Crystal structure and Hirshfeld surface analysis of (Z)-4-({[2-(benzo[b]thio-phen-3-yl)cyclo-pent-1-en-1-yl]meth-yl}(phen-yl)amino)-4-oxobut-2-enoic acid.

In the title compound, C24H21NO3S, the cyclopentene ring adopts an envelope conformation. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming ribbons along the a axis. Inter-molecular C-H⋯O hydrogen bonds connect these ribbons to each other, forming layers parallel to the (01) plane. The mol-ecular packing is strengthened by van der Waals inter-actions between the layers. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 46.0%, C⋯H/H⋯C 21.1%, O⋯H/H⋯O 20.6% and S⋯H/H⋯S 9.0%.

Application of the intramolecular Diels-Alder vinylarene (IMDAV) reaction for the synthesis of benzo-, carbocyclo-, thienothiopheneisoindolecarboxylic acids and its limitations.

Thienylallylamines, readily accessible from the corresponding thienyl aldehydes, react with maleic and trifluoromethylmaleic anhydrides leading to the formation of acids with a thieno[2,3-f]isoindole core. The reaction sequence involves two successive steps: acylation of the nitrogen atom of the initial allylamine and the intramolecular Diels-Alder vinylarene (IMDAV) reaction. The scope and limitations of the proposed method were thoroughly investigated. It has been revealed with the aid of X-ray analysis and DFT calculations that the key step, the IMDAV reaction, proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. The obtained functionally substituted thieno[2,3-f]isoindole carboxylic acids are potentially useful substrates for further transformations and bioscreening. The antimicrobial evaluation of the obtained compounds revealed that 1-oxo-2-(3-(trifluoromethyl)phenyl)hexahydrobenzo[4,5]thieno[2,3-f]isoindole-10-carboxylic acid is the most active sample in the synthesized library. It exhibits antibacterial activity against sensitive strains of Gram-positive bacteria, including S. aureus, Enterococcus faecium, Bacillus cereus, and Micrococcus luteus, as well as the Gram-negative bacteria E. coli and Pseudomonas fluorescens, with MIC values ranging from 4 to 64 µg mL-1. 9-Oxo-8-phenyloctahydronaphtho[2,1-d]thieno[2,3-f]isoindole-10-carboxylic acid showed antifungal activity against yeast culture C. albicans with a MIC value of 32 µM.

Crystal structure of [1,3-bis-(2,4,6-tri-methyl-phen-yl)imidazolidin-2-yl-idene]di-chlorido-(2-{[(2-methoxyeth-yl)(meth-yl)amino]-meth-yl}benzyl-idene)ruth-en-ium.

The title compound, [RuCl2(C33H43N3O)], is an example of a new generation of N,N-dialkyl ruthenium catalysts with an N-Ru coordination bond as part of a six-membered chelate ring. The Ru atom has an Addison τ parameter of 0.244, which indicates a geometry inter-mediate between square-based pyramidal and trigonal-bipyramidal. The complex shows the usual trans arrangement of the two chlorides, with Ru-Cl bond lengths of 2.3515 (8) and 2.379 (7) Å, and a Cl-Ru-Cl angle of 158.02 (3)°. One of the chlorine atoms and the atoms of the 2-meth-oxy-N-methyl-N-[(2-methyl-phen-yl)meth-yl]ethane-1-amine group of the title complex display disorder over two positions in a 0.889 (2): 0.111 (2) ratio.

Influence of the organic cation on the formation of hexahalotechnetates: X-ray, thermal and comparative analyses of non-covalent interactions.

