample with the lowest specific surface area and boron content exhibited the best electric conductivity and electrocatalytic properties in the OER.
    Language English
    Publishing date 2023-01-11
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662255-5
    ISSN 2079-4991
    ISSN 2079-4991
    DOI 10.3390/nano13020300
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  4. Article ; Online: Synthesis and structural, magnetic and spectroscopic characterization of iron(III) complexes with

    Tzani, Sofia / Pissas, Michael / Psycharis, Vassilis / Pantazis, Dimitrios A / Sanakis, Yiannis / Raptopoulou, Catherine P

    Dalton transactions (Cambridge, England : 2003)

    2023  Volume 52, Issue 6, Page(s) 1582–1594

    Abstract: Reactions of methyl-2-pyridyl ketone, pyCOMe, with ... ...

    Abstract Reactions of methyl-2-pyridyl ketone, pyCOMe, with FeCl
    Language English
    Publishing date 2023-02-07
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/d2dt03944c
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Heterometallic clusters based on an uncommon asymmetric "V-shaped" [Fe

    Savva, Maria / Alexandropoulos, Dimitris I / Pissas, Michael / Perlepes, Spyros P / Papatriantafyllopoulou, Constantina / Sanakis, Yiannis / Tasiopoulos, Anastasios J

    Dalton transactions (Cambridge, England : 2003)

    2023  Volume 52, Issue 21, Page(s) 6997–7008

    Abstract: The synthesis, crystal structures, Mössbauer spectra and variable temperature dc and ac magnetic susceptibility studies of a new family of trinuclear heterometallic ... ...

    Abstract The synthesis, crystal structures, Mössbauer spectra and variable temperature dc and ac magnetic susceptibility studies of a new family of trinuclear heterometallic Fe
    Language English
    Publishing date 2023-05-30
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/d2dt03938a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: LAPONITE® nanodisk-“decorated” Fe₃O₄ nanoparticles: a biocompatible nano-hybrid with ultrafast magnetic hyperthermia and MRI contrast agent ability

    Basina, Georgia / Diamantopoulos, George / Devlin, Eamonn / Psycharis, Vassilis / Alhassan, Saeed M. / Pissas, Michael / Hadjipanayis, George / Tomou, Aphrodite / Bouras, Alexandros / Hadjipanayis, Constantinos / Tzitzios, Vasileios

    Journal of materials chemistry B. 2022 July 6, v. 10, no. 26

    2022  

    Abstract: Magnetic Fe₃O₄ nanoparticles “decorated” by LAPONITE® nanodisks have been materialized utilizing the Schikorr reaction following a facile approach and tested as mediators of heat for localized magnetic hyperthermia (MH) and as magnetic resonance imaging ( ...

    Abstract Magnetic Fe₃O₄ nanoparticles “decorated” by LAPONITE® nanodisks have been materialized utilizing the Schikorr reaction following a facile approach and tested as mediators of heat for localized magnetic hyperthermia (MH) and as magnetic resonance imaging (MRI) agents. The synthetic protocol involves the interaction between two layered inorganic compounds, ferrous hydroxide, Fe(OH)₂, and the synthetic smectite LAPONITE® clay Na₀.₇⁺[(Si₈Mg₅.₅Li₀.₃)O₂₀(OH)₄]₀.₇⁻, towards the formation of superparamagnetic Fe₃O₄ nanoparticles, which are well decorated by the diamagnetic clay nanodisks. The latter imparts high negative ζ-potential values (up to −34.1 mV) to the particles, which provide stability against flocculation and precipitation, resulting in stable water dispersions. The obtained LAPONITE®-“decorated” Fe₃O₄ nanohybrids were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, dynamic light scattering (DLS) and vibrating sample magnetometry (VSM) at room temperature, revealing superior magnetic hyperthermia performance with specific absorption rate (SAR) values reaching 540 W gFₑ⁻¹ (28 kA m⁻¹, 150 kHz) for the hybrid material with a magnetic loading of 50 wt% Fe₃O₄/LAPONITE®. Toxicity studies were also performed with human glioblastoma (GBM) cells and human foreskin fibroblasts (HFF), which show negligible to no toxicity. Furthermore, T₂-weighted MR imaging of rodent brain shows that the LAPONITE®-“decorated” Fe₃O₄ nanohybrids predominantly affected the transverse T₂ relaxation time of tissue water, which resulted in a signal drop on the MRI T₂-weighted imaging, allowing for imaging of the magnetic nanoparticles.
    Keywords X-ray diffraction ; absorption ; ambient temperature ; brain ; clay ; fever ; fibroblasts ; flocculation ; glioblastoma ; heat ; humans ; magnetism ; nanohybrids ; rodents ; smectite ; spectroscopy ; toxicity ; transmission electron microscopy
    Language English
    Dates of publication 2022-0706
    Size p. 4935-4943.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2702241-9
    ISSN 2050-7518 ; 2050-750X
    ISSN (online) 2050-7518
    ISSN 2050-750X
    DOI 10.1039/d2tb00139j
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Trinuclear Ni

