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In this study, phenolphthalein-based ligand L compound derivatized with R-2-phenylglycinol was synthesized and its structure was characterized by 1H-NMR and FTIR spectroscopy. Optical properties of the prepared phenolphthalein-based ligand L towards different cations were investigated by fluorescence and UV-VIS spectroscopy in ethanol-water (95/5; v/v) medium. It was determined that ligand L showed a strong, selective and sensitive fluorescence at 454 nm towards the Zn2+ cation compared to other cations. The mechanism of ligand L complexing with Zn2+ was explained by ICT and inhibition of C=N isomerization and complexation. Fluorescence titration study was performed between ligand L and Zn2+ cation and necessary sensor parameters were examined. According to the Job plot, the complexing ratio was determined as 1:2. The binding constant was calculated as 1.72 x 1012 (logK= 12.24) according to the Benesi-Hildebrand equation. The limit detection value was calculated as 118 nM. When all data were examined, it was determined that the prepared phenolphthalein-based ligand L showed selective and sensitive fluorescence sensor properties against Zn2+ cation., Bu çalışmada (R)-(-)-2-fenilglisinol ile türevlendirilmiş fenolftalein tabanlı ligand L bileşiği sentezlendi ve yapısı 1H-NMR ve FTIR spektroskopisi ile karakterize edildi. Hazırlanan fenolftalein tabanlı ligand L’nin farklı katyonlara karşı optik özellikleri etanol-su (95/5; v/v) ortamında floresans ve UV-GB spektroskopisi ile incelendi. Ligand L’nin Zn2+ katyonuna karşı diğer katyonlara göre 454 nm’de şiddetli, seçimli ve hassas bir floresans özelliği gösterdiği belirlendi. Ligand L’nin Zn2+ ile kompleksleşme mekanizması, ICT ve C=N izomerizasyonunun engellenmesi ve kompleksleşme ile açıklandı. Ligand L ile Zn2+ katyonu arasında floresans titrasyon çalışması gerçekleştirildi ve gerekli sensör parametreleri incelendi. Job grafiğine göre, kompleksleşme oranı 1:2 olarak belirlendi. Bağlanma sabiti Benesi-Hildebrand denklemine göre 1,72x1012 (logK= 12,24) olarak hesaplandı. Limit algılama değeri 118 nM olarak hesaplandı. Tüm veriler incelendiğinde, hazırlanan fenolftalein tabanlı ligand L’nin Zn2+ katyonuna karşı seçimli ve hassas floresans sensör özellikleri gösterdiği belirlendi.

A switchable fluorescence sensor based on a calix (Monapathi et al., 2021) [4]arene:Cu

The polymeric calix[6]arene-tethered silica (C[6]TS) was prepared by the tethering of p-tert-butylcalix[6]arene onto 3-glycidoxypropyl-bonded stationary phase. The structural and composition analysis of the C[6]TS was performed by FTIR, XRD, TGA, and SEM techniques. C[6]TS was used as an adsorbent for the removal of 4-nitrophenol (4-NP) from aqueous solutions. Initial adsorption experiments demonstrated that C[6]TS showed outstanding performance for the removal of 4-NP. So it exhibited rapid and effective adsorption with a %83 yield within ten minutes. Subsequently, some adsorption criteria such as pH, initial concentration, contact time, sorbent dosage, and temperature were evaluated in detail. Thus, adsorption phenomena of 4-NP onto C[6]TS were clarified in this way.

This study describes the sensing studies of QCM sensor which modified with calixarene hydrazine amide derivative immobilized Merrifield resin (CIMR) for the p -nitrophenol (PNP) sensing in aqueous media. For this aim, first CIMR was prepared and its structure was characterized, and then it was coated onto the QCM crystal surface. The PNP sensing studies of CIMR modified QCM sensor revealed good results for PNP sensing. Thus, it was performed the sensing studies at different concentration and pHs in aqueous media. From the results, it was found that the limit of detection was 0.34 mM and optimum pH value was 10 for PNF sensing by CIMR modified QCM sensor. Moreover, it was calculated the adsorption capacity of CIMR as 372 mg/g from the Langmuir and Freundlich isotherm models.

It is crucial to determine and control the metronidazole (MET) ingredient in food and pharmaceuticals for human health and food safety. Even though many sensors have been previously reported to detect MET, there is still a need for a highly selective and sensitive, easy, fast, cost-effective sensor in this area. Herein, we report a fluorescent calix[4]arene derivative (PIMC) for highly selective and sensitive and facile and rapid MET detection based on fluorescence (FL) quenching. The highest FL quenching occurs when PIMC is exposed to MET solution at 400 nm (λex = 340). Owing to the quenching efficacy of MET linearly up to 5.5 × 104 nM was obtained a detection limit of 2.44 nM. Besides, interferences of other pharmaceuticals and ions on probe performance were investigated. The FL probe was successful in MET detection without the assistance of any separation techniques in a pharmaceutical sample (tablet) with an acceptable recovery of 101.3%. The applicability of the current probe as a paper-based sensor to MET detection has been successfully tested. As a result, the proposed probe presents a fast and suitable strategy to sensitive and selective detect MET and proves a good potential for practical applications, especially pharmaceutical preparations.