In this work, we have reviewed non-covalent interactions in technetium hexahalide compounds and obtained eight new compounds of the CatnTcHal6 type, where Cat = dimethylammonium, tetramethylammonium, caffeinium, benzothiazolium, nicotinamidium, and pyrazolium, and Hal = Cl, Br. SCXRD studies were carried out for new compounds. In some compounds, halide anions and/or crystallization water were present. In the compounds obtained, an essential influence on the formation of structures and crystal packing is exerted by the molecules of crystallization water and halide ions. Diethylammonium and nicotinamidium compounds, whose structures do not contain other ions and contain sufficiently strong non-covalent interactions, best bind hexahalotechnetates. π-Stacking interactions, anion-π interactions, and halogen bonds were found in the structures. The percentage contribution of the H⋯Hal/Hal⋯H interactions in the transition from fluorine to bromine in TcHal62- anions decreases, while the contribution of interactions of other types increases. The greatest variety of interactions in anions is observed for compounds of caffeinium and nicotinamidium with TcBr62-. The paper considers the processes of thermolysis of some new and previously known CatnTcHal6 compounds with various cations. It is shown that the thermal stability of the compounds is only due to the properties of the organic cation and does not depend on the nature of the halogen. The proposed stages of the process of thermolysis of the TcHal62- anion, accompanied by the reduction of technetium to metal, have been established.

Domino Three-Component N-Acylation/[4 + 2] Cycloaddition/Alder-ene Synthesis of Polysubstituted Benzo[f]isoindole-4-carboxylic Acids.

Diversely substituted, partially saturated benzo[f]isoindole-4-carboxylic acids were synthesized by a new three-component reaction (3CR) starting from cinnamic amines (3-arylallylamines), maleimides, and maleic anhydride. The process consists of N-acylation of the amines by maleic anhydride, intramolecular [4 + 2] cycloaddition in vinylarenes (the IMDAV reaction), and the concluding Alder-ene reaction between Diels-Alder intermediates and maleimides. All of the reaction steps proceed in a highly regio- and stereoselective manner, furnishing five adjacent chiral centers and leading to a single diastereoisomer of the title compound. The efficiency of the transformation is secured by thermal conditions or utilization of soft Lewis acids (Yb(OTf)3) as catalysts. The kinetics and mechanism of the 3CR were studied by using dynamic 19F NMR. Based on the NMR data and density functional theory (DFT) calculations, the IMDAV, not the Alder-ene, reaction is the rate-limiting step of the entire process.

Intramolecular Re···O Nonvalent Interactions as a Stabilizer of the Polyoxorhenate(VII).

The first polyoxorhenate(VII) compound, pyrazolium polyoxorhenate ((C4N2H5)2Re4O15), and two new rhenium(VII) and technetium(VII) salts have been synthesized and studied. The structure of Tc2O7 has been reinvestigated. The [Re4O15]2- polyoxoanion contains four Re(VII) atoms: one with an octahedral environment and three with a tetrahedral environment. Polyoxorhenate is formed in the presence of a buffering agent, pyrazole, the latter maintaining pH = 2.5 during the formation of crystals. The [Re4O15]2- polyoxoanion has novel stoichiometry and the cis-conformation, likely due to the stabilizing intramolecular nonvalence interactions. For the first time, intramolecular interactions of the Re···O, Re···µ-O, and O···O are described (previously known were only intermolecular ones). In all of the compounds, intermolecular Re···O interactions are observed, which, however, in other compounds, do not lead to the formation of polyoxometalates. The Hirshfeld surface analysis showed that the main contribution to intermolecular interactions is made by the O···H/H···O contacts, van der Waals interactions of the H···H for cations, and the O···O for anions. DFT calculations of the [Re4O15]2- geometry, compared with the crystallographic data, revealed a deviation in the angles. Mass spectroscopy of the red polyoxometalate [Tc20O68]4- was carried out for the first time. Comparison of the results of MALDI and LI for the first known polyoxometalates of the manganese subgroup made it possible to find general patterns of oligomerization for rhenium and technetium compounds. The ESI-MS and LI-MS methods applied to solution and crystals Re compounds made it possible to prove rhenium being able to form not only [Re4O15]2- but also heavier polyoxoanions.

Crystal structures and Hirshfeld surface analyses of N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol tribromide (1/1), N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1) and N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1).

