The reaction of Pb[BF(4)](2) in H(2)O/MeCN solution with the macrocycle 18-crown-6 gave the dinuclear complex [{Pb(18-crown-6)(H(2)O)(μ(2)-BF(4))}(2)][BF(4)](2), containing two nine-coordinate lead centres, each bound to all six oxygens of a crown ligand, one water molecule and bridged by two μ(2)-BF(4) groups. In contrast, the oxa-thia crown [18]aneO(4)S(2) gave the mononuclear [Pb([18]aneO(4)...

In the title compound, [Ba(C(14)H(20)O(5))(2)][Co(NCS)(4)], the Ba(II) and Co(II) ions are situated on twofold rotational axes, so asymmetric unit contains half each of the complex cations and anions. The Co(II) ion is coordinated by four N atoms [Co-N 1.83 (2), 1.95 (3) Å] in a distorted tetra-hedral geometry. The Ba(II) ion is coordinated by ten O atoms [Ba-O 2.766 (19)-2.859 (19) Å] from two...

The structures of five more phases of the structural family of compounds [M(H2O)2(15-crown-5)](NO3)2 have been determined. All of these phases are stable at room temperature or above, but transform to other phases if cooled slowly. All five phase transitions take place without significant damage to the single crystal. The M = Co phase, which has a three-dimensional hydrogen-bonding pattern, is ...

a simple and sensitive extraction-fluorimetric method for the determination of copper is reported. the 1,7-diaza-15-crown-5-copper-rose bengal (da15c5-cu-rb) ternary complex is quantitatively extracted into chloroform, diluted with ammoniacal acetone and its fluorescence intensity is measured at 570 nm with excitation at 540 nm. a linear calibration graph was obtained over the copper concentrat...

The synthesis of novel magnesium, copper, and metal-free porphyrazines, peripherally substituted with dithia-7-crown-2 (MPz(7)), dithia-15-crown-5 (MPz(15)), and dithia-18-crown-6 (MPz(18)) macrocycles is reported. These compounds are prepared starting from dicyanoethylene containing crown ethers 3, 2(1), and 2(2), respectively, which contain sulfur as well as oxygen heteroatoms. The "crowned" ...

The density of 15-crown-5 ether (15C5) solutions in the mixtures of N,N-dimethylformamide (DMF) and water (H2O) was measured within the temperature range 293.15-308.15 K using an Anton Paar oscillatory U-tube densimeter. The results were used to calculate the apparent molar volumes (VΦ ) of 15C5 in the mixtures of DMF + H2O over the whole concentration range. Using the apparent molar volumes an...

The structures of [M(H2O)2(15-crown-5)](NO3)2, M = Cu, Zn, Mg and Co, and 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane, have been redetermined at 294 and 90 K. The four structures, and a second form of the Cu structure, have been reported in the literature, but are all incorrect in some significant way. The structures, which all have at least two independent formula units (i.e. Z' > or = 2...

Introduction: F-labelled cells provide an important new technique to evaluate in vivo the migration of implanted cells such as in stem cell therapy [1]. F-marker substances such as perfluorocarbons (PFC ) have been used for cell tracking based on F spectroscopy [2]as well as F magnetic resonance imaging (MRI). We present first results of F MRI of fibroblasts and neuroblastoma cells labeled with...

A new fluorescent ionophore for alkaline earth metal ions, 4'-(9-fluorenecarboxamido)benzo-15-crown-5 (3), was synthesized; its photochemical behavior was investigated using UV, fluorescence, (1)H NMR, and (13)C NMR spectrometry. In the absence of a metal ion, the fluorene moiety showed weak fluorescence emission (fluorescence "Off" state). However, complexation with metal ions greatly enhanced...