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International audience; This contribution describes the synthesis, characterization, and catalytic implementation of the highly constrained molybdenum(VI) polymers [MoO2(LR)]n (with R = H (1), 3OMe (2), and 4OMe (3)) and cyclic tetramer [MoO2(L4OMe)]4·0.5MeCN (3′·0.5MeCN) with nicotinoyl hydrazonato ligands (LR) derived from salicylaldehyde (LH), 3-methoxy-2-hydroxybenaldehyde (L3OMe), or 4-methoxy-2-hydroxybenzaldehyde (L4OMe). In order to determine the most stable geometries, conformational analysis of the free and coordinated ligands in these assemblies was carried out through the potential energy surface scans using quantum-chemical methods. The mononuclear analogues [MoO2(HLR)(MeOH)]Cl (R = H (1a) and 3OMe (2a)), [MoO2(HLR)Cl] (R = 3OMe (2b) and 4OMe (3b)), and [MoO2(LR)(MeOH)] (R = H (1c), and 4OMe (3c-α and 3c-β)) were also synthesized and evaluated as potential precursors for reactions in the solid state. Vapor induced transformation of 2a quantitatively afforded complex 2b. The chemometric analysis using principal component analysis was applied to provide insight into the reaction profile. Thermally induced solid-state reactions resulted in the transformation of metallocycle 3′·0.5MeCN and monomeric complexes 1c, 2a, 3c-α, and 3c-β into the corresponding coordination polymers. The structural features responsible for these conversions are discussed in detail. Lastly, the metallosupramolecular architectures were tested as catalysts for cyclooctene epoxidation by using tert-butyl hydroperoxide as an oxidant in water or decane. Compound 3′ is shown to be the most effective and selective catalyst.

Five hexamolybdate and five octamolybdate-based organic–inorganic hybrid assemblies, with dioxomolybdenum(VI) hydrazonato complex cations, were synthesized from the [MoO2(acac)2] and isonicotinoyl hydrazone ligands bearing OH (H2L1, 2) and OMe (H2L3, 4) electron-donating groups. They can be classified into four categories including one known (i) [MoO2(HL1–4 ) (D)]2[Mo6O19]·xMeCN·yH2O, where D=H2O or MeCN, and three novel (ii) [Mo2O2(μ- O)2(HL3 )2][Mo6O19], (iii) [MoO2(HL1, 2)(H2O)]4[Mo8- O26]·xMeCN·yH2O, and (iv) [MoO2(H2L2, 4) (H2O)]2[Mo8O26]·xMeCN·yH2O, thus extending the structural landscape of Mo-complex–POM hybrids. Characterization of the hybrids, employing X-ray crystallography, IR-ATR, and TG analysis, was carried out. The effects of the reaction conditions and coordination nature of the Mo(VI) complex cations on the structure of the hybrid compounds were investigated. Relative differences in the standard Gibbs energies of formation (ΔΔfG°rel) of the structures were calculated to determine the possibility of developing the covalently anchored POM–Mo-complex hybrids. The impact of the metal–organic components and various solvents on the particular type of hybrid formation was evaluated.

Bacterial infections that do not respond to current treatments are increasing, thus there is a need for the development of new antibiotics. Series of 20 N-substituted quaternary salts of cinchonidine (CD) and their quasi-enantiomer cinchonine (CN) were prepared and their antimicrobial activity was assessed against a diverse panel of Gram-positive and Gram-negative bacteria. All tested compounds showed good antimicrobial potential (minimum inhibitory concentration (MIC) values 1.56 to 125.00 μg/mL), proved to be nontoxic to different human cell lines, and did not influence the production of reactive oxygen species (ROS). Seven compounds showed very strong bioactivity against some of the tested Gram-negative bacteria (MIC for E. coli and K. pneumoniae 6.25 μg/mL, MIC for P. aeruginosa 1.56 μg/mL). To establish a connection between antimicrobial data and potential energy surfaces (PES) of the compounds, activity/PES models using principal components of the disc diffusion assay and MIC and data towards PES data were built. An extensive machine learning procedure for the generation and cross-validation of multivariate linear regression models with a linear combination of original variables as well as their higher-order polynomial terms was performed. The best possible models with predicted R2(CD derivatives) = 0.9979 and R2(CN derivatives) = 0.9873 were established and presented. This activity/PES model can be used for accurate prediction of activities for new compounds based solely on their potential energy surfaces, which will enable wider screening and guided search for new potential leads. Based on the obtained results, N-quaternary derivatives of Cinchona alkaloids proved to be an excellent scaffold for further optimization of novel antibiotic species.

