Phenothiazinium photosensitisers IX. Tetra- and pentacyclic derivatives as photoantimicrobial agents

Methylene blue derivatives, synthesised as novel photosensitising agents are usually simple auxochromic variations on the lead compound. The current paper represents the initial report on the synthesis and biological testing of a new class of phenothiazinium derivatives, having either one or two tetrahydropyridine rings fused to the phenothiazinium chromophore. The derivatives exhibited extended absorption wavelengths, increased amphiphilic character and much greater photoantimicrobial efficacies compared to methylene blue, some examples being more effective even than dimethyl methylene blue. The high activities of this class of photosensitiser recommend its use in infection control, both locally and in blood product decontamination.     

s-Triazole systems. Part IV: Novel substituted thio-s-triazole derivatives

Interaction of (3-aryloxymethyl-4-phenyl-striazol-5-yl)thioacethydraz-ide ( la -c) with phenyl isocyanate and/or with methyl/phenyl isothiocyanate gave semicarbazides ( 2a -c) and thiosemicarbazides ( 3a-f ) respectively. Cyclization of ( 3a-f ) yielded s-triazoles ( 4a-f ). Compounds 4b,d,f were easily alkylated giving S-substituted thio-s-triazoles ( 5a-e ). Furthermore, compounds 4b,d,f underwent a Mannich reaction to give the expected Mannich bases ( 6a-f ). All compounds were fully confirmed by elemental and spectral analyses and have been screened in vitro, for antimicrobial activity.     

Arylmercury Compounds. Part VI. Asymmetric Diarylmercury Compounds

Asymmetric diarylmercury compounds were produced together with symmetric products via a symmetrization process. The asymmetric products could not be isolated from the reaction mixture and their existence was indicated through different analyses (mp, IR, PMR, mass spectra, elemental analysis and DTA). The asymmetric products were shown to be unstable and to disproportionate into two symmetric compounds at elevated temperatures, and in organic solvents even at room temperature.     

Efficient asymmetric TADDOLs-organocatalyzed cycloaddition for the synthesis of allyltin derivatives

We report here the results obtained in the study of organocatalytic asymmetric Diels–Alder reactions to optimize the synthesis of stereo defined allyltin derivatives using (Z)-2-(1-cyclohexenyl)-1-ethenyl(trineophyl)stannane (1) as diene and substituted dienophiles in the presence of (4R,5R)-α,α,α′,α′-tetraphenyl-1,3-dioxolane-4,5-dimethanol (TADDOL, I) and analogs (4R,5R)-α,α,α′,α′-tetra(1-naphtyl)-1,3-dioxolane-4,5-dimethanol (II) and (4R,5R)-α,α,α′,α′-tetra(9-phenantryl)1,3-dioxolane-4,5-dimethanol (III) as chiral catalysts to enhance stereoselectivity through hydrogen bond activation of the dienophile. Catalyst II provided excellent results and ultrasonic radiation at low temperature showed the shorter reaction times.     

Soap-based detergent formulations: VI. Alkylaryl sulfonamide derivatives as lime soap dispersing agents

Alkylbenzenes, such as industrial detergent alkylates, as well as pure 1-phenylalkanes whose side chain lengths varied C₈−C₁₂, were converted into the corresponding alkylbenzenensulfonyl chlorides with chlorosulfonic acid. Surface active sulfonamides were obtained from the reaction of the sulfonyl chlorides with various low mol wt aminosulfonic acids, such as N-methyltaurine, or with aminoalkyl esters of sulfuric acid, such as 2-aminoethyl hydrogen sulfate. The hydrolytic stability of the resulting surface active sulfonamide derivatives was investigated. As expected, the sulfonates were quite resistant to acid or alkaline hydrolysis, while the sulfates were more susceptible to hydrolysis. Hydrolytic stability of the sulfonamides was compared with that of the analogous fatty acid amide sulfactants. All of the compounds were excellent lime soap dispersing agents giving Borhetty-Bergman values of 4–10. The compounds were evaluated for detergency either alone or formulated either with tallow soap or with tallow soap and sodium silicate (Na₂O/SiO₂ ratio of 1∶1.6) The derivatives of the pure hydrocarbons which gave the best overall detergency were those of 1-phenyldecane and 1-phenyldodecane, whereas those of 1-phenyloctane exhibited poor detergency. This ranking was observed when the compounds were tested alone as well as when formulated. The sulfonamide derivatives of the detergent alkylate type of alkylbenzenes exhibited excellent detergency characteristics and showed substantial potentiation of detergency when mixed with soap or with a soap-sodium silicate blend. The detergency performance of some of these formulated detergents was equal to that of a commercial household detergent used as a control.     

