Two complexes of Sm(II) with crown ethers-electrochemical synthesis, structure and spectroscopy

Two complexes of divalent samarium have been synthesized by electrochemical reduction in methanol-tetrahydrofuran solutions: [Sm(18-crown-6)(ClO4)2] and [Sm(15-crown-5)2](ClO4)2. In [Sm(18-crown-6)(ClO4)2] the metal cation is ten-coordinate and its coordination sphere comprises six oxygen atoms of the crown ligand and four oxygen atoms from two perchlorate anions. [Sm(15-crown-5)2](ClO4)2 shows a sandwich structure with decacoordinate samarium located between two 15-crown-5 molecules. At 77 K both compounds show f-f luminescence originating from the 5D0 level, and also the 15-crown-5 complex shows a weak luminescence in the range 20000-25000 cm(-1), which has been tentatively interpreted as originating from 3P0 and 5H3 levels. At room temperature the emission of [Sm(15-crown-5)2](ClO4)2 is dominated by broad f-d bands. In the excitation spectra some Fano resonances have been observed. The 18-crown-6 compound is unstable, but the 15-crown-5 compound is fairly stable in air.     

Luminescent heptadentate Tb complex with pendant aza-15-crown-5 showing recognition of lactate and salicylate in aqueous solution

The coordinatedly unsaturated neutral complex TbL1 that possesses two labile metal-bound water molecules provides linear response to lactate in the range of 0-3.0 mM at the simulated extracellular background with the variations of Tb luminescence lifetime as output; the maximal amplification of the luminescence intensity of TbL1 reaches a factor of 135 upon titration with aromatic antenna salicylate in the physiological pH window.     

Conversion of molecular information by luminescent nanointerface self-assembled from amphiphilic Tb(III) complexes

A novel amphiphilic Tb(3+) complex (TbL(+)) having anionic bis(pyridine) arms and a hydrophobic alkyl chain is developed. It spontaneously self-assembles in water and gives stable vesicles that show sensitized luminescence of Tb(3+) ions at neutral pH. This TbL(+) complex is designed to show coordinative unsaturation, i.e., water molecules occupy some of the first coordination spheres and are replaceable upon binding of phosphate ions. These features render TbL(+) self-assembling receptor molecules which show increase in the luminescence intensity upon binding of nucleotides. Upon addition of adenosine triphosphate (ATP), significant amplification of luminescent intensity was observed. On the other hand, ADP showed moderately increased luminescence and almost no enhancement was observed for AMP. Very interestingly, the increase in luminescence intensity observed for ATP and ADP showed sigmoidal dependence on the concentration of added nucleotides. It indicates positive cooperative binding of these nucleotides to TbL(+) complexes preorganized on the vesicle surface. Self-assembly of amphiphilic Tb(3+) receptor complexes provides nanointerfaces which selectively convert and amplify molecular information of high energy phosphates linked by phosphoanhydride bonds into luminescence intensity changes.     

Bis(15-crown-5)-1,4-distyrylbenzene and its complexes with metal perchlorates: photonics and structure

Russian Chemical Bulletin - Photoprocesses of bis(15-crown-5)-1,4-distyrylbenzene (DSB) and its complexes with barium and lead perchlorates in MeCN were studied by absorption, luminescence, and...     

Non-cytotoxic, bifunctional EuIII and TbIII luminescent macrocyclic complexes for luminescence resonant energy-transfer experiments

A new macrocyclic ligand, L3, has been synthesised, based on the cyclen framework grafted with three phenacyl light-harvesting groups and a C5-alkyl chain bearing a carboxylic acid function as a potential linker for biological material. Acidity constants are determined by spectrophotometric titrations, as well as conditional stability constants for the resulting 1:1 complexes with trivalent lanthanide ions. The complexes have stabilities comparable to 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (dtma) complexes, with pLn approximately 12-13. Photophysical properties of the ligand and of the EuL3 and TbL3 complexes have been determined for both microcrystalline samples and solutions in water and acetonitrile. They point to the metal ion being present in an environment with axial symmetry derived from the C4 point group. The hydration number determined for TbL3 decreases with increasing pH value and becomes fractional at pH 7.5, which points to an equilibrium between two differently solvated species and probably to the participation of the deprotonated carboxylic acid chain in the complexation. The quantum yields in water (1.9% for EuIII, 3.4% for TbIII) are smaller than those for complexes with the symmetrically substituted parent macrocycle, but efficient luminescence resonant energy transfer (LRET) was observed when Cy5 dye was added to the solutions. Finally, the influence of the TbL3 complex on cell viability is tested on both malignant (5D10 mouse hybridoma, Jurkat human T leukaemia, MCF-7 human breast carcinoma) and non-malignant (Hacat human keratinocyte) cell lines. Cell viability after 24 h incubation at 37 degrees C with 500 microM TbL3 was >90% for all cell lines, except Jurkat (>70%). All of these properties make LnL3 complexes interesting potential probes for bioanalyses.     

