(−)‐Sparteine copper(II) diacetate

The chiral nitrogen‐chelating alkaloid (?)‐sparteine acts as a bidentate ligand, reacting with copper(II) acetate in ethanol to form the title complex, [Cu(CH₃COO)₂(C₁₅H₂₆N₂)], with the two acetate groups occupying the remaining coordination sites in a monodentate fashion to produce a distorted four‐coordinate tetrahedral structure. The dihedral angle between the N—Cu—N and O—Cu—O planes is 45.8 (3)°.     

Dibromido(dimethyl sulfoxide‐κO)(1,10‐phenanthroline‐κ2N,N′)copper(II)

The solvent effect on the molecular structures of copper(II) complexes produced from the reaction between CuBr₂ and 1,10‐phenanthroline is evident. The momomeric title compound, [CuBr₂(C₁₂H₈N₂)(C₂H₆OS)], which consists of discrete units, is produced from this reaction in dimethyl sulfoxide (DMSO), whereas a polymeric copper(II) compound is known to be produced from the same reaction in the poor coordinating solvent ethanol. The geometry around the copper(II) ion in the title compound is best described as trigonal–bipyramidal distorted square‐based pyramidal, with a τ value of 0.37. The two phenanthroline N atoms, the DMSO O atom and one of the Br atoms occupy the four basal positions, while the second Br atom occupies the axial position. The magnetic susceptibility data also indicate that the title compound is monomeric, but there is still a weak antiferromagnetic interaction between paramagnetic copper(II) centers via the intermolecular `Cu—Br...Br—Cu' contact pathway.     

Electrochemical behaviour of mononuclear Fe(III) complexes as models for oxygenases: reactivity of Fe(II) species electrochemically formed in situ toward dioxygen

In this paper, we report the electrochemical study of a family of mononuclear Fe(III) complexes [Fe(BMPA)Cl(3)] 1, [Fe(MPBMPA)Cl(3)] 2, [Fe(PBMPA)Cl(2)]3 and [Fe(PABMPA)Cl(2)](ClO(4)) 4, where the ligand BMPA is bis-(2-pyridylmethyl)amine, and MPBMPA, PBMPA and PABMPA are the N-methylpropanoate, N-propanoate and N-propanamide BMPA-derivatives, respectively. It was possible to verify the influence of the different ligands on the redox properties of the complexes and from this to classify the complexes according to their Lewis acidity through the Fe(III)/Fe(II) redox process, resulting in the following decreasing order in CH(3)CN solution: 4> 2> 1> 3. The effect of the solvents CH(3)CN and DMSO on their electrochemical properties was also determined. Furthermore, we investigated the reactivity of the electrochemically-generated Fe(II) complexes toward dioxygen and of the Fe(III) complexes toward superoxide through cyclic voltammetry. All the complexes reacted with dioxygen and superoxide in DMSO solution. Redox processes attributed to oxygenated species were observed in a more cathodic potential than those of the original compounds. According to the data, the new species Fe(II)-O(2) converts itself to Fe(III)-O(2)(-), which presents a new redox wave attributed to the process Fe(III)-O(2)(-) + e(-) --> Fe(II)-O(2)(-). The same species Fe(III)-O(2)(-) is formed from the reaction of the Fe(III) form of the complexes and KO(2).     

Synthesis and electrochemical properties of phthalocyanines with four 8-quinolinoxy-substituents

A metal-free phthalocyanine and its cobalt(II) and copper(II) phthalocyanate complexes were prepared by cyclotetramerization of 4-(8-quinolinoxy)phthalonitrile. The new compounds were characterized by elemental analyses, ¹H-n.m.r., i.r. and u.v.–vis. spectral data. Electrochemical measurements indicated that CoPc had two metal based and two ligand based redox couples, while H₂Pc and CuPc showed four ligand based redox couples. For all complexes, linear variation of the peak current of the first reduction peak (I _pc) with scan rate () indicated the adsorption of the complexes to the electrode surface.     

Determination of rare-earth elements in steels by radiochemical neutron activation analysis

For the separation of rare-earth elements from steel, with a cation exchange resin, separation experiments were performed on NIST reference materials of SRM-363 and SRM-364. Iron, Na, Cr, Mn, Co, Cu, As, Mo, Sb and W were separated in 2M hydrochloric acid, five rare-earth elements, La, Ce, Pr, Nd and Sm and three other elements, Hf, Zr and Ba were separated using 8M nitric acid. Each element was determined by a single comparator method using two monitors, gold and cobalt.     

Glass-encapsulated light harvesters: more efficient dye-sensitized solar cells by deposition of self-aligned, conformal, and self-limited silica layers

A major loss mechanism in dye-sensitized solar cells (DSCs) is recombination at the TiO(2)/electrolyte interface. Here we report a method to reduce greatly this loss mechanism. We deposit insulating and transparent silica (SiO(2)) onto the open areas of a nanoparticulate TiO(2) surface while avoiding any deposition of SiO(2) over or under the organic dye molecules. The SiO(2) coating covers the highly convoluted surface of the TiO(2) conformally and with a uniform thickness throughout the thousands of layers of nanoparticles. DSCs incorporating these selective and self-aligned SiO(2) layers achieved a 36% increase in relative efficiency versus control uncoated cells.     

A first-order differential double subordination with applications

Let q₁ and q₂ belong to a certain class of normalized analytic univalent functions in the open unit disk of the complex plane. Sufficient conditions are obtained for normalized analytic functions p to satisfy the double subordination chain q₁(z)?p(z)?q₂(z). The differential sandwich-type result obtained is applied to normalized univalent functions and to Φ-like functions.     

Fabrication and validation of a multi-channel type microfluidic chip for electrokinetic streaming potential devices

To elaborate on the applicability of the electrokinetic micro power generation, we designed and fabricated the silicon-glass as well as the PDMS-glass microfluidic chips with the unique features of a multi-channel. Besides miniaturizing the device, the key advantage of our microfluidic chip utilization lies in the reduction in water flow rate. Both a distributor and a collector taking the tapered duct geometry are positioned aiming the uniform distribution of water flow into all individual channels of the chip, in which several hundreds of single microchannels are assembled in parallel. A proper methodology is developed accompanying the deep reactive ion etching as well as the anodic bonding, and optimum process conditions necessary for hard and soft micromachining are presented. It has been shown experimentally and theoretically that the silicon-based microchannel leads to increasing streaming potential and higher external current compared to those of the PDMS-based one. A proper comparison between experimental results and theoretical computations allows justification of the validity of our novel devices. It is useful to recognize that a material inducing a higher magnitude of zeta potential has an advantage for obtaining higher power density under the same external resistance.     

Inclusion properties for certain classes of meromorphic functions associated with the Choi–Saigo–Srivastava operator

The purpose of the present paper is to introduce several new classes of meromorphic functions defined by using a meromorphic analogue of the Choi–Saigo–Srivastava operator for analytic functions and investigate various inclusion properties of these classes. Some interesting applications involving these and other classes of integral operators are also considered.