Search

High-level quantum mechanical (QM) calculations are indispensable for accurate explanation of natural phenomena on the atomistic level. Their staggering computational cost, however, poses great limitations, which luckily can be lifted to a great extent by exploiting advances in artificial intelligence (AI). Here we introduce the general-purpose, highly transferable artificial intelligence–quantum mechanical method 1 (AIQM1). It approaches the accuracy of the gold-standard coupled cluster QM method with high computational speed of the approximate low-level semiempirical QM methods for the neutral, closed-shell species in the ground state. AIQM1 can provide accurate ground-state energies for diverse organic compounds as well as geometries for even challenging systems such as large conjugated compounds (fullerene C60) close to experiment. This opens an opportunity to investigate chemical compounds with previously unattainable speed and accuracy as we demonstrate by determining geometries of polyyne molecules—the task difficult for both experiment and theory. Noteworthy, our method’s accuracy is also good for ions and excited-state properties, although the neural network part of AIQM1 was never fitted to these properties., Artificial intelligence is combined with quantum mechanics to break the limitations of traditional methods and create a new general-purpose method for computational chemistry simulations with high accuracy, speed and transferability.

We report a comprehensive quantum-chemical study on d(A)5·d(T)5 and d(G)5·d(C)5 DNA mini-helixes and the Dickerson dodecamer d[CGCGAATTCGCG]. The research was performed to model the evolution of the spatial structure of d(A)5·d(T)5 and d(G)5 d(C)5 DNA mini-helixes all the way from vacuum to water bulk. The influence of external factors such as the presence of counterions and the extent of hydration was included. Also, for comparison, limited calculations have been carried out on the Dickerson dodecamer. The study has been performed at the density functional theory level using B97D3 and ωB97XD exchange-correlation functionals augmented by the Def2SVP basis set. We found that the (dA)5·(dT)5 anion when placed in vacuum forms a DNA duplex, which possesses an intermediate form between a helix and a ladder. The presence of compensating Na+ counterions or explicit microhydration of minor and major grooves stabilizes a DNA mini-helix of B-shape. Factors such as water bulk play a minor role. Somewhat different behavior has been found in the case of the (dG)5·(dC)5 duplex. In this case, we observe the formation of B-type mini-helixes even for the (dG)5·(dC)5 anion placed in vacuum. This is due to an additional stabilization originated from the appearance of an extra hydrogen bond, compared to an AT base pair. To assess whether the obtained results are transferable to different sizes of mini-helixes, similar calculations have been performed for the duplex formed by the Dickerson dodecamer which contains a total of 12 dG·dC and dA·dT base pairs. It has been found that in vacuum, analogous to the d(A)5·d(T)5 duplex, this system possesses a shape which is also quite close to a ladder. However, the presence of factors such as hydration restores the B-type geometry. Also, our results completely in line with the results of electrospray-ionization experiments suggest that uncompensated by counterions the DNA backbone preserves the duplex geometry in vacuum. We present arguments that this state is kinetically unstable.

Optimized synthesis of 1-methyltetrazolo[5,1-a]isoindole-derived amides and thioamides was elaborated. Based on 13C NMR spectroscopy and X-Ray diffraction studies data, it was proposed that zwitterionic resonance structures contributed significantly to the structure of these compounds. Geometry optimization was performed in vacuo using m06-2x/cc-pvtz method taking into account polarizing effect of environment (PCM model) and specific intermolecular interactions. Electronic density distribution in these molecules was analyzed using NBO method. Using Δ(HOMOdiene–LUMOdienophile) for amides and thioamides in vacuo and in a protic solvent, possibility of Diels–Alder reaction was evaluated. Energies of π-π conjugation and n→σ* hyperconjugation for the amide derivative were estimated in vacuo, aprotic and protic solvents.