Effect of complexation on spectral and kinetic properties of crown-substituted photochromic spironaphthoxazines

The insertion of benzo-15-crown-5 or benzo-18-crown-6 as a substituent at the 9'-position of a spironaphthoxazine molecule increases the lifetime of the open form of spironaphthoxazine by a factor ofca. 2. The complex formation between the crown groups and Mg²⁺ or Ba²⁺ ions changes the lifetime slightly. The addition of benzo-18-crown-6 at the 5'-position leads to an increase in the lifetime of the open form by an order of magnitude and the appearance of absorption with a maximum at 16420 cm^–1 under dark conditions, which testifies to the stabilization of the open form. The addition of Ba²⁺ ions to this compound results in a further increase in the lifetime byca. 35% due to complex formation. The luminescence of the benzo-15-crown-5-substituted compound is probably caused by both the complexation with Mg²⁺ and the photochemical reaction induced by photoactive light and is accompanied by the irreversible loss of photochromism.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2220–2224, September. 1996.     

3-芳基戊二酰基双(4'-苯并-15-冠-5)的合成

苯甲醛和对氯苯甲醛在碱存在下分别与4'-乙酰基苯并-15-冠-5缩合, 生成冠醚化查尔酮1a和1b. 此二化合物作为中间体进一步与4'-乙酰基苯并-15-冠-5发生Michael反应, 生成两种酮型双冠醚2a和2b.     

Microtiterplate phosphate assay based on luminescence quenching of a terbium complex amenable to decay time detection

We describe a terbium-ligand complex (TbL) for a microtiterplate assay for phosphate (P) in the 0.3-100 μmol L⁻¹ range based on luminescence quenching. As the pH optimum is at neutral pH (7.4) the probe is quenched by both, primary (H₂PO₄⁻) and secondary phosphate (HPO₄²⁻). The LOD is 110 nmol L⁻¹. A Stern-Volmer study revealed that quenching is mostly static. Due to the ms-decay time of TbL, the first luminescence lifetime assay for phosphate could also be developed. The lifetime-based calibration plot is linear between 0.5 and 5 μmol L⁻¹ of P. The effect of various surfactants on assay performance and a study on interferents are presented. The probe was successfully applied to determination of P in commercial plant fertilizers and validated against the molybdenum blue test. The probe is the most sensitive lanthanide-based probe for phosphate.     

碲杂冠醚及其铂配合物的合成

本文通过双(2-羟基乙基)碲醚与二醇的二对甲苯磺酸酯缩合, 首次合成了一类新型的冠醚-碲杂冠醚及其中一个碲杂冠醚与二氯化铂的配合物,并对碲杂冠醚的合成方法.结构特征以及配位性能等进行了讨论.     

Maerocyelic polyether sulfide syntheses. The preparation of thia-crown-3,4, and 5 compounds

Macrocyelic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dithiol or sodium sulfide in ethanol. The trivial naming system for these compounds is an extension of the trivial crown nomenclature (5). A thia prefix is used to show that sulfur atoms have replaced ether oxygen atoms in the polyether ring. The following new compounds were prepared: 1-thia-(15-crown-5) (II) 1,4-dithia-(15-crown-5) (III) 1,7-dithia-(15-crown-5) (IV) 1,4-dithia-(12-crown-4) (VII) 1,4,7-trithia-(12-crown-4) (VIII) 1-thia-(9-crown-3) (IX) and 1,4-dithia-(9-crown-3) (X). Four other previously reported maerocyelic polyether sulfides were also prepared. The symmetry of the nmr spectra of these compounds gives added evidence for the proposed ring structures.     

Macrocyclic polycther sulfide syntheses. The preparation of thia-crown-5, 6 and 7 compounds

Macroeyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dimercaptan or sodium sulfide as reported in a previous paper (6). The following new compounds were prepared: 1,4,7-trithia(15-crown-5) (1); 1,4,10-trithia(15-crown-5) (II): 1,4,7,10-tetrathia(15-crown-5) (III); I-thia(18-crown-6) (IV); 1,4-dithia(18-crown-6) (V); 1,7-dithia(18-crown-6) (VI); 1,4,7-trithia(18-crown-6) (VII); 1,7-dithia(21-crown-7) (VIII); and 1,4,7-trithia(21-crown-7) (IX). The melting points of these and previously reported thia-crown compounds correlate with their structures. X-ray analyses of two thia-crown compounds indicate that the large sulfur atoms are directed away from the center of the ring.     

