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Thiocyanates form an important class of organic compounds commonly found in natural products that exhibit excellent antimicrobial activity. The electrophilic thiocyanation is one of the most effective methods of introducing a -SCN functional group to the parent organic molecule. In this work, we explored an eco-friendly and highly efficient method for thiocyanation of anilines and 1-(substituted benzylidene)-2-phenylhydrazines using commercially available N-bromoscuccinimide (NBS) and potassium thiocyanate (KSCN). The optimized protocol afforded thiocyanates with good regioselectivity and excellent yields in comparison to the available methods.

Aromatic amines (AAs) in urine typically require complex, labor-intensive and time-consuming sample preparation procedures before they can be analyzed. Usually it consists of hydrolysis, extraction and, especially when analyzed with GC, derivatization. Traditionally, these steps are done manually, significantly contributing to the total analysis time and providing opportunities for human errors. Automation presents several advantages, such as minimized human intervention and errors, and an overall greener analytical procedure.In this study, the automation of the AAs sample preparation procedure for urine samples was investigated. Problems encountered during the automation and adjustments made to the original protocol are discussed in detail. Some examples include volume limitations or needle penetration depth adjustments. Taking advantage of the automation, several steps of the sample preparation procedure could be further optimized, such as reaction/extraction times or some of the reagents which were not optimal for the automated set-up.The automated procedure presented here enables a user-friendly and green approach for the analysis of AA in urine, which could be used to gain a better understanding between smoking, AA concentrations in urine, and the risk of developing smoking related diseases.

Aromatic amines, the widely used raw materials in industry, cause long-term exposure to human bodies. They can be metabolized by cytochrome P450 enzymes to form active electrophilic compounds, which will potentially react with nucleophilic DNA to exert carcinogenesis. The short lifetime and versatility of the oxidant (a high-valent iron (IV)-oxo species, compound I) of P450 enzymes prompts us to use theoretical methods to investigate the metabolism of aromatic amines. In this work, the density functional theory (DFT) has been employed to simulate the hydroxylation metabolism through H-abstraction and to calculate the activation energy of this reaction for 28 aromatic amines. The results indicate that the steric effects, inductive effects and conjugative effects greatly contribute to the metabolism activity of the chemicals. The further correlation reveals that the dissociation energy of -NH2 (BDEN-H) can successfully predict the time-consuming calculated activation energy (R2 for aromatic and heteroaromatic amines are 0.93 and 0.86, respectively), so BDEN-H can be taken as a key parameter to characterize the relative stability of aromatic amines in P450 enzymes and further to quickly assess their potential toxicity. The validation results prove such relationship has good statistical performance (qcv2 for aromatic and heteroaromatic amines are 0.95 and 0.90, respectively) and can be used to other aromatic amines in the application domain, greatly reducing computational cost and providing useful support for experimental research.

This study reports a deep eutectic solvent based dispersive liquid-liquid microextraction (DES-DLLME) to extract aromatic amines (4-chloroaniline, 3-nitroaniline, 2-naphtylamine) in environmental water samples before their HPLC-UV determination. The hydrophobic deep eutectic solvent (DES) was prepared by mixing bis(2-ethylhexyl) phosphate (BEHP) as a hydrogen bond acceptor and phenol as a hydrogen bond donor. Affecting factors on the extraction of the aromatic amines were investigated and optimized. Optimum conditions were: DES type: BHHP-Ph ratio: 1 to 2; pH of solution: 8.0; DES volume: 80 µL, salt amount: 10% (w/v). Under optimum conditions, the developed method showed a wide linear range of 0.2–200 µg L−1 (R2 ≥ 0.99) with satisfactory recoveries (≥90.0%). The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.07–0.17 µg L−1 and 0.2–0.5 µg L−1, respectively. The enrichment factors were 170, 180 and 190 for 4-chloroaninile, 3-nitroaniline, 2-naphtylamine, respectively. Based on obtained results, the proposed method is straightforward, efficient, sensitive, and eco-friendly for the extracting and determining of the aromatic amines in environmental water samples.