Interatomic potentials derived with Machine Learning algorithms such as Deep-Neural Networks (DNNs), achieve the accuracy of high-fidelity quantum mechanical (QM) methods in areas traditionally dominated by empirical force fields and allow performing massive simulations. Most DNN potentials were parametrized for neutral molecules or closed-shell ions due to architectural limitations. In this work, we propose an improved machine learning framework for simulating open-shell anions and cations. We introduce the AIMNet-NSE (Neural Spin Equilibration) architecture, which can predict molecular energies for an arbitrary combination of molecular charge and spin multiplicity with errors of about 2–3 kcal/mol and spin-charges with error errors ~0.01e for small and medium-sized organic molecules, compared to the reference QM simulations. The AIMNet-NSE model allows to fully bypass QM calculations and derive the ionization potential, electron affinity, and conceptual Density Functional Theory quantities like electronegativity, hardness, and condensed Fukui functions. We show that these descriptors, along with learned atomic representations, could be used to model chemical reactivity through an example of regioselectivity in electrophilic aromatic substitution reactions., Quantum mechanical calculations of molecular ionized states are computationally quite expensive. This work reports a successful extension of a previous deep-neural networks approach towards transferable neural-network models for predicting multiple properties of open shell anions and cations.

Machine learning (ML) methods have become powerful, predictive tools in a wide range of applications, such as facial recognition and autonomous vehicles. In the sciences, computational chemists and physicists have been using ML for the prediction of physical phenomena, such as atomistic potential energy surfaces and reaction pathways. Transferable ML potentials, such as ANI-1x, have been developed with the goal of accurately simulating organic molecules containing the chemical elements H, C, N, and O. Here, we provide an extension of the ANI-1x model. The new model, dubbed ANI-2x, is trained to three additional chemical elements: S, F, and Cl. Additionally, ANI-2x underwent torsional refinement training to better predict molecular torsion profiles. These new features open a wide range of new applications within organic chemistry and drug development. These seven elements (H, C, N, O, F, Cl, and S) make up ∼90% of drug-like molecules. To show that these additions do not sacrifice accuracy, we have tested this model across a range of organic molecules and applications, including the COMP6 benchmark, dihedral rotations, conformer scoring, and nonbonded interactions. ANI-2x is shown to accurately predict molecular energies compared to density functional theory with a ∼106 factor speedup and a negligible slowdown compared to ANI-1x and shows subchemical accuracy across most of the COMP6 benchmark. The resulting model is a valuable tool for drug development which can potentially replace both quantum calculations and classical force fields for a myriad of applications.

A new synthetic route to the molecular clip with diphenylglycoluril and dibenzo-18-crown-6 using protection-deprotection protocol is proposed. Yield of desired compound has increased from 10-15% to 41%. Starting from 4,5-dibromobenzene-1,2-diol 4,5-dibromodibenzo-18-crown-6 and then tetrabromo-substituted molecular clip were obtained. The target molecular clip was obtained by bromine cleavage by hydrogenolysis. Stability constants were determined by spectrophotometric titration with alkali metal cations and paraquat. Quantum-chemical calculations confirm the assumption of additional stabilization of complex with K+ by π–π stacking between the terminal aromatic fragments with formation of a “pseudocryptand” type structure. The structures of complexes of the molecular clips with paraquat were determined by X-ray crystallography.

A systematic topological analysis of fluorinated pyridines and benzenes is reported. Fluorine and nitrogen atoms are considered to be isolobal with respect to the supramolecular architecture in the crystalline phase. The comparison of the intermolecular interaction energies demonstrates that nitrogen atom within the aromatic ring and fluorine as a substituent both induce the same type of molecular arrangement in the solid state. Based on this, we suggest a general isotypic transformation principle for molecular crystals.

Hantzsch reaction has been successfully employed for a one-step assembling of pyranopyridine fragment to produce 5Н,9Н-pyrano[2',3':5,6]- chromeno[4,3-b]pyridine-5,9-diones which upon treatment with binucleophiles undergo chemoselective γ-pyrone ring opening with the concomitant recyclization to give five-membered cycles, providing a concise route to 6-pyrazolyl(isoxazolyl)-5H-chromeno[4,3-b]- pyridin-5-ones.

The complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives has been studied both in solution and in the solid state. In this paper we studied the influence of the crown ether ring size and the nature of the substituents at the nitrogen atoms of the paraquat derivatives on the composition and stability of these complexes.

Maximum diversification of data is a central theme in building generalized and accurate machine learning (ML) models. In chemistry, ML has been used to develop models for predicting molecular properties, for example quantum mechanics (QM) calculated potential energy surfaces and atomic charge models. The ANI-1x and ANI-1ccx ML-based general-purpose potentials for organic molecules were developed through active learning; an automated data diversification process. Here, we describe the ANI-1x and ANI-1ccx data sets. To demonstrate data diversity, we visualize it with a dimensionality reduction scheme, and contrast against existing data sets. The ANI-1x data set contains multiple QM properties from 5 M density functional theory calculations, while the ANI-1ccx data set contains 500 k data points obtained with an accurate CCSD(T)/CBS extrapolation. Approximately 14 million CPU core-hours were expended to generate this data. Multiple QM calculated properties for the chemical elements C, H, N, and O are provided: energies, atomic forces, multipole moments, atomic charges, etc. We provide this data to the community to aid research and development of ML models for chemistry., Measurement(s)Quantum Mechanics • energy • force • multipole moment • atomic chargeTechnology Type(s)computational modeling techniqueFactor Type(s)atomSample Characteristic - Environmentorganic molecule Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12046440

Computational modeling of chemical and biological systems at atomic resolution is a crucial tool in the chemist’s toolset. The use of computer simulations requires a balance between cost and accuracy: quantum-mechanical methods provide high accuracy but are computationally expensive and scale poorly to large systems, while classical force fields are cheap and scalable, but lack transferability to new systems. Machine learning can be used to achieve the best of both approaches. Here we train a general-purpose neural network potential (ANI-1ccx) that approaches CCSD(T)/CBS accuracy on benchmarks for reaction thermochemistry, isomerization, and drug-like molecular torsions. This is achieved by training a network to DFT data then using transfer learning techniques to retrain on a dataset of gold standard QM calculations (CCSD(T)/CBS) that optimally spans chemical space. The resulting potential is broadly applicable to materials science, biology, and chemistry, and billions of times faster than CCSD(T)/CBS calculations., Computational modelling of chemical systems requires a balance between accuracy and computational cost. Here the authors use transfer learning to develop a general purpose neural network potential that approaches quantum-chemical accuracy for reaction thermochemistry, isomerization, and drug-like molecular torsions.

The simplest o-amidino benzoic acid—2-(amino(imino)methyl)benzoic acid—has been isolated in 23 % yield as a side product of the reaction of phthalonitrile and ammonia along with desired 1-imino-1H-isoindol-3-amine. This amidino acid was fully characterized by nuclear magnetic resonance, IR spectroscopy, mass spectrometry; pKa values were also determined. X-ray diffraction study and quantum chemical calculations revealed that in the solid state it exists as a zwitterion that is stabilized by intermolecular hydrogen bonds.

Піперідини, спіросполучені з іншими гетероциклами як структурні елементи фармакологічно активних лейовані фраґменти» лігандів метаботропних рецепторів. Пропонується спосіб отримання похідних 1,2,8-триазаспіро[4.5]декану, який полягає в спіроанелюванні 1,4-дигідропіридинового та піразолонового циклів. При нагріванні 1-(феніл)алкіл-4-[2-[2-арилгідразоно]-1,3-діоксобутил]піридинію галогенідів у піридині або при взаємодії 1-(феніл)алкіл-4-[2-[2-арилгідразоно]-1,3-діоксобутил]піридинію галогенідів і 1-(феніл)алкіл-4-{1,3-діоксо-3-феніл-2-[2-(4-метилфеніл)гідразоно]пропіл}піридинію галогенідів з діізопропілетиламіном при 25оС відбувається внутрішньомолекулярне відновне алкілювання електрофільного піридинієвого катіону з утворенням 1-(феніл)алкіл-3-ацил-1,2,8-триазаспіро[4.5]деканів, які є твердими забарвленими речовинами. Вивчені спектральні властивості продуктів циклізації, на основі яких встановлено утворення спіросполученої системи та присутність фрагменту 1,4-дигідропіридину. Підтвердження їх будови отримане при проведенні РСА кристалу 3-ацетил-8-бензил-1-феніл-1,2,8-триазаспіро[4.5]дека-2,6,9-трієн-4-ону, який однозначно підтвердив ортогональність спіросполучених площин. Дигідропіридиновий цикл у молекулі не є плоским і знаходиться в конформації півкрісло, в якій спіроатом Карбону відхилений від площини інших атомів циклу, що є наслідком утворення внутрішньомолекулярного C-H…π водневого зв’язку.