In the title compounds, N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol tribromide (1/1), C4H9NO·C4H10NO+·Br3 - or [(C4H9NO)·(C4H10NO)](Br3), (I), N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1), C4H9NO·C4H10NO+·Br2I- or [(C4H9NO)·(C4H10NO)](Br2I), (II), and N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1), C4H9NO·C4H10NO+·Cl2I- or [(C4H9NO)·(C4H10NO)]·(Cl2I), (III), all the anions are almost linear in geometry and all the cations, except for the methyl H atoms, are essentially planar. In the crystal structure of (I), the cations are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. These dimers also exhibit O-H⋯O hydrogen bonding. Dimerized cation pairs and anions are arranged in columns along the a axis. In the crystal of (II), the cations are linked by pairs of O-H⋯O and C-H⋯O hydrogen bonds, forming an R 4 4(14) ring motif. These groups of cations and the anions form individual columns along the a axis and jointly reside in planes roughly parallel to (011). In the crystal of (III), cations and anions also form columns parallel to the a axis, resulting in layers parallel to the (020) plane. Furthermore, the crystal structures of (I), (II) and (III) are consolidated by strong halogen (Br and/or I and/or Cl)⋯H and weak van der Waals inter-actions. In addition to the structural evaluation, a Hirshfeld surface analysis was carried out.

Synthesis, crystal structure and Hirshfeld surface analysis of bis-(caffeinium) hexa-chlorido-platinum(IV) in comparison with some related compounds.

The mol-ecular and crystal structure of the title compound, (C8H11N4O2)2[PtCl6], synthesized from hexa-chloro-platinic acid and caffeine in methanol, was studied by single-crystal X-ray diffraction. The caffeinium cations form a double layer via hydrogen bonds and π-stacking inter-actions. The Hirshfeld surface analysis showed that the largest contribution to the crystal packing is made by H⋯H (31.2%), H⋯Cl/Cl⋯H (22.6%), O⋯H/H⋯O (21.9%) contacts for the cation and H⋯Cl/Cl⋯H (79.3%) contacts for the anion.

Mixed-Valence NpV/AnVI Molybdate Complexes with Single-Charge Outer-Sphere Cations.

Five new mixed-valence NpV/AnVI molybdates of the composition [C(NH2)3]3[(NpVO2)(NpVIO2)(MoO4)3(H2O)]·H2O (1), [C(NH2)3]3[(NpVO2)(NpVIO2)(MoO4)3(H2O)]·3H2O (2), Na3[(NpVO2)(PuVIO2)(MoO4)3(H2O)]·nH2O (3), Na6[(NpVO2)2(UVIO2)(MoO4)5]·13H2O (4), and LiNa2[(NpVO2)(NpVIO2)2(MoO4)4(H2O)]·4H2O (5) have been synthesized and structurally characterized. The coordination polyhedra of the NpV and AnVI atoms in compounds 1-5 are pentagonal bipyramids. The basis of structures 1-3 is anionic layers of the composition [(NpVO2)(AnVIO2)(MoO4)3(H2O)]n3n-. Three crystallographically independent molybdate ions are tridentate-bridging ligands. The water molecule, which is a part of the anion layer, is coordinated to the NpV atom. The anionic layers in complexes 2 and 3 have the same structure, different from 1. The basis of structure 4 is anionic layers of the composition [(NpVO2)2(UVIO2)(MoO4)5]n6n-, the structure of which differs from the structure of anionic layers in 1-3. Complex 5 has a three-dimensional (3D) structure. The spectra of all compounds in the UV-visible and IR ranges were measured and analyzed.

Crystal structure and Hirshfeld surface analysis of (22 RS,23 SR,25 RS,26 SR)-23,25,5-trimethyl-21-(2,2,2-tri-fluoro-acet-yl)-5-aza-2(2,6)-piperidina-1,3(2,5)-di-furana-cyclo-hexa-phan-24-one.

The title compound, C20H21F3N2O4, features a main twelve-membered difuryl ring with which the furan rings make dihedral angles of 76.14 (5) and 33.81 (5)°. The dihedral angle between the furan rings is 42.55 (7)°. The six-membered nitro-gen heterocycle has a twist-boat conformation. In the crystal, pairs of mol-ecules are connected by inter-molecular C-H⋯O inter-actions, generating an R 2 2(14) ring motif. These pairs of mol-ecules form zigzag chains along the a-axis direction by means of C-H⋯F inter-actions. Furthermore, C-H⋯π and C-F⋯π inter-actions link the mol-ecules into chains along the b-axis direction, forming sheets parallel to the (001) plane. These sheets are also connected by van der Waals inter-actions.