6‐Pyridinium benzo[a]phenazine‐5‐oxide derivatives as visible photosensitisers for polymerisation

Several 6‐pyridinium benzo[a]phenazine‐5‐oxide derivatives have been synthesised and characterised by proton nuclear magnetic resonance spectroscopy and mass spectrometry. The spectroscopic and electrochemical properties of these dyes were examined. The dyes were used as reducible sensitisers for selected electron donors (phenylthioacetic acid, phenoxyacetic acid, N‐phenylglycine, and ethyl 4‐N,N‐dimethylaminobenzoate) and as oxidisable sensitisers for electron acceptors (onium and N‐alkoxypyridinium salts). These photoredox pairs were found to be effective visible‐wavelength photoinitiators for the free radical polymerisation of trimethylolpropane triacrylate under visible light. The cationic photopolymerisation of cyclohexene oxide by the studied dyes and the onium salt photoredox pairs was ineffective. The obtained results are discussed on the basis of both free energy change for electron transfer to or from the benzo[a]phenazine dyes and the photochemical properties of the dyes, particularly their photobleaching. The proposed mechanism of dye fading is supported by density functional theory calculations and spectroscopic characterisation of the radical cation of the dye.     

Studies of platinum electroplating baths Part VI: Influence of some experimental parameters on deposit quality

The influence of the conditions on the rate of Pt electroplating and the quality of the deposited layers are reported for the Pt 5Q bath (26mM Pt(NH3)4HPO4 +ap0mM sodium phosphate buffer adjusted to pH 10.4 with NaOH). It is confirmed that much higher rates of deposition can be achieved using constant potential control and the resulting deposits are less stressed than those formed by constant current plating. Deposition with high current efficiency is possible at 358K but again it is more readily achieved at constant potential; the rate of deposition is, however, lower and the plate quality is not as good as observed at 368K. Finally it is reported that three types of deposit can be identified by scanning electron microscopy (almost featureless, hemispherical growth centres leading to cauliflower deposits, and angular crystallites) depending on the cathode potential.     

Studies of platinum electroplating baths Part VI: Influence of some experimental parameters on deposit quality

The influence of the conditions on the rate of Pt electroplating and the quality of the deposited layers are reported for the Pt 5Q bath (26mM Pt(NH3)4HPO4 +ap0mM sodium phosphate buffer adjusted to pH 10.4 with NaOH). It is confirmed that much higher rates of deposition can be achieved using constant potential control and the resulting deposits are less stressed than those formed by constant current plating. Deposition with high current efficiency is possible at 358K but again it is more readily achieved at constant potential; the rate of deposition is, however, lower and the plate quality is not as good as observed at 368K. Finally it is reported that three types of deposit can be identified by scanning electron microscopy (almost featureless, hemispherical growth centres leading to cauliflower deposits, and angular crystallites) depending on the cathode potential.     

Mixed-mode fracture behaviour of refractories with asymmetric wedge splitting test. Part II: Experimental case study

The asymmetric wedge splitting test for performing mixed-mode loading and its numerical evaluation has been presented in a companion paper (Part I). In this work (Part II), the influences of various levels of mode II loading on damage behaviour of refractories with different brittleness were experimentally investigated by comparing mode I and mixed-mode fractures under symmetric and asymmetric wedge splitting loading with seven different wedge angles. The digital image correlation technique was also used for strain maps visualization as well as the deformation parameters acquisition.With the increase of asymmetric wedge angle, the fracture behaviour becomes unstable what is associated with steeper load-displacement curves, more instantaneous energy release and restrained fracture process zone development. The in-plane shear loading contributes to the accelerated extension of the crack tip and its deviation from central plane. Meanwhile, the co-existing local shear stresses caused by the refractory's heterogeneity lead to crack path deflection as well.     