    Georgopoulou, Anastasia N / Pissas, Michael / Psycharis, Vassilis / Sanakis, Yiannis / Raptopoulou, Catherine P

    Molecules (Basel, Switzerland)

    2020  Volume 25, Issue 10

    Abstract: The reaction of the Schiff base ... ...

    Abstract The reaction of the Schiff base ligand
    MeSH term(s) Coordination Complexes/chemical synthesis ; Coordination Complexes/chemistry ; Lanthanum/chemistry ; Ligands ; Magnetic Fields ; Molecular Structure ; Nickel/chemistry ; Schiff Bases/chemical synthesis ; Schiff Bases/chemistry
    Chemical Substances Coordination Complexes ; Ligands ; Schiff Bases ; Lanthanum (6I3K30563S) ; Nickel (7OV03QG267)
    Language English
    Publishing date 2020-05-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules25102280
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    Zs.MO 81: Show issues

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  8. Article ; Online: LAPONITE® nanodisk-"decorated" Fe

    Basina, Georgia / Diamantopoulos, George / Devlin, Eamonn / Psycharis, Vassilis / Alhassan, Saeed M / Pissas, Michael / Hadjipanayis, George / Tomou, Aphrodite / Bouras, Alexandros / Hadjipanayis, Constantinos / Tzitzios, Vasileios

    Journal of materials chemistry. B

    2022  Volume 10, Issue 26, Page(s) 4935–4943

    Abstract: ... Magnetic ... ...

    Abstract Magnetic Fe
    MeSH term(s) Clay ; Contrast Media/chemistry ; Ferric Compounds/chemistry ; Hyperthermia, Induced ; Magnetic Resonance Imaging/methods ; Nanoparticles/chemistry ; Silicates ; Water/chemistry
    Chemical Substances Contrast Media ; Ferric Compounds ; Silicates ; Water (059QF0KO0R) ; laponite (D703131383) ; Clay (T1FAD4SS2M)
    Language English
    Publishing date 2022-07-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 2702241-9
    ISSN 2050-7518 ; 2050-750X
    ISSN (online) 2050-7518
    ISSN 2050-750X
    DOI 10.1039/d2tb00139j
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Magnetic fluid hyperthermia simulations in evaluation of SAR calculation methods.

    Papadopoulos, Costas / Efthimiadou, Eleni K / Pissas, Michael / Fuentes, David / Boukos, Nikolaos / Psycharis, Vassilis / Kordas, George / Loukopoulos, Vassilios C / Kagadis, George C

    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)

    2020  Volume 71, Page(s) 39–52

    Abstract: Purpose: The purpose of this study is to employ magnetic fluid hyperthermia simulations in the precise computation of Specific Absorption Rate functions -SAR(T)-, and in the evaluation of the predictive capacity of different SAR calculation methods.: ... ...