Study of complexation of phenylaza-15-crwon-5, 4-nitrobenzo- 15-crown-5, and benzo-15-crown-5 with Ag+, Tl+ and Pb2+ ions in methanol by competitive potentiometry

The complexation reaction of phenylaza-15-crwon-5, 4- nitrobenzo- 15-crown-5, and benzo-15-crown-5 with Ag⁺, Tl⁺ and Pb²⁺ ions in methanol solution have been studied by a competitive potentiometric method. The Ag⁺/Ag electrode used both as an indicator and reference electrode in a concentration cell. The emf of cell monitored as the crown ethers concentration varies through the titration. The stoichiometry and stability constants of resulting complexes have been evaluated by MINIQUAD. The stoichiometry for all resulting complexes was 1:1. The stability of these metal ions with derivatives of 15-crown-5 are in order phenylaza-15-crown-5 > Benzo-15-crown-5 > 4-nitrobenzo-15-crown-5, and for the each used crown ethers are as Pb²⁺ > Ag⁺ > Tl⁺. The effect of the substituted group on the stability of resulting complexes was considered. The obtained results are novel and interesting.     

The luminescent properties of divalent europium complexes of crown ethers and cryptands

The luminescent properties of divalent europium complexes with crown ether, azacrown ether, N-pivot-azacrown ether, and cryptand in methanol or water have been systematically investigated under UV irradiation. These divalent europium complexes show greatly enhanced emission from 417 nm to 488 nm in the visible blue region in comparison with that of the methanol solution of EuCl₂. The aqueous solution of EuCl₂ is non-luminescent. This obvious distinction in luminescent properties between the macrocyclic ligand-coordinated divalent europium and uncoordinated divalent europium is attributed to the “insulation effect” of Eu²⁺ ion from the solvent molecules of CH₃OH and H₂O by the macrocyclic crown ether or cryptand encapsulation to divalent europium. Moreover, these macrocyclic ligands provide an additional restriction to the electronic charge expansion of the excited Eu²⁺. This also contributes to the enhancement of the Eu²⁺ luminescence. Among all the investigated macrocyclic ligands, 15-crown-5 (15C5) affords the largest enhancement to the Eu²⁺ emission. The intensity of the Eu²⁺–15C5 complex is 690 times that of the EuCl₂ methanol solution with the same Eu²⁺ concentration. This special emission enhancement effect is related to the particular complex composition of 1:3 (Eu²⁺:15C5) and corresponding configuration of Eu²⁺–15C5 complex in methanol. Concerning the mechanism, the luminescence enhancement of divalent europium by complexation with these macrocyclic crown ether or cryptand ligands is found to be initiated from the decrease in non-radiative rate constant rather than from the increase in radiative one.

The divalent europium complexes of methacrylate polymeric polyether derivatives such as 15C5-, 18-crown-6- (18C6), and cryptand [2.2.1]- or [2.2.2]-containing polymer and copolymer have also been prepared. Their luminescent properties in solid state have been studied to aim for practical application. As a similar situation to the simple polyether complexes, the divalent europium complex with 15C5-containing polymer or copolymer shows the largest luminescent enhancement effect. Its emission intensity reaches about 20% that of the commercial inorganic luminescence product CaWO₄:Pb (NBS 1026). In addition, the doping effect of several divalent ions, namely Mg, Sr, Ba and Zn in polymeric complexes, has also been investigated according to the luminescence concentration quenching mechanism in solid state luminescence materials. The emission intensity of 15C5-containing polymer europium(II) complex is raised to twice stronger by doping of Zn²⁺ ion.     

A polarographic study of some complexes of Tl(I) with polyoxa macrocyclic ligands

The log β₁ values at 25° for the reaction in aqueous solution of Tl(I) with 15-crown-5, benzo-15-crown-5, 18-crown-6 and dicyclohexyl-18-crown-6 (isomer cis-syn-cis) have been determined by d.c. and a.c. polarographic measurements.     

3-芳基戊二酰基双(4′-苯并-15-冠-5)的合成

苯甲醛和对氯苯甲醛在碱存在下分别与4′-乙酰基苯并-15-冠-5缩合,生成冠醚化查尔酮1a和1b。此二化合物作为中间体进一步与4′-乙酰基苯并-15-冠-5发生Michael反应,生成两种酮型双冠醚2a和2b。     

A PGSE diffusion and electrophoretic NMR study of Cs+ and Na+ dynamics in aqueous crown ether systems

Multinuclear pulsed gradient spin-echo (PGSE) NMR diffusion and linewidth measurements were used to probe binding and transport in aqueous Na+-15-crown-5, Na+-18-crown-6, Cs+-15-crown-5 and Cs+-18-crown-6 systems. Since direct PGSE observation of many alkali cations is precluded by either low inherent sensitivity or rapid relaxation (or both), the feasibility of proton-detected electrophoretic NMR (ENMR) measurements to complement PGSE data was investigated. ENMR measurements were performed on aqueous Cs+-, Li+-, Na+-, K+-, and Rb+- 18-crown-6 systems. The data analysis is based on a two-site binding model and its corresponding association constants. Cs+ was found to bind considerably more tightly to 18-crown-6 (K=8 M-1) than to 15-crown-5 (K approximately 2 M-1), whereas Na+ had almost equal affinity (K approximately 4.5 M-1) for 15-crown-5 and 18-crown-6. The difficulties encountered in analysing the NMR parameters, methodological limitations and the implied need for more complicated binding models are discussed.     

