Formation of Micrometer Scale Metal Structures on Glass by Selective Electroless Plating on Photopatterned Titanium and Copper Containing Films.

A procedure for formation of catalytic SiO2 substrate adhesive layer patterns and selective electrochemical metal deposition on the catalyst images was investigated. A photoreactive solution containing a diazonaphthoquinone sulfonate ester and Ti and Cu complexes was developed to deposit Cu catalyst-TiO2 adhesive layer latent images on glass. Sub-micrometer/micrometer scale positive tone photoactive TiCu complex film patterns were formed using a conventional photolithography technique. The Cu ions in 40-50 nm thick Ti and Cu oxide layers formed by pyrolysis of the TiCu complex films were reduced, residual Cu displaced with Pd then the porous Ti oxide structure filled and plated with Cu by selective electroless then electrolytic plating. Annealing the Cu plating filled TiO2 layers on glass resulted in formation of a smooth Ti3+/Cu1+ oxide interface that enabled formation of 20 µm thick Cu deposits on glass substrate with up to 1 kN/m adhesion strength. The adhesion strength was attributed to chemical bonding of Ti3+ and Cu1+ oxides to the glass and Ti4+ oxide to the Cu plating that was formed upon annealing the Cu filled TiO2 interlayer. Furthermore, a dip coating procedure was adapted that allowed copper film deposition on the entire surface of a 300 µm thick glass substrate with 50 µm in diameter holes enabling formation of electrically conductive through glass substrate interconnects.

Metallic film formation using direct micropatterning with photoreactive metal complexes.

Palladium, cobalt, and nickel in complex with photoacid-generating ligands, 4-(2-nitrobenzyloxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol, were prepared in solution. Films formed from the metal complex solutions perform as positive-tone, directly photopatternable palladium, cobalt, nickel oxide, or composite film precursors. After exposure, acid-bearing selectively soluble complexes could be removed to give patterned films upon developing in aqueous base, which were transformable to the corresponding pattern-preserving metal/metal oxide film. The photodynamics of photoinduced solubility and direct micropatterning of palladium, cobalt, nickel, and palladium/nickel oxide composite films were investigated. Employing palladium as the initiator for autocatalytic chemical plating, selective direct copper plating on palladium film on polyethylene naphthalate and palladium/nickel oxide composite film on glass was accomplished.

Species dependence of the redox potential of the primary electron donor p700 in photosystem I of oxygenic photosynthetic organisms revealed by spectroelectrochemistry.

The redox potential of the primary electron donor P700, E(m)(P700/P700(+)), of Photosystem I (PSI) has been determined for 10 oxygenic photosynthesis organisms, ranging from cyanobacteria, red algae, green algae to higher plants, by spectroelectrochemistry with an optically transparent thin-layer electrode (OTTLE) cell to elucidate the scattering by as much as 150 mV in reported values of E(m)(P700/P700(+)). The E(m)(P700/P700(+)) values determined within error ranges of ± 1-4 mV exhibited a significant species dependence, with a span >70 mV, from +398 to +470 mV vs. the standard hydrogen electrode (SHE). The E(m)(P700/P700(+)) value appears to change systematically in going from cyanobacteria and primitive eukaryotic red algae, then to green algae and higher plants. From an evolutionary point of view, this result suggests that the species believed to appear later in evolution of photosynthetic organisms exhibit higher values of E(m)(P700/P700(+)). Further, the species dependence of E(m)(P700/P700(+)) seems to originate in the species-dependent redox potentials of soluble metalloproteins, Cyt c(6) and plastocyanin, which re-reduce the oxidized P700 in the electron transfer chain.

Photoacid generating ligands for development of positive-tone directly photopatternable metal complexes.

Photoacid generating ligands, 4-(2-nitrobenzy-loxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol, and indium tin and titanium complexes thereof, were synthesized. These metal complexes perform as positive-tone, directly photopatternable indium tin oxide (ITO) or titanium oxide film precursors. After exposure, acid-bearing selectively soluble complexes could be removed to give patterned films upon developing in aqueous base, which were transformable to the corresponding pattern-preserving metal oxide film. Micropatterning of ITO and titanium oxide films was accomplished with the photoreactivity of the 2-nitrobenzyloxycarbonyl (NBOC) and 6-nitroveratryloxycarbonyl (NVOC) moiety bearing ligands.

Spectroelectrochemistry of P700 in native photosystem I particles and diethyl ether-treated thylakoid membranes from spinach and Thermosynechococcus elongatus.

