A series of adamantane-based amino acid derivatives incorporating γ-aminobutyric acid (GABA) as a spacer, with the general structure Ad-CH2-CO-GABA-X-OMe (where X represents L-tryptophan (Trp), L-histidine (His), H-Ala-((S)-2-oxopyrrolidin-3-yl)-OMe (Pld), or L-methionine (Met)), were synthesized and evaluated in vitro for their antiviral activity against rimantadine-resistant influenza A virus strains A/Moscow/78/2020(H1N1)pdm09 and A/Cheboksary/125/2020(H1N1)pdm09. The results demonstrated that the presence of an L-tryptophan residue is crucial for effective inhibition of influenza virus replication, with the corresponding derivative exhibiting potent activity at an IC50 of 0.5 µg/mL. A comparative analysis of structural features and antiviral properties was conducted between the adamantane derivatives and analogous derivatives of the closo-decaborate anion ([B10H10]2-) functionalized with identical amino acid residues Na2[B10H9-O(CH2)2O(CH2)3C(O)-X-OCH3] (X = Trp, His) and spacers of comparable length. This study suggests that combining adamantane-based compounds with closo-decaborate clusters could lead to the development of highly effective therapeutic compositions with enhanced efficacy and improved safety profiles.

The coordination behavior of neutral azaheterocyclic carboxylic acids (HQln is quinoline-2-carboxylic acid, HQox is quinoxaline-2-carboxylic acid) with silver(I) in the presence of the decahydro-closo-decaborate anion has been systematically investigated. The structural diversity of the resulting complexes is governed by a delicate interplay between the acid-base properties of the organic ligand and the coordination ability of the boron cluster. For the boron cluster anions, HQln acts as a neutral bidentate ligand, forming coordination polymer [Ag2(DMF) (HQln)[B10H10]] sustained by Ag center dot center dot center dot H-B interactions. In contrast, the more acidic HQox can form either a coordination polymer with the neutral ligand, [Ag2(HQox)2[B10H10]] or a known 3D-framework with the deprotonated Qox- anion, {Ag6[B10H10]Qox4}m, depending on concentration of the auxiliary organic ligand. Replacing the boron hydride cluster with chlorinated analogs [BnCln]2- (n = 10, 12), which are weaker coordinating anions, results in silver cationic complexes [Ag(HQln)2]+ with boron clusters as counterions [Ag(HQln)2]2[BnCln] (n = 10, n = 12) isolated as DMF solvates. The structures of all compounds were determined by single-crystal X-ray diffraction, and the factors controlling the product formation are discussed.

A series of novel substituted derivatives of the closo-decaborate anion [B10H10]2− bearing alkoxy spacer chains of varying length derived from ring-opened crown ethers (12-crown-4, 15-crown-5, and 18-crown-6) with pendant L-amino acid methyl ester residues (L-tryptophan and L-histidine) have been synthesized. The synthetic approach involved the nucleophilic ring-opening of oxonium crown ether derivatives of the closo-decaborate anion followed by coupling with amino acid methyl esters via mixed anhydride activation. The obtained compounds were characterized by multinuclear NMR spectroscopy (1H, 11B, 13C), IR spectroscopy, elemental analysis, and electrospray ionization mass spectrometry (ESI-MS). The compounds were obtained as sodium salts and evaluated for their in vitro cytotoxic and antiviral properties against the influenza A virus strain A/Moscow/78/2020 (H1N1)pdm09, which contains the S31N mutation conferring resistance to adamantane-class drugs. Cytotoxicity was assessed on MDCK cells, and antiviral activity was determined by cell ELISA. The results revealed a clear structure–activity relationship: the length of the alkoxy spacer chain significantly influenced both antiviral activity and selectivity. The shortest spacer (derived from 12-crown-4) proved to be optimal, while elongation of the chain led to a decrease in antiviral potency. The compound containing a 12-crown-4-derived spacer and a tryptophan methyl ester residue exhibited the highest selectivity index (SI = 155) with low cytotoxicity (CC50 = 155 µg/mL) and high antiviral activity (IC50 = 1.0 µg/mL). Tryptophan-containing derivatives consistently outperformed their histidine analogues, confirming the key role of the indole side chain in antiviral activity. Overall, the closo-decaborate platform with crown ether-derived spacers and amino acid ester pendant groups represents a promising scaffold for the development of low-toxicity, highly selective inhibitors of influenza A virus replication. The compound with the 12-crown-4-derived spacer and a tryptophan methyl ester residue merits further investigation as the most promising among the synthesized samples.