    Abstract Purpose: The purpose of this study is to employ magnetic fluid hyperthermia simulations in the precise computation of Specific Absorption Rate functions -SAR(T)-, and in the evaluation of the predictive capacity of different SAR calculation methods.
    Methods: Magnetic fluid hyperthermia experiments were carried out using magnetite-based nanofluids. The respective SAR values were estimated through four different calculation methods including the initial slope method, the Box-Lucas method, the corrected slope method and the incremental analysis method (INCAM). A novel numerical model combining the heat transfer equations and the Navier-Stokes equations was developed to reproduce the experimental heating process. To address variations in heating efficiency with temperature, the expression of the power dissipation as a Gaussian function of temperature was introduced and the Levenberg-Marquardt optimization algorithm was employed to compute the function parameters and determine the function's effective branch within each measurement's temperature range. The power dissipation function was then reduced to the respective SAR function.
    Results: The INCAM exhibited the lowest relative errors ranging between 0.62 and 15.03% with respect to the simulations. SAR(T) functions exhibited significant variations, up to 45%, within the MFH-relevant temperature range.
    Conclusions: The examined calculation methods are not suitable to accurately quantify the heating efficiency of a magnetic fluid. Numerical models can be exploited to effectively compute SAR(T) and contribute to the development of robust hyperthermia treatment planning applications.
    MeSH term(s) Algorithms ; Calorimetry ; Computer Simulation ; Hot Temperature ; Humans ; Hyperthermia, Induced/methods ; Linear Models ; Magnetics ; Magnetite Nanoparticles ; Normal Distribution ; Reproducibility of Results
    Chemical Substances Magnetite Nanoparticles
    Language English
    Publishing date 2020-02-20
    Publishing country Italy
    Document type Journal Article
    ZDB-ID 1122650-x
    ISSN 1724-191X ; 1120-1797
    ISSN (online) 1724-191X
    ISSN 1120-1797
    DOI 10.1016/j.ejmp.2020.02.011
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    In stock of ZB MED Cologne/Königswinter

    Zs.B 2941: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
    ab Jg. 2022: Lesesaal (EG)

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  10. Article ; Online: Interactions between H-bonded [Cu(μ

    Mathivathanan, Logesh / Boudalis, Athanassios K / Turek, Philippe / Pissas, Michael / Sanakis, Yiannis / Raptis, Raphael G

    Physical chemistry chemical physics : PCCP

    2018  Volume 20, Issue 25, Page(s) 17234–17244

    Abstract: The X-ray crystal structure of the CuII complex [Cu3(μ3-OH)(μ-pz)3(PhCOO)3]- (pz- = pyrazolato anion) shows an isosceles triangular core, further forming a hexanuclear H-bonded aggregate. Cleavage of the H-bonds in solution results in isolated trinuclear ...

    Abstract The X-ray crystal structure of the CuII complex [Cu3(μ3-OH)(μ-pz)3(PhCOO)3]- (pz- = pyrazolato anion) shows an isosceles triangular core, further forming a hexanuclear H-bonded aggregate. Cleavage of the H-bonds in solution results in isolated trinuclear species. Analysis of variable temperature magnetic susceptibility data of a powder sample shows an antiferromagnetically-coupled Cu3-core with a doublet ground state and isotropic exchange parameters (Jave = -355 cm-1, Hiso = -JijSiSj). The fitting of magnetic data requires the inclusion of antisymmetric exchange, AE (HAE = Gij·Si × Sj) with Gz = 31.2 cm-1 and no detectable inter-Cu3 isotropic exchange. X-band EPR spectroscopy in a frozen tetrahydrofuran solution of the compound indicates isolated Cu3-species with g‖,eff = 2.25, g⊥,eff = 1.67. The small value of g⊥,eff (≪2.0) is consistent with the presence of AE in agreement with the analysis of the magnetic measurements. The parallel component exhibits a hyperfine pattern corresponding to one I = 3/2 nucleus with A‖ = 425 MHz. This implies a specific exchange coupling scheme obeying the order |J12| = |J13| < |J23| consistent with the crystallographically determined two long and one short CuCu distances. The role of AE in modulating the hyperfine parameters in antiferromagnetic Cu3 clusters is studied. EPR spectra at X- and Q-band were performed with powder samples of the cluster at liquid helium temperatures. The spectra in both bands are consistent with two interacting Sa,b = 1/2 species in the point dipolar approximation. Fitting of the spectra reveals that each spin is characterized by g‖ = 2.24, g⊥ = 1.65 which is in agreement with an isolated Cu3 cluster in the ground state. The determined inter-spin distance of 4.4-4.5 Å is very close to the distance between the Cu(1) and Cu(1)' sites of the two trimeric units as imposed crystallographically (4.3 Å). This constitutes further verification of the specific exchange coupling scheme within each trimer. Magnetostructural correlations previously adopted for antiferromagnetically coupled Cu3 clusters are discussed in the light of the combined magnetic measurements and EPR spectroscopy.
    Language English
    Publishing date 2018-06-27
    Publishing country England
    Document type Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/c8cp02643b
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