Thin Films of Chlorinated Vanadyl Phthalocyanines as Active Layers of Chemiresistive Sensors for the Detection of Ammonia.

Halogenated metal phthalocyanines are promising materials for the manufacture of active layers of chemiresistive sensors for the detection of various gases. Despite the high interest in such sensors, there are few systematic studies of the position of halogen substituents in phthalocyanine macroring on the chemiresistive response of their films to gases. In this work, we prepared and studied films of novel tetrachlorosubstituted vanadyl phthalocyanine derivatives with Cl substituents in the peripheral (VOPcCl-p) and nonperipheral (VOPcCl-np) positions of the phthalocyanine ring as active layers of chemiresistive sensors to reveal the effect of the position of substituents on their structure and sensor response to low concentrations of NH.

Platinum(IV) Carbonato Complexes: Formation via the Addition of CO to the [Pt(OH)] Anion and Generation of Platinum(IV) Oxide Nanoparticles for the Preparation of Catalysts.

A combination of multinuclear nuclear magnetic resonance spectroscopy and theoretical calculation based on density functional theory was used for a speciation study of Pt in solutions prepared either by the interaction of [Pt(OH)] with gaseous CO in an alkaline solution of platinum(IV) hydroxide ([Pt(OH)(HO)]) or by the dissolution of [Pt(OH)(HO)] in an aqueous KHCO solution. The formed solutions contained coexisting Pt(IV) carbonato complexes with κ- and κ-coordination modes. The gradual condensation of mononuclear Pt species in such bicarbonate solutions resulted in the formation of PtO nanoparticles aggregating into a solid precipitate on prolonged aging.

Cobalt and Iron Phthalocyanine Derivatives: Effect of Substituents on the Structure of Thin Films and Their Sensor Response to Nitric Oxide.

In this work, we study the effect of substituents in cobalt(II) and iron(II) phthalocyanines (CoPcR and FePcR with R = H, F, Cl, tBu) on the structural features of their films, and their chemi-resistive sensor response to a low concentration of nitric oxide. For the correct interpretation of diffractograms of phthalocyanine films, structures of CoPcCl and FePcCl single crystals were determined for the first time. Films were tested as active layers for the determination of low concentrations of NO (10-1000 ppb).

Sulfuric Acid Solutions of [Pt(OH)(HO)]: A Platinum Speciation Survey and Hydrated Pt(IV) Oxide Formation for Practical Use.

The systematic study of the platinum speciation in sulfuric acid solutions of platinum (IV) hydroxide {[Pt(OH)(HO)], HHPA} was performed with the use of a combination of methods. Depending on the prevailing Pt form, the three regions of HSO concentration were marked: (1) up to 3 M HSO forms unstable solutions gradually generating the PtO·HO particles; (2) 4-12 M HSO, where the series of mononuclear aqua-sulfato complexes ([Pt(SO)(HO)], where = 0···4) dominate; and (3) 12 M and above, where, along with [Pt(SO)(HO)] species, the polynuclear Pt(IV) species and complexes with a bidentate coordination mode of the sulfato ligand are formed. For the first time, the salts of the aqua-hydroxo Pt(IV) cation [Pt(OH)(HO)]SO (triclinic and monoclinic phases) were isolated and studied with a combination of methods, including the single-crystal X-ray diffraction.

The formation of free ions and electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane-chloroform mixtures at low concentrations of AOT.

The electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane-chloroform mixtures was studied as a function of the chloroform content (from 0 to 100 vol%). The nanoparticles were stabilized by sodium bis-(2-ethylhexyl)sulfosuccinate (AOT, Aerosol OT) with a concentration of 2.5 × 10-4 mol L-1.

Synthesis and Concentration of Organosols of Silver Nanoparticles Stabilized by AOT: Emulsion Versus Microemulsion.

In this work, we tried to combine the advantages of microemulsion and emulsion synthesis to obtain stable concentrated organosols of Ag nanoparticles, promising liquid-phase materials. Starting reagents were successively introduced into a micellar solution of sodium bis-(2-ethylhexyl)sulfosuccinate (AOT) in n-decane in the dynamic reverse emulsion mode. During the contact of the phases, Ag passes into micelles and Na passes into emulsion microdroplets through the cation exchange AOTNa + AgNO = AOTAg + NaNO.

Structure of adsorption layer of silver nanoparticles in sodium bis(2-ethylhexyl) sulfosuccinate solutions in n-decane as observed by photon-correlation spectroscopy and nonaqueous electrophoresis.

Photon correlation spectroscopy, nonaqueous electrophoresis, and transmission electron microscopy were used to study the structure of silver nanoparticles (NPs) in n-decane, as a dependence of the concentration of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and temperature. If the concentration of AOT is lower than the critical micelle concentration (CMC), a silver NP is covered with a monolayer of AOT and reveals no electrophoretic mobility. At average concentrations (from CMC to 0.