Influence of Substituents in a Six-Membered Chelate Ring of HG-Type Complexes Containing an N→Ru Bond on Their Stability and Catalytic Activity.

An efficient approach to the synthesis of olefin metathesis HG-type catalysts containing an N→Ru bond in a six-membered chelate ring was proposed. For the most part, these ruthenium chelates can be prepared easily and in high yields based on the interaction between 2-vinylbenzylamines and Ind II (the common precursor for Ru-complex synthesis). It was demonstrated that the increase of the steric volume of substituents attached to the nitrogen atom and in the α-position of the benzylidene fragment leads to a dramatic decrease in the stability of the target ruthenium complexes. The bulkiest iPr substituent bonded to the nitrogen atom or to the α-position does not allow the closing of the chelate cycle. N,N-Diethyl-1-(2-vinylphenyl)propan-1-amine is a limiting case; its interaction with Ind II makes it possible to isolate the corresponding ruthenium chelate in a low yield (5%). Catalytic activity of the synthesized complexes was tested in RCM reactions and compared with α-unsubstituted catalysts obtained previously. The structural peculiarities of the final ruthenium complexes were thoroughly investigated using XRD and NMR analysis, which allowed making a reliable correlation between the structure of the complexes and their catalytic properties.

New Preparative Approach to Purer Technetium-99 Samples-Tetramethylammonium Pertechnetate: Deep Understanding and Application of Crystal Structure, Solubility, and Its Conversion to Technetium Zero Valent Matrix.

99Tc is one of the predominant fission products of 235U and an important component of nuclear industry wastes. The long half-life and specific activity of 99Tc (212,000 y, 0.63 GBq g-1) makes Tc a hazardous material. Two principal ways were proposed for its disposal, namely, long-term storage and transmutation. Conversion to metal-like technetium matrices is highly desirable for both cases and for the second one the reasonably high Tc purity was important too. Tetramethylammonium pertechnetate (TMAP) was proposed here as a prospective precursor for matrix manufacture. It provided with very high decontamination factors from actinides (that is imperative for transmutation) by means of recrystallisation and it was based on the precise data on TMAP solubility and thermodynamics accomplished in the temperature range of 3-68 °C. The structure of solid pertechnetates were re-estimated with precise X-ray structure solution and compared to its Re and Cl analogues and tetrabutylammonium analogue as well. Differential thermal and evolved gas analysis in a flow of Ar-5% H2 gas mixture showed that the major products of thermolysis were pure metallic technetium in solid matrix, trimethylammonium, carbon dioxide, and water in gas phase. High decontamination factors have been achieved when TMAP was used as an intermediate precursor for Tc.

Microbial methane cycling in sediments of Arctic thermokarst lagoons.

Thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release in Arctic permafrost landscapes. We studied the fate of methane (CH4 ) in sediments of a thermokarst lagoon in comparison to two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia through the analysis of sediment CH4 concentrations and isotopic signature, methane-cycling microbial taxa, sediment geochemistry, lipid biomarkers, and network analysis. We assessed how differences in geochemistry between thermokarst lakes and thermokarst lagoons, caused by the infiltration of sulfate-rich marine water, altered the microbial methane-cycling community. Anaerobic sulfate-reducing ANME-2a/2b methanotrophs dominated the sulfate-rich sediments of the lagoon despite its known seasonal alternation between brackish and freshwater inflow and low sulfate concentrations compared to the usual marine ANME habitat. Non-competitive methylotrophic methanogens dominated the methanogenic community of the lakes and the lagoon, independent of differences in porewater chemistry and depth. This potentially contributed to the high CH4 concentrations observed in all sulfate-poor sediments. CH4 concentrations in the freshwater-influenced sediments averaged 1.34 ± 0.98 µmol g-1 , with highly depleted δ13 C-CH4 values ranging from -89‰ to -70‰. In contrast, the sulfate-affected upper 300 cm of the lagoon exhibited low average CH4 concentrations of 0.011 ± 0.005 µmol g-1 with comparatively enriched δ13 C-CH4 values of -54‰ to -37‰ pointing to substantial methane oxidation. Our study shows that lagoon formation specifically supports methane oxidizers and methane oxidation through changes in pore water chemistry, especially sulfate, while methanogens are similar to lake conditions.