The redox potentials (E(composite function')) of P700 in intact and diethyl ether-treated thylakoid membranes as well as native photosystem (PS) I particles from spinach and Thermosynechococcus elongatus have been measured by a spectroelectrochemistry with an error range of +/-2-3 mV. Stepwise removal of antenna pigments by ether treatment caused distinct shifts of the E( composite function') value with increasing degree of water saturation in ether; negatively from +471 to +428 mV for spinach, but positively from +423 to +436 mV for T. elongatus. Such a contrasting behavior is discussed by invoking the mode of action of ether on the microenvironments around P700.

Significant species-dependence of P700 redox potential as verified by spectroelectrochemistry: comparison of spinach and Theromosynechococcus elongatus.

The redox potentials of P700, the primary electron donor of photosystem (PS) I, of spinach and Thermosynechococcus elongatus were determined by means of spectroelectrochemistry with an error range of +/-2-3 mV, to find that the redox potential of P700 in T. elongatus is lower by ca. 50 mV as compared with spinach. The shift in the P700 redox potential of PS I core particles prepared by harsh detergent treatments remained to within 10 mV for both organisms. These results show that the 50 mV difference in the P700 redox potential between the two organisms is not a detergent-induced artifact but reflects an intrinsic property of each PS I.

Reversed-phase HPLC determination of chlorophyll a' and naphthoquinones in photosystem I of red algae: existence of two menaquinone-4 molecules in photosystem I of Cyanidium caldarium.

Chlorophyll (Chl) a', the C13(2)-epimer of Chl a, is one of the two Chl molecules constituting the primary electron donor (P700) of photosystem (PS) I of a thermophilic cyanobacterium Synechococcus elongatus. To examine whether PS I of other oxygenic photosynthetic organisms in general contain one Chl a' molecule in P700, the pigment composition of thylakoid membranes and PS I preparations isolated from red algae Porphyridium purpureum and Cyanidium caldarium was examined by reversed-phase HPLC with particular attention to Chl a' and phylloquinone (PhQ), the secondary electron acceptor of PS I. The two red algae contained one Chl a' molecule at the core part of PS I. In PS I of C. caldarium, two menaquinone-4 (MQ-4) molecules were detected in place of PhQ used by higher plants and cyanobacteria. The 1:2:1 stoichiometry among Chl a', PhQ (MQ-4) and P700 in PS I of the red algae indicates that one Chl a' molecule universally exists in PS I of oxygenic photosynthetic organisms, and two MQ-4 molecules are associated with PS I of C. caldarium.

Evaluation of the carrier potential for the lipid dispersion system with lipophilic compound.

KW-3902 (a newly synthesized adenosine A(1)-receptor antagonist) has potent diuretic and renal protective activities and was formulated in lipid dispersion systems, i.e., lipid emulsions and liposomes. The objective of the present study was to evaluate the carrier potential of these lipid dispersion systems, which is explained here as the ability of the formulation to retain the drug in its dispersed phase. The relative affinity of the drug to the formulation, K(f/b), was defined as a parameter in order to assess the performance of the formulations and was obtained from the in vitro blood component binding study. The results indicated that KW-3902 showed higher relative affinity to the liposome formulation than to the lipid emulsion. Moreover, the total amount of drug retained in the dispersion system depended on both K(f/b) and the dosing volume. The usefulness of the parameter, K(f/b), was discussed as an indicator for a carrier potential to understand the properties of the formulations.

Reversed-phase HPLC determination of chlorophyll a' and phylloquinone in Photosystem I of oxygenic photosynthetic organisms. Universal existence of one chlorophyll a' molecule in Photosystem I.

Chlorophyll (Chl) a', the C132-epimer of Chl a, is a constituent of the primary electron donor (P700) of Photosystem (PS) I of a thermophilic cyanobacterium Synechococcus (Thermosynechococcus) elongatus, as was recently demonstrated by X-ray crystallography. To determine whether PS I of oxygenic photosynthetic organisms universally contains one molecule of Chl a', pigment compositions of thylakoid membranes and PS I complexes isolated from the cyanobacteria T. elongatus and Synechocystis sp. PCC 6803, the green alga Chlamydomonas reinhardtii, and the green plant spinach, were examined by simultaneous detection of phylloquinone (the secondary electron acceptor of PS I) and Chl a' by reversed-phase HPLC. The results were compared with the Chl a/P700 ratio determined spectrophotometrically. The Chl a'/PS I ratios of thylakoid membranes and PS I were about 1 for all the organisms examined, and one Chl a' molecule was found in PS I even after most of the peripheral subunits were removed. Chl a' showed a characteristic extraction behaviour significantly different from the bulk Chl a in acetone/methanol extraction upon varying the mixing ratio. These findings confirm that a single Chl a' molecule in P700 is the universal feature of PS I of the Chl a-based oxygenic photosynthetic organisms.