Κατάλογος Προσωπικού

ΑΝΑΣΤΑΣΙΟΣ ΚΕΡΑΜΙΔΑΣ

KERAMIDAS ANASTASIOS
22892764
...
ΚΑΘΗΓΗΤΗΣ/ΡΙΑ
Τμήμα Χημείας
ΘΕΕ 02 - Σχολή Θετικών και Εφαρμοσμένων Επιστημών,
Πανεπιστημιούπολη

Keramidas graduated from the Department of Chemistry at University of Ioannina in 1988. During the four years of his undergraduate studies he was awarded four times with the fellowship for the outstanding undergraduate students from the Greek National Fellowship Institute. He received the Ph.D. from the same University in 1992 for research related to the bioinorganic chemistry of vanadium. In 1994 he moved to Colorado State University where he worked in the design and synthesis of new antidiabetic vanadium based drugs. Since 1997 hold an academic position at the University of Cyprus, Department of Chemistry. He was the head of the Chemistry Department from 2008 up to 2010 and he has served the University from several posts. He participated also in other committees. Currently he is the Deputy head of the Department of Chemistry at the University of Cyprus.

His research group is consisted from four graduate students and two Post Docs. Twelve Ph.D. students have graduated (one got an academic position at Cyprus University of Technology and three has an academic at University of Nicosia) and two masters.

His research is focusing: 1) Interaction of metal ions with para- quinones/semiquinones/hydroquinones, focusing on metal-ligand pH, temperature and/or photo induced electron transfer, the selective chemical or photochemical water oxidation or dioxygen activation, 2) Chemistry and photochemistry of organic lanthanides with applications in OLEDs and solar spectrum condensation, 3) Design and synthesis of organic molecules that selectively bind heavy metal ions for mining Uranyl ion from sea 4) Synthesis and anticancer and/or properties of metal - tocopherol / tocotrienol conjugated molecules.

His research work has been published in international scientific journals (98 publications cited 2500 times, h index = 28), books (5 chapters in books), three application has been patented. He has been involved in the translation of one book from english to greek for teaching purposes and he wrote the manual for the Inorganic teaching lab course and the notes for eight different undergraduate and graduate teaching courses. He has present his work orally in more than 85 conferences, in 31 of them he was invited speaker. He organized two international conferences. He is associated editor of the journals ‘Bioinorganic Chemistry and Applications’ ‘Symmetry’ and ‘Current Indian Science: Coordination Chemistry’ and in the editorial board of the local Journal “Peri Chimeias (About Chemistry)” of the Pancyprian Union of Chemists. He had refereed more than 250 papers and research proposals from ACS, VCH-Wiley, RSC, Elsevier etc journals, funding organizations, Cyprus industry and R&D spin off companies. He collaborates with scientists from several Universities and Research Institutes. Some of them are: Colorado State University, University of Ioannina, University of Patras, University of Crete, Cyprus University of Technology, University of Glasgow, University of Lisbon.

His research is focusing: 1) Interaction of metal ions with para- quinones/semiquinones/hydroquinones, focusing on metal-ligand pH, temperature and/or photo induced electron transfer, the selective chemical or photochemical water oxidation or dioxygen activation, 2) Chemistry and photochemistry of organic lanthanides with applications in OLEDs and solar spectrum condensation, 3) Design and synthesis of organic molecules that selectively bind heavy metal ions for mining Uranyl ion from sea 4) Synthesis and anticancer and/or properties of metal - tocopherol / tocotrienol conjugated molecules.
 
SUSS project, Uranium Mininig fro Sea Water

Selected Publications 
 


 
Solar charging of a Zn-air battery
2023
Keramidas, A.; Lianos, P. J. Power Sources 2023, 555
https://doi.org/10.1016/j.jpowsour.2022.232384

Solar-charging of Zn-air batteries has been studied by employing a photoelectrocatalytic or a photovoltaic system. Discharging of a Zn-air battery corresponds to oxidation of Zn and formation of ZnO. Charging is the reverse action, i.e., the reduction of ZnO and deposition of metallic Zn on the Zn electrode. In a typical Zn-air battery, charging also corresponds to water oxidation on the counter electrode and oxygen evolution. Because of the high overpotential for the oxygen evolution reaction, charging of the battery necessitates very high voltages, much higher than the voltage produced by the battery. This problem can be overcome by substituting oxygen evolution reaction by photocatalytic oxidation of an organic substance, which may be a biomass waste. This photoelectrocatalytic charging was presently realized with 100% Faradaic efficiency. More than 2 V of power gain was achieved through photoelectrocatalytic charging, i.e., a small input voltage was then necessary in order to charge the battery. Battery charging was also possible by using a photovoltaic cell as long as the cell provides enough open circuit voltage to overcome battery potential, overpotentials and losses. In the present case charging was possible with a commercial photovoltaic cell generating 2.25 V at an incident light intensity of 100 mW cm−2.scription...