Functionalisation of lyocell. Part 1: Amination of lyocell with m-phenylenediaminesulphonic acid derivatives

A series of four colourless, water-soluble agents, based on m -phenylenediaminesulphonic acid, and designed to aminate lyocell, have been synthesised. Each agent carried one or two aromatic amino groups ortho to a water solubilising sulphonic acid group, together with one or two electrophilic groups. The electrophilic groups studied were dichlorotriazinyl, monochlorotriazinyl, vinylsulphonyl and triazinyl betaine. The agents were applied to lyocell by padding techniques, and neutral-exhaustion dyeing of the aminated fibres, with low, medium and high reactivity reactive dyes, in the presence of salt, were performed. Only the high reactivity dichlorotriazinyl dye gave encouraging results. The aminated fabrics, containing aromatic amino groups with an o -sulphonic acid, were insufficiently nucleophilic to allow significant covalent bonding with the low/medium reactivity dyes at both 60 and 80 °C.     

Ketene N,S-acetals in heterocyclic synthesis: Part 1: Synthesis of N-phenyl-2-ylidene and 2,5-diylidene-4-thiazolidinone derivatives

Ketene N,S-acetal potassium salts (2a–g), prepared via reaction of active methylenes (1a–g) with phenyl isothiocyanate in the presence of potassium hydroxide, were allowed to react with ethyl chloroacetate or chloroacetamide to afford the corresponding 2-ylidene-4-thiazolidinones (3a–g) in good yields. Compounds (3a–g) reacted with a variety of aromatic aldehydes to afford the corresponding 5-arylidene-2-ylidene-4-thiazolidinone derivatives (10a–e). Reaction of compound (3a) with triethylorthoformate afforded 5-ethoxymethylene-2-ylidene-4-thiazolidinone derivative (7), which was allowed to react with ammonia or phenyl hydrazine to give the corresponding enamino or hydrazino derivatives (8a) or (8b), respectively.     

Starch derivatives of a high degree of functionalization. VI. Multistep carboxymethylation

For the first time, carboxymethyl starch (CMS) samples with a very high degree of substitution (DS_CM = 2.1) were synthesized by multistep carboxymethylation under heterogeneous reaction conditions in methanol/water with sodium hydroxide and monochloroacetic acid as an etherifying agent. The stepwise increase in the total DS_CM value gradually decreased with an increasing DS_CM value of the starting polymer. The determination of the functionalization pattern of CMS by ¹H‐NMR spectroscopy after chain degradation indicated a high preference for 2‐O‐substitution. The distribution of the carboxymethyl functions was in the order O‐2 ? O‐6 > O‐3. A detailed analysis of the depolymerized sample by means of high‐performance liquid chromatography and capillary electrophoresis revealed a monomer composition that was in very good agreement with the statistical model of Spurlin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 743–752, 2002     

Organoclay/thermotropic liquid crystalline polymer nanocomposites. Part VI: Effects of intercalated organoclay on nanocomposite morphology,thermal and rheological properties

A study of a typical intercalated structure of a thermotropic liquid crystalline polymer (TLCP) with organoclay was performed to elucidate the influence of intercalated organoclay on the TLCP molecules, especially on their liquid crystallinity, thermal and rheological properties. The intercalated structures were confirmed in TLCP and organoclay formed molecular interactions with TLCP molecules in the system. Such intercalated structures caused the glass transition temperature of the nanocomposite to become invisible in thermal measurement and also caused loss of liquid crystallinity. The TLCP molecules inside the organoclay galleries showed higher thermal stability and transition temperatures, but the orderly structure of the TLCP molecules outside the galleries was destroyed by the organoclay, causing the TLCP to display lower thermal stability and transition temperatures than pristine TLCP. At 185°C, where TLCP is in the nematic phase, the nanocomposite had three orders of magnitude higher viscosity in the linear viscoelastic region than that of TLCP, with chain mobility and relaxation time slowed due to the intercalated effects in the nanocomposite. Steady shear altered the domain sizes and oriented the highly anisotropic organoclay layers or tactoids along the shear direction.     

Mixed-mode fracture behaviour of refractories with asymmetric wedge splitting test. Part I: Numerical implementation and validation

The suitability of asymmetric wedge splitting test (WST) for mode I/II mixed-loading was validated by FE simulation with a three-dimensional heterogeneous continuum FE model. The unsymmetrical strain and stress patterns were observed for mixed-mode loading. Compared with mode I loading of symmetric WST, the introduction of in-plane shear accelerates the crack extension and deviation from symmetry plane with a smaller fracture process zone. Additionally, the asymmetric WST with small, medium and large wedge angles were simulated for sensitivity analysis. With the increasing of asymmetric wedge angle, the recorded vertical load-displacement curves turn from “mild” to “steep”, and the ratio of mode I to mode II fracture energy G_I/G_II decreases accordingly while the symmetric one has the highest G_I proportion. The asymmetric WST with large wedge angle deforms the most at same applied vertical loading displacement, while all WSTs show similar damaged elements amount at the same crack mouth opening displacement.     

