Sol-gel preparation and luminescence properties of nano-structured hybrid materials incorporated with europium complexes

Microporous silica gel has been prepared by the sol-gel method utilizing the hydrolysis and polycondensation of tetraethylorthosilicate (TEOS). The gel has been doped with the luminescent ternary europium complex Eu(TTA)(3)(.)phen: where HTTA=1-(2-thenoyl)-3,3,3-trifluoracetone and phen=1,10-phenanthroline. By contrast to the weak f-f electron absorption bands of Eu3+, the complex organic ligand exhibits intense near ultraviolet absorption. Energy transfer from the ligand to Eu3+ enables the production of efficient, sharp visible luminescence from this material. Utilizing the polymerization of methyl methacrylate, the inorganic/polymer hybrid material containing Eu(TTA)(3)(.)phen has also been obtained. SEM micrographs show uniformly dispersed particles in the nanometre range. The characteristic luminescence spectral features of europium ions are present in the emission spectra of the hybrid material doped with Eu(TTA)(3)(.)phen.

Synthesis and electrochemical characteristics of lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate

Four lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate were prepared and characterized by elemental analyses, LR, UV-Visible,H-1 NMR, XPS and molar conductance. The redox properties of the lutetium complex with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate in dichloromethane were studied by cyclic voltammetry.

Preparation, characterization and photophysical properties of layered zirconium bis(monohydrogenphosphate) intercalated with rare earth complexes

Two kinds of rare earth (RE) complexes were intercalated into zirconium bis(monohydrogenphosphate) (alpha -ZrP) by exchanging the RE complexes into the p-methyoxyaniline (PMA) preintercalated compound Zr(O3POH)(2). 2PMA (alpha -ZrP . 2PMA). Powder X-ray diffraction patterns reveal that Eu(DBM)(3)phen (DBM: dibenzoylmethane, phen: 1,10-phenanthroline) and Tb(AA)(3)phen (AA: acetylacetone) intercalated into alpha -ZrP . 2PMA. This was confirmed by the UV-visible spectra of both the RE complexes and the assemblies. At the same time, the assemblies have better luminescent properties, and the fluorescent lifetimes of RE3+ in the excited state in the assemblies are much longer than those in the complexes. The stabilities of the assemblies under UV radiation are much better than those of the RE complexes.

Preparation and luminescence properties of sol-gel hybrid materials incorporated with europium complexes

Microporous silica gel has been prepared by the sol-gel method utilizing the hydrolysis and polycondensation of tetraethylorthosilicate (TEOS). The gel has been doped with the luminescent ternary europium complex Eu(TTA)(3). phen: where HTTA = 1-(2-thenoyl)-3,3,3-trifluoracetone and phen = 1,10-phenanthroline. By contrast to the weak f-f electron absorption bands of Eu3+, the complex organic ligand exhibits intense near ultraviolet absorption. Energy transfer from the ligand to Eu3+ enables the production of efficient, sharp visible luminescence from this material. Utilizing the polymerization of methyl methacrylate or ethyl methacrylate, the inorganic/polymer hybrid materials containing Eu(TTA)(3). phen have also been obtained. SEM micrographs show uniformly dispersed particles in the nanometre range. The characteristic luminescence spectral features of europium ions are present in the emission spectra of the hybrid material doped with Eu(TTA)3 phen. (C) 2000 Kluwer Academic Publishers.

The efficient syntheses of three novel bridging phenanthroline ligands and their binuclear ruthenium(II) complexes

Three bridging ligands (L) and their binuclear phenanthroline ruthenium(II) complexes {[Ru(1,10-phenanthroline)(2)](2)(L)}(PF6)(4) were synthesized and characterized by IR, H-1 NMR, and elemental analysis, where L are 1,8-adipoylamido-bis(1,10-phenanthroline-5-yl) (L-1), 1,11-azelaoylamidobis(1, 10-phenanthroline-5-yl) (L-2), and p-phthaloylamido-bis(1,10-phenanthroline-5-yl) (L-3).