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes.

This paper presents synthetic methods for the preparation of Tc(III) and Tc(IV) coordination compounds with thiourea. We have shown that the main product of the synthesis is the complex [TcTu5X]X2, (Tu = (NH2)2CS, X = Cl, Br) and not [TcTu6]Cl3·4H2O, as previously thought. Tu2[TcX6]X2·3H2O is the main technetium-containing byproduct of the reaction. All reaction products, including byproducts, were characterized by X-ray diffraction analysis. We also measured the solubility for the obtained Tc(III) complexes. This research work considers the process of thermolysis of the obtained Tc(III) complexes and shows that the presence of sulfur atoms in the coordination sphere can inhibit the process of metal formation in an argon-hydrogen medium. The analysis of nonvalent interactions in Tc(III) complexes showed that the main contribution is made by van der Waals interactions of the H···H type (40.8-42.3%) and hydrogen bonds Hal···H/H···Hal and H···S/S···H, which are 41.6-44.5% in total. As the temperature decreases, the proportion of H···H contacts and H bonds decreases, and when the halogen (Cl by Br) is replaced, the proportion of H bonds increases and the proportion of van der Waals interactions decreases.

Crystal structure and Hirshfeld surface analysis of 10-hy-droxy-2-(4-meth-oxy-phen-yl)-3-oxo-2,3,3a,4,10,10a-hexa-hydro-1H-9-thia-2-aza-cyclo-penta-[b]fluorene-4-carb-oxy-lic acid dimethyl sulfoxide-d6 monosolvate.

In the title compound, C22H19NO5S·C2D6OS, the central six-membered ring has a slightly distorted boat conformation, while the fused pyrrolidine ring adopts an envelope conformation. These conformations are stabilized by O-H⋯O hydrogen bonds between the main compound and solvent mol-ecules. In addition, intra-molecular C-H⋯O hydrogen bonds in the main mol-ecule form two S(6) rings. Mol-ecules are connected by pairs of inter-molecular C-H⋯O hydrogen bonds, forming dimers with a R 2 2(8) motif. These dimers form a three-dimensional network through O-H⋯O, O-H⋯S and C-H⋯O hydrogen bonds with each other directly and through solvent mol-ecules. In addition, weak π-π stacking inter-actions [centroid-to-centroid distances = 3.9937 (10) and 3.9936 (10) Å, slippages of 2.034 and 1.681 Å] are observed. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 41.7%, O⋯H/H⋯O 27.7%, C⋯H/H⋯C 17.0%, and S⋯H/H⋯S 7.5%.

Different Modes of Acid-Promoted Cyclooligomerization of 4-(4-Thiosemicarbazido)butan-2-one Hydrazone: 14-Membered versus 28-Membered Polyazamacrocycle Formation.

Unprecedented self-assembly of a novel 14-membered cyclic bis-thiosemicarbazone or/and a 28-membered cyclic tetrakis-thiosemicarbazone upon acid-promoted cyclooligomerization of 4-(4-thiosemicarbazido)butan-2-one hydrazone has been discovered. A thorough study of the influence of various factors on the direction of macrocyclization provided the optimal conditions for the highly selective formation of each of the macrocycles in excellent yields. Plausible pathways for macrocyclizations have been discussed. The macrocycle precursor was prepared by the reaction of readily available 4-isothiocyanatobutan-2-one with an excess of hydrazine.

Novel Synthesis Methods of New Imidazole-Containing Coordination Compounds Tc(IV, V, VII)-Reaction Mechanism, Xrd and Hirshfeld Surface Analysis.