 

 
Experimental and Theoretical Investigation of the Mechanism of the Reduction of O2 from Air to O22- by VIVO2+-N,N,N-Amidate Compounds and Their Potential Use in Fuel Cells.
2023
Papanikolaou, M.; Drouza, C.; Amoiridis, A.; P.;Keramidas, A. D. Inorg. Chem. 2023
https://doi.org/10.1021/acs.inorgchem.3c03272

The two-electron reductive activation of O2 to O22– is of particular interest to the scientific community mainly due to the use of peroxides as green oxidants and in powerful fuel cells. Despite of the great importance of vanadium(IV) species to activate the two-electron reductive activation of O2, the mechanism is still unclear. Reaction of VIVO2+ species with the tridentate-planar N,N,N-carboxamide (ΗL) ligands in solution (CH3OH:H2O) under atmospheric O2, at room temperature, resulted in the quick formation of [VV(═O)(η2-O2)(κ3-L)(H2O)] and cis-[VV(═O)23-L)] compounds. Oxidation of the VIVO2+ complexes with the sterically hindered tridentate-planar N,N,N-carboxamide ligands by atmospheric O2 gave only cis-[VV(═O)23-L)] compounds. The mechanism of formation of [VV(═O)(η2-O2)(κ3-L)(H2O)] (I) and cis-[VV(═O)23-L)] (II) complexes vs time, from the interaction of [VIV(═O)(κ3-L)(Η2Ο)2]+ with atmospheric O2, was investigated with 51V, 1H NMR, UV–vis, cw-X-band EPR, and 18O2 labeling IR and resonance Raman spectroscopies revealing the formation of a stable intermediate (Id). EPR, MS, and theoretical calculations of the mechanism of the formation of I and II revealed a pathway, through a binuclear [VIV(═O)(κ3-L)(H2O)(η11-O2)VIV(═O)(κ3-L)(H2O)]2+ intermediate. The results from cw-EPR, 1H NMR spectroscopies, cyclic voltammetry, and the reactivity of the complexes [VIV(═O)(κ3-L)(Η2Ο)2]+ toward O2 reduction fit better to an intermediate with a binuclear nature. Dynamic experiments in combination with computational calculations were undertaken to fully elucidate the mechanism of the O2 reduction to O22– by [VIV(═O)(κ3-L)(Η2Ο)2]+. The galvanic cell {Zn|VIII,VII||Id, [VIVO(κ3-L)(H2O)2]+|O2|C(s)} was manufactured, demonstrating the important applicability of this new chemistry to Zn|H2O2 fuel cells technology generating H2O2 in situ from the atmospheric O2.

 

 
Four electron selective O2reduction by a tetranuclear vanadium(IV/V)/hydroquinonate catalyst: Application in the operation of Zn-air batteries.
2022
Keramidas, A. D.; Hadjithoma, S.; Drouza, C.; Lianos, P. New J. Chem. 2022, 46 (2), 470-479
https://pubs.acs.org/doi/10.1021/acs.inorgchem.3c03272