Chromium(VI) contamination of drinking water arises from industrial activity wherever there is a lack of environmental legislation enforcement regarding the removal of such pollutants. Although it is possible to remove such harmful metal ions from drinking water through large-scale facilities, there currently exists no safe and simple way to filter chromium(VI) oxoanions at the point of use (which is potentially safer and necessary in remote locations or humanitarian scenarios). High-surface-area cloth substrates have been functionalized with calixarene molecules for the selective capture of aqueous chromium(VI) oxoanions in the presence of structurally similar anions. This is accomplished by pulsed plasmachemical deposition of a linker layer and subsequent functionalization with dimethylaminomethyl-calixarene (5,11,17,23-tetrakis[(dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene). Chromium(VI) oxoanions are captured by simply passing polluted water through the functionalized cloth, while other ions not harmful/beneficial to human health remain in the water. These cloth filters are simple to use, highly selective, and easily recyclable-thus making them attractive for point-of-use application in geographic regions lacking appropriate wastewater treatment plants or flawed environmental monitoring systems. Chromium(VI) pollutants have been successfully removed from real-world contaminated industrial wastewater streams using the dimethylaminomethyl-calixarene functionalized cloths.

This article describes the preparation of calix[4]arene-bonded silica gels (C[4]BS and DMC[4]BS), and their application to the removal of some selected phenolic compounds such as phenol (PHE), p-chlorophenol (PCP), m-nitrophenol (MNP) and p-nitrophenol (PNP) from aqueous solutions by adsorption method. In initial adsorption experiments appeared that C[4]BS was much more effective in adsorption of PNP rather than PHE, PCP and MNP, whereas DMC[4]BS exhibited too little adsorption ability towards all phenols. Herein, it was concluded that the hydrogen bonding capacities of both phenols and calix[4]arene based adsorbents played a predominant role in the interactions between adsorbate and adsorbent within the adsorption mechanism. Thus, in subsequent studies, the C[4]BS was employed as an adsorbent in the adsorption of PNP, and adsorption conditions were optimized. Furthermore, isotherm and kinetic studies were performed to clarify the phenomena of PNP adsorption onto C[4]BS.

This study describes the tethering of dimethylamionomethyl bonded calixarene (DMAM-calixarene) onto cotton fabric surface functionalized with poly(glycidyl methacrylate) (PGMA) linker layer using initiated chemical vapor deposition (iCVD) technique and the efficient adsorption capability of DMAM-calixarene functional textiles for the toxic hexavalent chromium from polluted water. The characterization of DMAM-calixarene-tethered textile fabric was performed by FTIR and XPS spectroscopy. Cr(VI) solutions was passed over packed DMAM-calixarene-tethered textile fabric adsorbent and the highest adsorption was observed at pH 2 in dichromate anion form of COS. The regeneration and selectivity studies indicate that the DMAM-calixarene-tethered textile fabric has outstanding adsorbent features in used experimental conditions for hexavalent chromium. Moreover, it was observed that both H-bonding and electrostatic interactions were significant factors in the dichromate anion adsorption process. Thus, this study clearly revealed that any DMAM-calixarene-tethered textile fabric can be easily used as a selective hexavalent chromium capture filter in geographic regions lacking appropriate wastewater purification systems.

This study presents the sensing studies of QCM sensors which coated with calix[4]arene derivatives bearing different functional groups towards some selected Volatile Organic Compounds (VOCs). Initial experiments revealed that QCM sensor coated with calix-3 bearing bromopropyl functionalities was relatively more effective sensor for methylene chloride (MC) emissions than the other calix[4]arene coated QCM sensors, in aqueous media. In further experiments, this effective calix-3 coated QCM sensor were used in detailed sensing studies of selected VOCs. However, the results demonstrated that calix-3 coated QCM sensor was most useful sensor for toluene (TOL) emissions among all. Moreover, the sensing of TOLs with calix-3 coated QCM sensor was also evaluated in terms of sorption phenomena. Consequently, calix-3 coated QCM sensor was good sensor for TOL emissions, and thus it demonstrated that the coating of QCM sensor surface with calixarenes was good approach for sensing of the VOCs. (C) 2017 Elsevier B.V. All rights reserved.

