The preclinical bioanalytical process with animal models begins with sampling biological fluids and tissue. The goal is to understand oral absorption kinetics, distribution, metabolism, excretion, blood brain barrier penetration, drug-drug interactions, and the influences on biomarkers, hematology, electrophysiology, cardiology, blood pressure and behavior. An overview is obtained by periodic blood sampling of 8 - 12 samples over a total time span of 10 - 24h. Urine, feces, bile and microdialysates can augment the information available from whole blood. In today’s preclinical environment, the majority of samples are processed by LC/MSMS augmented by robotic sample preparation tools. These tools save labor and improve precision for smaller volume/lower concentration samples. Our laboratories have been engaged in a project that is focused on improving both the quality and throughput for laboratory animal studies, while providing for reduced numbers of animals and enhanced animal comfort. We have implemented a robotic system that can accomplish most of the above goals for laboratory rats, dogs and primates. Studies with mice are at an earlier stage, but feasibility has been demonstrated. This presentation is a progress report on this evolving research program in cooperation with multiple pharmaceutical and drug development companies. We will illustrate results and discuss future directions.

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The surface chemical compositions of solid samples from environmental and geological sources can differ from the bulk or average compositions, because of changes caused by adsorption, dissolution, oxidation, etc. Accordingly, analytical information on surface layers is important for a better understanding of the environmental chemistry involving solid surfaces. The rapid development of surface-analytical techniques has enabled us to probe the surface chemistry of environmental and geological solid samples of complex composition. This article demonstrates some examples of important items of information that can be obtained by applying surface-analytical techniques, such as X-ray photoelectron spectroscopy and secondary ion mass spectrometry, to environmental and geological samples. The surface analysis of fly ashes, soils, sediments and weathered silicate minerals is reviewed.

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A new screening assay was described for the determination of endocrine disrupting chemicals (EDCs), such as synthetic estrogens, with an array-type DNA glass slide having characteristics of 1) a high sample throughput, 2) a compact size allowing a small sample volume, and 3) a sensitive determination based on the estrogen-dependent binding of the human estrogen receptor α (hERα) with its estrogen responsive element (ERE; Vit. A₂ gene promoter). We devised a glass slide on which a thin agarose gel was mounted. Avidin was then covalently immobilized on each well of the glass slide after the gel was activated by a NaIO₄ solution. Also, the biotinylated ERE as a DNA probe was immobilized on the gel layer through avidin-biotin binding. After the estrogen-dependent binding of a yellow fluorescent protein-fused hERα (YFP-hERα) to ERE on the gel layer, the fluorescence intensity of YFP-hERα quantitatively extracted into the gel was directly determined with a fluorescence microplate reader. Pre-incubation of YFP-hERα with estrogen at 37°C for 30min enhanced the estrogen-dependent hERα-ERE binding. The determined hormonal activities of estrogens on the interaction of YFP-hERα with ERE were as follows in their decreasing order: diethylstilbestrol (DES) > 17β-estradiol (E₂) ≈ ethynylestradiol (EE₂) > 4-hydroxy tamoxifen (OHT) > clomiphene (Clo). The present method provides a sensitive estrogen-dependent dose-response curve down to ∼10^-13 M in the case of DES. This method will become a competitive alternative to the conventional in vitro assays, such as a DNA-binding assay using radioisotopes.

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Aqueous solutions of ascorbic acid in unsupported and supported aqueous solutions and real samples were studied by the kinetics-sensitive double-step voltcoulommetric method with the aim to contribute to a better understanding of its behavior in biological systems. The data obtained from measurements made on analytes prepared in the laboratory, as well as those made on real samples (some commercial orange drinks, flash of the fresh fruits) point to the redox reaction of L-ascorbic acid (L-AH₂) being very sensitive to both the presence of dissolved gaseous species (O₂, CO₂) and the ionic strenght in the analyte. Either the dissolved gaseous species, or the higher ionic strength caused by both the presence of supporting electrolyte and increased total concentration of ascorbic acid, respectively, give birth to the degradation of L-AH₂. Naturally, the highest percentage of L-AH₂ was spotted in fresh fruit.