We introduce a modular, chemically inspired deep neural network model for prediction of several atomic and molecular properties., Atomic and molecular properties could be evaluated from the fundamental Schrodinger’s equation and therefore represent different modalities of the same quantum phenomena. Here, we present AIMNet, a modular and chemically inspired deep neural network potential. We used AIMNet with multitarget training to learn multiple modalities of the state of the atom in a molecular system. The resulting model shows on several benchmark datasets state-of-the-art accuracy, comparable to the results of orders of magnitude more expensive DFT methods. It can simultaneously predict several atomic and molecular properties without an increase in the computational cost. With AIMNet, we show a new dimension of transferability: the ability to learn new targets using multimodal information from previous training. The model can learn implicit solvation energy (SMD method) using only a fraction of the original training data and an archive median absolute deviation error of 1.1 kcal/mol compared to experimental solvation free energies in the MNSol database.

Arylglyoxal hydrates interact with N-alkoxyureas and N-hydroxyurea in acetic acid with selective formation of 3-alkoxy-5-arylimidazolidine-2,4-diones and 5-aryl-3-hydroxyimidazolidine-2,4-diones, respectively. The structures of 3-methoxy-5-phenylimidazolidine-2,4-dione, 3-ethoxy-5-phenylimidazolidine-2,4-dione, and 3-butoxy-5-(4-chlorophenyl)imidazolidine-2,4-dione were studied by X-ray structural analysis.

The influence of chlorine substituents on the molecular arrangement in the solid state of chlorinated benzoyl-ferrocene derivates with restricted molecular flexibility was investigated by crystal structure determinations and theoretical calculations. Four different chlorinated benzoyl-ferrocene derivates were crystallized from a saturated CHCl3 solution and analyzed by X-ray diffraction. Under consideration of the structural restrictions, a comparable trend of rearrangement in the crystal organization with increasing number of chlorine atoms is observed, which is analogous to findings for chlorine-substituted benzenes. More important, the molecules arrange in layers (1 and 4) and columns (2 and 3) and in all cases with repulsively orientated CF3···CF3 substituents. In addition, Cl···Cl interactions are visible in 1 (type I) and 4 (type II). Furthermore, the crystal packing motifs were also analyzed based on ab initio quantum-chemical calculations of the intermolecular interaction energy, using the B97-D3/def2-TZVP method. According to the topology of intermolecular interaction, the crystal structures have either columnar or layered structure depending on the presence of Cl substituent in para-position of benzene ring. It was also found that Cl···Cl interactions play a secondary role in crystal organization, and the substituent effect is maybe due to polarization of the aromatic ring, which leads ultimately to an increase in the energy of stacking interactions between the aryl substituents. Analysis of the crystal structures of chlorine substituents on the molecular arrangement in the solid state of restricted molecular flexible chlorinated benzoyl-ferrocene derivates shows a trend of rearrangement in the crystal organization with increasing number of chlorine atoms.

Octahydroacridine-4-carbonitrile (carboxamide) was shown to react with aryldiazonium salts and other electrophilic reagents in acidic and neutral media. The reactions occurred at the methine carbon atom, forming the corresponding 4-functionalized derivatives. The obtained azo compounds decomposed at 140–155°С with elimination of nitrogen and gave products formed by the reactions of radical intermediates.

