A New Composition for Co(II)-porphyrin-based Membranes Used in Thiocyanate-selective Electrodes

Vlascici, Dana; Fagadar‐Cosma, Eugenia; Bizerea-Spiridon, Otilia

doi:10.3390/s6080892

Cited by 26 publications

(28 citation statements)

References 14 publications

(16 reference statements)

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“…In connection with our previous concerns about the synthesis of porphyrins and their use in the design of optoelectronic nanomaterials [27], medical application as ionophores in the construction of ion selective membrane electrodes for monitoring thiocyanate-anion in biological fluids of smokers [28,29] and also based on the examination of the results reported in literature regarding the structures of the porphyrins used as PDT photosensitizers, this paper is focused on the synthesis and characterization of a series of new second generation asymmetrical meso-tetraphenylporphyrins, differentiated by substituents in the meta positions of the phenyl rings with either -OH or -OCH 3 groups, and in the para positions only with p-OCH 3 groups. A new series of differentially functionalized porphyrins was obtained by a multicomponent synthesis, i.e.…”

Section: Design Of New Unsymmetrically Substituted Porphyrins With Hymentioning

confidence: 99%

Combinatorial Synthesis and Characterization of New Asymmetric Porphyrins as Potential Photosensitizers in Photodynamic Therapy

Fagadar‐Cosma¹,

Cseh²,

Badea³

et al. 2007

CCHTS

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Porphyrins play a major role as active photosensitizers in noninvasive optical photodynamic therapy (PDT). In a modular approach, this paper presents a short review of the recent developments of porphyrin structures and materials with improved photosensitizing properties and then presents the synthesis and characterization of a series of new second generation asymmetrical meso-tetraphenylporphyrins varied by substituent in the meta positions of the phenyl rings with either -OH or -OCH3 groups, whereas in the para positions only with -OCH3 groups. The new series of differentially functionalized porphyrins were obtained by a combinatorial multicomponent synthesis (Adler-Longo method) by simultaneously using two different aldehydes: 3,4-dimethoxybenzaldehyde and 3-hydroxybenzaldehyde. The porphyrins were isolated, purified and characterized by HPLC, TLC, UV-vis, fluorescence, MS, 1H-NMR, and 13C-NMR analysis, accompanied by DEPT 135 experiments. Because of the fact that the medium in cancerous tissues is often more acidic than in normal tissues, the capacity of these porphyrins to exist simultaneously in aggregated and protonated forms was also investigated, in tetrahydrofuran (THF) and acid THF-water systems, underlying the changes in the photophysical behaviour. The relative fluorescence quantum yields (Phif) were calculated in comparison with meso-tetraphenylporphyrin (TPP), and the values between 0.14-0.26 were found to be promising for further trials. The series of asymmetrically substituted tetraphenylporphyrins, as the new class of supramolecular materials, are suitable for further functionalization in order to improve their photophysical properties, and they could represent interesting potential PDT photosensitizers.

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Section: Design Of New Unsymmetrically Substituted Porphyrins With Hymentioning

confidence: 99%

Combinatorial Synthesis and Characterization of New Asymmetric Porphyrins as Potential Photosensitizers in Photodynamic Therapy

Fagadar‐Cosma¹,

Cseh²,

Badea³

et al. 2007

CCHTS

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“…To date, only one paper has been reported on the use of a Rh(III)-porphyrins within polymeric membrane electrodes, and the authors suggested these electrodes as thiocyanate selective sensors 24. However, no comprehensive studies were conducted on the question of nitrite-selectivity.…”

mentioning

confidence: 99%

Polymeric Membrane Electrodes with High Nitrite Selectivity Based on Rhodium(III) Porphyrins and Salophens as Ionophores

Pietrzak

Meyerhoff

2009

Anal. Chem.