The reduction of dioxygen plays a crucial role in both natural and artificial systems exhibiting peroxidase like activity, utilizing O2 as a cheap and green oxidant in several applications including the development of new effective sources of clean energy. The exploration of new facile and cost-efficient electrocatalysts which promote the interconversion between H2O and O2 remains a crucial challenge. In this work, the applicability of peroxidase mimicking tetranuclear vanadium(IV/V) hydroquinonate, 1, as a proton-coupled electron transfer (PCET) oxygen reduction electrocatalyst to metal–air batteries is presented. Cyclic and rotating disk voltammetry studies show that the O2 reduction is associated with the PCET mechanism. Measurements of the O2 consumption vs. pH reveal that two molecules of 1 reduce one molecule of O2 supporting a 4e reduction of O2 to H2O. 51V NMR spectroscopy used for H2O2 trap experiments supports the 4e reduction of O2. Exhaustive electrolysis shows that the redox reactions of 1 are fully reversible in the presence of O2. Compound 1 was used as a catalyst for the O2 reduction in a Zn–air battery. Aqueous solutions of the complex were transformed into gels by the addition of a small quantity of sulfuric acid. Then, the complex in the form of gel was easily deposited on a carbon cloth electrode and was directly applied for the construction and operation of a Zn–air battery. The presence of the complex resulted in a large increase of the current and the power produced by the cell, particularly in an acidic electrolyte where the complex operates the best. The application of the biomimetic complex 1 in the operation of metal–air batteries opens a new and interesting route for applying such molecules in a wide range of high importance technological applications.

 

 
Hafnium(IV) Chemistry with Imide-Dioxime and Catecholate-Oxime Ligands: Unique {Hf5} and Metalloaromatic {Hf6}-Oxo Clusters Exhibiting Fluorescence. IDOI: 10.1021/acs.inorgchem.2c01768.
2022
Bandeira, N. A. G.; Miras, H. N.; Keramidas, A. D. Inorg. Chem. 2022, 61 (50), 20253-20267
https://pubs.acs.org/doi/full/10.1021/acs.inorgchem.2c01768

Write here the descHafnium(IV) molecular species have gained increasing attention due to their numerous applications ranging from high-resolution nanolithography, heterogeneous catalysis, and electronics to the design of molecule-based building blocks in metal–organic frameworks (MOFs), with applications in gas separation, sorption, luminescence sensing, and interim storage of radioactive waste. Despite great potential, their chemistry is relatively underdeveloped. Here, we use strong chelators (2Z-6Z)-piperidine-2,6-dione (H3pidiox) and 2,3-dihydroxybenzaldehyde oxime (H3dihybo) to synthesize the first ever reported pentanuclear {Hf5/H3pidiox} and hexanuclear {Hf6/H3dihybo} clusters (HfOCs). The {Hf6} clusters adopt unique core structures [Hf6IV3-O)2(μ-O)3] with a trigonal-prismatic arrangement of the six hafnium atoms and have been characterized via single-crystal X-ray diffraction analysis, UV–vis spectroscopy in the solid state, NMR, fluorescence spectroscopy, and high-resolution mass spectrometry in solution. One-dimensional (1D) and two-dimensional (2D) 1H NMR and mass spectroscopies reveal the exceptional thermodynamic stability of the HfOCs in solution. Interestingly, the conjunction of the oxime group with the catechol resulted in the remarkable reduction of the clusters’ band gap, below 2.51 eV. Another prominent feature is the occurrence of pronounced metalloaromaticity of the triangular {Hf3} metallic component revealed by its NICSzz scan curve calculated by means of density functional theory (DFT). The NICSzz(1) value of −44.6 ppm is considerably higher than the −29.7 ppm found at the same level of theory for the benzene ring. Finally, we investigated the luminescence properties of the clusters where 1 emits light in the violet region despite the lack of fluorescence of the free H3pidiox ligand, whereas the {Hf63 shifts the violet-emitting light of the H3dihybo to lower energy. DFT calculations show that this fluorescence behavior stems from ligand-centered molecular orbital transitions and that HfIV coordination has a modulating effect on the photophysics of these HfOCs. This work not only represents a significant milestone in the construction of stable low-band-gap multinuclear HfIV clusters with unique structural features and metal-centered aromaticity but also reveals the potential of Hf(IV) molecule-based materials with applications in sensing, catalysis, and electronic devices.ription...

 

 
A Combined Experimental and Theoretical Investigation of Oxidation Catalysis by cis-[VIV(O)(Cl/F)(N4)]+Species Mimicking the Active Center of Metal-Enzymes.
2022
Papanikolaou,M.G.;Drouza, C.;Miras, H. N.; Keramidas, A.D. Inorg. Chem. 2022, 61 (46), 18434-18449
https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c02526