WOS: 000480664200019, PubMed: 31357279, This paper describes the sensing studies of a chiral calix[4]arene receptor (5) having (R)-2-phenylglycinol moiety for arginine enantiomers (D-/L-arginine) by using Quartz Crystal Microbalance (QCM) technique. The initial experiments have revealed that the chiral calix[4]arene 5 coated QCM (CCC-QCM) sensor showed good sensing for arginine enantiomers, such that it has exhibited higher sensing towards D-arginine than that of L-arginine. It has been determined that the sensitivity, limit of detection values of CCC-QCM sensor for the D-/L-arginine solutions as 0.024/0.023 Hz/mu M and 0.38/1.29 mu M, respectively. On the other hand, the racemic mixture studies were optimized using the response surface methodology with central composite design. Consequently, it has been demonstrated that the QCM sensor modification with a calix[4]arene receptor bearing asymmetric centers provided rapid, real-time, sensitive and effective sensing of arginine enantiomers., Scientific and Technological Research Council of Turkey (TUBITAK-Grant)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115Z249]; Research Foundation of the Selcuk UniversitySelcuk University [16401003]; Konya, Turkey, We thank the Scientific and Technological Research Council of Turkey (TUBITAK-Grant Number 115Z249) and the Research Foundation of the Selcuk University (SUBAP-Grant Number 16401003), Konya, Turkey and for financial support of this work produced from Farabi Temel's Ph.D. Thesis.

WOS: 000485967900003, This article describes the enantiomeric discrimination properties of new chiral calix[4]arene derivatives bearing (S)-/(R)-1-phenylethylamine moieties (5a and 5b, respectively) towards the 1-phenylethylamine enantiomers on QCM surface. Initial experiments demonstrated that the 5b coated QCM sensor was the most effective sensing material for enantiomeric discrimination of (R)-/(S)-1-phenylethylamine by exhibiting much more sensing ability towards (R)-enantiomer than (S)-enantiomer. Sensitivity, detection limit and time constant of the 5b coated QCM sensor has been were calculated as 0.082 Hz/mu M, 2.7 mu M, and 319.2 s, respectively. Additionally, effects of calixarene content and different coating technique on enantiomeric discrimination, and Langmuir and Freundlich isotherms of the sensing results also were studied. As a result, it has been demonstrated that the coating of QCM sensor with a chiral calix[4]arene (5b) having (S)-1-phenylethylamine moieties provides substantially enantiomeric discrimination of 1-phenylethylamine enantiomers., Technical Research Council of Turkey (TUBITAK-Grant) [115Z249]; Research Foundation of the Selcuk UniversitySelcuk University [16401003]; Konya, Turkey, We thank the Technical Research Council of Turkey (TUBITAK-Grant No. 115Z249) and the Research Foundation of the Selcuk University (SUBAP-Grant No. 16401003), Konya, Turkey and for financial support of this work produced from Egemen Ozcelik's M.Sc. Thesis.

This paper describes the synthesis of new chiral calix [4]arene derivative having (R)-2-phenylglycinol moiety (compound 6), and its chiral recognition studies for ascorbic acid (AA) enantiomers by using Quartz Crystal Microbalance (QCM). Initial experiments indicated that the outstanding selective chiral recognition (alpha) was observed as 2.61 for L-enantiomer of AA. The sensitivity (S) and the limit of detection (LOD) values for L-AA were calculated as 0.0226 Hz/mu M and 0.63 mu M, respectively. Furthermore, the sorption behavior and mechanism of AA onto compound 6 film were evaluated and the sorption data exhibited a good correlation with the Freundlich isotherm models. The maximum uptake of L-AA by the sensor was found as 5895.76 mg/g. In conclusion, chiral recognition of AA enantiomers as real-time, sensitive, selective and effective was performed by a calixarene derivative coated QCM sensor.

WOS: 000464948100021, PubMed: 30931505, We describe the synthesis of new chiral calix[4]arene derivatives having (R)-1-phenylethylamine, (S)-1-phenylethylamine, (R)-2-phenylglycinol, and (S)-2-phenylglycinol moieties, and chiral recognition studies for enantiomers of some selected -amino acid derivatives such as alanine, phenylalanine, serine, and tryptophan using a quartz crystal microbalance (QCM). Initial experiments indicated that the highest selective chiral recognition factor was 1.42 for alanine enantiomers. The sensitivity, limit of detection, and time constant for l-alanine were calculated as 0.028 Hz/M, 60.9 M, and 36.2 s, respectively. The results indicated that real-time, sensitive, selective, and effective chiral recognition of alanine enantiomers was achieved with a QCM sensor coated with a chiral calix[4]arene derivative having (R)-2-phenylglycinol moieties., Technical Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115Z249]; Research Foundation of Selcuk University (SUBAP grant), Konya, Turkey [16401003], We thank the Technical Research Council of Turkey (TUBITAK grant number 115Z249) and the Research Foundation of Selcuk University (SUBAP grant number 16401003), Konya, Turkey, and for financial support of this work produced from FT's Ph.D. thesis.