Several primary aromatic amines (AAs) are known or suspected carcinogens. Despite this, the exposure of pet animals to this class of chemicals is unknown. In this study, we investigated the occurrence of 30 AAs and two tobacco chemical markers (nicotine and cotinine) in 63 pet urine (42 dog and 21 cat) and 77 pet feces (37 dog and 40 cat) samples collected from the Albany area of New York State. Eight of the 30 AAs (∑8AAs) were found in > 38% of dog and cat urine samples, at median concentrations of 7.99 (range: 0.42–52.3 ng/mL) and 31.4 (2.63–75.9) ng/mL, respectively. Nine of the 30 AAs (∑9AAs) were found in > 73% of dog and cat feces samples, at median concentrations of 278 (range: 61.7–613 ng/g) and 240 (55.4–645) ng/g dry wt, respectively. Among the 30 AAs, 2,6-dimethylaniline (2,6-DMA) accounted for the highest median concentrations in both urine and fecal samples. Median concentrations of nicotine and cotinine were below 0.92 ng/mL in urine and below 3.86 ng/g in feces of both dogs and cats. No significant relationship was found between AA concentrations and pet age or gender. The lack of significant Spearman’s rank correlation between the concentrations of AA and nicotine in pet urine/feces suggested that sources other than tobacco smoke contributed to AA exposure in pets. Furthermore, the calculated fecal excretion rates of AAs were higher than the intake rates (estimated through reverse dosimetry), which indicates that cats and dogs are exposed to AA precursors such as azo dyes. Concentrations in urine and feces reflected exposure to direct and indirect exposure sources, respectively, of AAs.

A tris(pentafluorophenyl)borane catalysed method for the synthesis of boronic acid esters from aromatic amines in yields of up to 93% was devised. Mild conditions, benign reagents, short reaction times, low temperatures and a wide substrate scope characterize the method. The reaction was found applicable to the synthesis of boronic acid ester derivatives of complex drug molecules in up to 86% isolated yield and high purity suitable for labelling. These boronates were subsequently labelled with [18F]fluoride ion in radiochemical yields of up to 55% with and even without isolation of the boronate-intermediate.

Four liquid aromatic nitrogen-containing compounds, viz. aniline, pyridine, 2-methylpyridine, and 2,6-dimethylpyridine, were analyzed with molecular dynamics simulations, three-dimensional reference interaction site model, and density functional theory calculations. These liquids are found to have multimeric ordered structures stabilized by π-stacking and C-H∙∙∙π interactions. The solutes solvation free energy computed with the reference interaction site model is in good agreement with the experimental results, and performs better than the conductor like polarizable continuum model used in electronic structure calculation.

Despite various methods for preparation of tetrazoles, they are suffering from some disadvantages such as low yield, long reaction times and harsh reaction conditions, and there are still high demands to improve the common procedures to solve problems. So, the new copper nano-catalyst was prepared by coating of the Fe3O4 magnetic nanoparticles with tetraethyl orthosilicate, functionalization with 3-chloropropyltrimethoxysilane and 3-mercapto-1,2,4-triazole ligands as well as the subsequent complexation with CuCl2. The obtained catalyst was then characterized by different methods (ICP, XRD, EDX, SEM, TEM, TG-DTA and VSM) and applied as a heterogeneous nano-catalyst for the synthesis of diverse tetrazoles from the reaction of various aromatic amines with sodium azide and triethyl orthoformate in solvent-free condition at 100°C in good to high yields.

Although primary aromatic amines (AAs) are widely used in consumer products, little is known about their occurrence in indoor dust. A liquid chromatography – tandem mass spectrometry (LC-MS/MS) method was applied for the determination of 29 AAs and two tobacco smoke markers (nicotine and cotinine) in 256 house dust samples collected from 10 countries. Of the 29 AAs analyzed, p-anisidine, o-anisidine, 2,6-dimethylaniline (2,6-DMA), p-cresidine (p-CD), p-toluidine (p-TD), 4,4′-methylenedianiline (4,4′-MDA), ortho/meta-toluidine (o/m-TD), 4-chloroaniline (4-CA), 2,4-diaminotoluene (2,4-DAT), aniline, and 2-naphthylamine (2-NA) as well as nicotine and cotinine, were found prevalent in house dust samples. Sum median concentrations of AAs and tobacco smoke markers varied from 29.6 to 576 ng/g (overall median: 200 ng/g) and 10.8 to 2920 ng/g (415 ng/g), respectively. Among AAs, aniline was the abundant contaminant, found at median concentrations ranging from 19.6 ng/g (Colombia) to 334 ng/g (South Korea). Nicotine was detected in all indoor samples at median concentrations ranging from 9.92 ng/g (Colombia) to 2790 ng/g (India) ng/g. Concentrations of AAs in indoor dust were significantly correlated with those of nicotine. Estimated daily intake (EDI) of select AAs through the ingestion of house dust was in the range of 0.019–3.03 ng/kg-bw/day, which was five orders of magnitude below the tolerance limits.