Reaction of VIVOCl2 with the nonplanar tetradentate N4 bis-quinoline ligands yielded four oxidovanadium(IV) compounds of the general formula cis-[VIV(O)(Cl)(N4)]Cl. Sequential treatment of the two nonmethylated N4 oxidovanadium(IV) compounds with KF and NaClO4 resulted in the isolation of the species with the general formula cis-[VIV(O)(F)(N4)]ClO4. In marked contrast, the methylated N4 oxidovanadium(IV) derivatives are inert toward KF reaction due to steric hindrance, as evidenced by EPR and theoretical calculations. The oxidovanadium(IV) compounds were characterized by single-crystal X-ray structure analysis, cw EPR spectroscopy, and magnetic susceptibility. The crystallographic characterization showed that the vanadium compounds have a highly distorted octahedral coordination environment and the d(VIV–F) = 1.834(1) Å is the shortest to be reported for (oxido)(fluorido)vanadium(IV) compounds. The experimental EPR parameters of the VIVO2+ species deviate from the ones calculated by the empirical additivity relationship and can be attributed to the axial donor atom trans to the oxido group and the distorted VIV coordination environment. The vanadium compounds act as catalysts toward alkane oxidation by aqueous H2O2 with moderate ΤΟΝ up to 293 and product yields of up to 29% (based on alkane); the vanadium(IV) is oxidized to vanadium(V), and the ligands remain bound to the vanadium atom during the catalysis, as determined by 51V and 1H NMR spectroscopies. The cw X-band EPR studies proved that the mechanism of the catalytic reaction is through hydroxyl radicals. The chloride substitution reaction in the cis-[VIV(O)(Cl)(N4)]+ species by fluoride and the mechanism of the alkane oxidation were studied by DFT calculations.

 

 
Acid/base responsive assembly/dis-assembly of a family of zirconium(iv) clusters with a cyclic imide-dioxime ligand.
2022
Papanikolaou, M. G.; Keramidas, A. D.; Miras, H. N. Dalton Trans. 2022, 51 (5), 1806-1818
https://pubs.rsc.org/en/content/articlelanding/2022/dt/d1dt03641f

The hydrolytically stable dioxime ligand (2Z-6Z)-piperidine-2,6-dione (H3pidiox) acts as a strong chelator mainly with hard metals in high oxidation states, a pre-requisite for potential applications in metal sequestering processes from aqueous solutions. Reaction of ZrCl4 with H3pidiox in methanol gives the mononuclear compound [ZrIV112-H2pidiox-O,N,O′)2(OH2)2]Cl2·H2O·CH3OH (1), while the same reaction mixture in the presence of KOH gave the pentanuclear ZrOC [ZrIV52-OH)4(OH2)42–η112-Hpidiox-O,N,O′)4111-HpidioxO,N,O′)4]·5KCl·3CH3OH·8H2O (2). Compound 1 is formed at very acidic pH = 0, and the pentanuclear ZrOC 2 at higher pH values (pH = 2). Compounds 1 and 2 were characterized by single crystal X-ray structure analysis, multi-nuclear NMR spectroscopy and ESI-MS spectrometry. The single crystal X-ray structure analysis of 1 revealed a mononuclear zirconium(IV) compound containing an eight-coordinate zirconium atom bound to two singly deprotonated H2pidiox ligands and two water molecules in a severely distorted bicapped octahedral geometry. The pentanuclear ZrOC 2 constitutes the second example of a Zr5 cluster to be reported and the first one in which the four zirconium atoms are arranged in a tetrahedral arrangement with the fifth occupying the center of the tetrahedron. 1D and 2D NMR spectroscopies of the acidic CD3OD solutions of complex 1 reveal a fast equilibrium between 1 and 2. Addition of KOH into a CH3OH solution of 2 results in the controlled fast transformation of 2 to an asymmetric hexanuclear ZrOC 3 as evidenced by the NMR and real-time ESI-MS solution studies. Further addition of KOH to the solution of 3 leads to the ZrOC 4, and on the basis of NMR and ESI-MS data and in comparison with the known hexanuclear titanium(IV)/H3pidiox cluster, it is concluded that the cluster 4 should have a hexanuclear structure. Electrospray ionization mass spectrometry (ESI-MS) demonstrated not only the structural stability 1 and 2 in solution, but also revealed the reversible pH driven dis-assembly/re-assembly process between the monomeric 1 and the pentanuclear ZrOC 2.

