Synthesis and enantiomeric recognition studies of a novel 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups

A novel optically active 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups was synthesized and its enantiomeric recognition properties were examined towards the enantiomers of tetrabutylammonium salts of chiral α-hydroxy and N-protected α-amino acids using UV–vis spectroscopy

Synthesis and Complexation Studies of Optically Active Aza- and Diazacrown Ethers Containing a Pyrene Fluorophore Unit

Novel enantiopure azacrown [(R,R)-1 and (S,S)-1] and diazacrown [(R,R)-2–(R,R)-4 and (S,S)-2–(S,S)-4] ethers containing a pyrene fluorophore unit and two phenyl groups at their chiral centers were obtained in multistep syntheses. The action of these chemosensors is based on the photoinduced electron transfer (PET) process, thus they show fluorescence enhancement in the presence of protonated primary amines and amino acid esters. Their recognition abilities toward the enantiomers of 1-phenylethylamine hydrogen perchlorate (PEA), 1-(1-naphthyl) ethylamine hydrogen perchlorate (NEA), phenylglycine methyl ester hydrogen perchlorate (PGME), and phenylalanine methyl ester hydrogen perchlorate (PAME) were examined in acetonitrile using fluorescence spectroscopy

Nitrogén-, kén- és foszforatomot tartalmazó koronaéterek szintézise, molekuláris felismerése és alkalmazása = Synthesis, molecular recognition and application of crown ethers containing nitrogen, sulfur and phosphorus atoms

A kereskedelemből könnyen beszerezhető és viszonylag olcsó alapanyagokból kiindulva piridino-, ill. akridino-18-korona-6 éter alapú királis állófázisokat állítottunk elő, és ezeken jó hatásfokkal rezolváltunk racém protonált primer aminokat, aminosavakat és azok származékait HPLC-vel. Akridin egységet tartalmazó enantiomertiszta koronaétereket szintetizáltunk, és potenciametriás mérések alapján kimutattuk, hogy ezek közül az egyik figyelemre méltó enantioszelektivitást mutat a protonált 1-feniletil-amin enantiomerjeival szemben, míg egy másik kiemelkedő szelektivitással komplexálja az ezüst iont. Optikailag aktív monoaza-18-korona-6 étereket állítottunk elő, ezeket különböző fluorofor (BODIPY, akridinon, N-metilakridinon) jelzőegységgel láttuk el, és fotofizikai módszerekkel behatóan tanulmányoztuk ezek komplexképzését királis vegyületek enantiomerjeivel, ill. különböző fémionokkal szemben. Néhány esetben figyelemre méltó szelektivitást mutattunk ki. Akridinon fluoreszcens jelzőegységet tartalmazó bisz(azakoronaéter) típusú makrociklusokat szintetizáltunk, és a két aza-18-korona-6 éter receptor egységet tartalmazóról kimutattuk, hogy az mind 1:1, mind 1:2 ligandum-fémion arányú komplexek kialakítására képes. Könnyen deprotonálható dialkilhidrogén-foszfát, ill. diarilfoszfinsav egységet tartalmazó enantiomertiszta koronaétereket állítottunk elő, és részletesen tanulmányoztuk utóbbi enantioszelektív komplexképzését protonált primer aralkil-aminokkal. | We prepared chiral stationary phases based on pyridino- and acridino-18-crown-6 ethers starting from commercially available and relatively cheap materials, and using them we resolved racemic protonated primary amines, amino acids and their derivatives efficiently by HPLC. We synthetized enantiopure crown ethers containing an acridine unit, and showed by potentiometric measurements that one of them had a reasonable selectivity for the enatiomers of protonated 1-phenylethylamine, and another one complexed silver ion with very high selectivity. We prepared optically active monoaza-18-crown-6 ethers, attached different fluorofor signalling units (BODIPY, acridinon, N-methylacridinon) to them, and using photophysical methods we thoroughly studied their complexation with the enantiomers of different chiral compounds, and several metal ions, respectively. In a few cases these ligands demonstrated remarkable selectivity. We synthetized bis(azacrown ether)s containing an acridinone signalling unit, and we showed that the one having two aza-18-crown-6 ether receptor units is able to form complexes with both 1:1 and 1:2 ligand to metal ion ratios. We prepared enantiopure proton-ionizable crown ethers containing an dialkylhidrogenphosphate or a diarylphosphinic acid unit, and we thoroughly studied the enantioselective complex formation of the latter with protonated primary aralkyl amines

Larger Groups, Smaller Enantioselectivity? Two Anthracene-Containing, Pyridino-Crown Ether-Based Fluorescent Sensor Molecules

(R,R)- and (S,S)-enantiomers of anthracene-containing pyridino-18-crown-6 ether having tert-butyl groups at the stereogenic centers were prepared with the aim of achieving higher enantioselectivity than for the reported (S,S)-analogue having isobutyl groups. The enantiomeric recognition abilities of the new sensor molecules toward chiral protonated primary amines and amino acid esters were studied in acetonitrile by UV–vis and fluorescence spectroscopies. The pKa values of these pyridino-crown ethers and their reported (S,S)-analogues having methyl or isobutyl groups have also been determined in acetonitrile

Unique fluoride anion complexation in basic media by 5,5-dioxophenothiazine bis(phenylurea) and bis(phenylthiourea)

The anion recognition properties of the newly synthesized 5,5-dioxophenothiazine bis(phenylurea) and bis(phenylthiourea) were investigated in acetonitrile using UV–vis spectroscopy. While most of the studied anions were bound only by the neutral receptors, fluoride and acetate were complexed even by the deprotonated ones

Synthesis and characterization of a novel, colored lipophilic additive for spectral imaging the transport in ionophore based ion-selective membranes

The synthesis and application of a novel colored lipophilic additive (2,4,6-trinitro-3-pentadecylphenol (TNPDP)) as optical tracer for imaging membrane transport is presented. It was found that TNPDP (estimated pK a = 5.53) does not dissociate completely in the studied membranes, even in the presence of the highly basic ETH 5294 chromoionophore (pK a = 12.0). In voltage polarization experiments the TNPDP compounded, ETH 5294 based membranes behaved similarly to fixed site membranes, i.e., the external field did not induce concentration polarization in TNPDP and the protonated chromoionophore. To interpret this peculiar behavior, original methods have been implemented to i) compare the diffusion properties and determine the diffusion coefficients of multiple species in ion-selective membranes by hyperspectral imaging, and ii) determine the ion pair formation constant of the ETH 5294 with the novel colored lipophilic anion and a commonly used tetraphenylborate derivative by impedance spectroscopy. Using the merged membrane method individual diffusion coefficients of (2.39 ± 0.07) × 10-8 cm2/s (N = 5), and (2.34 ± 0.02) × 10-8 cm2/s (N = 2) were determined for the unprotonated form of ETH 5294 and for the undissociated form of TNPDP, respectively. Once in combination with a counter anion, the diffusion coefficient of the protonated ETH 5294 depended on the properties of the lipophilic anion in the membrane. The apparent diffusion coefficient of the protonated ETH 5294 were much smaller when paired with TNPDP ((1.8 ± 0.8) × 10-9 cm2/s, N = 9) than with tetrakis[3,5- bis(trifluoromethyl)phenyl]borate (TFPB) ((1.19 ± 0.42) × 10 -8 cm2/s, N = 5). In agreement, the ion pair formation constants of the ETH 5294 with TNPDP (3.14 × 104 M -1) were almost three orders of magnitude higher than with TFPB (83 M-1). © 2006 Wiley-VCH Verlag GmbH & Co. KGaA