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.

Effect of structures of modifiers on electrochemistry of di-mu-oxo dimanganese 2,2'-bipyridine complex

The gold electrodes modified with 2-picolinic acid , nicotinic acid, iso-nicotinic or thiophene were prepared using membrane transfer method, The electrochemistry of di-mu-oxodimanganese 2,2'-bipyridine complex was studied in the acetic acid buffer solution at different modified gold electrodes, It was found that the modifiers which can promote the electrochemical reaction of the complex should be of at least two functional groups, One group can be bound to the electrode surface and the other can form electron transfer pathway between the modifier and the complex through sal; bridge or hydrogen bond, In addition, the mechanism of the electrochemical reaction was discussed.

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.

Effects of organic modifiers on solute retention and electrokinetic migrations in micellar electrokinetic capillary chromatography

Influences of seven organic modifiers, including urea, methanol (MeOH), dioxane (DIO), tetrahydrofuran (THF), acetonitrile (ACN), 1-propanol (1-PrOH) and 2-propanol (2-PrOH), on the solute retention and the electrokinetic migrations in micellar electrokinetic capillary chromatography (MEKC) are investigated with sodium dodecyl sulfate (SDS) micelle as pseudostationary phase. It is observed that in the limited concentration ranges used in the MEKC systems the effect of organic modifier concentration on the retention can be described by the equation logk'=logk'(w)-SC for most binary aqueous-organic buffer, but deviations from this retention equation are observed at ACN and particularly THF as organic modifiers. With parameter S as a measure of the elutropic strength, the elutropic strength of the organic modifiers is found to follow a general order urea modifiers studied. The electroosmotic mobility decreases linearly with increasing modifier concentrations. The strength of modifiers to suppress the electroosmotic mobility follows the order urea < MeOH, ACN < DIO, THF, 1-PrOH, 2-PrOH. The addition of ACN affects the electrophoretic mobility of the SDS micelle in different patterns depending on the buffer composition used, while the addition of the other modifiers leads to a rough linear decrease of the electrophoretic mobility of the SDS micelle. The suppressing strength of THF on the electrophoretic mobility of the SDS micelle is strongly related to the buffer composition, whereas the suppressing strength for the other modifiers follows the sequence urea < MeOH < DIO, 1-PrOH, 2-PrOH. The migration time window is expanded by the use of organic modifiers. Urea and MeOH have the least expanding strength while ACN, DIO, THF, 1-PrOH and 2-PrOH have the highest expanding strength on the migration time window.