 

 
Charging a vanadium redox battery with a photo(catalytic) fuel cell.
2021
Dracopoulos, V.; Keramidas, A.; Pereira, M. C.; Lianos, P. Sol. Energy Mater. Sol. Cells 2021, 221
https://www.sciencedirect.com/science/article/pii/S0927024820304876

A Photo(catalytic) Fuel Cell based on a CdS/TiO2 photoanode and using ethanol as model fuel has been studied as an electric power source to charge a vanadium redox battery. The Photo Fuel Cell was tested under various current production conditions in terms of stability and power output capacity. The cell was functional and produced substantial electric power by consuming an organic fuel under simulated solar energy irradiation. However, it has been found that CdS sensitizer may undergo a self-oxidation process which is relatively fast when the current output is large but is much slower when the current production is low. The conditions for slow self-oxidation have thus been delimited and this allowed determining the conditions for charging the vanadium redox battery using electricity produced by the Photo Fuel Cell. These findings set the basis for production of sustainable electricity and for its storage in a vanadium redox battery.

 

 
Synthesis, Structural, and Physicochemical Characterization of a Ti6and a Unique Type of Zr6Oxo Clusters Bearing an Electron-Rich Unsymmetrical {OON} Catecholate/Oxime Ligand and Exhibiting Metalloaromaticity.
2020
Papanikolaou, M. G.; Keramidas, A. D.; Miras, H. N. Inorg. Chem. 2020, 59 (24), 18345-18357
https://pubs.acs.org/doi/full/10.1021/acs.inorgchem.0c02959

The chelating catechol/oxime ligand 2,3-dihydroxybenzaldehyde oxime (H3dihybo) has been used to synthesize one titanium(IV) and two zirconium(IV) compounds that have been characterized by single-crystal X-ray diffraction and 1H and 13C NMR, solid-state UV–vis, and ESI-MS spectroscopy. The reaction of TiCl4 with H3dihybo and KOH in methanol, at ambient temperature, yielded the hexanuclear titanium(IV) compound K2[TiIV63-O)2(μ-O)3(OCH3)4(CH3OH)2(μ-Hdihybo)6]·CH3OH (1), while the reaction of ZrCl4 with H3dihybo and either nBu4NOH or KOH also gave the hexanuclear zirconium(IV) compounds 2 and 3, respectively. Compounds 13 have the same structural motif [MIV63-Ο)2(μ-Ο)3] (M = Ti, Zr), which constitutes a unique example with a trigonal-prismatic arrangement of the six zirconium atoms, in marked contrast to the octahedral arrangement of the six zirconium atoms in all the Zr6 clusters reported thus far, and a unique Zr6 core structure. Multinuclear NMR solution measurements in methanol and water proved that the hexanuclear clusters 1 and 3 retain their integrity. The marriage of the catechol moiety with the oxime group in the ligand H3dihybo proved to be quite efficient in substantially reducing the band gaps of TiO2 and ZrO2 to 1.48 and 2.34 eV for the titanium and zirconium compounds 1 and 3, respectively. The application of 1 and 3 in photocurrent responses was investigated. ESI-MS measurements of the clusters 1 and 3 revealed the existence of the hexanuclear metal core and also the initial formation of trinuclear M3 (M = Ti, Zr) building blocks prior to their self-assembly into the hexanuclear M6 (M = Ti, Zr) species. Density functional theory (DFT) calculations of the NICSzz scan curves of these systems revealed that the triangular M3 (M = Ti, Zr) metallic ring cores exhibit pronounced metalloaromaticity. The latter depends upon the nature of the metallic center with NICSzz(1) values equal to −30 and −42 ppm for the Ti (compound 1) and Zr (compound 2) systems, respectively, comparable to the NICSzz(1) value of the benzene ring of −29.7 ppm calculated at the same level of theory.

 

 
Electrocatalytic hydrogen production by dinuclear cobalt(ii) compounds containing redox-active diamidate ligands: A combined experimental and theoretical study.
2020
Papanikolaou, M. G.; Keramidas, A. D.; Miras, H. N. Dalton Trans. 2020, 49 (44), 15718-15730
https://pubs.rsc.org/en/content/articlelanding/2020/dt/d0dt02617d