Nitriles in heterocyclic synthesis. Part III: New sulpha drugs related to cyanopyridine derivatives

4-Hydroxyacetophenone (1) was reacted with cinnamonitrile derivatives (2–6) to give 3-cyano-4-(substituted phenyl)-6-(p-hydroxyphenyl)-pyridines (7–11). Interaction of compounds 7–9 with 4-substituted heterocyclo-benzenesulphonyl diazoniura chloride gave the corresponding 3-cyano-4-(sub-stituted phenyl)-6-(3′-azobenzene sulphonamido-4′-hydroxyphenyl) pyridines (12–29). The corresponding iron (III) copper (II) and mercury (II) chelates were also prepared in a 1:2 metal-to-ligand ratio. All the synthesized compounds were characterized on the basis of microanalysis, IR and ¹H-NMR spectrometry.     

Polyimide asymmetric membranes: Elaboration,morphology, and gas permeation performance

Asymmetric 2,2‐bis‐(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride (6FDA)‐2‐methyl‐1,3‐phenylenediamine (mPDA) polyimide membranes were prepared according to a phase‐inversion mechanism by using different solvent/nonsolvent blends. The membrane formation mechanism and the final performances of the asymmetric membranes have been found both nonsolvent and solvent nature dependent. From the visualization of cross sections of asymmetric membranes by scanning electron microscopy and the study of the permeation of two gases (N₂, CO₂) through asymmetric membranes, a relationship between elaboration conditions and asymmetric membranes characteristics could be drawn. The organization of polymer chains in solution strongly affects the final polymer arrangement and thus the final performances of the membrane. The influence of preliminary solvent evaporation before immersion has been shown to be dependent on the structure of the asymmetric membrane: finger‐like or sponge‐like structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1838–1848, 2003     

Strain-induced crystallization,Part III: Theory

A nucleation theory for strain-induced crystallization is formulated to explain and to predict the effects of molecular strain on crystallization kinetics and crystallite size. Unlike any current theories that have based their formulations on some assumed extended-chain line nuclei or folded-chain crystals, the present theory avoids all assumptions concerning the crystal morphology. It is based on experimental findings which indicate limited crystal growth in the strain direction, following a reciprocal dependence of crystal thickness on supercooling ΔT. (ΔT = T, ? T, where the equilibrium melting temperature, T, is a variable dependent on degree of molecular strain prior to strain-induced crystallization.) It is predicted that the logarithm of the nucleation rate, N^o, is dependent on (T)²/T(ΔT) or T/T(ΔT), and that the critical nucleus thickness l^*o is shown to be proportional to T/ΔT. In addition, expressions are also presented, including examples, to show the dependence of N^o, l^*o and T^o_m on degree of molecular strain, ?, or melt entropy reduction, Δs′. Our analysis predicts that, on comparing a polyethylene crystallized in the presence of strain to one crystallized in the absence of strain at 130°C, an increase in “coil” dimension of less than about 50 percent can bring about a 10⁴ fold increase in heterogeneous nucleation rate, a 30–40 percent reduction in critical nucleus thickness and a 10°C increase in equilibrium melting temperature. These results will be discussed and compared with available experimental evidence.     

Pyrolytic Reactions of Carbohydrates. Part VI. Isothermal Decomposition of Cellulose In Vacuo,in the Presence of Additives

The isothermal decomposition of cellulose at 250 and 275°C has been investigated in the presence of neutral, acidic, and basic additives. The composition of the volatile fractions and of the residue has been studied and the influence of the additives on the course of the thermal decomposition is discussed.     

Synthesis and dyeing properties of novel disperse dyes. Part 2: Pyrazole disperse dye derivatives

Several new disperse dyes derived from thiosemicarbazides and acetoacetanilide have been synthesised. The dye structures were ascertained by chemical analysis and infrared measurements. Prepared dyes were used for dyeing nylon fabric by the exhaustion method. The colour strengths and dye fixation on the fabric were also determined. The results suggest a practical significance.