Gheorghe Fagadar-Cosma

Gheorghe Fagadar-Cosma


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 July 2018 in Sensors
Verified
Journal Article
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DVDana Vlascici
Dana Vlascici
NPNicoleta Plesu
Nicoleta Plesu
GFGheorghe Fagadar-Cosma
Gheorghe Fagadar-Cosma
ALAnca LASCU
Anca LASCU
MPMihaela Petric
Mihaela Petric
Eugenia FAGADAR-COSMAEugenia FAGADAR-COSMA
Eugenia FAGADAR-COSMA
Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) was used in the construction of new ion-selective sensors. The potentiometric response characteristics (slope and selectivity) of iodide and bromide-selective electrodes based on (PtTMeOPP) metalloporphyrin in o-nitrophenyloctylether (NPOE), dioctylphtalate (DOP) and dioctylsebacate (DOS) plasticized poly(vinyl chloride) membranes are compared. The best results were obtained for the membranes plasticized with DOP and NPOE. The sensors have linear responses with near-Nernstian slopes toward bromide and iodide ions and good selectivity. The membrane plasticized with NPOE was electrochemically characterized using the EIS method to determine its water absorption and the diffusion coefficient into the membrane.

6 July 2013 in BMC Chemistry
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DVDana Vlascici
Dana Vlascici
IPIuliana Popa
Iuliana Popa
VCVlad A Chiriac
Vlad A Chiriac
GFGheorghe Fagadar-Cosma
Gheorghe Fagadar-Cosma
HPHoria Popovici
Horia Popovici
Eugenia FAGADAR-COSMAEugenia FAGADAR-COSMA
Eugenia FAGADAR-COSMA
Background: Copper is an essential trace element with a great importance in industry, environment and biological systems. The great advantage of ion-selective sensors in comparison with other proposed techniques is that they are measuring the free metal ion activity which is responsible for their toxicity. Porphyrins are known to be among the best ionophores in formulation of ion-selective sensors.Results: A symmetrically substitutedmeso-porphyrin, namely: 5,10,15,20-tetrakis(4-allyloxyphenyl)porphyrin (TAPP) was used in the construction of a new copper selective-sensor and was also tested for the removal of copper from waste waters. The potentiometric response characteristics (slope and selectivity) of copper-selective electrodes based on TAPP ino-nitrophenyloctylether (o-NPOE), dioctyl phtalate (DOP) and dioctyl sebacate (DOS) plasticized with poly(vinyl chloride) membranes are compared.Conclusions: The best results were obtained for the membrane plasticized with DOP. The sensor has linear response in the range 1x10-7– 1x10-1M with 28.4 ± 0.4 mV/decade near-Nernstian slope towards copper ions and presents good selectivity. Due to its chelating nature, the same porphyrin was also tested for the retention of copper from synthetic copper samples, showing a maximum adsorption capacity of 280 mg/g.

17 December 2014 in Molecules
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Eugenia FAGADAR-COSMAEugenia FAGADAR-COSMA
Eugenia FAGADAR-COSMA
DVDana Vlascici
Dana Vlascici
GFGheorghe Fagadar-Cosma
Gheorghe Fagadar-Cosma
APAnca Palade
Anca Palade
ALAnca LASCU
Anca LASCU
ICIleana Cernica
Ileana Cernica
The present report deals with the tailoring, preparation and characterization of novel nanomaterials sensitive to CO2 for use in detection of this gas during space habitation missions. A new nanostructured material based on mixed substituted asymmetrical A3B porphyrin: 5-(4-pyridyl)-10,15,20-tris(3,4-dimethoxyphenyl)-porphyrin (PyTDMeOPP) was synthesized and characterized by 1H-NMR, FT-IR, UV-vis, fluorescence, MS, HPLC and AFM. Introducing one pyridyl substituent in the 5-meso-position of porphyrin macrocycle confers some degree of hydrophilicity, which may cause self-assembly properties and a better response to increased acidity. The influence of pH and nature of the solvent upon H and J aggregates of the porphyrin are discussed. Porphyrin aggregation at the air–THF interface gave a triangular type morphology, randomly distributed but uniformly oriented. When deposition was made by multiple drop-casting operations, a network of triangles of uniform size was created and a porous structure was obtained, being reorganized finally in rings. When the deposition was made from CHCl3, ring structures ranging in internal diameter from 300 nm to 1 µm, but with the same width of the corona circular of approx. 200 nm were obtained. This porphyrin-based material, capable of generating ring aggregates in both THF and CHCl3, has been proven to be sensitive to CO2 detection. The dependence between the intensity of porphyrin UV-vis absorption and the concentration of CO2 has a good correlation of 98.4%.