The nature of the chalcogen atom (S vs. Se) in Ag( i ) triphenylphosphine chalcogenide complexes was found to be a critical factor governing their reactivity toward 2,2′-bipyridine, leading to mononuclear or tetranuclear products.

In this work, Ag[1,2-B12H10(NH3)(OH)] was first isolated and their complexation was studied with a number of N-and O-donor ligands, including Me2CO, MeOH, MeCN, Me2SO, and ethylenediamine. It was found that Me2CO and MeOH are not involved in the metal coordination, and homoleptic complexes {Ag[1,2-B12H10(NH3)(OH)]}center dot Me2CO (1) and {Ag[1,2-B12H10(NH3)(OH)]}center dot MeOH (2) were isolated with solvated organic molecules. Acetonitrile and dimethylsulfoxide form heteroleptic complexes {(Ag(MeCN)[1,2-B12H10(NH3)(OH)])(Ag[1,2-B12H10(NH3)(OH)])}n (3) and{(DMSO)2Ag[1,2-B12H10(NH3)(OH)]}2 (4) with both the boron cluster and organic ligands being coordinated. Ethylenediamine form polymeric cationic silver complex with boron clusters as counterions{[(Ag(en)][1,2-B12H10(NH3)(OH)]}n center dot nDMF (5). Structures of compounds 1-5 were determined by single-crystal X-ray diffraction.

Ag 2 [B 10 H 10 ] and Tl 2 [B 10 H 10 ] belong to the family of closo -hydroborates which are considered as promising solid electrolytes for battery applications.

Ag2[B10H10] and Tl2[B10H10] belong to the family of closo-hydroborates which are considered as promising solid electrolytes for battery applications. To study the dynamical properties of these compounds at the microscopic level, we have measured the 1H, 11B, and 205Tl nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates over the temperature range of 80-545 K. For both compounds, our measurements have revealed fast reorientational motion of the [B10H10]2- anions. The reorientational jump rates are found to reach ∼108 s-1 near 380 K for Ag2[B10H10] and near 480 K for Tl2[B10H10]. This reorientational motion is characterized by the activation energies of 352 (18) meV and 685 (40) meV, respectively. For Tl2[B10H10], our experiments have not revealed any effects of long-range translational cation mobility at the NMR frequency scale up to 500 K.

A novel synthetic methodology for the preparation of amino-substituted derivatives of the octahydrotriborate anion has been developed, based on the direct reaction of the [B3H8]- anion with amine hydrochlorides. Additionally, the established approach involving the formation of the key [B3H7THF] intermediate in toluene, using zirconium(IV) chloride as a halide source, has been significantly optimised. These advanced strategies enabled the synthesis of a comprehensive series of previously inaccessible substituted triborane derivatives with various diamines [B3H7Nu], where Nu is ethylenediamine, 1,2-propylenediamine, N,N-dimethylethylenediamine (DMEDA), N,N-diethylethylenediamine (DEEDA), 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, o-phenylenediamine (OPDA) and N-phenyl-1,2-phenylenediamine. The versatility of these compounds was further demonstrated through their conversion to stable protonated salts. The molecular structures of four representative examples-[B3H7NH2C6H11], [B3H7NH2(C6H4)NHC6H5], [B3H7NH2C2H4NH(C2H5)2]Cl and [B3H7NH2C3H6NH(CH3)2]I and the monoborane byproduct [BH2(CyNH2)2]Cl-were unambiguously determined by single-crystal X-ray diffraction, providing definitive structural insight into this new class of boron-nitrogen compounds and confirming the coordination mode and supramolecular architecture.