In this work, an environment-friendly enzymatic strategy was developed for the valorisation of dye-containing wastewaters. We set up biocatalytic processes for the conversion of azo dyes representative of the main classes used in the textile industry into valuable aromatic compounds: aromatic amines, phenoxazinones, phenazines, and naphthoquinones. First, purified preparations of PpAzoR azoreductase efficiently reduced mordant, acid, reactive, and direct azo dyes into aromatic amines, and CotA-laccase oxidised these compounds into phenazines, phenoxazinones, and naphthoquinones. Second, whole cells containing the overproduced enzymes were utilised in the two-step enzymatic conversion of the model mordant black 9 dye into sodium 2-amino-3-oxo-3H-phenoxazine-8-sulphonate, allowing to overcome the drawbacks associated with the use of expensive purified enzymes, co-factors, or exquisite reaction conditions. Third, cells immobilised in sodium alginate allowed recycling the biocatalysts and achieving very good to excellent final phenoxazine product yields (up to 80%) in water and with less impurities in the final reaction mixtures. Finally, one-pot systems using recycled immobilised cells co-producing both enzymes resulted in the highest phenoxazinone yields (90%) through the sequential use of static and stirring conditions, controlling the oxygenation of reaction mixtures and the successive activity of azoreductase (anaerobic) and laccase (aerobic).

Ten azobenzene dyes were tested for their thermal degradation products from ambient temperature to 800 °C using a thermogravimetric technique. Degradation products were analyzed at each 100 °C increment using gas chromatography-mass spectrometry. Products were identified based on their mass spectral data and their retention times. Thermal degradation from all dyes resulted in loss of the azo group as nitrogen gas and aromatic free radicals. Electron withdrawing groups enhance the dissociation of the phenyl nitrogen bond at the benzene moiety carrying the electron withdrawing group. On the other hand, electron donating groups inhibited the dissociation of the phenyl-N bond of the benzene moiety carrying the electron donating groups. The loss of nitrogen molecule from the dyes appeared to be taken place in a two-step rather than a one-step reaction in which the phenyl nitrogen bond of the phenyl group carrying the electron withdrawing group splits to form phenyl and azo phenyl radicals following by the loss of a nitrogen molecule and a new phenyl radical. This was also supported by calculating degradation reaction enthalpies and bond dissociation energies using density functional theory quantum mechanics.

Aromatic amines are an important class of chemicals which are used as building blocks for the synthesis of polymers and pharmaceuticals. In this study we establish a de novo pathway for the biosynthesis of the aromatic amines para-amino-phenylethanol (PAPE) and para-amino-phenylacetic acid (4-APA) in Escherichia coli. We combined a synthetic para-amino-l-phenylalanine pathway with the fungal Ehrlich pathway. Therefore, we overexpressed the heterologous genes encoding 4-amino-4-deoxychorismate synthase (pabAB from Corynebacterium glutamicum), 4-amino-4-deoxychorismate mutase and 4-amino-4-deoxyprephenate dehydrogenase (papB and papC from Streptomyces venezuelae) and ThDP-dependent keto-acid decarboxylase (aro10 from Saccharomyces cerevisiae) in E. coli. The resulting para-amino-phenylacetaldehyde either was reduced to PAPE or oxidized to 4-APA. The wild type strain E. coli LJ110 with a plasmid carrying these four genes produced (in shake flask cultures) 11 ± 1.5 mg l−1 of PAPE from glucose (4.5 g l−1). By the additional cloning and expression of feaB (phenylacetaldehyde dehydrogenase from E. coli) 36 ± 5 mg l−1 of 4-APA were obtained from 4.5 g l−1 glucose. Competing reactions, such as the genes for aminotransferases (aspC and tyrB) or for biosynthesis of L-phenylalanine and L-tyrosine (pheA, tyrA) and for the regulator TyrR were removed. Additionally, the E. coli genes aroFBL were cloned and expressed from a second plasmid. The best producer strains of E. coli showed improved formation of PAPE and 4-APA, respectively. Plasmid-borne expression of an aldehyde reductase (yahK from E. coli) gave best values for PAPE production, whereas feaB-overexpression led to best values for 4-APA. In fed-batch cultivation, the best producer strains achieved 2.5 ± 0.15 g l−1 of PAPE from glucose (11% C mol mol-1 glucose) and 3.4 ± 0.3 g l−1 of 4-APA (17% C mol mol−1 glucose), respectively which are the highest values for recombinant strains reported so far.

