Showing papers in "Applied Organometallic Chemistry in 1996"
TL;DR: In this article, a review of phthalocyanine-ines suitable for the development of chemical sensors is provided. And the interaction mechanism between phthaloxyanine films and analyte molecules is also discussed.
Abstract: This paper provides a review of phthalocyan- ines suitable for the development of chemical sensors. Phthalocyanines may be utilized for different types of chemical sensors, including in particular electronic conductance sensors [such as semiconductive, field-effect transistor (FET), solid-state ionic and capacitance sensors], mass-sensitive sensors utilizing a quartz crystal microbalance (QCM) and surface acoustic-wave (SAW) sensors, and optical sensors. The phthalocyanines used are discussed in terms of their physical and chemical properties, as well as their sensitivity, selectivity and reversibility towards the detection of NO2 and organic solvent vapours. The interaction mechanism between phthalocyanine films and analyte molecules is also discussed.
198 citations
TL;DR: The third-order nonlinear optical properties of a series of organoboron compounds containing dimesitylboron moieties have been investigated by third harmonic generation (THG) measurements at 1.907 μm.
Abstract: The third-order nonlinear optical properties (second molecular hyperpolarizabilities, γ), of a series of organoboron compounds containing dimesitylboron moieties have been investigated by third harmonic generation (THG) measurements at 1.907 μm. Symmetric systems with B(mes) 2 groups (mes=2,4,6-Me 3 C 6 H 2 ) at both ends, e.g. (mes) 2 B-Y-B(mes) 2 where Y=(C 6 H 4 ) n (n=1,2) or trans-trans-CH=CH(C 6 H 4 ) n -CH=CH- (n=1,2), were prepared as well as push-pull systems of the form D-Y-B(mes) 2 where D=MeS, Me 2 N, H 2 N, etc., and Y=C 6 H 4 , C 6 H 4 -C=C, C 6 H 4 -CH=CH-, C 6 H 4 -CH=CH-C 6 H 4 . The B(mes) 2 group compares favorably with the more commonly used NO 2 acceptor function for enhancing γ. Values of γ increase significantly with increasing length of π-conjugation for both symmetric and unsymmetric molecules. The MeS group is much more efficient than MeO for enhancing γ. Values as high as 229 x 10 -36 esu are reported for trans-trans-(mes) 2 -B-CH=CH-(C 6 H 4 ) 2 -CH=CH-B(mes) 2 which has a λ max for absorption of 370 nm. Crystal and molecular structures of the bis(dimesitylboryl) benzene and anthracene compounds 1,4-C 6 H 4 -{B(mes) 2 } 2 and 9,10-C 14 H 8 {B(mes) 2 } 2 are reported, as are fluorescence maxima for the symmetric molecules.
155 citations
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TL;DR: In this article, the adsorption ability of coral limestones with an aqueous solution of aluminium sulfate and thereby aluminium-loaded coral limstones (Al-CL) was examined.
Abstract: Coral limestones were treated with an aqueous solution of aluminium sulfate and thereby aluminium-loaded coral limestones (Al-CL) were prepared. By use of Al-CL as an adsorbent, the adsorption of inorganic arsenic compounds (arsenate [As(V)] and arsenite [As(III)] and of organic arsenic compounds (methylarsonic acid, dimethylarsinic acid, and arsenobetaine) was examined. The adsorption ability of Al-CL is superior to that of iron(III)-loaded coral limestone (Fe-CL) for As(V), As(III), methylarsonic acid and dimethylarsinic acid. The adsorption of As(V) and As(III) is almost independent of the initial pH over a wide range (2 or 3 to 11). The addition of other anions, such as chloride, nitrate, sulfate and acetate, in the solution does not affect the adsorption of As(V) and As(III), whereas the addition of phosphate greatly interferes with the adsorption. Arsenic adsorption is effectively applied to a column-type operation and the adsorption capability for As(V) is 150 μg/g coral limestone.
69 citations
68 citations
TL;DR: A review of analytical methods for determination of tin and speciation of organotin compounds can be found in this paper, in the hope that it will be of value to those interested in initiating a programme for assessing the impact of such species on the environment.