Background The chronic consumption of androgenic anabolic steroids has shown to cause atrial arrhythmias. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate repolarization dispersion measured from the 12-lead surface electrocardiogram (including Tp-e interval, Tp-e/QT ratio, and Tp-e/cQT ratio) in bodybuilders who are using anabolic androgenic steroids (AAS). Methods We selected a population of 33 competitive bodybuilders, including 15 actively using AAS for ≥ 2 years (users) and 18 who had never used AAS (nonusers), all men. Results QT, cQT, QTd, cQTd, JT, and cJT were significantly increased in AAS users bodybulders compared to the nonusers (all P < 0.001). Tp-e interval, Tp-e/QT ratio, and Tp-e/cQT ratio were also significantly higher in AAS user group compared to the nonuser group (all P < 0.001). QRS duration was not different between the groups. There were negative correlation between Em and Tp-e, Tp-e/QT ratio, Tp-e/cQT ration (r = −0.657, P < 0.01; r = −0.607, P = 0.02; r = −0.583, P = 0.02; respectively).There were also negative correlation between Sm and Tp-e, Tp-e/QT ratio, Tp-e/cQT ration (r = −0.681, P < 0.01; r = −0.549, P = 0.03; r = −0.544, P = 0.023; respectively). Conclusion In conclusion, we have presented a strong evidence suggesting that Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were increased in AAS users, which suggest that there might be a link between AAS use and ventricular arrthymias and sudden death.

WOS: 000346136500011 PubMed: 25036324 Objective: Restless legs syndrome (RLS) is a common sleep disorder in which patients feel unpleasent leg sensations and urge to move the legs during rest, especially at night, and symptoms are improved by leg movement. Prior studies analyzing the associations between cardiovascular disease and restless legs syndrome has shown controversial results. The goal of the study was to estimate the relationship between restless legs syndrome and slow coronary flow (SCF). Methods: The present study was cross-sectional and observational and consists of 176 individuals who underwent coronary angiography and had angiographically normal coronary arteries of varying coronary flow rates. The study included 86 patients with isolated SCF and 90 control participants with normal coronary flow (NCF). RLS was assessed the day after the coronry flow was evaluated, using a self-administered questionnaire based on the International Restless Legs Study Group criteria. The following question was asked: "Do you have unpleasant leg sensations (like crawling, paraesthesia, or pain) combined with motor restlessness and an urge to move?" The possible responses were as follows: no, less than once/month, 2-4 times/month, 5-14 times/month, and 15 or more times per month. Those who answered that they had these feelings were asked the following two more questions: 1) "Do these symptoms occur only at rest and does moving improve them?" and 2) "Are these symptoms worsen in the evening/at night compared with the morning?" RLS is considered to be probable if the participant has answered "yes" for all three of the above questions, and has a frequency of >= 5 times/month. Student's t-test, Mann-Whitney U test, multiple logistic regression analysis were used for statistical analysis. Results: The prevalence of restless legs syndrome was 48 (27%) and increased significantly with age. Patients with SCF have more likely had RLS than the control group (p

In this study, both boron-doped and -undoped poly(vinyl alcohol)/Calix[4]arene fibers were prepared by using an electrospinning technique. Obtained fibers were characterized by FT-IR, DSC, and SEM techniques. The DSC results show that the degradation of the boron-doped fibers started at much higher temperatures. This result indicates the addition of boron increased the thermal stability of the fibers. SEM pictures show that both of the fiber samples are nonbeaded with diameters ranging from 0.5 to 1 mu m. The fiber diameters are not homogeneous and uniformly distributed for boron-undoped samples.

Background: We aimed to assess atrial electromechanical delay (AEMD) in patients who had undergone heart transplantation. Methods: A total of 32 patients who underwent biatrial anastomosis heart transplantation (24 men, 8 women; mean age: 42±11 years) and 30 healthy volunteers (20 men, 10 women; mean age: 36±13 years) were included in the study. Atrial electromechanical coupling (PA), intra-AEMD, and inter-AEMD were measured. Results: PA lateral (68±7 vs. 51±11 ms, p

This paper describes the sensing studies of QCM sensors with coated some calixarene derivatives bearing different functional groups for some selected Volatile Organic Compounds (VOCs) such as acetone, acetonitrile, carbon tetrachloride, chloroform, methylene chloride (MC), N,N-dimethylformamide, 1,4-dioxane, ethanol, ethyl acetate, xylene, methanol, n-hexane and toluene. The initial experiments have revealed that whole the calix[4]arene modified QCM sensors exhibited strongest sensing ability to MC emissions. Thus, the detailed studies were performed for only MC emissions after the determination of relatively more effective calix-coated QCM sensors for MC emissions in aqueous media. The results demonstrated that QCM sensor coated with calix-7 bearing both amino and imidazole groups was most useful sensor for MC emissions with 54.1ppm of detection limit. Moreover, it was understood that cyclic structures, H-bonding capabilities and also good preorganization properties of calixarene derivatives played an important role in VOC sensing processes.