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A sensitive adsorptive stripping voltammetric method for the determination of dinitrophenolic herbicides, dinoseb (DSB) and dinoterb (DTB) at a bare carbon paste electrode (CPE) and a clay modified carbon paste electrode (CMCPE) was developed. A systematic study of various experimental conditions, such as the pH, accumulation variables and composition of a modifier on the adsorptive stripping response, were examined by using differential pulse voltammetry. A significant improvement was observed in the sensitivity by using the present method with CMCPE. When CMCPE was used, a linear response was obtained over the concentration range 2 × 10^-10 to 3 × 10^-7 M and 6 × 10^-10 to 6 × 10^-7 M with lower detection limits of 1 × 10^-10 M and 5.4 × 10^-10 M for dinoseb and dinoterb, respectively, at an accumulation time of 100 s. The interference from other herbicides and ions on the stripping signals of both compounds was also evaluated. The described method was applied to estimate of the dinoseb and dinoterb in environmental samples.

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Atmospheric H₂O₂ is typically determined by enzymatically mediated fluorogenic reactions that do not discriminate between H₂O₂ and organic peroxides. Reactions of Ti(IV) with H₂O₂ has also been the basis of colorimetric measurements of H₂O₂ but is too insensitive. A more sensitive determination is possible with the Ti(IV)-4-(2-pyridylazo)resorcinol (PAR) complex, however, unreacted PAR must be chromatographically separated. A titanium(IV)-porphyrin complex, oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) [TiO(tpypH₄)⁴⁺], (TiTPyP) was introduced for the measurement of aqueous H₂O₂. In this paper, we show that TiTPyP can be used for measuring H₂O_2(g), it does not respond to CH₃HO₂. With a proper membrane collector, practically there is no interference from concurrently present gaseous SO₂ and O₃. The approach permits a S/N = 3 limit of detection (LOD) of 26 pptv with a 50 mm path liquid core waveguide (LCW) absorbance detector and a light emitting diode based light source. This is adequate for real atmospheric measurements.

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The purpose of this study is to clarify the chemical characterization of PM_2.5 and PM₁₀ in diesel exhaust particles (DEP). Sampling of PM_2.5 and PM₁₀ in DEP was carried out in November 1999 using an automobile exhaust testing system at the National Traffic Safety and Environment Laboratory, with a diesel truck (engine type: direct injection, displacement: 7961 cc, carrying weight: 2020 kg, equivalent inertia weight: 5600 kg) placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km/h, M-15 test pattern and 60%-revolution/40%-load of maximum power. Samples were collected on a polycarbonate membrane filter (Nuclepore^®, pore size: 0.8 μm) using a MiniVol Portable Air Sampler (Airmetrics Co., Inc.). The concentrations of several elemental and ionic species in the PM_2.5 and PM₁₀ samples were determined by particle induced X-ray emission (PIXE) and ion chromatography analysis. PIXE analysis of the PM_2.5 and PM₁₀ samples revealed 15 elements, of which Na, Mg, Si, S, Cl, Ca, Fe and Zn were found to be the major components. Ionic species were Cl^-, No₂^-, No₃^-, So₄^2-, Na⁺, NH₄⁺, K⁺ and Ca²⁺. Concentrations of elements and ionic species under the sampling condition of 60%-revolution/40%-load were highest in comparison with those of the other sampling conditions. The elemental and ionic species data were compared for PM_2.5 and PM₁₀; PM_2.5 concentrations were 70% or more of PM₁₀ concentrations for the majority of elements, and concentrations of ionic species in PM_2.5 and PM₁₀ were almost identical.

