Olefin metathesis reactions of carbene-stabilized ruthenium nanoparticles were exploited for the incorporation of multiple functional moieties onto the nanoparticle surface. When the nanoparticles were cofunctionalized with 4-vinylbenzo-18-crown-6 and 1-vinylpyrene, the resulting particles exhibited fluorescence characteristics that were consistent with dimeric pyrene with a conjugated chemical...

K 2 Se5 has been prepared by crystallization from a potassium polyselenide solution in DM F. In a similar way [Na(15-crown-5)]2Se5 can be prepared by crystallization from a sodium poly­ selenide solution in D M F in the presence o f 15-crown-5. Both compounds were characterized by FIR spectroscopy as well as by X-ray structure determinations. K 2 Se5: Space group P 2,2,2,, Z 4, 1659 observed in...

silica-grafted n-propyl-diaza-15-crown-5 (sgpdc) with immobilized palladium nanoparticles was found as an efficient heterogeneous catalytic system for the heck and suzuki coupling reactions and satisfied results were obtained. different derivatives of aryl halides and alkenes under the heck reaction were converted to the corresponding products with good efficiency. the presence of electron-dona...

the extraction-separation of lanthanum and europium ions with bis(2-ethylhexyl) phosphoric acid (dehpa) in cyclohexane was improved by adding 12-crown-4 (12c4) to the aqueous phase as a masking agent. in the presence of this crown ether the extraction curve of lanthanum ions versus ph shifts to the higher ph region, while the curve is not influenced for the europium ions. consequently the separ...

We developed an optrode sensing device that utilizes a polymerized colloidal array (PCCA) photonic crystal material. This array diffracts light in the visible spectral region due to the periodic spacing of colloidal particles. The PCCA changes diffraction wavelength due to binding of Pb2+ to an 18-crown-6 ether molecular recognition agent. This optrode consists of a probe assembly that contains...

A new crown ether-POM (POM = polyoxometalate) adduct with the molecular formula [(C14H20O5)4(H3O)3]PMo12O40 · 0.5CH3CN (1) was isolated from the mixed solvent of acetonitrile and methanol. The adduct is constructed from Keggin [PMo12O40]3− anions and [(C14H20O5)(H3O)] and [(C14H20O5)2(H3O)] cations via electrostatic and hydrogen bonding interactions. The supramolecular interactions combine the ...

GNPs (gold nanoparticles) as an eye-catching sensor rely on the high extinction coefficients and the shift of the surface plasmon band which signals the disperse-to-aggregate transformation. The selectivity of the sensors is dictated by the surface functionality whose density presumably has a positive correlation with the sensitivity toward the targeted analyte. To improve the analytical perfor...

The synthesis of some thio-oxocrown ether ligands, B1 (1,4-dithio-12-crown-4), B2 (1,7-dithio-12-crown-4), B3 (1,7-dithio-15-Crown-5), B4 (1,7-dithio-18-crown-6), B5 (1,10-dithio-18-crown-6), B6 (1,10-dithio-21-crown-7), under mild conditions, were reported. The ligands were characterized by FT-IR, H NMR and GC-MS spectroscopy. The formation of 1:1 ligand complexes with a variety of metal salts...

Crown ethers are small, cyclic polyethers that have found wide-spread use in phase-transfer catalysis and, to a certain degree, in protein chemistry. Crown ethers readily bind metallic and organic cations, including positively charged amino acid side chains. We elucidated the crystal structures of several protein-crown ether co-crystals grown in the presence of 18-crown-6. We then employed biop...

The compound (μ-3,3',3'',3'''-{[2,5,8,15,18,21-hexa-oxatricyclo-[20.4.0.0(9,14)]hexa-cosa-1(22),9,11,13,23,25-hexa-ene-11,12,24,25-tetra-yl]tetra-kis-(methyl-ene)}tetra-kis-(1-methyl-1H-imidazol-2-yl))bis-[(η(4)-cyclo-octa-1,4-diene)rhodium(I)] bis-(hexa-fluoridophosphate) acetonitrile sesquisolvate dihydrate, [Rh2(C8H12)2(C40H42N8O6)](PF6)2·1.5CH3CN·2H2O, crystallized from acetonitrile under a...