We report the comprehensive DFT based comparison of geometrical and energetic parameters of the d(A)3·d(T)3 and d(G)3·d(C)3 nucleic acid mini-helixes performed at B97-D3 and M06-2× levels of theory. We studied the ability of mini-helixes to retain the conformation of B-DNA in the gas phase and under the influence of water bulk, uncompensated charges, and counter-ions. The def2-SV(P) and 6-31G(d,p) basis sets have been used for B97-D3 and M06-2× calculations, correspondently. To estimate basis set superposition error, the recently developed semi-empirical procedure that calls geometrical counterpoise type correction for inter- and intra-molecular basis set superposition error (gcp) has been used in the case of def2-SV(P) basis set. We found that both considered DFT functionals predict very similar results for geometrical ad energetic characteristics. We also found that in contrast to average classical molecular dynamics and data of simple geometrical models, both considered DFT functionals predict the existence of duplex specific geometries. A prediction of interaction energies of d(A)3d(T)3 and d(G)3d(C)3 duplexes accomplished in this study also verifies the applied models and confirms reliability of the new computational gcp technique.

The molecular complexes of tetrahydrofuran (THF) and diethyl ether (DEE) with chloroform (CF), dichlodromethane (DCM) and bromoform (BF) have been synthesised by in situ cryo-crystallization and their structures have been determined by single-crystal X-ray diffraction. CF forms 2:1 co-crystals with THF and DEE, where the components are linked in isolated 2:1 complexes by Cl3 C-H…O interactions. Molecules of components in THF-BF complex form halogen-bonded chains, while the complexes DCM and BF with DEE contain two independent pairs of the components linked by C-H…O contacts. Supramolecular architecture of the molecular complexes is analysed using energy-based topology of intermolecular interactions.

Crystals of molecular complexes of trimethyltrioxane (TMT) with chloroform (CF), bromoform (BF), dichloromethane (DCM), and dibromomethane (DBM) as well as those of pure TMT were grown in situ and characterized by single crystal X-ray crystallography. The CF and BF complexes, as well as those of DCM and DBM, are isostructural. The packing motifs were examined using the vector analysis of pairwise energies of intermolecular interactions. The method shows some deficiencies of the traditional approach based on the analysis of geometrical parameters of short intermolecular contacts.

A new method based on reaction of 4-bromobut-2-enoates with N-alkylimidazoles was proposed for obtaining 1R-1H-imidazo[1,2-a]pyridin-4-ium-8-olate and 1-R-8-methoxy-1H-imidazo[1,2-a]pyridin-4-ium derivatives. The structures of synthesized compounds were confirmed by 1H, 13C NMR, elemental analysis, and X-ray data.

The influence of CH3/CHF2/CF3-exchange on the molecular arrangement in the solid state of the low melting compounds α-toluene 1, (difluoromethyl)benzene 2, and (trifluoromethyl)benzene 3 was investigated by crystal structure determinations and theoretical calculations. The compounds were crystallized by in situ crystallization directly on the diffractometer and analyzed by X-ray diffraction. The crystal packing motifs were also analyzed based on ab initio quantum-chemical calculations of the intermolecular interaction energy, using the B97-D3/def2-TZVP method.

The molecular structure and relative stability of isomeric dihydropyridines have been calculated using the density functional theory and the Moller–Plesset second-order perturbation theory. The results of the calculations demonstrate that 3,4- and 2,3-dihydropyridines are the most stable species despite the presence of a 4π-electron conjugated system within the ring. A comparison of the relative energy of acyclic analogs of dihydropyridines indicates that this is caused by the internal properties of the conjugated system. The remaining dihydropyridines are strongly destabilized by the formation of antiaromatic conjugated (or quasi-conjugated) systems due to the interaction of pz atomic orbitals of the carbon and nitrogen atoms with the pseudo-π fragment orbital of the methylene group. Application of the more accurate CCSD(T)/CBS method results in considerable stabilization of 1,4-dihydropyridine. However, the order of stability of other isomers remains the same as it was found at the MP2 level of theory.