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It is well-documented that organic compounds form strong complexes with most metals in aquatic systems, and that seawater is a complex medium which contains a large variety of organic and inorganic ligands, including colloidal matter. We suggest that most trace metals are complexed in seawater and that some inorganic metals complexes are either labile or not stable. In contrast, metal-organic complexes are often stable and need various and specific treatments to be dissociated. In this paper we try to illustrate a good tendency of some trace metals to be complexed by organic ligands in seawater. A solid-phase extraction method was applied using a C18 column as a resin that is able to separate metals complexed by neutral organic ligands, and the chelamine resin to separate metal species that are present as labile inorganic complexes. The determination of total dissolved metal concentrations was achieved by formatting a metal-8-hydroxyquinoline complex, followed by adsorption on C18 columns and ICP-AES analysis.

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The electrical decomposition of 4-chlorophenol in water was examined with iridium dioxide doped on a titanium electrode. A number of electrical degradation products of 4-chlorophenol, such as hydroquinone and chlorohydroquinone via the addition of hydroxyl radicals, and dichlorophenol through addition of chlorine radical, were observed as major products. Moreover, hydroxylated chlorobiphenylethers, hydroxylated dibenzo-p-dioxin/furans and hydroxylated chlorobiphenyls formed by a dimerization process during the electrolysis process of 4-chlorophenol were also observed. On the other hand, benzoquinone, muconic acid and aldehyde derivatives that were further oxidative products of hydroquinone formed by photocatalysis process, were not observed. The electrical decomposition products of 4-chlorophenol were trimethylsilylated and then identified by gas chromatography-mass spectrometry. The degradation rate of 4-chlorophenol in water by iridium oxide electrode was measured against the electrical process duration. After iridium electrical process for 120 min, about 50% of 4-chlorophenol was converted into a number of products through oxidation processes. On the basis of the identified products, the degradation pathways of 4-chlorophenol under electrolysis process were proposed.

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Ten carbamate pesticides including four suspected endocrine disruptors, methomyl, benomyl(carbendazim), aldicarb and carbaryl, were simultaneously analyzed by LC/ESI/MS. The influence of the matrix on the variation of the ion signal intensities of (M + H)⁺ and adduct ions was investigated. Although the intensities of three oxamyl ions changed depending on the matrix, the variation in the concentration calculation of oxamyl was reduced by using the sum total of the area value of two ions. The limits of the quantitation of ten pesticides without a concentration procedure were from 0.4-30μg/l. The solid-phase recovery rates of ten pesticides spiked into tap water and raw water were in the range of 69-111%. Using this method, the concentrations of the pesticides in tap and raw water sampled at 14 monitoring points in Hyogo Prefecture were determined. Carbendazim in three raw water samples and carbofuran in one of these three samples were detected at low concentrations (less than 0.32μg/l).

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The reactions within a recently introduced NO₂-sensitive polymeric membrane based on aquacyanocobalt(III)-cobyrinate are described. The detailed reaction mechanism was investigated in three ways: using UV/VIS-spectroscopy, determining the reaction products and investigating the influence of other gases. It could be shown that the membrane’s high sensitivity and selectivity derives from the remarkable reaction of NO₂ with this cobyrinate derivative, which yields nitric and nitrous acid. This reaction can be transduced with a consecutive protonation of the included chromoionophore into an optical signal, which allows the detection of NO₂ in the ppb-range.

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In the absence of any special luminescent reagents, a weakly chemiluminescent emission was observed during the decomposition of hydrogen peroxide, catalyzed by transition-metal ions, such as Cu(II) and Co(II), in basic aqueous solution. The chemiluminescent intensity was significantly enhanced by the addition of ethyldimethylcetylammonium bromide and uranine. The signal-to-noise ratio (S/N) was proportional to the concentrations of Cu(II) and Co(II). Based on these phenomena, a flow-injection chemiluminescent method for the simultaneous separation and determination of Cu(II) and Co(II) was developed. The detection limits of the present chemiluminescent method for Cu(II) and Co(II) were 7.5 and 0.01 ng/ml, respectively. After ion chromatographic separation of Cu(II) and Co(II) by an IonPac CS5A column with oxalic acid and lithium hydroxide monohydrate as the eluent, the present chemiluminescent system was used as a post-column detector for these two transition metal ions in natural water samples.