Herein, a mild and efficient method for synthesis of highly stable palladium nanoparticles (PdNPs) on Aristolochia Olivieri (AO) extract as a support and reducing agent is described. Investigation of catalytically activity of obtained catalyst (AO@PdNPs) was performed for the reduction of nitroaromatic compounds. Of note are the functional group tolerance, fast rate, and the ability to apply a scope of nitro compounds (up to 30). The synthesized catalyst was characterized with UV−visible spectra, FE-SEM, EDS, XRD, AAS, FT-IR, and TEM techniques. The corresponding amine product was obtained excellent to high yields. The catalytic activity of AO@ PdNPs for the hydrogenation of 4-methyl-2-nitroaniline and 4-methoxy-2-nitroaniline was pursued by UV-visible spectroscopy which presented excellent activity of catalyst.

Cu,H2-bis-porphyrin (Cu,H2-Por2), in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions.

A continuous-flow procedure for the synthesis of β-amino acid esters has been developed via lipase-catalyzed Michael reaction of various aromatic amines with acrylates. Lipase TL IM from Thermomyces lanuginosus was first used to catalyze Michael addition reaction of aromatic amines. Compared with other methods, the salient features of this work include green reaction conditions (methanol as reaction medium), short residence time (30 min), readily available catalyst and a reaction process that is easy to control. This enzymatic synthesis of β-amino acid esters performed in continuous-flow microreactors is an innovation that provides a new strategy for the fast biotransformation of β-amino acid esters.

MIL-100(Fe, Cr) and MIL-101(Cr) were synthesized by the hydrothermal method and applied to the adsorptions of five aromatic amines from aqueous solutions. These three metal-organic frameworks (MOFs) were well characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and surface area analysis. The adsorption mechanism of three MOFs and the effects of the structures of MOFs on the adsorption of aromatic amines were discussed. The results show that the cavity system and suitable hydrogen bond acceptor were important factors for the adsorption for five aromatic amines of aniline, 1-naphthalamine, o-toluidine, 2-amino-4-nitrotoluene and 2-nitroaniline: (a) the saturated adsorption capacity of aniline, 1-naphthylamine and o-toluidine on MIL-100(Fe) were 52.0, 53.4 and 49.6 mg/g, respectively, which can be attributed to the intermolecular hydrogen bond interaction and cavity system diffusion. (b) The adsorption capacity of 2-nitroaniline and 2-amino-4-nitrotoluene on MIL-101(Cr) were 54.3 and 25.0 mg/g, respectively, which can be attributed to the more suitable pore size of MIL-101(Cr) than that of MIL-100(Fe, Cr). The MOFs of MIL-100(Fe) and MIL-101(Cr) can be potential materials for removing aromatic amines from aqueous solutions.

AbstractMany well-established methods for determining the antioxidant capacities in several samples have been described in literature. However, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) are the main two methods that utilize radicals as spectrophotometric probes for analysis. Nevertheless, these methods have certain limitations because of their slower kinetics, solvent polarity effects, the hydrophilicity and lipophilicity of the compounds, chemical costs, etc. In this study, a spectrophotometric method for determining the antioxidant capacity in beverages was developed based on an exploration of the cation radical derived from DEPD. This method was based on the oxidation of aromatic amines with Fe(III) ions at pH 4.0, which leads to their corresponding purple cation radicals (DEPD•+) with λmax values at 500 and 540 nm. The addition of an antioxidant after the formation of the radical leads to a reduction in color intensity that is proportional to the antioxidant concentration in the medium. Results obtained using this method were compared with the Folin-Ciocalteau, ABTS and DPPH methods in terms of applications in wines, teas, and infusions samples. Linear correlation analysis at a 95% confidence level was employed to compare the results, which were in good agreement with a correlation coefficient of r > 0.9000. Thus, the developed method was simple, accurate, and consistent with other assays for the determination of the total amount of phenolic compounds and antioxidant capacity.

A facile and moderately functional-group-tolerant synthetic method for the preparation of 7,8-diaza[5]helicenes has been developed. It comprises of an oxidative ring-closing process of 1,1’-binaphthalene-2,2’-diamine (BINAM) derivatives with a chlorine-containing oxidant (t-BuOCl) in the presence of a base (2,6-lutidine). In addition the basic physicochemical properties of newly synthesized compounds have been investigated.