The two red centrosymmetric Ni(II) tetrameric complexes with defective double-cubane core, [Ni2L2(H2O)]2·0.75 CH3OH (1) and [Ni2L2(CH3CN)]2 (2) (H2L = N-(2-hydroxy-5-methylphenyl)- salicylideneimine), have been isolated and magnetically characterized, emphasizing the effect of the reaction temperature on structural and magnetic properties of isolated complexes. Prevailing antiferromagnetic interactions in the complexes are observed leading to the non- magnetic ground state. Comparation with the known magneto-structural correlations in nickel cubane and dicubane complexes is discussed.

Synthesis of hydrazones was performed via both conventional and solvent-free routes using the corresponding hydrazide (isonicotinic hydrazide, nicotinic hydrazide, 2- aminobenzhydrazide or 4- aminobenzhydrazide) and appropriate aldehyde (salicylaldehyde, 3- methoxysalicylaldehyde or 4- methoxysalicylaldehyde). A systematic study dedicated to solvatomorphism or polymorphism screening resulted in the formation of twelve novel crystalline forms, and eight of these were characterized via the single crystal X-ray diffraction method. In all studied structures, the molecules were assembled into endless supramolecular chains, discrete rings, chains of rings or nets. The mechanochemical synthesis employing liquid-assisted grinding was also applied and the nicotinic- and isonicotinic- based hydrazones were found to form readily from their corresponding precursors. The chemometric study using principal component analysis for mechanochemical synthesis monitoring was implemented for the first time to provide an insight into the reaction profiles. A thoughtful combination of ex situ powder X-ray diffraction and chemometric analysis was essential to identify a stepwise mechanism for the hydrazone formation via an intermediate phase. In five investigated reactions the first principal component accounted for at least 75% of the total variance, whereas in the case of two reactions this component accounted for 69.72 and 46.23% of the total variance. The hydrazones were also evaluated for cytotoxic activity in vitro. All compounds exhibited weak to moderate cytotoxicity against THP-1 and no cytotoxicity against HepG2 cells. Substantial antibacterial activity was obtained against Moraxella catarrhalis while no growth inhibition of Staphylococcus aureus, Enterococcus faecalis and Escherichia coli was observed.

A study of strong halogen bonding within three series of halogen-bonded complexes, derived from seven para-substituted pyridine derivatives and three N-halosuccinimides (iodo, bromo and chloro), has been undertaken with the aid of single-crystal diffraction, solution complexation and computational methods. The halogen bond was compared with the hydrogen bond in an equivalent series based on succinimide. The halogen-bond energies are in the range −60 to −20 kJ mol−1 and change regularly with pyridine basicity and the Lewis acidity of the halogen. The halogen-bond energies correlate linearly with the product of charges on the contact atoms, which indicates a predominantly electrostatic interaction. The binding enthalpies in solution are around 19 kJ mol−1 less negative due to solvation effects. The optimised geometries of the complexes in the gas phase are comparable to those of the solid-state structures, and the effects of the supramolecular surroundings in the latter are discussed. The bond energies for the hydrogen-bonded series are intermediate between the halogen-bond energies of iodine and bromine, although there are specific differences in the geometries of the halogen- and hydrogen-bonded complexes.

Synthesis of hydrazones (1a–4a and 1b–4b), quinazolines (3c*MeOH and 3d*MeOH), and hydrazone- Schiff bases (4c and 4d) is achieved by combining suitable aldehydes (2, 3- or 2, 4- ihydroxybenzaldehyde) with four hydrazides (isonicotinic, nicotinic, and 2- or 4-aminobenzoic acid hydrazide). A suite of approaches for their preparation is described: solution-based synthesis, mechanosynthesis, and solid-state melt reactions. The mechanochemical approach is generally a better choice for the quinazolines, while the solid-state melt reaction is more efficient for derivatives of (iso)nicotinic based hydrazones. Crystalline amine-functionalised hydrazones 4a and 4b undergo post-synthetic modifications in reactions with 3- or 4- pyridinecarbaldehyde vapours to form hydrazone- Schiff bases 4a-3py, 4b-3py, 4a-4py, and 4b4py. Mechanochemical and vapour-mediated reactions are followed by ex situ powder X-ray diffraction and IR-ATR methods, respectively. The chemometric analysis of these data using principal component analysis provided an insight into the reaction profiles and reaction times. Azines (5a and 5b), achieved from aldehydes and hydrazine, reversibly change colour in response to temperature changes. The structures of all products are ascertained by a combined use of spectroscopic and X-ray diffraction methods. The cytotoxic and antimicrobial activities of all compounds against selected human cancer cell lines and bacterial strains are evaluated.