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by progressive replacement of ventricular myocytes with variable amounts of fibrous and adipose tissue. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp‐e) may correspond to the transmural dispersion of repolarization and that increased Tp‐e interval and Tp‐e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate repolarization dispersion measured from the 12‐lead surface electrocardiogram (including Tp‐e interval, Tp‐e/QT, and Tp‐e/QTc ratio) in asymptomatic ARVD patients METHODS: We selected 27 patients with asymptomatic ARVD and 27 age‐ and gender‐match young, healthy volunteers. RESULTS: Tp‐e interval, Tp‐e/QT and Tp‐e/QTc ratio were also significantly higher in ARVD group compared to the control group (all P < 0.001). There were negative correlation between S global and Tp‐e, Tp‐e/QT, Tp‐e/QTc ration (r = −0.57, P = 0.02; r = −0.85, P = 0.02; r = −0.63, P < 0.01; respectively). There were also negative correlation between Sm global and Tp‐e, Tp‐e/QT, Tp‐e/QTc ration (r = −0.61, P < 0.01; r = −0.67, P < 0.01; r = −0.68, P < 0.01; respectively). Moreover, Em global were negative correlation between Tp‐e, Tp‐e/QT, and Tp‐e/QTc (r = − 0.64, P < 0.001, r = − 0.75, P < 0.01; r = −0,69, P < 0.01; respectively) CONCLUSION: In conclusion, we have presented strong evidence suggesting that Tp‐e interval, Tp‐e/QT ratio, and Tp‐e/QTc ratio were increased in asymptomatic ARVD patients.

We have prepared new diamino derivatives of p-tert-butylcalix[4]arene from the reduction of corresponding amide derivatives. The examination of their recognition abilities towards some selected oxyanions shows that the new calix[4]arene amines are mostly more effective receptors than their amide derivatives for dichromate anions and nitrite, and capable of extracting these anions in yields as high as 95%. However, neither the calix[4]arene amines nor their corresponding amides were capable of extracting phosphate or nitrate at pH 1.5.

This communication describes preparation, characterization, and the evaluation of sorption properties of a calix[4]arene-based chitosan polymer (C[4]BCP). C[4]BCP was used to sorption studies of some heavy metal cations (Co(2+), Ni(2+), Cu(2+), Cd(2+)(,) Hg(2+) and Pb(2+)) and dichromate anions (Cr(2)O(7)(2-)/HCr(2)O(7)(-)) as sorbent material. Also the supporting material (chitosan) was used for comparison in these experiments. The results for heavy metal cations showed that C[4]BCP was excellent sorbent and the effect of chitosan was low. In the sorption studies of dichromate anions, C[4]BCP was highly effective sorbent at pH 1.5.

This article describes the removal of chromium anions from aqueous solutions by using nanofiltration-complexation consisting of pilot-scale nanofiltration equipment (Osmonics Sepa CF Membrane Cell) and water-soluble p-sulfonated calix[4]arene ligand. For the determination of optimum removal conditions of the chromium anions, the effect of pH, ligand cavity size, and foreign anions on the retention of the chromium anions in nanofiltration-complexation system was also evaluated. The results showed that water-soluble p-sulfonated calix[4]arene was an effective and selective ligand for the chromium anions over Cl− , SO4 2 − and NO3 − anions in nanofiltration-complexation system at pH 9.4.

In the present study, Cu(II) removal from aqueous solutions by sorption was investigated. Aminopropyl silica gel-immobilized calix[4]arene polymer (APSIC[4]P) was used in sorption as sorbent. During the experimental part of this study, the effect of parameters, such as pH, initial Cu(II) concentration, temperature on Cu(II) removal was observed. In addition, sorption isotherm studies and column studies were made. Maximum Cu(II) removal was obtained at pH 6 and 25 °C. In the isotherm studies, Langmuir and Freundlich isotherm models were applied and it was determined that the experimental data confirmed to Langmuir isotherm model. Batch sorption capacity ( q 0 ) was calculated as 5.08 mg/g. The capacity value for column study was obtained by graphical integration as 1.14 mg/g. The Thomas and the Yoon–Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristics parameters of the column useful for process design.

Herein the removal and recovery of chromium anions from aqueous solutions by using nanofiltration pilot‐scale equipment (Osmonics Sepa CF Membrane Cell) with a water‐soluble amino calix[4]arene derivative was studied. To understand the selectivity, the authors also examined the retention of chromium anions in the presence of Cl−, NO3 −, SO4 2−, HSO4 −, CO3 2−, PO4 3−, H2PO4 − anions in nanofiltration‐complexation. From the results water‐soluble amino calix[4]arene was effective and selective ligand for dichromate anions over nitrate anions, in a nanofiltration‐complexation system at pH 2.5. Moreover, the recovery and reusability studies of dichromate and nitrate anions and also ligand were performed.

In this paper, the adsorbents were prepared from cellulose-grafted with calix[4]arene polymers (CGC[4]P-1 and CGC[4]P-2) and their sorption properties studied. The polymers were characterized by Fourier transform infrared spectroscopy, elemental analysis, thermal gravimetric analysis and scanning electron microscopy. They were then used to evaluate the sorption properties of some heavy metal cations (Co 2+ , Ni 2+ , Cu 2+ , Cd 2+ , Hg 2+ and Pb 2+ ) and dichromate anions (Cr 2 O 7 2− /HCr 2 O 7 − ). Results showed that CGC[4]P-2 was a good sorbent for heavy metal cations while CGC[4]P-1 was ineffective. In the studies of dichromate anion sorption, it was observed that CGC[4]P-2 was a more highly effective sorbent at pH 1.5 than was CGC[4]P-1.