31 July 2012 in Molecules
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SISmaranda Iliescu
Smaranda Iliescu
MAMaite-Gyl Augusti
Maite-Gyl Augusti
Eugenia FAGADAR-COSMAEugenia FAGADAR-COSMA
Eugenia FAGADAR-COSMA
NPNicoleta Plesu
Nicoleta Plesu
GFGheorghe Fagadar-Cosma
Gheorghe Fagadar-Cosma
Gheorghe IliaGheorghe Ilia
Gheorghe Ilia
This paper is directed towards the development of safe, and thermally stable solid polymer electrolytes. Linear phosphorus-containing (co)polyesters are described, including their synthesis, thermal analysis, conductivity, and non-flammability. Polycondensation of phenylphosphonic dichloride (PPD) with poly(ethylene glycol) (PEG 12000) with and without bisphenol A (BA) was carried out using solid-liquid phase transfer catalysis. Potassium phosphate is used as base. Yields in the range of 85.0–88.0%, and inherent viscosities in the range of 0.32–0.58 dL/g were obtained. The polymers were characterized by gel permeation chromatography, FT-IR, 1H- and 31P-NMR spectroscopy and thermal analysis. Their flammability was investigated by measuring limiting oxygen index values. The polymers are flame retardants and begin to lose weight in the 190 °C–231 °C range. Solid phosphorus- containing (co)polyesters were complexed with lithium triflate and the resulting ionic conductivity was determined. Conductivities in the range of 10−7–10−8 S cm−1 were obtained.

21 October 2017 in Molecules
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Eugenia FAGADAR-COSMAEugenia FAGADAR-COSMA
Eugenia FAGADAR-COSMA
VBValentin Badea
Valentin Badea
GFGheorghe Fagadar-Cosma
Gheorghe Fagadar-Cosma
APAnca Palade
Anca Palade
ALAnca LASCU
Anca LASCU
MGMihaela Gherban
Mihaela Gherban
The successful preparation of a novel dimer complex formed between 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-porphyrin Fe(III) chloride and (5,10,15,20-tetraphenylporphinato) dichlorophosphorus(V) chloride using the well-known reactivity of the P–X bond is reported. The obtained complex was characterized by UV-vis, Fourier transform infrared spectroscopy (FT-IR), fluorescence, 1H-NMR, 13C-NMR, and 31P-NMR spectroscopic techniques and also by additional Heteronuclear Single Quantum Coherence (HSQC) and Heteronuclear Multiple Bond Correlation (HMBC) experiments in order to correctly assign the NMR signals. Scanning electron microscopy (SEM) and EDX quantifications completed the characterizations. This novel porphyrin dimer complex demonstrated fluorescence sensing of H2O2 in water for low oxygen concentrations in the range of 40–90 µM proving medical relevance for early diagnosis of diseases such as Alzheimer’s, Parkinson’s, Huntington’s, and even cancer because higher concentrations of H2O2 than 50 μM are consideredcytotoxic for life. Due to its optical properties, this novel metalloporphyrin–porphyrin based complex is expected to show PDT and bactericidal activity under visible-light irradiation.