Showing papers by "Mustafa Yilmaz published in 2006"

Synthesis and evaluation of the Cr(VI) extraction ability of amino/nitrile calix[4]arenes immobilized onto a polymeric backbone

Abstract: 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.

Immobilization of Cyclic Alkylamine Calix[4]arene Derivatives on Merrifield Resin: Evaluation of Extraction Ability Toward Dichromate

Abstract: Two new calix[4]arene‐based polymeric resins were synthesized via nucleophilic substitution reactions involving 5,11,17,23‐tetrakis(N‐piperidinomethyl)‐25,26,27,28‐tetrahydroxycalix[4]arene ( 2 ) and 5,11,17,23‐tetrakis[4‐carboethoxy‐N‐piperidino]‐25,26,27,28‐tetrahydroxycalix[4]arene ( 4 ) as precursors with Merrifield resin. Extraction studies were performed by liquid–liquid extraction and solid–liquid adsorption procedures. The monomeric compounds showed excellent extraction ability toward dichromate in liquid–liquid extraction systems. Polymeric resin 3 with calixarene moieties exhibited high adsorption properties, while resin 5 showed lower adsorption of dichromate in solid–liquid extractions.

A Calix[4]arene‐Containing Polysiloxane Resin for Removal of Heavy Metals and Dichromate Anion

Abstract: 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.

Chiral Schiff base derivatives of calix[4]arene: synthesis and complexation studies with chiral and achiral amines

Abstract: Novel chiral Schiff base derivatives of calix[4]arenes 1 – 3 have been prepared from the reaction of 5,17-diformyl-25,27-dipropoxy-26,28-dihydroxycalix[4]arene 4 with ( S )-(−)-1-phenylethylamine, ( R )-(−)-1-cyclohexylethylamine, and ( R )-(−)-2-heptylamine, respectively, by a convenient method in 69–80% yields. Spectrophotometric titrations have been performed in CHCl 3 at 20–30 °C in order to obtain the binding constants ( K ) and thermodynamic quantities (Δ H and Δ S ) for the stoichiometric 1:1 inclusion complexation of various amines with these new host compounds. The molecular recognition abilities and enantioselectivity for guests ( R )- and ( S )-α-phenylethylamine, 3-morpholinopropylamine and n -butylamine are discussed from a thermodynamic point of view.

Synthesis and chiral recognition properties of two novel chiral calix[4]arene tartaric ester derivatives

Abstract: Two new chiral calix[4]arene derivatives containing tartaric acid ester moieties were synthesized. The chiral calix[4]arenes are in a ‘ cone ’ conformation according to NMR spectroscopy. The chiral recognition capabilities of 1 – 4 toward the guests, 1,2-propanediol and serine methyl ester hydrochloride (SerOMe), were investigated ( 1 H NMR spectroscopy). The extraction properties of compounds 1 and 2 toward selected α-amino acid methyl esters were also studied.

Synthesis of p‐tert‐Butylcalix[4]arene Dinitrile Bonded Aminopropyl Silica and Investigating Its Usability as a Stationary Phase in HPLC

Abstract: 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]...

Synthesis and binding properties of two polymeric thiacalix[4]arenes

Abstract: 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.

Synthesis and chiral recognition abilities of new calix[6]arenes bearing amino alcohol moieties

Abstract: 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.

The usefulness of tissue doppler imaging in the determination of left ventricular diastolic filling pressure. Comparison with other techniques.

Abstract: The further examination of left ventricular diastolic function (LVDF) is important in terms of early diagnosis, therapy and follow-up of heart failure. Although cardiac catheterization is considered as the most accurate method in the evaluation of diastolic function, since it is invasive, noninvasive methods are preferred. This study was undertaken to examine whether mitral annular velocities assessed by pulsed tissue Doppler imaging (PTDI) were associated with invasive measures of diastolic LV pressure and whether additional information was gained over traditional transmitral and pulmonary venous flow velocity parameters. Doppler examination was performed in 102 patients referred to our clinic for cardiac catheterization. Doppler signals from the mitral inflow, pulmonary venous inflow, and PTDI of the mitral annulus were obtained. Mean left ventricular diastolic pressure (M-LVDP) was measured. The relationship between echocardiographic parameters and M-LVDP was investigated.A significant correlation was observed between M-LVDP and E/septal Em (r = 0.52, p < 0.000), E/lateral Em (r = 0.45, p < 0.0001), E/posterior Em (r = 0.46, p < 0.0001) E/anterior Em (r = 0.49, p < 0.0001), E/mean Em (r = 0.49, p < 0.0001), PVadur - MVadur (r = 0.51, p < 0.0001). The best echocardiographic parameters correlating with M-LVDP were E/septal Em and PVa-dur - MVa-dur. In conclusion, PTDI could be used in the assessment of LVDP. However, the combination of transmitral flow and pulmonary venous flow velocities with annular velocity can be proposed as the best method for assessing LV filling pressure that combines the influence of transmitral driving pressure and myocardial relaxation.

Computations between Metallocalix[4]arene Host and a Series of Four Oil-Based Fuel Pollutant Guests

Abstract: Calculations using PM3 and mechanics methods on metallocalix[4]arene hosts (1-10) and substituted dibenzothiophene guests (A-D), which are generally known as oil-based fuel pollutants, show that host-guest formation is energetically favored. Calculations have been carried out for both 1/1 and 1/4 ratios of host/guest. There is no direct bonding between the metal center of the host and the sulfur of the guest in the host-guest complex. Sterically hindered dibenzothiophene guests show similar energies to the unhindered analogs. For calix[4]arenes (5-10) in partial cone conformations and having hydrogen rather than p-tert-butyl groups on the wide rim, host-guest formation occurs within the narrow rim rather than the wide rim. Host-guest association appears to occur via - interactions between host and guest phenyl groups rather than via metal-sulfur bonding. The study has importance especially in oil refining to obtain environmentally safe fuel oils and help supramolecular chemists in designing and synthesizing more sophisticated host molecules for the removal of sulfur from crude oil / refinery oil.

Synthesis of a Calix[4]crown‐6 Cone Conformer‐Based Oligomer and its Metal Cation Extraction Abilities

Abstract: A new calixcrown‐6 oligomer 5 was synthesized by reacting a 1,3‐distal di‐amino derivative of cone p‐tert‐butylcalix[4]crown‐6 with malonyl dichloride. Extraction studies with precursor monomers 2 and 3 and oligomer 5 showed differences in their metal cation extraction behavior and selectivity. Precursors monomers 2 and 3 were selective for Hg2+; whereas, oligomer 5 showed high affinity towards both alkali (Li+, Na+, K+, and Cs+) and heavy metal cations (Cu2+, Cd2+, Hg2+ and Pb2+).

Prospects to search for E6 isosinglet quarks in ATLAS

Abstract: We consider pair production of new down-type isosinglet quarks originating from E_{6}, which is the favorite gauge symmetry group in superstring inspired GUT models. The study concentrates on the possibility of observing the pair production of the lightest of the new quarks, D, in the ATLAS detector at the forthcoming LHC accelerator, in the channel D\bar{D}\to ZjZj . Both signal and background events are studied using tree level event generators based on Monte Carlo techniques. The detector effects are taken into account using the ATLAS fast simulation tool, ATLFAST. It is shown that ATLAS can observe the D quark within the first year of low luminosity LHC operation if its mass is less than 650 GeV. For the case of two years of full luminosity running, 1 TeV can be reached with about three sigma significance.