In the field of antitumor DNA-intercalating agents, 9-anilinoacridines play an important role due to their antiproliferative properties. Several cancer chemotherapeutics such as amascrine and nitracrine have been developed as anticancer agents. In the present study, several 2-methyl-9 substituted (AS 0–8) acridines were synthesized by nucleophilic substitution of 2-methyl-9-chloroacridine (AS) with aromatic amines. The structures of novel compounds were determined using spectroscopic methods. Three compounds were evaluated for antiproliferative activity against A-549 (Human, small cell lung carcinoma) and MCF-7 (Human, breast cancer) cell lines using the MTT assay. Compound AS-2 showed higher in vitro cytotoxic activity against A-549 and MCF-7 cancer cell lines with CTC50 187.5 and 212.5 μg/ml respectively. The cancer cell cytotoxicity of acridines against A-549 cell line was found to be more active than MCF-7 cell line.

It has been found that numerous yeast-like microorganisms from the genera Geotrichum, Trichmporon, Candida, Rhodotorula and Sporobolomyces occurring in wastewater treatment systems biocenoses arę able to utilize aniline, p-nitroaniline and acetanilide as a sole C-source. High active in this respect were strains belonging to the species of Geoirichum candidum, G. sericeum and Candida boidinii.

The exploitation and use of alternative synthetic methods, in the face of classical procedures that do not conform to the ethics of green chemistry, represent an ever-present problem in the pharmaceutical industry. The procedures for the synthesis of benzimidazoles have become a focus in synthetic organic chemistry, as they are building blocks of strong interest for the development of compounds with pharmacological activity. Various benzimidazole derivatives exhibit important activities such as antimicrobial, antiviral, anti-inflammatory, and analgesic activities, and some of the already synthesized compounds have found very strong applications in medicine praxis. Here we report a selective and sustainable method for the synthesis of 1,2-disubstituted or 2-substituted benzimidazoles, starting from o-phenylenediamine in the presence of different aldehydes. The use of deep eutectic solvent (DES), both as reaction medium and reagent without any external solvent, provides advantages in terms of yields as well as in the work up procedure of the reaction.

The transformation of aromatic nitrocompounds into amines by CO/H2O is catalyzed by palladium(II) complexes. Recently, we have proposed that the catalytic cycle includes Pd0 as the transient intermediate and herein, for the first time, we describe the application of palladium nanoparticles (PdNPs) stabilized by monodentate N-heterocyclic ligands as nanocatalysts facilitating the reduction of Ar−NO2 into Ar−NH2 by CO/H2O. Among the series—Pd(II) complexes, PdNPs and commercial Pdblack—the highest catalytic activity was observed for PdNPs (3.0 ± 0.5 nm) stabilized by 4-Me-pyridine in the presence of 2-Cl-pyridine. The results may be helpful for mechanistic considerations on the role of metallic nanoparticles as active species in other organic processes.

Background and aims : Aniline as one of the aromatic amines is a widely distributed environmental pollutant resulting from the manufacture of dye materials and agricultural chemicals such as herbicides. It is frequently used by the industry such as the raw material in the manufacture of dyes, rubbers, pharmaceutical preparation, plastic and paint. It is also a common by product from paper and textile industries. Aniline has been found to distribute in an aqueous environment and interfere with aquatic species life . It is known to be carcinogenic for human and also reacts easily in the blood, thereby preventing oxygen uptake. The purpose of this study is to investigate the performance of electrochemical process for the treatment of a hard biodegradable compound called aniline from synthetic wastewater using iron electrodes in a batch laboratory-scale system. Methods: This Experimental study was carried out in a laboratory scale and in a glass reactor. The effect of operating parameters such as voltage, pH, reaction time and initial Aniline concentration on the removal efficiency has been investigated. Results: In operational conditions of 10 volts, 100 mg/L of initial Aniline concentration, acidic pH of 5.5 and 1 cm interelectrode distance following 120 minutes, the removal efficiency of aniline and COD were obtained 92% and 60% respectively . Conclusion: The results indicated that electrochemical process can be used as an effective method for Aniline removal from industrial wastewater.

This paper describes a simple, sensitive and environmentally benign method for the direct determination of aniline and its derivatives in environmental water samples by capillary zone electrophoresis (CZE) with field-enhanced sample injection. The parameters that influenced the enhancement and separation efficiencies were investigated. Surprisingly, under the optimized conditions, two linear ranges for the calibration plot, 1–50 ng/mL and 50–1000 ng/mL (R > 0.998), were obtained. The detection limit was in the range of 0.29–0.43 ng/mL. To eliminate the effect of the real sample matrix on the stacking efficiency, the standard addition method was applied to the analysis of water samples from local rivers.