The article describes the syntheses and complexation properties of new calixarene-based extractants, which have been synthesized from 5,11,17,23-tetra-tert-butyl-25,26,27-tris(chlorocarbonylmethoxy)-28-hydroxycalix[4]arene and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(chlorocarbonylmethoxy)calix[4]arene by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine, respectively. p-tert-Butylcalix[4]arene teraamide was converted to its methyl iodide salt by refluxing with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7−/Cr2O72− anions. The complexing properties of the extractants toward selected alkali/transition metal cations and HCr2O7−/Cr2O72− anions are reported. It has been observed that both receptors do not extract alkali metal cations but show excellent selectivity toward transition metals. The protonated pyridinium forms of the receptors are effective for transferring the HCr2O7−/Cr2O72− anions from an aqueous into a dichloromethane layer.

Herein the synthesis and extraction abilities of new d-/l-phenylalaninol substituted p-tert-butylcalix[4]arene triamide derivatives (3 and 4) towards amino acids are reported. These compounds (3 and 4) have been easily synthesized via aminolysis of p-tert-butylcalix[4]arene trimethylester (2) with d-/l-phenylalaninol in methanol-toluen solvent system at one step. The extraction properties of the prepared chiral calix[4]arene triamide derivatives (3 and 4) towards some selected amino acid methylesters are studied by liquid–liquid extraction. Results show that these chiral calix[4]arene triamide derivatives (3 and 4) exhibited a good affinity towards all amino acid species without any remarkably discrimination.

Bu çalışma yeni polimerik kaliksaren türevinin hazırlanması ve p -nitrofenolün (PNF) adsorpsiyonunda sorbent malzemesi olarak uygulanmasını içermektedir. Kaliksaren türevleri 1-5'in hazırlanmasından sonra, 5 no'lu moleküle aminopropil silika jel destek maddesi tutturularak polimerik kaliksaren 6 türevi elde edildi. Bütün bileşikler, FTIR, 1 H NMR, elemental analizi, TGA ve SEM gibi metotlar kullanılarak karakterize edildi. Aminopropil silika jel immobilize kaliks[4]aren (K[4]APS) 6 , PNF adsorpsiyonu çalışmalarında sorbent olarak kullanılmış ve pH, etkileşim süresi, konsantrasyon, proses sıcaklığı ve sorbent dozajı gibi parametreler çalışıldı. Sonuçlara göre, 6 no'lu molekülün PNF adsorpsiyonu için optimum koşullar pH 6, etkileşim süresi 1 saat, PNF konsantrasyonu 5.0x10-5 M, sorbent dozajı 0.025g ve proses sıcaklığı 25o C olarak bulundu. PNF adsorpsiyon mekanizması, Langmuir ve Freundlich izotermleri ile değerlendirildi., This study describes the preparation of a new polymeric calix[4]arene derivative and its application as a sorbent material in adsorption of p -nitro phenol (PNP). Thus after the preparing of the precursor calixarene derivatives (1 -5), compound 5 was immobilized onto aminopropyl silica gel supporting material to obtain polymeric calix[4]arene (6 ). All compounds were characterized by using some methods such as FTIR, 1 H NMR, elemental analysis, TGA and SEM. Aminopropyl silica gel- immobilized calix[4]arene (C[4]APS) 6 was used as a sorbent in the adsorption studies of PNP and it was examined some parameters such as pH, contact time, initial concentration, process temperature and sorbent dosage. The results showed that pH 6, contact time 1 hour, the concentration of 5.0x10-5 M PNP, 0.025 g of sorbent dosage and 25o C of temperature was found as optimum parameters of PNP adsorption by 6 . Also Langmuir and Freundlich isotherms were evaluated to clarify the PNP adsorption mechanism.

Three new calix[4]arene based polymeric resins (6, 7 and 8) have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetrakis-[(N,N-dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 3, and 5,11,17,23-tetracyanomethyl-25,26,27,28-tetrahydroxycalix[4]arene 4 as precursors with a Merrifield resin. The extraction studies were made by using liquid–liquid extraction, solid–liquid batchwise and packed-column sorption procedures, and effect of different anion to extraction of dichromate anion was examined by using NO 3 - , Cl−, SO 4 2 - and their mixtures. The experimental results showed that these calix[4]arene based polymeric resins have high extraction abilities towards Na2Cr2O7 as compared to their monomeric precursors, and also dichromate anion was extracted in high ratios even in presence of different anions.

Herein the synthesis and recognition abilities towards amino acids and amino alcohols of new d -/ l -phenylalaninol substituted p - tert -butylcalix[6]arenas are reported. These compounds, 6 and 7 have been synthesized via nucleophilic substitution reactions involving 5,11,17,23,29,35- tert -butyl-37,38-dimethoxy-39,40,41,42-( p -tosylethoxy)calix[6]arene 5 with d -/ l -phenylalaninol in dry THF. The extraction properties of 6 and 7 towards some selected amino acid methylesters and amino alcohols have been studied by liquid–liquid extraction. These results show that chiral calix[6]arene derivatives exhibit a good affinity towards all amino acids and amino alcohols.