Abstract: The growing awareness over the environmental fate of organotin compounds is reflected in the large number of analytical methods developed for their separation. Organotin compounds have varying degrees of toxicological properties, depending on the nature and number of alkyl groups bonded to the tin atom. Most of the analytical speciation methods applied to actual environmental media have involved prior derivatization to transform organotin compounds into volatile hydrophobic analytes amenable to separation and identification by gas chromatography coupled to a sensitive and selective tin-detector. Evidence exists that members of the same homologous series are related by environmental degradation pathways. Chemical treatment prior to analysis, or high temperatures associated with gas chromatography separation, may alter the relative amounts of organotins in samples and blur the true environment picture. To avoid species redistribution that may occur during derivatization or gas speciation analysis, methods based on liquid chromatography and supercritical fluid chromatography have been investigated. This review documents analytical methods for determination of tin and speciation of organotin compounds, in the hope that it will be of value to those interested in initiating a programme for assessing the impact of such species on the environment.
64 citations
TL;DR: Transition-metal sandwich complexes incorporating bifacially coordinated C 2 B 3 planar carborane rings form a large and varied family of generally air-stable, highly robust compounds that feature multidecker stacking as discussed by the authors.
Abstract: Transition-metal sandwich complexes incorporating bifacially coordinated C 2 B 3 planar carborane rings form a large and varied family of generally air-stable, highly robust compounds that feature multidecker stacking. As a group, these complexes offer a number of advantages that are potentially of interest in the development of new electronic, magnetic and/or optical materials. They are remarkably versatile, accommodating a wide range of metals and organic substituents ; they are soluble in organic solvents and are typically resistant to air and moisture ; they can be reversibly oxidized and reduced ; in many cases they are paramagnetic, exhibiting substantial electron delocalization of the unpaired electrons between metal centers. Moreover, the small carborane starting materials can now be prepared in large (ca 100 g) quantities, making the complexes readily accessible. A brief overview of this area is presented with emphasis on the systematic utilization of metallacarborane sandwich complexes in the construction of large multimetallic systems and studies of their electronic and molecular structures.
62 citations
59 citations
TL;DR: In this paper, an organotin speciation method was optimized for the simultaneous determination of mono-, di- and tri-butyltin compounds and mono, di-and tri-phenyltin compound in water.
Abstract: An organotin speciation method was optimized for the simultaneous determination of mono-, di- and tri-butyltin compounds and mono-, di- and tri-phenyltin compounds in water. The procedure was based on a one-step simultaneous ethylation and extraction using the sodium tetraethylborate reagent directly in the aqueous phase in the presence of an isooctane layer. Direct extract analysis was performed using capillary gas chromatography and flame photometric detection (GC-FPD). This derivatization procedure reduces drastically the number of analytical steps, thus saving time and improving reliability. Relative detection limits range from 0.4 to 0.8 ng dm -3 for butyltin species and from 0.7 to 2.1 ngdm -3 for phenyltin species; the linearity ranges from 0 to 400 ngdm -3 . Analysis of environmental aqueous samples and a Certified Reference Material (CRM) demonstrates the accuracy of the analytical method.
TL;DR: In this article, new siloxanyl-modified carbohydrate surfactants of the amide and glycoside type have been synthesized by coupling between defined as well as higher-molecular-weight siloxanes and carbohydrate structures via spacers of different lengths and hydrophilic power.
Abstract: New siloxanyl-modified carbohydrate surfactants of the amide and glycoside type have been synthesized by coupling between defined as well as higher-molecular-weight siloxanes and carbohydrate structures via spacers of different lengths and hydrophilic power. Linear and branched monohydrogen di-, tri-, tetra- and penta-siloxanes and polyhydrogen siloxanes as well as mono- and di-saccharide lactone structures have been found to be good starting materials for the synthesis of amides, often in quantitative yield, whereas glycosides had to be prepared in low-yield multistep sequences including protection/deprotection steps. Selected strategies were applied to polysiloxanes yielding quantitatively a broad variety of carbohydrate-modified comb-like structures. The new substances were characterized by means of 13 C NMR spectroscopy, GC, capillary GC, GC-MS coupling and elemental analysis.
TL;DR: The distribution of arsenic species, including trivalent methylarsenicals, was observed in coastal seawater of Tosa Bay and Uranouchi Inlet Japan as mentioned in this paper, and seasonal variations in the concentrations of arsenicals were observed both in the water column and in surface sediments.