The chiral dicobalt(II) complex [CoII22-L)2] (1) (H2L = N2,N6-di(quinolin-8-yl)pyridine-2,6-dicarboxamide) and its tert-butyl analogue [CoII22-LBu)2] (2) were synthesized and structurally characterized. Addition of one equivalent of AgSbF6 to the dichloromethane solution of 1 and 2 resulted in the isolation of the mixed-valent dicobalt(III,II) species [CoIIICoII2-L)2]SbF6 (3) and [CoIIICoII2-LBu)2]SbF6 (4). Homovalent 1 and 2 exhibited catalytic activity towards proton reduction in the presence of acetic acid (AcOH) as the substrate. The complexes are stable in solution while their catalytic turnover frequency is estimated at 10 and 34.6 h−1 molcat−1 for 1 and 2, respectively. Calculations reveal one-electron reduction of 1 is ligand-based, preserving the dicobalt(II) core and activating the ligand toward protonation at the quinoline group. This creates a vacant coordination site that is subsequently protonated to generate the catalytically ubiquitous Co(III) hydride. The dinuclear structure persists throughout where the distal Co(II) ion modulates the reactivity of the adjacent metal site by promoting ligand redox activity through spin state switching.

 

 
Use of chalcogenide-semiconductor-sensitized titania to directly charge a vanadium redox battery.
2020
Andrade, T. S.; Keramidas, A.; Lianos, P. Nanomaterials 2020, 10 (6), 1-8

Unmediated charging of a battery using solar radiation is a very attractive project of solar energy conversion and storage. In the present work, solar energy was converted into electricity using a photocatalytic fuel cell operating with a chalcogenide-semiconductor-sensitized nanoparticulate titania photoanode and an air-cathode functioning by oxygen reduction. This cell produced sufficient energy to directly charge a vanadium redox battery functioning with a VOSO4 electrolyte and carbon paper electrodes. The whole system is characterized by ease of construction and simplicity of conception; therefore, it satisfies conditions for practical applications.

 

 
Photoelectrocatalytic production of hydrogen peroxide using a photo(catalytic) fuel cell.
2020
Keramidas, A.; Lianos, P. Journal of Photochemistry and Photobiology A: Chemistry 2020, 389,
https://www.sciencedirect.com/science/article/pii/S1010603019315679

Photoelectrochemical production of hydrogen peroxide has been studied by using a two-compartment photoelectrochemical cell operating in the Photo(catalytic) Fuel Cell mode, i.e. it run without any external bias, simply by shining light and generating current. The photoanode was made of CdS quantum dots deposited on nanocrystalline titania, which was first formed on a transparent fluorine doped tin oxide electrode. The photoanode operated in an alkaline environment with added ethanol as model fuel. An air-breathing cathode was made by depositing carbon black on carbon cloth, without any additives of particular functionalities. Best results were obtained by using a neutral electrolyte (Na2SO4) in the cathode compartment. Hydrogen peroxide was produced during cell operation in a cumulative manner adding up to 1400 mg/l (41 mM) in three hours of operation. The rate of hydrogen peroxide production during this period of time remained practically constant and was 5.7 μmole/min, which corresponds to an average Faradaic efficiency of 74%. These data characterize a system with satisfactory performance that may be used for solar fuel production.

 

 
Controlled one pot synthesis of polyoxofluorovanadate molecular hybrids exhibiting peroxidase like activity.
2019
Nicolaou, M.; Drouza, C.; Keramidas, A. D. New J. Chem. 2019, 43 (45), 17595-17602
https://pubs.rsc.org/en/content/articlelanding/2019/nj/c9nj01999e

Three unique mixed-valence polyoxofluorovanadate clusters have been synthesized through a facile preparation process. The structure of these clusters is controlled by the addition of organic ligands. Single-crystal X-ray diffraction revealed that the clusters have the formula (XyH2)4[VV10VIV4O14(μ-O)103-O)103-F)2F4] (1), (Xy = m-xylylenediamine), (pyH)4(H)2[VV10VIV2O12(μ-O)83-O)103-F)2(pic)2] (2) and (pyH)4(H)3(Na+)[VV7VIV2O9(μ-O)83-O)45-F)(pic)4]2 (3), (py = pyridine, pic = picolinate), with 2 and 3 representing the first examples of polyoxofluorovanadate clusters coordinated to a chelating ligand. The electron paramagnetic resonance (EPR) spectroscopy of 1 revealed that the spins of the VIV centers are coupled to each other, in contrast to the isolated spins of the isostructural [VV12VIV2O16(μ-O)103-O)103-F)2(L)2]6−, where L: im = imidazole (4); py (5). The trigonal bipyramidal coordinated VV atoms of 14 and 5 mimic the structure of the active site of the vanadium dependent peroxidases and 4 and 5 exhibit peroxidase like activity.