The in situ condensation reaction of 2-hydrazinobenzothiazole with salicylaldehyde, 3,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, 2-methoxy-1-naphthaldehyde, 4-methoxy-1-naphthaldehyde and 6-methoxy-2-naphthaldehyde produced 9 hydrazone Schiff bases (L1–L9, respectively) which were identified and characterized by elemental analysis, IR and NMR spectroscopy. The crystal and molecular structures of four Schiff bases (L1, L7–L9) have been determined by the single-crystal X-ray diffraction method confirming the imino form of L1 and the amino tautomeric form of L7–L9 compounds. Molecular structure analysis also confirmed that reported compounds are E-isomers relative to exo C = N imino bond. The Nhydrazino–H group of amino tautomers forms Nhydrazino–H···Nthiazolyl intermolecular hydrogen bonds shaping molecules into R 2 2 (8) rings, while imino tautomer of L1 forms C(4) infinite helical chains via Nthiazolyl–H···Nhydrazino type of intermolecular hydrogen bond. The methoxy group (L7–L9) further shaped these primary supramolecular synthons into different supramolecular arrangements via C–H···O, C–H···N and C–H···S intermolecular hydrogen bonds. The role of aryl substituents in the shaping and stabilization of supramolecular architectures of L1, L7–L9 is supported by quantum chemical calculations. Strong antiproliferative effects on tumor cells and cytotoxic effects on fibroblasts are shown for all ligands L1–L9 with exception of L6 and L7 that had no effect on fibroblast cells.

Halohydrin dehalogenase from Arthrobacter sp. AD2 catalysed azidolysis of epoxides with high regioselectivity and low to moderate (S)-enantioselectivity (E = 1–16). Mutation of the asparagine 178 to alanine (N178A) showed increased enantioselectivity towards styrene oxide derivatives and glycidyl ethers. Conversion of aromatic epoxides was catalysed by HheA-N178A with complete enantioselectivity, however the regioselectivity was reduced. As a result of the enzyme-catalysed reaction, enantiomerically pure (S)-β-azido alcohols and (R)-α-azido alcohols (ee ⩾ 99%) were obtained.

Motivated by diverse biological and pharmacological activity of quinuclidine and oxime compounds we have synthesized and characterized novel class of surfactants, 3-hydroxyimino quinuclidinium bromides with different alkyl chains lengths (CnQNOH ; n = 12, 14 and 16). The incorporation of nonconventional hydroxyimino quinuclidinium headgroup and variation in alkyl chain length affects hydrophilic-hydrophobic balance of surfactant molecule and thereby physicochemical properties important for its application. Therefore, newly synthesized surfactants were characterized by the combination of different experimental techniques: X-ray analysis, potentiometry, electrical conductivity, surface tension and dynamic light scattering measurements, as well as antimicrobial susceptibility tests. Comprehensive investigation of CnQNOH surfactants enabled insight into structure-property relationship, i.e. way in which the arrangement of surfactant molecules in the crystal phase correlates with their solution behavior and biologically activity. The synthesized CnQNOH surfactants exhibited high adsorption efficiency and relatively low critical micelle concentrations. In addition, all investigated compounds showed very potent and promising activity against Gram-positive and clinically relevant Gram-negative bacterial strains compared to conventional antimicrobial agents: tetracycline and gentamicin. The overall results indicate that bicyclic headgroup with oxime moiety, which affects both hydrophilicity and hydrophobicity of CnQNOH molecule in addition to enabling hydrogen bonding, has dominant effect on crystal packing and physicochemical properties. The unique structural features of cationic surfactants with hydroxyimino quinuclidine headgroup along with diverse biological activity have made them promising structures in novel drug discovery. Obtained fundamental understanding how combination of different functionalities in a single surfactant molecule affects its physicochemical properties represents a good starting point for further biological research.