In situ synthesis of terbium-benzoic acid complex in sol-gel derived silica by a two-step sol-gel method

Terbium complexes with benzoic acid and its derivatives o-hydroxybenzoic acid and p-hydroxybenzoic acid were in situ synthesized in sol-gel derived silica matrix via a two-step sol-gel process. The formation process of the complex was characterized by fluorescence spectra, absorption spectra and IR spectra. The gels that contain in situ synthesized complexes exhibit the characteristic emission bands of terbium ion. The fluorescence lifetimes of Tb3+ in the silica gels are longer than those in the pure complexes and in the solutions that contain the corresponding complexes. (C) 2000 Elsevier Science Ltd. All rights reserved.

Luminescent properties of organic-inorganic hybrid monoliths containing rare-earth complexes

Transparent organic-inorganic hybrid monoliths containing rare-earth complexes (Eu(TTA)(3)Phen, Tb(Sal)(3)) were prepared via the sol-gel technique. It could be observed by transmission electron microscopy that the fluorescent particles are distributed in the matrix at the microscopic level. The matrix is composed of organic-inorganic semiinterpenetrating networks, i.e., PHEMA-SiO2 system. The fluorescence emission spectra of samples are similar to those from corresponding powdered Eu(III) and Tb(III) complexes, and the half-widths of the strongest bands are less than 10 nm, which indicates that the monolith exhibits high fluorescence intensity and color purity. Furthermore, the fluorescence spectra exhibit no obvious change with decreasing nanoparticle size of the rare-earth complex. The fluorescence lifetimes of samples are longer than pure Eu(III), Tb(III) complexes, respectively. Samples irradiated with an UV lamp (365 nm) are still transparent but become bright red and green in color due to fluorescence of Eu(III) and Tb(III) complexes. (C) 2000 Elsevier Science B.V. All rights reserved.

Synthesis, 2D NMR, electrochemistry and luminescence of ruthenium(II) complexes with 2,2 '-bipyridine and 5-(omega-bromoalkylamido)-1,10-phenanthroline

The efficient synthesis of 5-(5-bromovaleramido)-1,10-phenanthroline, 5-(6-bromohexanamido)-1,10-phenanthroline, and 5-(11-bromoundecanamido)-1,10-phenanthroline are described, which reacted with cis-Ru(bpy)(2)Cl-2. 2H(2)O and sodium hexafluorophosphate to form Ru(bpy)(2)[phen-NHCO(CH2)(n)Br](PF6)(2) (n = 4, 5 or 10; phen = 1,10-phenanthroline). The intricate H-1 NMR spectra at low field of these complexes were completely assigned in virtue of H-1-H-1 COSY technique. Cyclic voltammetry was used to study electrochemical behaviours of these complexes, and their luminescent properties were investigated with fluorescent spectra.

The synthesis of some 1,1 '-ferrocene dichalcogenato complexes containing chromium, molybdenum and tungsten

Both dinuclear [3] ferrocenophane derivatives of the type Fe(C5H4E)(2)[MLn] [E = S,Se; MLn = Cp* - Cr(NO) (1), Cp* Mo(NO) (2a,2b), CpMo(NO) (3), Cp* W(NO) (4a,4b), Ca2Mo (6b), Cp2W (7a)] and trinuclear 1,1' - ferrocene dichalcogenato complexes Fe(C5H4E)(2)[MLn](2)[MLn = Cp* Cr(NO)(2), E = S(8a), Se(8b)] were synthesized and characterized by their IR, H-1 MMR and EI - MS spectra as well as their elemental analyses.

Pentamethylcyclopentadienyl halfsandwich rhodium complexes containing 1,1 '-ferrocene dichalcogenido chelate ligands

The heterobimetallic complexes Cp * Rh(CN Bu-t)(EC5H4)(2)Fe [E = S(2),Se(3), Te(4)] have been synthesized by the reaction of halfsandwich rhodium complex Cp * Rh(CNtBu) Cl-2 with Fe(C5H4ELi)(2). 2THF. Oxidation of 2,3 by AgBF4 to give ferrocenium - type salts [Cp * Rh(CNtBu) (EC5H4)(2)Fe] (+) [BF4] (-) [E = S(5),Se(6)] also occurs readily. The new complexes have been characterized by MS IR, H-1 and C-13 NMR spectroscopy and elemental analysis.