The complexation of iron(II)/iron(III), cobalt(II), and nickel(II) with 1,10-phenanthroline (phen) in the presence of the highly chlorinated boron cluster anion [B12Cl12]2-was investigated. The reactions of FeCl2 and NiCl2 with phen (1:3 ratio) readily form the stable tris-chelate complexes [M(phen)3][B12Cl12] (M = Fe (1), Ni (2)), which were isolated and characterized by X-ray diffraction. In contrast to the reducing behavior of [BnHn]2-anions (n = 10, 12), the [B12Cl12]2-anion does not reduce iron(III), allowing for the first isolation of a stable iron(III) complex with a polyhedral borane counterion. Specifically, the reaction of FeCl3 with phen (1:2 ratio) yielded the binuclear mu-oxo complex [Cl(phen)2FeOFe(phen)2Cl][B12Cl12] (3). Surprisingly, all attempts to form analogous tris-chelate cobalt(II) complex with [B12Cl12]2-were unsuccessful, resulting only in the precipitation of known cobalt phenanthroline chlorides or nitrates, while the borate salt remained unreacted. This inertness was confirmed by direct mixing experiments and reactions with cobalt(III) ammine complexes. However, the hydroxyl-functionalized analog, [B12Cl10(OH)2]2-, effectively formed the ion-pair complex [Co(phen)3][B12Cl10(OH)2] (4). The results highlight a stark difference in the coordinating and crystallizing ability of [B12C12]2-compared to its well-studied hydride analogs and less chlorinated counterparts, underscoring the critical role of the anion hydrophobicity and specific functionalization in stabilizing metal complexes and their rapid precipitation from the reaction solution.

The emergence of drug-resistant influenza virus strains necessitates the development of novel antiviral agents with unique mechanisms of action. This study presents the synthesis and in vitro evaluation of a new class of antiviral compounds: sodium salts of amino acid ester conjugates based on the closo-dodecaborate anion [B12H12]2−, linked via a tetrahydropyran-derived spacer (Na2[B12H11O(CH2)6C(O)X], where X = L-Trp-OMe (Na22); L-His-OMe (Na23); L-Met-OMe (Na24); Pld-OMe (Na25)). The antiviral activity was assessed against contemporary, multidrug-resistant influenza A virus strains, including A/Cheboksary/125/2020 (H1N1)pdm09 and A/IIV-Orenburg/83/2012 (H1N1)pdm09. Cross-platform comparison revealed that the dodecaborate-tryptophan conjugate Na22 exhibited comparable efficacy to its lead decaborate analog against the Orenburg strain while demonstrating potent activity (IC50 = 5.0 µg/mL) against the Cheboksary strain with reduced susceptibility to neuraminidase inhibitors (oseltamivir; zanamivir) and complete resistance to M2 channel blockers. The histidine-based conjugate Na23 also showed significant efficacy against the Cheboksary strain, while methionine and lactam derivatives (Na24; Na25) remained inactive. This work confirms boron clusters as versatile platforms for antiviral development and establishes structure–activity relationships crucial for optimizing both B10 and B12-based therapeutics against resistant influenza strains.

In this work, two-layer cermet composites based on TiB-(20, 30 and 40 wt%)Ti were obtained from the initial powder components of titanium and boron using the free Self-Propagating High-Temperature Synthesis (SHS) compression method, which combines combustion in the mode of self-propagating high-temperature synthesis and shear deformation of combustion products. The combustion characteristics of selected compositions and the temperature profiles arising at the interface between the cermet layer and the titanium layer were studied. The general rules of the effect of the initial composition of cermet composites and technological parameters of free SHS compression on the phase composition, structure, and mechanical properties were established. Tribological tests of the surface and cross-section of the obtained cermet composites of the studied compositions were carried out depending on the orientation of titanium monoboride whiskers in the volume of the sample. Dependence of the friction coefficient on the travel length of the counterbody and 3D images of wear grooves are provided. The interface between cermet and Ti layers was studied. It was shown that this interface is formed due to diffusion and convective mixing of synthesis products and melt of the surface of the titanium layer. Bending tests of the resulting two-layer cermet composites showed that fracture does not occur at the cermet/Ti interface, which qualitatively indicates good adhesive strength between the layers. It was established that after melting and crystallization, the titanium layer consists of two modifications: alpha-Ti and a small amount of beta-Ti, the presence of which leads to an increase in the hardness of the layer up to 1.5 times.

Silver(I) complexation with substituted (benzoimidazol-2-yl)methanamines Bz–CH2–NH–R (Bz is 1-methylbenzimidazole, R is anisole (L1) or 1-isopropylbenzimidazole (L2)) in the presence of boron cluster anions [BnHn]2– (n = 10, 12) has been studied for the first time. The influence of substituent R in the benzimidazole derivative on the composition and structure of the resulting compounds has been determined. Coordination compounds [Ag(L1)2]xAn (x = 1, An = Ag[B10H10]mm–; x = 2, An = [B12H12]2–), featuring closo-borate anions in the outer coordination sphere and monodentately coordinated ligands L1, have been synthesized and structurally characterized. Additionally binuclear complexes [Ag2(L2)2[µ-BnHn]] have been obtained, in which L2 is coordinated bidentately, forming a seven-membered metallacycle, while anions [BnHn]2– (n = 10, 12) act as bridging ligands. The structural features of the synthesized compounds have been analyzed, including the coordination mode of the organic ligands and the occurrence of positional and bond isomerism in compounds with coordinated boron cluster anions.