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Derivative spectrophotometric procedures and an isocratic high performance liquid chromatographic method for the determination of butamyrate citrate (Sinecod^®, Safarol^®) in cough syrups have been developed. In the spectrophotometric method, direct measurement of the drug at its absorption maxima is impossible because of interference from different absorbing excipients. Extraction of butamyrate citrate was performed with n-pentane/isopropyl alcohol. Quantification was carried out through the use of ¹D derivative at a trough depth of 253.6 nm where interferences from other coextracted compounds are negligible. The extraction efficiency expressed as a % recovery and precision were assessed by fortifying placebo syrup(s) with known amounts of the compound. Also, a reversed phase high performance liquid chromatographic method was used with a mobile phase containing 0.015 M aqueous tetraethylammonium hydrogen sulfate, methanol and acetonitrile 40:30:30 adjusted to pH 3.50 with ammonium hydroxide. The retention behavior of butamyrate citrate as a function of both pH and salt concentration in the aqueous portion of the mobile phase was investigated. Quantification was achieved with UV detection at 258 nm based on peak area. The HPLC method clearly separates the analyte from its degradation products derived after storage of samples under different stress conditions such as acid, alkaline, temperature, oxygen and light. The described methods were successfully applied to the determination of butamyrate citrate in commercial pharmaceutical products and in placebo syrups prepared in the laboratory with good accuracy and precision. The results of the present study show that the use of the derivatives and the HPLC procedure provide precise and sensitive methods for the determination of the compound in pharmaceutical formulations.

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A flow injection analysis system of hydrogen peroxide was developed. The present system is based on measuring of the absorbance of a quinoid dye formed by the following reaction catalyzed by peroxidase: Phenol + 4-Aminoantipyrine + 2H₂O₂ → Quinoid dye + 4H₂O. A column packed with aminopropyl-glass beads modified with a manganese(III)-tetra(4-carboxyphenyl)porphine derivative (Mn-TCPP_G column), which has peroxidase-like activity, was used in place of an immobilized peroxidase column in the above reaction. The linear range of the calibration curve was 0.4 - 80 μg/ml hydrogen peroxide. The relative standard deviation of this system was 2.97% (n = 100, 10 μg/ml hydrogen peroxide 20 μl injection). The Mn-TCPP_G column has sufficiently stability for the continuous injection of hydrogen peroxide untill 100 times. The advantageous feature of the Mn-TCPP_G column was a less-electrostatic interaction between the mother glass beads and the anionic chromogen or quinoid dye formed and the stability in terms of the storage, temperature and moisture. The determination of serum glucose was achieved by attaching an immobilized glucose oxidase column to this system without deproteinization.

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A flow-injection electrochemiluminescent method for L-cysteine determination has been developed based on its enhancement of the electrochemiluminecence of luminol at a glassy carbon electrode. This method is simple and sensitive for cysteine determination. Under the selected experimental parameters, the linear range for cysteine concentration was 1.0 × 10^-6 - 5.0 × 10^-5 mol/l, and the detection limit was 0.67 μmol/l (S/N = 3). The relative standard deviation for 11 measurements of 1.0 × 10^-5 mol/l cysteine was 4.5%. The proposed method has been applied to the detection of cysteine in pharmaceutical injections with satisfactory results.

