Photoelectrochemical laser imaging on anodically prepared α-PbO thin films

The influence of various potential windows on the synthesis of α-PbO and the uniformity of its formation over the entire surface of the lead electrode has been studied by scanning a laser beam over the entire surface and measuring the corresponding photocurrent using the photoelectrochemical laser imaging technique. This technique revealed that a very uniformly distributed highly (110) plane oriented thin film of α-PbO is obtained by potentiodynamic anodization of the lead electrode in an alkaline medium at 80 ^°C in the potential range of ?0.32 to +0.08 V vs SCE, giving the highest (73%) quantum yield at 480 nm, an open-circuit photopotential of 800 mV and a short-circuit photocurrent of 5.5 mA cm^?2. Gärtner analysis suggests that the highest photoactivity achieved with this material is due to the formation of a large space charge width (0.63 m) and diffusion length (0.36 m) of the minority carriers and absorption of almost 100% of the light (480 nm) within the space charge and diffusion regions.     

Donor-acceptor interaction promoted gelation: visual observation of color change

An anthrylidene derivative of arjunolic acid could immobilize varieties of organic solvents at low concentrations in the presence of an electron-deficient guest. Gelation in the presence of picric acid in organic solvents could be observed visually with concomitant color change. Electron micrographs of the xerogels showed a fibrous structure having fibers of submicron diameters. [structure: see text].     

Syntheses, structures, absorption and emission properties of a tetraiminodiphenol macrocyclic ligand and its dinuclear Zn(II) and Pb(II) complexes

Synthesis of a Robson type macrocyclic ligand [H₄L](ClO₄)₂ (1) obtained on condensation of 2,6-diformyl-4-methylphenol and 2,2′-dimethyl-1,3-diaminopropane, template synthesis of a dinuclear lead(II) complex [Pb^II₂L(NO₃)₂] (2), synthesis of a dinuclear zinc(II) complex [Zn^II₂L(NO₃)(H₂O)](ClO₄) (3) through metal substitution reaction and synthesis of another dinuclear zinc(II) complex [Zn^II₂L(H₂O)₂](ClO₄)₂·(H₂O)₂ (4) obtained directly from 1 are described in the present study. Crystal structure determinations of 1 and 3 have been carried out. Both the compounds 1 and 3 crystallize in the orthorhombic system with the space groups Fdd2 and P2₁2₁2, respectively. Spectrophotometric and spectrofluorometric titrations of 1 with triethylamine as well as with zinc(II) acetate are also reported.     

Synthesis and characterization of new poly(ether amide)s based on a new cardo monomer

A new cardo diamine monomer 3, 3‐bis‐[4‐{2′trifluoromethyl 4′‐(4″‐aminophenyl) phenoxy} phenyl]‐2‐phenyl‐2, 3‐dihydro‐isoindole‐1‐one ( 4 ) has been synthesized from potentially cheap phenolphthalein as the starting material. This diamine was used for the synthesis of a new poly(ether amide) and two co‐poly(ether amide)s using 4, 4′‐diaminodiphenyl ether (ODA) as co‐monomer by direct solution polycondensation with 5‐t‐butyl iso‐phthalic acid. These new polymers showed inherent viscosities of 0.48–0.62 dL g^?1. The resulting poly(ether amide) and co‐poly(ether amide)s were readily soluble in polar aprotic solvents like NMP, DMF, DMAc, DMSO, and pyridine. The polymers have been fully characterized by ¹H and ¹³C NMR, FTIR spectroscopy, and elemental analysis. These polymers showed glass transition temperatures in the range of 267–310°C. Thermogravimetric analysis indicated high thermal stability of these polymers at 5 and 10% weight loss temperature in air above 357°C and 419°C, respectively. The poly(ether amide) films cast from DMAc were flexible with tensile strength up to 91 MPa, elongations at break up to 11%, and modulus of elasticity up to 1.82 GPa. X‐ray diffraction measurements indicate the amorphous nature of the poly(ether amide)s. Copyright © 2009 John Wiley & Sons, Ltd.     

Molecular Bases for Anesthetic Agents: Halothane as a Halogen‐ and Hydrogen‐Bond Donor

Although instrumental for optimizing their pharmacological activity, a molecular understanding of the preferential interactions given by volatile anesthetics is quite poor. This paper confirms the ability of halothane to work as a hydrogen‐bond (HB) donor and gives the first experimental proof that halothane also works as a halogen‐bond (HaB) donor in the solid state and in solution. A halothane/hexamethylphosphortriamide co‐crystal is described and its single‐crystal X‐ray structure shows short HaBs between bromine, or chlorine, and the phosphoryl oxygen. New UV/Vis absorption bands appear upon addition of diazabicyclooctane and tetra(n‐butyl)ammonium iodide to halothane solutions, indicating that nitrogen atoms and anions may mediate the HaB‐driven binding processes involving halothane as well. The ability of halothane to work as a bidentate/tridentate tecton by acting as a HaB and HB donor gives an atomic rationale for the eudismic ratio shown by this agent.     

Radiating and nonradiating dispersion-managed solitons

Using spectral analysis, we present the salient features of the radiating behavior of optical solitons in dispersion-managed fiber systems. Depending on the map strength of the system, we find a rich variety of dynamic states that includes weak, moderate, and strong radiation states. We establish the existence of a critical map strength at which a Gaussian-shaped light pulse with a large initial dressing undergoes highly stable nonradiative propagation over transoceanic distances.     

The reactivity of a ruthenium(III) ammine complex, [Ru(NH3)5Cl]Cl2, towards α-N-heterocyclic mono- and di-carboxylic acids. The synthesis and characterisation of biologically active mixed ligand ruthenium(III) complexes

Ruthenium(III) complexes containing one, two or three -N-heterocyclic mono- and di-carboxylic acid groups were prepared from the ammine complex, [Ru(NH₃)₅Cl]Cl₂ by judicious interplay of controlling factors such as the metal:ligand ratio, reflux time etc. All the complexes were characterised by elemental analyses, spectroscopic (u.v.-vis., i.r., e.p.r.) techniques, magnetic measurements (at room temperature) and conductance measurements in solution. The electrochemical behaviour of the soluble complexes was studied by cyclic voltammetry. Their biological activity, in terms of the growth inhibition of Escherichia coli 10536, has been examined.