The aim of this study was to investigate the feasibility of FTIR-ATR spectroscopy coupled with the multivariate numerical methodology for qualitative and quantitative analysis of binary and ternary edible oil mixtures. Four pure oils (extra virgin olive oil, high oleic sunflower oil, rapeseed oil, and sunflower oil), as well as their 54 binary and 108 ternary mixtures, were analyzed using FTIR-ATR spectroscopy in combination with principal component and discriminant analysis, partial least-squares, and principal component regression. It was found that the composition of all 166 samples can be excellently represented using only the first three principal components describing 98.29% of total variance in the selected spectral range (3035-2989, 1170-1140, 1120-1100, 1093-1047, and 930-890 cm(-1)). Factor scores in 3D space spanned by these three principal components form a tetrahedral-like arrangement: pure oils being at the vertices, binary mixtures at the edges, and ternary mixtures on the faces of a tetrahedron. To confirm the validity of results, we applied several cross-validation methods. Quantitative analysis was performed by minimization of root-mean-square error of cross-validation values regarding the spectral range, derivative order, and choice of method (partial least-squares or principal component regression), which resulted in excellent predictions for test sets (R(2)0.99 in all cases). Additionally, experimentally more demanding gas chromatography analysis of fatty acid content was carried out for all specimens, confirming the results obtained by FTIR-ATR coupled with principal component analysis. However, FTIR-ATR provided a considerably better model for prediction of mixture composition than gas chromatography, especially for high oleic sunflower oil.

Adulteration of hempseed (H) oil, a well known health beneficial nutrient, is studied in this work by means of 1H NMR spectroscopy. H oil samples were mixed with cheap and widely used oils such as rapeseed (R) oil and sezame (Se) and sunflower (Su) oil. Many samples of different geographic origins were taken into account. Binary mixture sets of hempseed oil with these three oils (HR, HSe and HSu) were considered. 1H NMR spectra of pure oils and their mixtures were recorded and quantitative analyses were performed using Partial Least Squares Regression (PLS), First-Break Forward Interval PLS methods (FB-FiPLS) and Interval Ridge Regression (iRR). The obtained results show that each particular oil can be very successfully quantified (RMSEP 1.4–3.0%), and that NMR coupled with iRR has a great potential in studying signals of low intensity belonging to oil microconstituents. This means that 1H NMR spectroscopy coupled with multivariate methods can rapidly and effectively determine both the fatty acid profile and the level of adulteration in the adulterated hempseed oil for these studied and frequently used adulterant oils.

In the search for a new class of potential antimicrobial agents, five novel N-substituted imidazole 2-aldoximes and their six quaternary salts were evaluated. The antimicrobial activity was assessed against a panel of representative Gram-positive and Gram-negative bacteria, including multidrug resistant bacteria. All compounds demonstrated potent in vitro activity against the tested microorganisms, with MIC values ranging from 6.25 to 50.0 μg/mL. Among the tested compounds, two quaternary compounds (N-but-3-enyl- and meta- (10) or para- N-chlorobenzyl (11) imidazolium 2-aldoximes) displayed the most potent and broad-spectrum activity against both Gram-positive and Gram-negative bacterial strains. The broth microdilution assay was also used to investigate the antiresistance efficacy of the both most active compounds against a set of Enterobacteriaceae isolates carried a multiple extended-spectrum β-lactamases (ESBLs) in comparison to eight clinically relevant antibiotics. N-but-3-enyl-N-meta-chlorobenzyl imidazolium 2-aldoxime was found to possess promising antiresistance efficacy against a wide range of β-lactamases producing strains (MIC 2.0 to 16.0 μg/mL). Best results for that compound were obtained against Escherichia coli and Enterobacter cloacae producing multiple β-lactamases form A and C molecular classes, which were 32- and 128-fold more potent than ceftazidime and cefotaxime, respectively. To visualize the results, principal component analysis was used as an additional classification tool. The mixture of ceftazidime and compound 10 (3 μg:2 μg) showed a strong activity and lower the necessary amount (up to 40-fold) of 10 against five of ESBL-producing isolates (MIC ≤ 1 µg/mL).

Six non−symmetric enaminones 4-[(2-hydroxy-5-methylphenyl)amino]pent-3-en-2-one ( H 2 L 1 ), 4-[(2-hydroxy-4-methylphenyl)amino]pent-3-en-2-one ( H 2 L 2 ), 4-[(4-hydroxy-2-methylphenyl)amino)]pent-3-en-2-one ( H 2 L 3 ), 3-[(2-hydroxy-5-methylphenyl)amino]-1-phenylbut-2-en-1-one ( H 2 L 4 ), 3-[(2-hydroxy-4-methylphenyl)amino]-1-phenylbut-2-en-1-one ( H 2 L 5 ) and 3-[(4-hydroxy-2-methylphenyl)amino]-1-phenylbut-2-en-1-one ( H 2 L 6 ) have been prepared by solution based method. The enaminones were characterized by elemental and DSC analysis, NMR and IR spectroscopy. Crystal and molecular structures of H 2 L 1 , H 2 L 2 , H 2 L 4 and H 2 L 6 were determined via single crystal X−ray analysis. The prepared enaminones were screened against THP-1 and HepG2 cells, and Staphylococcus aureus , Enterococcus faecalis , Escherichia coli and Moraxella catarrhalis bacteria to assess their cytotoxic and antibacterial activity, respectively. All compounds proved to be non-cytotoxic and showed mild or no antibacterial activity. Quantum mechanical calculations suggest that the presence of hydroxy group in ortho position, combined with the methyl group on the same aromatic ring, has a significant impact on the biological activities.