冠醚硒菁染料的合成

合成了对称和非对称两个新的冠醚硒菁染料2,2'-二乙基-45,4'5'-双并-(15-冠-5)硒碳菁碘化季铵盐和2,2'-二乙基-4,5-并-(15-冠-5)硒碳菁碘化季铵盐以用三种新的中间体2,2'-二硝基-4,5,4',5'-双并-(15-冠-5)二苯基二硒化物, 2-甲基-5,6-并-(15-冠-5)苯并硒唑和2-甲基-3-乙基-5,6-并-(15-冠-5)苯并硒碘化季铵盐。报道了它们的红外、紫外、核磁共振、质谱数据。     

Complexation of Macrocyclic Compounds with Silver Ions in Surfactant Media

This paper is a report on the complexation studies of silverions with certain water soluble crown ethers viz., 15-crown-5,18-crown-6, cyclam, diaza 15-crown-5 and certain water insolublecrown ethers viz., benzo 15-crown-5, dibenzodiaza 15-crown-4,dibenzyldiaza 18-crown-6 in some nonionic surfactants viz.,polyoxyethylated alkyl phenol (TX 100), polyoxyethylene (20)sorbiton monolaurate (Tween 20), polyoxyethylene (20) sorbitonmonoleate (Tween 80) and polyoxyethylated glyco monolaurylether (Brij 35) by potentiometry. In addition, conductometry wasalso used to study the complexation of oxa crown ethers to comparethe results obtained by potentiometry, which were found to be ingood agreement with each other. The complexation studies indicate1:1 complex formation between the silver ion and macrocycle, thelog_ML ⁿ⁺ values being in the range 1 to 9.     

Luminescence determination of sodium and potassium using molecular sensors on the basis of terbium(III) complexes of 4-carboxybenzocrown ethers

The spectral luminescent properties of terbium(III) complexes of 4-carboxybenzo-15-crown-5 (L₁) and 4-carboxybenzo-18-crown-6 (L₂) are studied. The quenching of the luminescence of lanthanide by alkali metal ions is discovered, which is referred to as the formation of mixed Tb(III)-L₁-Na⁺ and Tb(III)-L₂-K⁺ complexes. The complexes are useful as molecular sensors for the luminescence determination of Na⁺ and K⁺ with the detection limits 1.5 and 25.0 μg/mL. Using the Tb(III)-L₁ complex, sodium can be determined in the presence of a 1000-fold excess of potassium. The developed procedures are utilized for the determination of KCl in the Kalipoz medication in tablet form and the total sodium salts (NaCl, NaHCO₃) in the Trisol solution for infusions.     

Liquid crystal polymers containing macroheterocyclic ligands. III. Side chain liquid crystalline polymethacrylates containing mesogenic units based on diarylacetylenes and benzo-15-crown-5

The synthesis and polymerization of 4′-[4-ethynyl-1-(11-methacryloylundecan-1-yloxy) benzene] benzo-15-crown-5 ( 8 ), 4′-[4-ethynyl-4′-(11-methacryloylundecan-1-yloxy) biphenyl] benzo-15-crown-5 ( 15 ), 4′-[2-ethynyl-6-(11-methacryloylundecan-1-yloxy) naphthalene] benzo-15-crown-5 ( 24 ), and 4′-[2-ethynyl-6-(11-methacryloylundecan-1-yloxy)naphthalene]-5′-ethylbenzo-15-crown-5 ( 35 ) is described. The synthesis and characterization of 4′-[4-(4-ethynyl-1-(2-ethynyl-6-(6-hydroxyhexan-1-yloxy)naphthathalene)benzene]) benzo-15-crown-5 ( 29 ) is also presented. Both monomers and polymers were characterized for their mesomorphic behavior. 8 , poly( 8 ), and 15 are crystalline. Due to the insolubility of 15 , poly( 15 ) could not be synthesized. 24 is crystalline, while poly( 24 ) displays a monotropic nematic mesophase. 29 exhibits also a monotropic nematic mesophase. 35 is crystalline, while poly( 35 ) displays an enantiotropic nematic mesophase which is kinetically controlled due to its close proximity to the glass transition temperature.