Two new polymeric thiacalix[4]arenes were synthesized by the reaction of 5,11,17,23-tetra- tert -butyl-25,27-bis[(4-aminobenzyloxy)-26,28-dihydroxy]thiacalix[4]-arene 3 with terephthaloyl dichloride and 5,11,17,23-tetra- tert -butyl-25,26,27,28-tetrahydroxy-thiacalix[4]arene 1 with chloromethylated polystyrene (Merrifield’s resin). Complexation studies were made by using liquid–liquid and solid–liquid extraction procedures. It was found that the soluble polymeric thiacalix[4]arene derived from terephthaloyl dichloride is better at removing alkali (Li + , Na + , K + , and Cs + ) and heavy metal (Cu 2+ , Cd 2+ , Hg 2+ , Pb 2+ , Co 2+ and Ni 2+ ) cations than the precursor thiacalix[4]arenes. Both the soluble polymer and the cross-linked polymer derived from Merrifield’s resin are more efficient at removing transition metals from solution than the precursor thiacalix[4]arene.

The chromatic separation of adenine, adenosine, cytosine, phenol, benzene, and toluene were investigated by using 5,11,17,23‐tert‐butyl‐25,27‐bis(cyanomethoxy)‐26‐(chloroformyl)‐28‐hydroxy‐calix[4]...

A new calix[4]arene‐based polysiloxane resin (CBPSR) was prepared from 5,11,17,23‐tert‐butyl‐25,27‐bis(cyanomethoxy)‐26‐(chloroformyl)‐28‐hydroxy‐calix[4]arene via nucleophilic substitution reaction with 3‐aminopropyltriethoxysilane and followed by copolymerization with octyltriethoxysilane. Batchwise extraction studies have revealed a high adsorption ability of the calix[4]arene‐nitrile derivatives loaded resin toward heavy metals (Cu2+, Co2+, Cd2+, Ni2+, Hg2+ and Pb2+) and dichromate anion (Cr2O7 2−). Liquid–liquid extraction studies show that the monomeric analogs (2, 3 and 4) do not exhibit a good affinity toward these ions.

The article describes the synthesis and extraction properties of new (S)-(-)-1-phenylethylamine substituted p-tert-butylcalix[4]arene/calix[4]arene. These compounds have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(2-hydroxyethoxy)calix[4]arene (4a), or 5,11,17,23-tetra-H-25,26,27,28-tetra(2-hydroxyethoxy)calix[4]arene (4b) with (S)-(-)-1-phenylethylamine in dry THF. The extraction properties of ligands 5a and 5b towards the some selected α-amino acid methylesters and chiral α-amines are also reported. It has been observed that receptor 5a was an excellent ionophore for α-amino acid methylesters/α-amines and good extractant than 5b. However, both of the ligands did not display any selectivity towards the configurations of this species.

This article describes a convenient method for the synthesis of two new polymeric resins via nucleophilic substitution reactions involving 5,11,17,23-tetrakis[(propylthio)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 4 , and 5,11,17,23-tetrakis[(methylthio)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 6 , as precursors with Merrifield's resin. The extraction studies were made using both liquid–liquid extraction and solid–liquid batchwise sorption procedures. The calix[4]arene based polymeric resins have high extraction ability toward metal cations and Na 2 Cr 2 O 7 as compared to their monomeric precursors.

The present work describes the synthesis of a new monomeric dibenzonitrile derivative of p‐tert‐butylcalix[4]arene containing a polymerizable group at its lower rim. This monomer with an acryl amide group has been copolymerized with styrene yielding a linear polymer with pendant calixarene groups. Extraction studies with this monomer and its copolymer show no selectivity for metal cations. Nevertheless, dibenzonitrile groups with calixarene moiety provide a suitable binding site for transferring metal salt (NaHCr2O7) as an ion‐pair.

A convenient synthesis and Cr(VI) extraction properties of a new calix[4]arene-based receptor (5), which has been synthesized from 5,17-diformyl-25,27-dimethoxycarbonylmethoxycalix[4]arene (4) by treatment with 3-aminomethylpyridine in one step, are described. The receptor 5 contains four pyridinyl groups, two on each rim. Two of them are joined by an amide linkage onto the lower rim, and other two are linked by an imine-type linkage onto the upper rim of the calix[4]arene moiety. Receptor 5 is very soluble in water at low pH (

The synthesis of the cone conformers of 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-nitrobenzyloxy)-26,28-dihydroxy]-calix[4]-arene (2), 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-nitrobenzyloxy)]calix[4]arene-crown-6 (3) and 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-aminobenzyloxy)]calix[4]arene-crown-6 (4) containing polymerizable side arms, along with their oligomeric analogue 5, is reported. Extraction studies with monomers 3 and 4 and the oligomer 5 show no difference in their extraction behavior and selectivity, whereas, ionophore 2 is a poor extractant for alkali metal cations. These observations suggest that, substitution of side arms on the lower rim of calix moiety can enhance the calix[4]-crown-6 cone conformers function to extract alkali metal cations in two phase extraction systems.