Abstract: The distribution of arsenic species, including trivalent methylarsenicals, was observed in coastal seawater of Tosa Bay and Uranouchi Inlet Japan. In Tosa Bay, most arsenic was dissolved in the inorganic form throughout the year and the concentration of total dissolved arsenic was higher than that in Uranouchi Inlet. The sum of methylarsenicals found in surface waters comprised 2-25% and 10-82% of the total dissolved arsenic in Tosa Bay and Uranouchi Inlet, respectively. In Uranouchi Inlet, seasonal variations in the concentrations of arsenicals were observed both in the water column and in surface sediments. The maximum concentrations of methylarsenicals appeared during summer, and became comparable to those of inorganic arsenicals in surface water. The concentration of trivalent methylarsenicals was usually low, and their seasonal changes seemed to be independent of those of the pentavalent species. The variations in methylarsenic(V) concentration did not coincide with those of chlorophyll a in either Tosa Bay or Uranouchi Inlet. These results suggested that methylarsenic(V) in natural waters was produced not directly by the activity of phytoplankton but through decomposition of organic matter by bacteria.
TL;DR: A review of the use of high-performance liquid chromatography (HPLC) for the speciation of organotin compounds which are primarily of significance in the marine environment, is divided into sections on the basis of the different HPLC modes of separation as discussed by the authors.
Abstract: This review of the use of high-performance liquid chromatography (HPLC) for the speciation of organotin compounds which are primarily of significance in the marine environment, is divided into sections on the basis of the different HPLC modes of separation. However, it should be noted that such a classification does not exist in reality. For instance, in an ion-pair reversed-phase system the separation mechanism for the ionic solutes may be ion-pair partitioning, or ion exchange, or both. The relevant practical information (e.g. column type, mobile phase, method of detection and detection limit) is presented in tabular form. A brief overview of the reported detection methods is included, because the delay in development of an easily interfaced, specific and sensitive detector has hindered the use of HPLC for organotin speciation studies. The literature reviewed covers publications from 1977, the year of the first application of HPLC to organotin speciation, to April 1995.
TL;DR: Among zooplankton analyzed in the present study, two carnivorous species, i.e. Amphipoda (Themistosp) and Sagittoidea (Sagittasp), contained arsenobetaine as the dominant arsenic species as discussed by the authors.
Abstract: Major water-soluble arsenic compounds accumulated in some zoo- and phyto-plankton were identified. Zooplankton were collected at sampling stations in the Sea of Japan by a Norpac net towed from 600 m depth to the surface. Phytoplankton were cultivated under axenic conditions. Water-soluble arsenic compounds were extracted repeatedly from plankton tissues by aqueous methanol. The arsenic compounds in the extracts were analyzed by HPLC–ICP/MS.
Among zooplankton analyzed in the present study, two carnivorous species, i.e. Amphipoda (Themistosp.) and Sagittoidea (Sagittasp.), contained arsenobetaine as the dominant arsenic species. Arsenobetaine was the major species in Euphausiacea (Euphausiasp.), also. The most abundant arsenic compound in the herbivorous Copepoda species (Calanussp.), on the other hand, was an arsenic-containing ribofuranoside with a sulfate ester group, and arsenobetaine was only a minor component. Phytoplankton contained arsenic-containing ribofuranosides apparently in a species-speific manner. The arsenic compounds in zooplankton seem to reflect their feeding habit; i.e. carnivorous species eating zooplankton or other small animals accumulate arsenobetaine, while herbivorous ones eating phytoplankton accumulate arsenic-containing ribofuranosides as major arsenic compounds.
TL;DR: It was found that Dunaliella sp.
Abstract: Uptake and reduction of arsenate [AS(V)] by Dunaliella sp. cells were determined to investigate the metabolic processes of arsenic in the alga. Cellular uptake of arsenic by Dunaliella sp. cells was markedly affected by the form of arsenic in the medium. The content of arsenic taken up by Dunaliella sp. cells increased rapidly with time on addition of As(V) to the medium. However, in the case of addition of arsenite [As(III)], the gradient of arsenic uptake by Dunaliella sp. cells was low, and arsenic content was small. In the water-soluble fraction of arsenic taken up by Dunaliella sp. cells with exposure to As(V), arsenic was in the forms of organic arsenic, As(V) and As(III). The content of As(V) in the water-soluble fraction increased with exposure time. The content of As(III) also increased with time, but remained constant after 5h of exposure. On the other hand, organic arsenic content was small and did not increase with time. It was found that Dunaliella sp. takes up As(V) and readily reduces it to As(III).