A new procedure for full conformational analyses comprising the statistical analysis of molecular dynamics trajectories was developed and applied. This method included a coordinate space for sampling using molecular dynamics simulations, reduction of dimensionality using tensor decomposition tools, determination of probability distributions in a reduced space, and finally the search for all of the strict extrema points of probability distributions. These extracted extrema points formed an initial guess for geometry optimization and clustering of conformers. A complete conformational space of 1-oxaspiro[2, 5]octane and its cis- and trans-4-, 5- and 6-methyl substituted derivatives was also determined. In each case, eight conformers were found with two chair-like conformers predominant at room temperature. It was found that chair-like conformers with an epoxide ring oxygen atom in the pseudo-axial position had less strain, as well as all of their conformers with the methyl substituent in an equatorial position on a cyclohexane moiety.

Developing new antibiotics is currently very important since antibiotic resistance is one of the biggest problems of global health today. In the search for a new class of potential antimicrobial agents, ten new compounds were designed and synthesized based on the quinuclidinium heterocyclic core and the oxime functional group. The antimicrobial activity was assessed against a panel of representative gram-positive and gram-negative bacteria. All compounds demonstrated potent activity against the tested microorganisms, with the minimum inhibitory concentration (MIC) values ranging from 0.25 to 256.00 &mu, g/mL. Among the tested compounds, two quaternary compounds, para-N-chlorobenzyl and meta-N-bromobenzyl quinuclidinium oximes, displayed the most potent and broad-spectrum activity against both gram-positive and gram-negative bacterial strains (MIC values from 0.25 to 4.00 &mu, g/mL), with the lowest value for the important multidrug resistant gram-negative pathogen Pseudomonas aeruginosa. In the case of Klebsiella pneumoniae, activity of those compounds are 256-fold and 16-fold better than gentamicin, respectively. MTT assays showed that compounds are nontoxic for human cell lines. Multi-way analysis was used to separately reduce dimensionality of quantum chemical data and biological activity data to obtain a regression model and the required parameters for the enhancement of biological activity.

The reaction of [CoIII(4,4′dmsalen)(CH2Cl)(L)], where 4,4′dmsalen = 4,4′-dimethylsalen and L = solvent, with pyridine led to the isolation of [CoIII(4,4′dmsalen)(CH2py)(Cl)], in a two-step process involving a metallacyclized intermediate, cis β [CoIII(4,4′dmsalenCH2)(py)(L)]+, whereas a parallel direct conversion through the displacement of a Cl atom from the axial CH2Cl group of [CoIII(4,4′dmsalen)(CH2Cl)(L)] may be ruled out. Natural bond orbital analysis of the structures show that the ylide carbon atom has lower orbital occupancies in the cyclized complex, thus making it more susceptible to a nucleophilic attack of pyridine. The calculated potential energy surfaces indicate that the most energy feasible reaction path would be for the complex [CoIII(4,4′dmsalenCH2)(py)ax(H2O)]+, with an entering pyridine molecule and a leaving equatorial water molecule. Experimental kinetic studies of the formation of the ylide complex starting from [CoIII(4,4′dmsalenCH2)(py)eq(H2O)]+ strongly suggest that it is possible to obtain the ylide complex through an alternative, less energetically favourable path.