A simple and efficient one-pot method for the preparation of aromatic iodides has been developed by sequential diazotization–iodination of aromatic amines employing sodium nitrite and sodium iodide in the presence of acidic ionic liquid N-methyl-2-pyrrolidonum hydrosulfate ([H-NMP]HSO4). The diazonium salts that are formed by this ionic liquid are stable at room temperature and react rapidly with sodium iodide to produce aryl iodides in moderate to good yields. The mild reaction conditions, straightforward procedure, inexpensive and green method make these transformations superior to the reported

Polyethylene glycol was easily grafted to silica gel and used as a solid–liquid phase transfer catalyst in the reduction of aromatic nitro compounds. This silica-grafted polyethylene glycol is proved to be an efficient heterogeneous catalyst in the reduction of nitroarenes to the corresponding aromatic amines with zinc powder in water. The reduction reactions proceeded efficiently with excellent chemoselectivity without affecting other sensitive functional groups.

Maleic anhydride was reacted with p-aminophenol and p-toluidine in the presence of di-phosphorus pentoxide (P2O5) as a catalyst to produce two compounds: N-(4-hydroxy-phenyl)maleimide (I) and N-(4-methylphenyl)maleimide (II). The new azo compounds I(a-c) and II(a-c) were prepared by the reaction of I and II with three different aromatic amines, namely aniline, p-aminophenol and p-toluidine. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, 13C-NMR, mass spectrum and UV/Vis spectroscopy.

The occurrence of mutagenicity in primary aromatic amines has been investigated using conformal prediction. The results of the investigation show that it is possible to develop mathematically proven valid models using conformal prediction and that the existence of uncertain classes of prediction, such as both (both classes assigned to a compound) and empty (no class assigned to a compound), provides the user with additional information on how to use, further develop, and possibly improve future models. The study also indicates that the use of different sets of fingerprints results in models, for which the ability to discriminate varies with respect to the set level of acceptable errors.

Abstract: Chemical shifts of the para carbon atoms, δ(13C-4), in a series of aromatic amines were used to calculate the Ãp, ÃR and ÃOR substituent constants for different amino groups. 1-Pyrrolidino, N,N-di-n-butylamino and N,N-diethylamino groups were found to be the most strong electron-donors. ortho-Substitution decreases the donor properties of the amino group. The amino groups in 2,6-di-i-propylaniline and N,N-2,6-tetramethylaniline have very weak electron-donor properties. The nitrogen atom in benzoquinuclidine and N,N-dimethyl-2,6-di-i-propylaniline have an electron-acceptor character. The calculated substituent constants of the amino groups studied are consistent with the spectral and reactivity data available in literature. Values of δ(15N) cannot be used as a direct measure of electronic effects of the N atom in anilines.

Based on the hypothesis on the presence of double metal cyanides in the primordial oceans, a series of nano-sized metal(II) hexacyanocobaltate(III) (MHCCo) with the general formula: M3[Co(CN)6]2•xH2O (where M = Zn, Fe, Ni and Mn) has been synthesized. Surface interaction of aromatic amines, namely aniline, 4-chloroaniline, 4-methylaniline and 4-methoxyaniline with MHCCo particles has been carried out at the concentration range of 100–400 μM at pH~7.0. The percentage binding of aromatic amines on MHCCo surface was found to be in the range of 84%–44%. The trend in adsorption was in accordance to the relative basicity of the studied amines. At the experimental pH, amines reacted rapidly with the surface of the iron(II) hexacyanocobaltate, producing colored products that were analyzed by Gas Chromatography Mass Spectroscopy (GC-MS). GC-MS analysis of the colored products demonstrated the formation of dimers of the studied aromatic amines. Surface interaction of aromatic amines with MHCCo was studied by Fourier Transform Infrared (FT-IR) spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM). The change in amine characteristic frequencies, as observed by FT-IR, suggests that interaction took place through the NH2 group on amines with metal ions of hexacyanocobaltate complexes. FE-SEM studies revealed the adherence of 4-methoxyaniline on zinc hexacyanocobaltate particles surface. We proposed that MHCCo might have been formed under the conditions on primitive Earth and may be regarded as an important candidate for concentrating organic molecules through the adsorption process.