TL;DR: The influence of the counterion X group on the toxicity of organotins was discussed in this article, where it was found that when X is a small easily ionizable group, it has little effect on toxicity; however, when it is a large organic groups, it does change the bioactivity of the organotin.
Abstract: The inhibition by 20 organotin compounds (R n SnX 4-n ), which included some newly synthesized pesticides, of the growth of two green algae (Scenedesmus obliquus and Platymonas sp.) was studied. The influence of the counterion X group on the toxicity of organotins was discussed. The destruction of submicrostructures of the algal cell by organotins was viewed by micrography and electron microscope scanning. It was found that the toxicity of the organotins varied significantly according to their substitution. The order of toxicity is tri- » di- ≥ mono-organotins. Within the same substituent series, the toxicity depends on the properties of both R and X groups. The larger and the more lipophilic the R group, the more toxic is the organotin. The influence of the X group is more complex: when X is a small easily ionizable group, it has little effect on the toxicity; however, when it is a large organic group, it does change the bioactivity of the organotin. Large organic groups may influence the polarizability of the central tin atom, and so change the toxicity of organotins.
TL;DR: In this article, a branched siloxanyl-modified carbohydrate surfactants have been synthesized by coupling mono-, di-and poly-functional siloxanes to carbohydrate units either via a branch-shaped spacer or by attaching a separate modifying element to a straight-chained structure.
Abstract: Branched siloxanyl-modified carbohydrate surfactants have been synthesized by coupling mono-, di- and poly-functional siloxanes to carbohydrate units either via a branched spacer or by attaching a separate modifying element to a straight-chained structure. Hydrophilic as well as extremely hydrophobic elements have been incorporated successfully. Siloxanyl-modified carbohydrates bearing a secondary amino function were alkylated in regioselective reactions by different epoxides ranging from glycidol- to siloxanyl-modified allyl glycidyl ether derivatives. Alternatively, carbohydrate-modified piperazinyl structures yielded cyclic subunits after alkylation. Structures bearing two identical hydrophilic groups are accessible by alkylation of carbohydrate-modified bisamides. The derivatives synthesized were characterized by means of GC, NMR and elemental analysis.
TL;DR: Results suggest that the consequence of auto-oxidation of Hb could condition the effects of some organotin compounds, including tributyltin chloride and its degradation products monobutyltin and dibutylt in.
Abstract: Tributyltin chloride and its degradation products monobutyltin and dibutyltin act as water pollutants, owing to the use of tributyltin chloride as a biocide in marine paint formulations. These compounds are lipid-soluble and undergo bioaccumulation and bioconcentration. Salmo irideus trout erythrocytes were studied to evaluate the possible effects of these compounds on freshwater fish, which could be exposed to long-term effects due to bioaccumulation of organotins. Data showed that tributyltin increases the haemolysis rate, starting at 10 μM, while dibutyltin has a scant protective effect at each concentration tested. Similar studies were performed in the presence of carbon monoxide (CO), which is protective against membrane oxidative stress due to haemoglobin (Hb) auto-oxidation. In these conditions all the organotins tested induced an increase in the haemolysis rate. These results suggest that the consequence of auto-oxidation of Hb could condition the effects of some organotin compounds. Steady-state fluorescence of probes embedded in the lipidic part of the membrane was used to evaluate the modifications induced by organotins to the physico-chemical state of phospholipids.
TL;DR: A range of substituted ferrocenes has been synthesized and studied for flame retardancy and smoke suppression on incorporation into plasticized PVC at 0.1-5.0 phr as discussed by the authors.