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Several porphyrin and salophen complexes with Rh(III) are examined as ionophores to prepare nitrite selective polymeric membrane electrodes. All ionophores tested exhibit preferred selectivity towards nitrite anion. Enhanced potentiometric nitrite selectivity is observed in the presence of either lipophilic anionic as well as cationic sites within the membranes, suggesting that the ionophores can function via either a charged or neutral carrier response mechanism. Among a range of complexes and membrane formulations examined, optimal nitrite selectivity and reversible response down to 5 × 10 −6 M is achieved using Rh(III)-tetra(t-butyl-phenylporphyrin) as the ionophore in the presence of lipophilic cationic sites in plasticized PVC membrane. Response times are substantially longer than typical membrane electrodes apparently due to slow nitrite ligation reaction however, a significant improvement in dynamic EMF response can be realized by optimizing the membrane formulation and increasing temperature. The selecitivity observed with these membranes is greater than the best nitrite selective electrodes reported to the date in the literature based on lipophilic Co (III)-corrin complexes, allowing the new nitrite electrodes to be utilized to determine the level of nitrite in meats with good correlation to the colorimetric Griess assay method.Ion-selective polymeric membrane electrodes (ISEs) for cations and anions have become widespread analytical tools over the past three decades. 1,2 They are based on a generic sensing principle in which different lipophilic ionophores can be employed within the polymer membranes to yield devices with high selectivity for a wide range of ions. Generally, it has been found that the development of ionophores capable of selective interaction with specific anions is far more challenging than for cations, owing to the highly varied sizes and shapes of anionic species. 1 Among the anion-selective carriers examined to date, lipophilic metal cationligand complexes, such as metalloporphyrins, metallophthalocyanines, and metallosalophens have received considerable attention due to their good chemical and thermal resistance. 3 Moreover, it has been demonstrated repeatedly that the anion selectivity of these complexes depends mainly on the specific nature of the central metal cation and hence fundamental knowledge about the chemical ligation properties of metal ion centers of these complexes (i.e., relative affinity towards different anions) can help predict the anion-selectivity of membranes formulated with such species.There is a growing interest in devising simple sensors to detect nitrite due to the important role of this anion in many fields. 4 Nitrite ion is commonly used as an additive in some foods and as a corrosion inhibitor. 5,6,7 Moreover, it can be formed as a result of the degradation of fertilizers. 8,9,10 Its determination is important for environmental reasons as well as for public health, since highly carcinogenic N-nitrosoamines can be formed by the reaction of nitri...

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“…As can be seen from the table, the proposed electrode in comparison of recent reports in the literature has fast response time 27,41,[44][45][46][47][48][49][50][51][52][53]56,57,59,62 with good Nernestian slope 26,27,40,48,52,53,57,60 , wide linear dynamic range and low detection limit 26,27,40, 43-46,48-53, 56,57,59,60 and specially using ability in very wide pH range (1.7-11.5). …”

Section: Selectivitymentioning

confidence: 80%

Highly Thiocyanate‐Selective Membrane Electrode Based on the Bis(Benzoylacetone) propylenediimine Copper(II)Complex

et al. 2007

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A potentiometric thiocyanate-selective sensor based on copper(II) bis(benzoylacetone)propylenediimine complex as a new neutral carrier for a thiocyanate-selective electrode is reported. The response mechanism is discussed in view of the UV spectroscopy technique. The sensor displays a near Nernestian slope of -57.4 ± 0.5 mV per decade. The working concentration range of the electrode is 8.0×10 -7 -1.0×10 -1 M with a detection limit of 7.4×10 -7 M. The response time of the sensor in the all concentration ranges is very short (5-10 s). The response of the sensor is independent of pH, in the pH range of 1.7-11.5. The best performance was obtained with a membrane composition of 32.69% PVC, 57.34% dibutyl phthalate, 6.82% complex and 3.15% methyltrioctylammonium chloride (MTOAC) as additive. The proposed electrode is more selective than other proposed methods for determination of thiocyanate ion over a wide variety of common inorganic and organic anions and it was successfully applied to direct determination of thiocyanate in the presence of other anions in biological, water and waste water samples.

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A New Composition for Co(II)-porphyrin-based Membranes Used in Thiocyanate-selective Electrodes

Cited by 26 publications

References 14 publications

Combinatorial Synthesis and Characterization of New Asymmetric Porphyrins as Potential Photosensitizers in Photodynamic Therapy

Combinatorial Synthesis and Characterization of New Asymmetric Porphyrins as Potential Photosensitizers in Photodynamic Therapy

Polymeric Membrane Electrodes with High Nitrite Selectivity Based on Rhodium(III) Porphyrins and Salophens as Ionophores

Highly Thiocyanate‐Selective Membrane Electrode Based on the Bis(Benzoylacetone) propylenediimine Copper(II)Complex

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