A combined molecular mechanics and quantum chemistry modeling was performed for investigation of the structure and relavive stability of two- and three-component complexes formed by the antituberculosis agent isoniazid with morpholinium (3-methyl-1,2,4-triazol-5-yl)thioacetate (MTTA). The possible interactions between the molecules were identified by molecular mechanics calculations, and the stability of the complexes was calculated by the density functional method B97-D/6-311G**, with accounting for the solvent effects in the SMD continuum model. The calculations showed that stable complexes of isoniazid with this thiatriazoline are possible both in the gas phase (ΔG298 = -13.6 kcal/mol) and in aqueous solution (ΔG298 = -7.6 kcal/mol). The formation of two-component complexes between isoniazid and MTTA without involving morpholine is considerably less favored (ΔG298 = -6.6 kcal/mol in the gas phase and ΔG298 = -2.6 kcal/mol in solution). Thus, morpholine may be considered as a component facilitating the formation of isoniazid complexes with MTTA.

Crystal structure of benzene–acetylene co-crystal was analysed based on calculated energies of intermolecular interactions between basic molecules located in asymmetric part of unit cell and their neighbours belonging to their first coordination sphere. It is demonstrated that the basic structural motif of the crystal is represented by infinite chains formed by the hydrogen-bonded benzene and acetylene molecules. Energy of interaction of the basic pair of molecules to neighbours within the chain is 2.2 times higher than the energy of interactions with molecules of any neighbouring chain. This ratio almost does not depend on method of calculation of interaction energy. Also, results of calculations were compared with analysis of topology of electron density distribution in crystal. The possibility to find the basic structural motif of the crystal based on properties of intermolecular bond critical points is demonstrated.

The condensation of 3-alkylamino-5-amino-1-phenyl[1,2,4]triazoles with β-keto esters or diethyl ethoxymethylenemalonate in the presence of acetic acid proceeds selectively to give 3-alkylamino-1-phenyl[1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-ones. The observed reaction pathway is explained using quantum-chemical calculations of the energies of possible isomeric heterocyclization products.

Treatment of cyclohexanone-2-carboxamide with cyclic ketones provides oxazine derivatives while refluxing in toluene with ammonium acetate and cyclic ketones yields substituted 2-spiropyrimidin-4-ones. Depending on the ratio of reactants, the oxazines and substituted 2-spiropyrimidin-4-ones under Vilsmeier-Haack conditions undergo formylation or an electrophilic rearrangement.

The cyclization of N-chloro-N-(2-phenylethoxy)urea in the presence of silver trifluoroacetate leads to the formation of 3,4-dihydro-1H-2,1-benzoxazine-1-carboxamide, while N-alkoxy-N'-aryl-N-chloro-ureas in the presence of sodium acetate form 1-alkoxy-1,3-dihydrobenzimidazol-2-ones. The structures of 3,4-dihydro-1H-2,1-benzoxazine-1-carboxamide and 1-methoxy-6-nitro-1,3-dihydrobenzimidazol-2-one were examined by X-ray structural analysis.

The interaction of new molecular clips containing diphenylglycoluril and benzocrown ethers moieties with alkali metals ions was studied. Stability constants were determined by spectrophotometric titrations with chloride salts in methanol. Complex stability and cation binding selectivity were shown to be dependent on the size of the crown ether moiety. The “sandwich-type” 1:1 (clip to cation) complexes and the “classical” 1:2 complexes were found. Their ratio varies depending on the molecular clips nature and on the cation type. It was found an unexpected selectivity of the molecular clip with benzo-15-crown-5 moieties toward K+ and Rb+ cations. The molecular structure of the clip complex with benzo-15-crown-5 fragments and sodium picrate was determined by X-ray crystallography. The crystal structure and solution-state structure were proven to be similar.