Abstract: A range of substituted ferrocenes has been synthesized and studied for flame retardancy and smoke suppression on incorporation into plasticized PVC at 0.1-5.0 phr. Smoke suppression by up to 50% and enhancement of the limiting oxygen index by up to 4 units were observed. The differences in performance could not be correlated with char formation, thermal analysis or chemical structure of the additive. A negative correlation was found between smoke suppression and flame retardancy. The most effective smoke suppressant additive appears to accelerate the rate of dehydrochlorination of PVC while the most effective flame retardant appears to have little effect on the dehydrochlorination process.
TL;DR: In this article, the temperature dependence of 1,6-diphenyl-1,3,5-hexatriene (DPH) and TMA-DPH fluorescence anisotropy has been studied to investigate the influence of mono-nbutyltin chloride (MBTC), di-n-butylp chloride (DBTC) and tri-nphenyl chloride (TPTC) on the physicochemical state of dipalmitoyl phosphatidylcholine.
Abstract: The temperature dependence of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylamino-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) fluorescence anisotropy has been studied to investigate the influence of mono-n-butyltin chloride (MBTC), di-n-butyltin chloride (DBTC) and tri-n-phenyl chloride (TPTC) on the physicochemical state of dipalmitoyl phosphatidylcholine. Below the lipid chain melting transition (T m ), fluorescence anisotropy values of DPH and TMA-DPH are increased by the presence of the organotins, without important modifications of the phase transition temperature. A possible difference in localization of the organotin compounds is suggested by the differential effect of the probes. It is suggested that there is localization in the hydrophobic core of the bilayer for TPTC, and at the head-group level for DBTC, and a homogeneous distribution in the bilayer for MBTC. Similar studies have been performed in liposomal suspensions of cardiolipin, phosphatidylserine and egg phosphatidylcholine.
TL;DR: In this paper, an evaluation of reversed-phase high-performance liquid chromatography (HPLC) employing mobile phases compatible with direct coupling to inductively coupled plasma-mass spectrometry (ICP-MS) is described for the selective and sensitive detection of organotin species.
Abstract: An evaluation of reversed-phase high-performance liquid chromatography (HPLC) employing mobile phases compatible with direct coupling to inductively coupled plasma-mass spectrometry (ICP-MS) is described for the selective and sensitive detection of organotin species. The findings of this study are compared with established methods, employing ion-exchange chromatography.
In order to achieve optimum performance, both the HPLC and ICP-MS were optimized for speciation work. The results from studies using various mobile phases for the separation of a range of tin compounds (inorganic tin, tributyltin, dibutyltin and monobutyltin) are discussed both in terms of resolution and compatibility with ICP-MS instrumentation. Tropolone, a commonly used complexing agent for organotin species, is also discussed with reference to the chromatographic separation of tin species.
Finally, the role of isotope dilution analysis in conjunction with HPLC-ICP-MS for organotin speciation is described with respect to the European Community Standards, Measurements and Testing (BCR) certified material programme.
TL;DR: The geochemical behavior of arsenic-bearing groundwaters from four areas-Fukuoka, Kumamoto, Fukui, and Takatsuki-has been reviewed and considered from the viewpoints of the chemical composition of the water, the geological setting of the host formation, and the arsenic content in sediments and rocks as mentioned in this paper.
Abstract: The geochemical behavior of arsenic-bearing groundwaters from four areas-Fukuoka, Kumamoto, Fukui, and Takatsuki-has been reviewed and considered from the viewpoints of the chemical composition of the water, the geological setting of the host formation, and the arsenic content in sediments and rocks. In all the areas except Fukui, arsenic-bearing water is concluded to have come from a specific aquifer during water-sediment interactions. Stagnant groundwater, having reducing and alkaline properties, played a significant role in the release of arsenic from such Quaternary sediments as silt-clay layers and brownish-colored gravel beds.
TL;DR: In this article, it is inferred that the process is dominated by formation of transient silene, rearrangement to methylsilylene, silene and methyl silylene dehydrogenation, and polymerization of SiCH n (n < 4) species.
Abstract: CO 2 laser-induced infrared multiphoton decomposition (IRMPD) and SF 6 photosensitized decomposition (LPD) of silacyclobutane (SCB) and 1,3-disilacyclobutane (DSCB) in the gas phase results in the very efficient deposition of Si/C/H and SiC materials, and it is inferred that the process is dominated by formation of transient silene ; silene rearrangement to methylsilylene ; silene and methylsilylene dehydrogenation ; and polymerization of SiCH n (n < 4) species. The deposits are sensitive to oxygen. Decomposition and SiC formation are favoured with IRMPD experiments conducted with high-energy fluxes. The laser technique is promising for low-temperature chemical vapour deposition of amorphous SiC.