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A new approach for developing a cloud-point extraction-flame atomic absorption spectrometric method has been described and used for the determination of cobalt. In this approach, water was removed from the final diluted surfactant rich phase obtained in cloud-point extraction procedure. The results indicated that removing water from this phase increased the enhancement factor by 4-fold. 1-(2-Pyridylazo)-2-naphthol (PAN) and octylphenoxypolyethoxyethanol (Triton X-114) were used as a hydrophobic ligand and a nonionic surfactant, respectively. The chemical variables affecting the preconcentration step were optimized. The effect of the water concentration in the final diluted methanolic surfactant solution on the analytical signal was investigated. The results showed that the analytical signal decreased by 30% and 52% in 15% and 25% water concentrations in methanol, respectively. An enhancement factor of 115 was obtained for cobalt extracted from only 10 ml of a sample. The detection limit obtained under the optimal condition was 0.38 μg l^-1. The proposed procedure was applied to the determination of cobalt in urine samples.

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A flow-injection on-line preconcentration-electrothermal atomic absorption spectrometric (ETAAS) method coupled with a coprecipitation method has been developed for the determination of lead in seawater. The combination of two preconcentration procedures, coprecipitation with iron(III) hydroxide and solid-phase extraction with a lead-selective resin, Pb·Spec^TM, allowed the determination of lead at the ng kg^-1 level. Lead in 250 g of a sample solution was collected by coprecipitation with 10 mg of iron. The precipitate was dissolved in 25 ml of 1 mol l^-1 nitric acid; then, a 4-ml aliquot of the sample solution was introduced into the flow-injection system to preconcentrate and separate lead from iron on a Pb·Spec microcolumn. The sorbed lead was eluted with a 1.0 × 10^-4 mol l^-1 EDTA solution. The 30-μl portion of the eluate corresponding to the highest analyte concentration zone was injected into a graphite furnace. The overall enhancement factor was about 200 for 250 g of the sample. The average and standard deviation of ten blank values obtained were 1.7 ng and 0.38 ng, respectively. The recovery was 93.7 ± 5.0% for seawater spiked with 20 ng kg^-1 lead. The proposed method is applicable to the analysis of seawater for lead at slightly higher levels.

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A rapid and sensitive method has been proposed for the sequential determination of chromium(III) and total chromium in water samples by flame atomic absorption spectrometry combined with a flow injection on-line preconcentration on a double-microcolumn. The chromium(III) and total chromium in samples were retained on a double-microcolumn with a cation exchange resin, respectively, and eluted directly into a nebulizer by 3 mol L^-1 HNO₃. The characteristic concentration (gives a derivative absorbance of 0.0044) and the detection limit (3σ) for chromium were 0.512 μg L^-1 and 0.647 μg L^-1 for a preconcentration time of 1 min, respectively. This is an improvement of 20 and 14-times than those of conventional FI-FAAS. The proposed method allows the determination of chromium in the range of 0 - 90 μg L^-1 with a relative standard deviation of 3.63% at the 10 μg L^-1 level. The method has been applied for the analysis of chromium in reference water of National Research Center for Certified Reference Materials (GBW08607) and other water samples with satisfactory results.

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A PTFE Babington nebulizer equipped with a hood was investigated for inductively coupled plasma atomic emission spectrometry in conjunction with a PTFE cyclone chamber, in order to nebulize various sample solutions containing high salts, hydrofluoric acid and/or suspended solid. A hood of 3 mmφ (nozzle side) - 5 mmφ (outlet side) and 6 mm in length gave a comparable or higher sensitivity compared to a system with a commercially available concentric nebulizer and a glass cyclone chamber. Moreover, the present nebulizer was fully interchangeable with a concentric one at normal argon pressure, attaining sufficient stability, a short wash-out time and good nebulizing of high matrices solutions. The present system was successfully applied to the determination of trace impurities in highly pure silica powders.

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We report here on the use of the photoacoustic technique for the determination of low concentrations of total iron in corn meal samples. The determination of this element in food is of considerable interest because several foods are currently enriched with it at proper levels in order to increase the resistance of people, after consumation, to several diseases, such as anemia. The proposed technique is based on an open photoacoustic cell configuration in conjunction with a suitable colorimetric method. We applied it to a measurement of the total iron concentration in corn meal samples. The results agree very well with those obtained using a conventional spectrophotometric method, showing the possibilities of new experimental methodologies based on photothermal methods to perform this kind of study, with the advantage of a higher sensitivity and increment of the range of appreciable absorbance.