This paper describes the synthesis and anticholinesterase potency of Cinchona-based alkaloids ; ten quaternary derivatives of cinchonines and their corresponding pseudo- enantiomeric cinchonidines. The quaternization of quinuclidine moiety of each compound was carried out with groups diverse in their size: methyl, benzyl and differently meta- and para-substituted benzyl groups. All of the prepared compounds reversibly inhibited human butyrylcholinesterase and acetylcholinesterase with Ki constants within nanomolar to micromolar range. Five cinchonidine derivatives displayed 95-510 times higher inhibition selectivity to butyrylcholinesterase over acetylcholinesterase and four were potent butyrylcholinesterase inhibitors with K(I) constants up to 100 nM, of which N-para- bromobenzyl cinchonidinium bromide can be considered a lead for further modifications and optimizations for possible use in the treatment of neurodegenerative diseases

Based on a new family of NiII cubane-like clusters, this work addresses current challenges in the synthesis, analysis and dynamics of single-molecule-magnet (SMM) systems. Investigation of various synthetic routes and desorption–sorption processes yielded a series of isomorphous compounds: [Ni4L4(CH3OH)4]·xsolv, [Ni4L4(CH3OH)4] and [Ni4L4]. In order to analyze these deceivingly simple materials, several analytical and quantum mechanical methods had to be used. This revealed materials with mixed lattice solvents, statistical disorder of the solvent, and disordered [Ni4L4] cores which offered an insight into the risks of the self-assembly process and interconversion dynamics of the investigated NiII family. These findings also allowed structural–magnetic relationships to be established, and the outcomes were exploited in two ways: first, the effect of the coordinated and lattice solvent on the magnetic properties was examined, and second, magnetic properties were used to facilitate crystal structure determination., New Journal of Chemistry, 40 (8), ISSN:1144-0546, ISSN:0398-9836, ISSN:1369-9261

New mechanochemical pathways for the transformation of six N-heterocyclic carbonyl com- pounds into oximes using hydroxylamine hydrochloride were explored. Reactions were performed first without any base since the heterocyclic moieties (imidazole, benzimidazole, pyridine and quinuclidine) have an intrinsic basic nitrogen atom. This green, solvent free method was suitable for all compounds (up to quantitative yields) except for N-benzyl substituted imidazole and benzimidazole-2-carbaldehyde. For the slower reacting aldehydes, reactions with liquid assisted grinding and addition of sodium hydroxide were performed as well. Conformational analysis and quantum-chemical calculations revealed steric and electronic reasons for the lower reactivity of N-benzyl substituted derivatives.

Extra virgin olive oil samples were collected from different geographical areas of Central Dalmatia region in Croatia including locations both on the coast and islands. This set included 41 oils of cul-tivar Oblica, 1 per cultivars Coratina and Leccino, and 5 of mixed cultivars Lastovka and Oblica. Attenuated total reflectance (ATR) spectra of non-treated samples were recorded and principal component analysis (PCA) was carried out on a set of obtained spectra, as well as their first and second derivatives. The quality of PCA models was assessed using leave-one-out cross-validation and optimal number of principal components was determined. In the case of ATR spectra, the first principal component accounted for 42.92 % of the total variance among the samples and the optimal number of components was 6, whereas in the case of second derivatives the first principal component accounted for 95.76 % of the total variance and the optimal number of components was 3. Classification of olive oils on the basis of geographical origin was proposed and underlying spectral differences among the spectra were determined by investigating principal component loadings. These differences arise as a result of variations in fatty acid composition. It was found out that ATR in combination with PCA could easily distinguish between samples collected from the coastal area and those from the islands. Classification results were further confirmed by using spherical principal components procedure, projection pursuit and robust PCA, as well as hierarchical cluster analysis.(doi: 10.5562/cca2377)

The orientations of chiral quinuclidin-3-ol esters and benzoylcholine in the active site of horse butyrylcholinesterase have been investigated by flexible ligand docking. Change of the esters' acyl moiety as well as the substituent at the quinuclidinium nitrogen atom affected the activity and stereoselectivity of the biotransformations. Analysis of interactions in the active site revealed the most important binding pat-terns for enantiomers, which define their reactivity. Calculated Gibbs energies of binding obtained by mo-lecular docking simulations were well correlated to the experimentally determined binding affinities of the investigated chiral esters. (doi: 10.5562/cca2060)

The condensation reaction between carbohydrazide and salicylaldehyde in different solvents gave mono(salicylidene)carbohydrazide (1). The structure of 1 in solution has been determined by using experimental (NMR and UV spectroscopies and Mass spectrometry) and quantum chemical (DFT) meth- ods. It has been demonstrated that 1 adopts the hydroxy-one tautomeric form which is in accordance with previously published results for the related systems. Changes in NMR chemical shifts and calculations have pointed towards a formation of intra- and intermolecular hydrogen bonds, the later being weaker and easily broken at higher temperatures. These results can further be exploited for better understanding of the role hydrogen bonds can play in bioactivity of related derivatives. (doi: 10.5562/cca2123)