The character of intermolecular interactions of the bromide anion and organic cation in crystal of 4-amino-1-(β-phenylethyl)-1,2,4-triazolium bromide was studied by a combination of X-ray diffraction data and M06-2X/cc-pvtz quantum chemical calculations. The existence of binding anion...π-system interactions was shown, and their characteristics were studied.

The two-component condensation of 2-chloro- or 2-bromo-N-ethoxycarbonylmethylpyridinium halides and aryl- or hetarylmethylidenemalononitriles gave ethyl 2-[2-(dicyanomethylidene)pyridin-1(2H)-yl]-3-arylacrylates. Correlation NMR spectroscopy and X-ray diffraction structural analysis allowed the structural characterization of these products.

10-Amino-7,11-dicyano-9-aza-3-azoniaspiro[5,5]undeca-7,10-diene-8-selenolates have been obtained by the interaction of N-alkylpiperidin-4-ones with 2 equiv. cyanoselenoacetamide or with malononitrile and cyanoselenoacetamide. Aminomethylation of the obtained compounds proceeded under mild conditions and led to the formation of 8'-selenoxo-3',5',7',11'-tetraazaspiro[piperidine-4,13'-tri-cyclo[7.3.1.02,7]tridec[2]ene]-1',9'-dicarbonitriles. The structure of 1-methyl-5',11'-di(4-methyl-phenyl)-8'-selenoxo-3',5',7',11'-tetraazaspiro[piperidine-4,13'-tricyclo[7.3.1.02,7]tridec[2]ene]-1',9'-di-carbonitrile was determined by X-ray structural analysis.

The reactions of 2-(2-hetaryl)-2-(tetrahydrofuran-2-ylidene)acetonitriles with conformationally rigid and heterocyclic tertiary amines were investigated. Compounds with bipolar structures were obtained: 1-cyano-1-(2-hetaryl)-5-(pyridinium-1-yl)-1-penten-2-olates and 5-(4-aza-1-azoniobicyclo[2.2.2]oct-1-yl)-1-cyano-1-(2-hetaryl)pent-1-en-2-olates.

The reaction of 2-hetaryl-2-(tetrahydrofuran-2-ylidene)acetonitriles and 6-chloro-2-(2-hetarylidene)-3-oxohexanenitriles with amines was studied. It was shown that the reaction of primary aliphatic amines with 6-chloro-2-(2-hetarylidene)-3-oxohexanenitriles takes place through a stage involving the formation of 2-hetaryl-2-(tetrahydrofuran-2-ylidene)acetonitriles followed by opening of the furanylidene fragment of the latter and the formation of 2-(2-hetaryl)-6-hydroxy-3-(R-amino)-2-hexenenitriles.

KDP crystals with incorporated molecules of the luminophore 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (SPA) were grown from KH 2 PO 4 solutions by the temperature lowering method. The luminescence spectra of KDP/SPA crystals and SPA solutions in distilled water and in KH 2 PO 4 solutions, were studied. The increase of the dye content gives rise to excimer luminescence in the solutions and in KDP crystals, which is due to the formation of associated dye molecules. SPA molecules possessing negative electrostatic potential are incorporated into the pyramidal growth sector of KDP crystal.

The reactions of SnCl4 with picolinoylhydrazones of 2-hydroxybenz-(2-hydroxynaphth)aldehydes (H2Ps, H2Pnf) in CH3OH gave non-electrolyte complexes [SnCl3(Ps · H)] · CH3OH (I) and [SnCl3(Pnf · H)] · CH3OH (II). The imide form of the ligand coordinated to Sn(IV) through the azomethine nitrogen atom and oxyazine and oxy oxygen atoms was proved by UV/Vis, IR, and 1H NMR spectroscopy. The negative charge on the coordination unit thus arising is counterbalanced by the positive charge caused by the protonation of ligands at the pyridine nitrogen atom of the heterocycle. It was shown that dehydrochlorination of the complexes affords tin-containing species, which correlates with the presence of the corresponding peaks [SnCl2(Ps)]+ and [SnCl2(Pnf)]+ in their mass spectra. The molecular and crystal structures of complexes I and II were determined by X-ray diffraction.