In this work, we have proposed two new methods for the synthesis of [TcO2L4]+ (where L = imidazole (Im), methylimidazole (MeIm)) complexes using thiourea (Tu) and Sn(II) as the reducing agents. The main and by-products of the reactions were determined, and possible reaction mechanisms were proposed. We have shown that the reduction of Tc(VII) with thiourea is accompanied by the formation of the Tc(III) intermediate and further oxidation to Tc(V). The reaction conditions' changing can lead to the formation of Tc(VII) and Tc(IV) salts. Seven new crystal structures are described in this work: Tc(V) complexes, salts with Tc(VII) and Tc(IV) anions. For the halide salts of Tu the cell parameters were determined. In all of the obtained compounds, except for [TcO2(MeIm)4]TcO4, there are π-stacking interactions between the aromatic rings. An increase in the anion size lead to weakening of the intermolecular interactions. The halogen bonds and anion-π interactions were also found in the hexahalide-containing compounds. The Hirshfeld surface analysis showed that the main contribution to the crystal packing is created by the van der Waals interactions of the H···H type (42.5-55.1%), H···C/C···H (17.7-21.3%) and hydrogen bonds, which contribute 15.7-25.3% in total.

Nucleophilic Substitution Reactions in the [B3H8]- Anion in the Presence of Lewis Acids.

As a result of our study on the interaction between the octahydrotriborate anion with nucleophiles (Nu = THF, Ph3P, Ph2P-(CH2)2-PPh2 (dppe), Ph3As, Et3N, PhNH2, C5H5N, CH3CN, Ph2CHCN)) in the presence of a wide range of Lewis acids (Ti(IV), Hf(IV), Zr(IV), Al, Cu(I), Zn, Mn(II), Co(II) halides and iodine), a number of substituted derivatives of the octahydrotriborate anion [B3H7Nu] are obtained. It is found that the use of TiCl4, AlCl3, ZrCl4, HfCl4, CuCl and iodine leads to the highest product yields. In this case, it is most likely that the reaction proceeds through the formation of an intermediate [B3H7-HMXnx], which was detected by NMR spectroscopy. The structures of [Ph3P·B3H7] and [PhNH2·B3H7] were determined by X-ray diffraction.

Synthesis, crystal structure and Hirshfeld surface analysis of 2-(perfluoro-phen-yl)acetamide in comparison with some related compounds.

The mol-ecular and crystal structures of the title compound, C8H4F5NO, were examined by single-crystal X-ray diffraction and Hirshfeld surface analysis. The title compound was synthesized by a new method at the interface of aqueous solutions of LiOH and penta-fluoro-phenyl-aceto-nitrile. In the crystal, hydrogen bonds and π-halogen inter-actions connect the mol-ecules into double layers. Analysis of the Hirshfeld surface showed that the most important contributions to the crystal packing are made by F⋯F (30.4%), C⋯F/F⋯C (22.9%), O⋯H/H⋯O (14.9%), H⋯F/F⋯H (14.0%) and H⋯H (10.2%) contacts. The Hirshfeld surfaces of analogues of the title compound were compared and the effect of perfluorination on the crystal packing was shown.

Primary Amine Nucleophilic Addition to Nitrilium Closo-Dodecaborate [B12H11NCCH3]-: A Simple and Effective Route to the New BNCT Drug Design.

In the present work, a convenient and straightforward approach to the preparation of borylated amidines based on the closo-dodecaborate anion [B12H11NCCH3NHR]-, R=H, Alk, Ar was developed. This method has two stages. A nitrile derivative of the general form [B12H11NCCH3]- was obtained, using a modified technique, in the first stage. On the second stage the resulting molecular system interacted with primary amines to form the target amidine products. This approach is characterised by a simple chemical apparatus, mild conditions and high yields of the final products. The mechanism of the addition of amine to the nitrile derivative of the closo-dodecaborate anion was studied, using quantum-chemical methods. The interaction between NH3 and [B12H11NCCH3]- ammonia was chosen as an example. It was found that the structure of the transition state determines the stereo-selectivity of the process. A study of the biological properties of borylated amidine sodium salts indicated that the substances had low toxicity and could accumulate in cancer cells in significant amounts.