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The electrical potential differences were measured at various points in an organic phase of a water-oil-water liquid membrane system in which self-oscillations of an electrical potential difference occurred across a three-phases-liquid membrane by using an H-shaped cell. The electrical potential difference oscillated in the direction through the two aqueous phases, but not in its vertical direction. The amplitude of the self-oscillation greatly changed around the place where the horizontal tube was connected to the vertical tube, which had no surfactant.

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Based on the adsorption of Fe (EDTA)^- on a chitosan-coated glassy carbon electrode, a second-derivative square-wave voltammetry for the determination of the EDTA species in water samples was investigated. The measuring range of EDTA was from 6.0 × 10^-7 to 5.0 × 10^-5 mol/L with a correlation coefficient of 0.998 and a detection limit of 2.8 × 10^-7 mol/L. The relative standard deviation was less than 6.2% (n = 5) and the recovery was in the range of 98 − 105% for the determination of practical samples. The result was consistent with that from the HPLC method.

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A simple and rapid method involving high-performance liquid chromatographic separation, followed by photodiode array (PDA) and electrospray ionization-mass spectrometric (ESI-MS) detection of aromatic sulfonates in waste-water effluents of industrial units producing optical whitening agents, has been developed. The separation was achieved on a reversed-phase Hypersil C₁₈ column using gradient elution of a mobile phase consisting of 0.05 M ammonium formate-methanol with decreasing concentration of the buffer at room temperature. The minimum detection limits were determined to be in the range of 0.2 - 1.8 × 10^-9 g using PDA and ESI-MS detectors.

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Ferrocyanide-imprinted pyridine-carrying microspheres were prepared using ferrocyanide ions as a template. This method is based on a surface imprinting technique from the seed emulsion that consisted of 4-vinylpyridine (functional monomer), styrene, and butyl acrylate and a water mixture polymerization by a radical initiator. The ferrocyanide-imprinted microspheres had about 200 times higher adsorption affinity over the non-imprinted microspheres in ferrocyanide (template) ion adsorption. This imprinted microspheres also adsorbed other tripolyphosphate, pyrophosphate, and phosphate anions much more strongly than the non-imprinted microspheres did, but were not particularly specific in ferrocyanide ion adsorption.

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An on-line analytical system for the continuous monitoring of malondialdehyde (MDA) was developed. This method involves the use of microdialysis perfusion, on-line derivatization and on-line HPLC analysis. This method gave a linear response for MDA concentrations and HPLC peak areas in the range from 0.051 μM to 2.43 μM. The intra-day (RSD = 1.6 - 10.5%) and inter-day (RSD = 1.1 - 9.3%) precisions were acceptable. The average in vitro probe recovery of MDA standard was 18.4 ± 1.0%. The detection limit was 0.03 μM, corresponding to 0.6 pmol for an injection volume of 20 μl. This method was used for in vitro peroxidation investigations, which provided evidence for elevated MDA levels following the incubation of metal ions to a linoleic acid solution.

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A flow-injection analysis (FIA) with a chemiluminescence detection method was developed for the determination of ornidazole based on the inhibition intensity of chemiluminescence from the luminol-ferricyanide system. Under the condition of 1.0×10^-3 mol/L luminol and 5.0×10^-6 mol/L potassium ferricyanide, the response to the concentration of ornidazole is linear from 0.2 μg ml^-1 to 10 μg ml^-1, and a detection limit of 0.05 μg ml^-1 can be obtained. This method has been successfully applied to the determination of ornidazole in pharmaceutical preparations.

