Synthesis and structural characterization of a novel polymeric praseodymium(III) complex with a new flexible double betaine

A novel polymeric Pr(III) complex with a new double betaine, namely [{Pr(L-1)(1.5)(H2O)(2)}(n)] [ClOli4]3(n). nH(2)O (1) (L-1= 1,4-diazoniobicyclo[2,2,2]octane- 1,4-dipropionate), has been synthesized and characterized by X-ray analysis. In the title complex, the Pr(III) atom is nine-coordinated by seven oxygen atoms from five L-1 ligands and two aqua ligands. Each pair of adjacent praseodymium(III) atoms is linked by a pair of mu(3) chelating and bridging carboxylate groups, thus forming an infinite metal metal chain running parallel to the a direction, and such chains are cross-linked by flexible backbones of L-1 ligands into a three-dimensional network with the perchlorate anions and lattice water molecules accommodated in the interstitial space. The title complex crystallizes in the monoclinic space group P2(1)/n with a = 8.085(2), b = 14.316(3), c = 29.775(6) Angstrom, beta = 103.04(3)degrees and Z = 4.

Relationship between luminescence and matrices in the system Al2O3-B2O3-Ce2O3

The system Al2O3-B2O3-Ce2O3, with Al/B ratio varying from 4.5 to 2 and Ce/(Al + B) = 0.02, has been prepared at the temperature from 1 200 to 1 400 degrees C. Relationship between luminescence and matrices in the system Al2O3-B2O3-Ce2O3 was investigated. It was found that some changes of the matrices occurred with Al/B ratio varying from 4.5 to 2. These results lead to a great change in luminescence properties, indicating variation of Ce-surroundings of crystal field. With the decrease of the ratio from 3 to 2, the excitation and emission peaks shift to shorter wavelengths. it was also found that a new type of rare earth luminescent materials was obtained with appropriate Al/B ratio.

In-situ FTIR spectroelectrochemical investigation of cobalt(II)-cyanoferrate polymeric film coated on a glassy carbon electrode

Cobalt(II)-cyanoferrate polymeric film has been electrochemically deposited on a glassy carbon electrode and investigated by cyclic voltammetry and in-situ reflection FTIR spectroscopy. A reorientation of the terminal C=N groups upon redox reactions was proposed. The stretching vibration mode of the terminal C=N groups associated with Fe(III) was observed at 2122 cm(-1), however, the stretching vibration mode for terminal groups associated with Fe(II) did not appear. This process could result in a switch between lattice-closed and lattice-opened surface structure. (C) 1997 Elsevier Science B.V.

Synthesis, crystal structure and magnetic properties of a series of polymeric lanthanoid-copper complexes [Ln(2)Cu(3){O(CH2-CO2)(2)}(6)].nH(2)O (Ln=La, Nd, n=9; Ln=Er, n=6)

The reaction of diglycolic acid, O(CH2CO2H)(2), with Cu(NO3)(2) . H2O and lanthanoid nitrate hydrate produces a series of novel Ln-Cu mixed metal complexes, [Ln(2)CU(3){O(CH2CO2)(2)}(6)]. nH(2)O (Ln = La, Nd, n = 9; Ln = Er, n = 6), which have been characterized by elemental analysis, i.r. spectroscopy, magnetic measurements and X-ray crystallography. The Ln(3+) and Cu2+ ions are connected by the carboxylate groups of the ligands, resulting in the formation of a complicated network.

APPLICATION OF POLYBUTADIENE-BASED POLYMERIC SURFACTANTS IN LIQUID MEMBRANE SEPARATION

New polybutadiene-based surfactants (LYF) were synthesized by sulfonation of liquid polybutadiene with acetal sulfate at an elevated temperature, and their properties in a liquid surfactant membrane (LSM) separation process were examined by comparison with the two polyisobutylene-based surfactants ECA4360 and EM301. It was found that LYF surfactants had satisfactory overall properties as regards stability, swelling, and demulsification Of the W/O emulsion in the cases of both acidic and caustic internal aqueous phases.

THE USE OF LIGHT-MICROSCOPY FOR INVESTIGATIONS OF EPITAXIAL-GROWTH OF POLYMERS ON POLYMERIC SUBSTRATES

In order to study the oriented (epitaxial) crystallization of thermoplastic polymers on oriented polymer substrates, generally the transmission electron microscopy (TEM) is used. With this instrument, the crystallized material can easily be resolved and orientation relationships can be monitored by electron diffraction. Disadvantages are the time consuming sample preparations and difficulties in the in-situ observations of the crystallization events, because of the radiation sensitivity of the polymer crystals. It is demonstrated that these disadvantages of the TEM can be eleminated by the use of different methods of light optical contrasts under specific preparation conditions of the samples and that the optical microscopy being a supplementary method to the TEM for investigations of epitaxial crystallization.

Highly enantioselective resolution of terminal epoxides using polymeric catalysts

Poly-salen-Co(III) complexes were employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides and ee's up to 98% were obtained. In the HKR of epichlorohydrin, the polymeric catalysts can be recovered and modified for recycling. The recovered polymer catalyst shows good activity and selectivity. (C) 2002 Elsevier Science Ltd. All rights reserved.