 

 
H. N. Design and Assembly of Covalently Functionalised Polyoxofluorovanadate Molecular Hybrids.
2018
Nicolaou,M.;Papanikolaou,Keramidas,A.D.;Miras,Chemistry - A European Journal 2018,24 (15),3836-3845
https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/chem.201705730

Mixed-valent polyoxometalate (POM) clusters are one of the most interesting host species, showing a wide range of structural features and properties. The facile preparation and functionalisation of a mixed-valent polyoxofluorovanadates is reported, where two electrons are trapped to antipodal sites of the clusters. The first members of this family of clusters with the general formula, [VV12VIV2O16(μ-O)10(μ3-O)10(μ3-F)2(L)2]6−, where L: py=pyridine (1); pyr=pyrazine (2); im=imidazole (3), are unique organic-inorganic hybrids with the addition of a N-donor ligand at either end of the polyoxofluorovanadate. The composition and connectivity of 13 were characterised by single-crystal X-ray diffraction and electrospray ionisation mass spectrometry. Electron paramagnetic resonance spectroscopy revealed that the two well-separated VIV ions in each cluster are fully uncoupled with J=0, giving a degenerate singlet–triplet ground state. This attenuation of the exchange interaction is probed with density functional theoretical calculations that reveal that the inclusion of the fluoride ion in the cluster produces a bond pathway biased toward destructive interference between competing ferromagnetic and antiferromagnetic interactions. These robust molecular materials are the ideal combination of desirable electronic properties, with an organic handle with which they can be integrated into spintronic circuitry for molecular devices.

 

 
 
 

 Projects 
 


 
New quinone/hydroquinone metal complexes for the catalytic conversion of H2O/O2 to H2O2 and the construction of aqueous photosynthetic solar cells
01/06/2019 – 01/06/2022

Title: “New quinone/hydroquinone metal complexes for the catalytic conversion of O2 to H2O2 and the construction of aqueous photosynthetic solar cells”, Research Promotion Foundations: IΠΕ, Funding: 250000 Euros, Duration: 3 years (2019-2022), Coordinator: A. Keramidas.

 

 
New selective UO22+ chelate materials for the development of novel sensors and sequesters of Uranium from the sea
01/04/2022 – Current

Title: “New selective UO22+ chelate materials for the development of novel sensors and sequesters of Uranium from the sea”, Research Promotion Foundations: IΠΕ, Funding: 200000 Euros, Duration: 3 years (2022-2024), Coordinator: A. Keramidas.

 

 
New markers for the certification of quality and authentication of food staff by EPR
01/09/2008 – 30/08/2012

Title: “New markers for the certification of quality and authentication of food staff by EPR”, Research Promotion Foundations: IΠΕ, Funding: 400000 Euros, Duration: 4 years (2008-2012), Coordinator: C. Drouza.

 

 
 
 

 Patents 
 


 
Tocopherol ester compounds Cyprus
01/01/2015 – Current

KERAMIDAS, ODYSSEOS, PAPAS A. A. A. Tocopherol ester compounds Cyprus US6716873 01-01-2014


 
PROTOTYPE SYSTEMS OF THERANOSTIC BIOMARKERS FOR IN VIVO MOLECULAR MANAGEMENT OF CANCER
01/01/2016 – Current

ODYSSEOS, PITRIS, KERAMIDAS A. C. A. PROTOTYPE SYSTEMS OF THERANOSTIC BIOMARKERS FOR IN VIVO MOLECULAR MANAGEMENT OF CANCER Cyprus US20160376298 01-01-2016


 
PROTOTYPE SYSTEMS OF THERANOSTIC BIOMARKERS FOR IN VIVO MOLECULAR MANAGEMENT OF CANCER
01/01/2016 – Current

ODYSSEOS, PITRIS, KERAMIDAS A. C. A. PROTOTYPE SYSTEMS OF THERANOSTIC BIOMARKERS FOR IN VIVO MOLECULAR MANAGEMENT OF CANCER | [PROTOTYPSYSTEME VON THERANOSTISCHEN BIOMARKERN ZUR MOLEKULAREN IN-VIVO-VERWALTUNG VON KREBS] Cyprus EP3108900 01-01-2016