TL;DR: In this paper, the results indicate that, besides undergoing methylation, DMA can be demethylated to inorganic arsenic, and demethylation of DMA may be associated with intestinal bacteria.
Abstract: Metabolites of dimethylarsinic acid (DMA) were studied in rats chronically exposed to DMA in drinking water. The urine was collected by forced urination at the end of 8, 20 and 30 weeks and the feces at the end of 30 weeks. The samples were analyzed for arsenic species by a combined system of ion chromatography and inductively coupled plasma mass spectrometry (IC-ICP-MS). Increases in arsenite, DMA, trimethylarsine oxide and a still-to-be-identified arsenic compound (which was eluted immediately after monomethylarsonic acid on the chromatogram) were detected in both urine and feces. At the 100 mg l -1 dose, DMA was the main component in the urine; arsenite was a main component in the feces. The results indicate that, besides undergoing methylation, DMA can be demethylated to inorganic arsenic, and demethylation of DMA may be associated with intestinal bacteria.
TL;DR: In this article, three series of organotin compounds were screened in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease, and the series that were most active against this deadly fungus were those that contained the triphenyltin moiety.
Abstract: Three series of organotin compounds were screened in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease. The series that were most active against this deadly fungus were those that contained the triphenyltin moiety. In addition, the fungicidal activity of the triphenyltin compounds were found to be independent of the anionic group attached to the tin atom. However, there was a marked increase in the activity of the triphenyltins when a biologically active group which did not dissociate upon dissolution was incorporated into the overall molecule.
TL;DR: In this paper, the limitations of conventional gas chromatography-mass spectrometry (GC-MS) analyses for alkyl and aryl-tin compounds are discussed, particularly the excessive fragmentation from electron impact (EI) ionization.
Abstract: The limitations of conventional gas chromatography-mass spectrometry (GC-MS) analyses for alkyl- and aryl-tin compounds are discussed, particularly the excessive fragmentation from electron impact (EI) ionization. Negative EI methods exhibit low ionization capabilities and are restricted to compounds with an electronegative centre, and are thus not suitable for general routine analysis. Liquid chromatography-MS (LC-MS) interfaces offer potential advantages in terms of reduced sample work-up since no derivatization is required. Electrospray techniques give reproducible mass spectra for each compound studied under fixed instrumental parameters. Changes in the cone/repeller voltages can radically alter the observed mass spectra. High-mass species were observed for each compound studied and tentative structures for these species are proposed.
TL;DR: A flow-injection chemiluminescence (CL) method has been proposed for sensitive determination of arsenate, germanium, phosphate and silicate, after separation by ion chromatography (IC).
Abstract: A flow-injection chemiluminescence (CL) method has been proposed for sensitive determination of arsenate, germanate, phosphate and silicate, after separation by ion chromatography (IC) The post-column detection system involved formation of heteropoly acid in a H 2 SO 4 medium before the CL reaction with luminol in an NaOH medium For separation, heteropoly acid formation and the CL detection reaction, pH requirements were not compatible When present as a heteropoly acid complex with molybdenum(VI), germanium(IV) and silicon(IV) caused CL emission from oxidation of luminol, and such a CL oxidation of luminol was observed analogously for arsenic(V) and phosphorus(V) but with the addition of metavanadate ion to the acid solution of molybdate Good sensitivity for the three analytes arsenic(V), germanium(IV) and phosphorus(V) could be given by a single set of reagent conditions, chosen carefully Another set was suitable for determining phosphorus(V) and silicon(IV) The minimum detectable concentrations of arsenic(V), germanium(IV), phosphorus(V) and silicon(IV) were 10, 50, 1 and 10 (μg 1 -1 , respectively Linear calibrations for arsenic(V), germanium(IV), phosphorus(V) and silicon(IV) were established over the respective concentration ranges of 10-1000, 50-25000, 1-1000 and 50-10000 μg1 -1 The proposed IC-CL method was successfully applied to analyses of a seaweed reference material, rice wine and water samples