The article describes the syntheses and extraction properties of a new calixarenebased extractant 5, which has been synthesized from5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxycalix[4]arene(4) by treatment with isoniazid (isonicotinic acid hydrazide) in the presence ofpyridine. The compound 5 was converted to its methyl iodide salt (6) by refluxing 5 with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O 7 - /Cr2O 7 2- anions. The complexing properties of 5 toward selected alkali/transition metal cationsand HCr2O 7 - /Cr2O 7 2 - anions are reported. It has been observed that receptor 5 does not extract alkali metal cations but shows an excellent selectivity toward transition metals. The protonated pyridinium form of 5 is an effective formfor transferring the HCr2O 7 - /Cr2O 7 2- anions from an aqueous into adichloromethane layer.

Three newly synthesized polymer supported calix[4]arene ionophores (7–9) were synthesized, and their ion binding properties toward selected alkali (Li+, Na+, K+, Cs+) and transition metal (Hg2+, Ni2+, Cu2+, Co2+, Cd2+, and Pb2+) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7.

A new oligomeric calix[4]arene-thiacrown-4 (5) was synthesized via a condensation reaction of 5,11,17,23-tetra-tert-butyl-25,27-bis-(4-aminobenzyloxy)-calix[4]arene-thiacrown-4 (4) with adipoyl dichloride. In this oligomerization reaction only five/six calix[4]arene-thiacrown-4 units were linked in the oligomeric chain. The complexation studies of 5 were made with liquid–liquid- extraction and solid–liquid-sorption procedures. For comparison, the extraction efficiencies of monomers 1, 3, and 4 to selected transition metals are reported. The selectivity of monomers 3 and 4 toward Cu2+, Hg2+, and Pb2+ was lost after oligomerization in the two-phase extraction systems. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 186–193, 2004

Two new copolymers containing pendant calix[4]arene units with nitrile functionalities at their lower rim have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetra-tert-butyl-25,27-bis(cyanomethoxy)-26,28-dihydroxy-calix[4]arene (3) or 25,27-bis(cyanometh oxy)-26,28-dihydroxy-calix[4]arene (4) with 1,5-dibromopentane and bisphenol-A. The phase transfer studies were performed by using liquid–liquid extraction procedures. It has been deduced from the observations that both copolymers show a good phase transfer affinity toward selected alkali, alkaline earth, and transition metal cations, unlike their precursor (3).

An aminopropyl silica gel-immobilized calix[6]arene (C[6]APS) has been used for the removal of lindane from an aqueous solution in batch sorption technique. The C[6]APS was synthesized with p-tert-butylcalix[6]arene hexacarboxylate derivative and aminopropyl silica gel in the presence of N,N′-diisopropyl carbodiimide coupling reagent. The sorption study was carried out as functions of solution pH, contact time, initial lindane concentration, C[6]APS dosage and ionic strength of solution. The matrix effect of natural water samples on the sorption efficiency of C[6]APS was also investigated. Maximum lindane removal was obtained at a wide pH range of 2–8 and sorption equilibrium was achieved in 2 h. The isotherm analysis indicated that the sorption data can be represented by both Langmuir and Freundlich isotherm models. Increasing ionic strength of the solutions increased the sorption efficiency and matrix of natural water samples had no effect on the sorption of lindane. By using multilinear regression model, regression equation was also developed to explain the effects of the experimental variables.

Background Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by progressive replacement of ventricular myocytes with variable amounts of fibrous and adipose tissue. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate repolarization dispersion measured from the 12-lead surface electrocardiogram (including Tp-e interval, Tp-e/QT, and Tp-e/QTc ratio) in asymptomatic ARVD patients Methods We selected 27 patients with asymptomatic ARVD and 27 age- and gender-match young, healthy volunteers. Results Tp-e interval, Tp-e/QT and Tp-e/QTc ratio were also significantly higher in ARVD group compared to the control group (all P < 0.001). There were negative correlation between S global and Tp-e, Tp-e/QT, Tp-e/QTc ration (r = −0.57, P = 0.02; r = −0.85, P = 0.02; r = −0.63, P < 0.01; respectively). There were also negative correlation between Sm global and Tp-e, Tp-e/QT, Tp-e/QTc ration (r = −0.61, P < 0.01; r = −0.67, P < 0.01; r = −0.68, P < 0.01; respectively). Moreover, Em global were negative correlation between Tp-e, Tp-e/QT, and Tp-e/QTc (r = − 0.64, P < 0.001, r = − 0.75, P < 0.01; r = −0,69, P < 0.01; respectively) Conclusion In conclusion, we have presented strong evidence suggesting that Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were increased in asymptomatic ARVD patients.