Studies on the solution structures of lanthanide(III) complexes of DTPA-BIN by NMR

The solution structures of diamagnetic lanthanide (III) complexes of DTPA-BIN (Ln = La, Y, Lu, Sc) have been investigated by H-1 NMR, C-13 NMR and 2D NMR. For each complex, two or more species of asymmetric conformations with little distinction were identified at room temperature. And their solution structures vary with the radius of the central metals. NMR spectra support the hypothesis that Sc3+ with smaller radius formed an eight-coordinated structure with DTPA-BIN, La3+ with larger radius formed nine- or ten-coordinated structures with DTPA-BIN, and Y (DTPA-BIN) and Lu (DTPA-BIN) had nine-coordinated solution structures. The solution structure of Gd (DTPA-BIN) was obtained from the similarity of radius between Gd3+ and Y3+, which is a nine-coordinated structure formed by three nitrogens, three acetate oxygens, two acetyl oxygens, one water molecule and a gadolinium(III) cation.

Hydrothermal synthesis and crystal structure of [{Cu(2,2 '-bpy)(2)}(2)Mo8O26]: a beta-octamolybdate cluster covalently bonded to two {Cu(2,2 '-bpy)(2)}(2+) coordination complexes via bridging oxo groups

An organic-inorganic hybrid solid, (Cu(2,2'-bpy)(2))(2)Mo8O26, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Dark green crystals crystallize in the orthorhombic system, space group Pna21, a = 24.164(5), b = 18.281(4), c = 11.877(2) Angstrom, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V= 5247(2) Angstrom (3), Z = 4, lambda (MoK alpha) = 0.71073 Angstrom (R(F) = 0.0331 for 5353 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range 1.69 degrees < theta < 25.04 degrees using the omega -scan technique. The structure was solved by the direct method and refined by full-matrix least squares on F-2 using SHELXL-93. The structure of this compound consists of discrete (Cu(2,2'-bpy)(2))(2)Mo8O26 clusters, constructed from beta -octamolybdate subunits ((Mo8O26)(4-)) covalently bonded to two (Cu(2,2'-bpy)(2))(2+) coordination complexes via bridging oxo groups that connect two adjacent molybdenum sites. (C) 2001 Academic Press.

Synthesis and characterization of polynuclear half-sandwich lanthanoid complexes [Na(THF)(6)](2)[(Cp6Sm6Se13)-Sm-t] and [Li(LHF4](2)[Cp6Nd6Se13]

The half-sandwich tert-butyl cyclopentadienyl lanthanoid complexes {[Cp ' Ln(THF)](2)(mu (2)-Cl)(2)(mu (3)-Cl)(3)Na(THF)}(n) [Cp ' = eta (5)-' BuC5H4; Ln = Nd (1a), Sm (1b), Gd (1c), Yb (1d)] are prepared by the reaction of anhydrous lanthanoid trichloride, LnCl(3), with NaCp ' in THF solution. Complex 1b reacts with Na2Se5 to give hexanuclear samarium polyselenide complexes [Na(THF)(6)](2)[Cp-6' SM6(mu (6)-Se)(mu -Se-2)(6)] (2). An analogous cyclopentadienyl neodymium polyselenide complex [Li(THF)(4)](2)[Cp6Nd6(mu (6)-Se)(mu -Se-2)(6)] (3) is synthesized by the reaction of [CpNdCl2. 2LiCl . 5THF] with Na2Se5 in THF solution. The molecular structures of 1a and 2 were determined by X-ray crystal structure analysis. Complex 2 contains an interstitial selenium atom which is coordinated with six samarium atoms. (C) 2001 Elsevier Science BN. All rights reserved.

Gaseous dipeptide complexes with metal ions by electrospray ionization and tandem mass spectrometry

Electrospray ionization (ESI) and tandem mass spectrometry have been used to investigate the gas-phase interactions of five metal ions and seven dipeptides. For silver ion, two complexes ([M+Ag](+) and [2M+Ag](+)) were obtained as well as the one complex ([2M+Met-H](+)) for transition-metal ions. Upon collision activation, there is an obvious difference in MS/MS data between metal ion complex and the protonated molecule. The fragment pathway of each complex is related to the structures of dipeptide and the nature of metal ion which suggest that there are several interaction between the metal ions and dipeptides in gas phase.