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A flow-injection analysis (FIA) of paroxetine hydrochloride (PRX), a selective serotonin reuptake inhibitor (SSRI) currently used as an antidepressant drug, is described. A 0.1 mol dm^-3 acetate buffer at pH 3.07 was found to be the best solvent. The analyte was detected at 293 nm. The calibration equation was linear over the range of 1.07×10^-6 to 5.35×10^-6 mol dm^-3. The limit of detection (LOD) and the limit of quantitation (LOQ) were 3.2×10^-7 and 9.5×10^-7 mol dm^-3, respectively. The proposed method was applied to the determination of PRX in pharmaceutical preparations. The results were compared with those obtained by a conventional batchwise UV-spectrophotometry.

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A miniaturized fluorescence detector using a high-brightness light-emitting diode as an excitation source was constructed and evaluated. A windowless flow cell based on a commercial four-port cross fitting was designed to reduce the stray-light level and to eliminate the optical alignment. The observed detection limit for fluorescein was 26 nM in the continuous-flow mode. The error in the reproducibility of the responses was evaluated by the FIA method, and was found to be within 2% RSD.

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Determination of V(IV) based on its catalytic effect on the reaction between Methyl Orange and bromate in the presence of citric acid was studied. The calibration curve obtained by fixed-time method was linear in the range of 2.5-300 ng ml^-1. By use of slope method, a calibration curve containing two linear portions were obtained. Using fixed-time and slope methods, we obtained detection limits of 0.8 and 1.5 ng ml^-1, respectively. Fe²⁺, As(III), V(V) and Hg²⁺ interfered. The method was successful for analysis of water samples.

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C₂₇H₃₇O₄Cl is orthorhombic, P2₁2₁2₁. The unit-cell dimensions at 293 K are a=7.1388(15), b=12.9836(14), c=26.665(10)Å, V=2471.5(10)ų, D_x=1.239 g/cm³, and Z=4. The R value is 0.070 for 1458 observed reflections. The A, B, C and D rings occur in distorted envelope, distorted half-chair, chair, and envelope and a half-chair conformations. The molecules in the crystal are packed at the normal van der Waals distances.

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An X-ray structure determination shows that the Ni(II) ion is a distorted six-coordinated octahedron by four nitrogen atoms of the tetradentate tren ligand constituting the equatorial square base, and by two nitrogen atoms of the bidentate bpy ligand in a cis position. The two six-membered rings of bpy are coplanar and almost pararell. The tetradentate ligand consists of three five-membered chelate rings in gauche coformations. The Ni-N(tren) bond lengths of this complex are almost equivalent to the reported values.

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The macrocyclic tetradentate Ni(II) compound was obtained in a reaction and determined by X-ray diffraction. The crystal structure shows that the molecule is centrosymmetric, and Ni atom located in a square planar coordination environment. The two [(iPrO)₂PS₂]^- anions are outside the macrocycle complex to balance. The Ni-N bond lengths are in the range of 1.906(2) to 1.950(2)Å.

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The X-ray crystal structure of the title complex, Co(Cl₂bprpi) is described. In this complex the Co(II) center displays a distorted octahedral coordination geometry. The piperazine ring exhibits boat conformation, forming chelate rings and capping the Co atom. The N2-Co1-N3 angle is 69.41(15)°, extremely smaller than 90°. Because the small angle causes a large steric hindrance, the piperazine ring can be effective as an ion size-recognition site. The molecular structure is stabilized by intramolecular N-H…O hydrogen bonds and Cl…H contacts.

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The structure of 7,8-dihydroxy-4-methylcoumarin was determined by an X-ray diffraction method. The compound crystallized in the triclinic space group P1, Z=2, with a=7.631(2), b=9.456(5), c=7.075(3)Å, α=103.13(3), β=91.84(3), γ=68.21(3)°, and V=460.9(3)ų. The X-ray crystal structure was also compared with those of 5,7-dihydroxy-4-methylcoumarin and 7-hydroxy-4-methylcoumarin.

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