The complexation of Ag2[B12Br12] salts with nitrogen-containing (succinonitrile (L1), propylamine (L2), and dibutylamine (L3)) and oxygen-containing (12-crown-4 (L4)) organic ligands was studied. Compounds [Ag2(mu L1)2(L1)4][B12Br12] (1), [AgL2]2[B12Br12] (L = L2 (2), L3 (3)) and [Ag(L4)2]{Ag[B12Br12]}n (4) were isolated and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction (for 1, 2, 4). The cationic-anionic complex 4 is the first example of an anionic silver(I) complex with coordinated perhalogenated derivative of the boron cluster anion. In addition, the behavior of Ag2[B12Br12] in CH3OH used as a solvent was studied. As a result of recrystallization, polymeric complex {Ag2(CH3OH)4[B12Br12]}n (5) was obtained. As determined by X-ray diffraction, this compound also contains the coordinated [B12Br12]2- anion. Based on the result obtained, possible methods for forming target compounds are concluded.

The process of rearrangement of the octadecahydroeicosaborate anion [trans-B20H18]2- -> [iso-B20H18]2- in various solvents (acetonitrile, DMF, DMSO) under UV irradiation was studied using 11B NMR spectroscopy. It was found that the Hawthorne rearrangement process does not end with the formation of [iso-B20H18]2-. Over the course of several days, the resulting iso-isomer of the octadecahydroeicosaborate anion transitions into a new isomeric form [cross-B20H18]2- , detected by 11B and 11B{1H} COSY NMR spectroscopy. Quantum chemical calculations at the DFT-PBE/L22 level showed that the rearrangement of [trans-B20H18]2-to [iso-B20H18]2occurs in three stages. The maximum Gibbs activation energy along the reaction pathway is 35.6 kcal/mol. The isomerization of [iso-B20H18]2-into [cross-B20H18]2-occurs in a single stage, with the [cross-B20H18]2-isomer being thermodynamically more stable. The structure of [cross-B20H18]2- was determined by single-crystal X-ray diffraction for crystal (Ph4P)2[cross-B20H18]center dot 3CH3CN.

This article proposes carbocyclic derivatives of N-acylated esters of L-amino acids with aromatic carboxylic acids as antiviral small-molecule agents. To increase the water solubility of inhibitors that are insoluble in aqueous solutions, the target compounds were used as zinc(II) complexes. It has been shown that hydrophobic organic compounds in the form of zinc(II)-coordinated ligands are capable of suppressing the replication of the influenza A virus strain resistant to adamantane-type drugs. Zinc(II) chloride at the concentration used does not have antiviral or toxic effects in experiments in vitro.

Abstract The reaction between [Au(Ph3P)Cl] and [B20H18]2– in DMF gave unprecedented heptanuclear cationic cluster [Au7(Ph3P)7@C]2+ isolated as [Au7(Ph3P)7@C][B20H18][Au(Ph3P)Cl]·0.5DMF in one step. The final compound was studied by 11B NMR and IR spectroscopies, ESI MS, single-crystal and powder X-ray diffractions. No special reagents were used to obtain central carbon atom in the cluster [Au7(Ph3P)7@C]2+.

In this study, the complexation of silver(I) with azaheterocyclic ligands (bipy, phen) in the presence of perchlorinated borate anions, [B10Cl10]2– and [B12Cl12]2–, was investigated in acetonitrile. Complexes with the general formula [Ag2L4][BnCln] (L = bipy, phen; n = 10, 12) were successfully isolated. The final compounds were characterized using elemental analysis and IR spectroscopy. The structures of the [Ag2(bipy)4][BnCln] (n = 10, 12) complexes were elucidated via X-ray diffraction (CCDC nos. 2325088, 2358488). It was determined that the compounds consist of either a binuclear cationic silver(I) complex with azaheterocyclic ligands, [Ag2(bipy)4]2+, or two mononuclear complexes, [Ag(bipy)2]22+, with the boron cluster anions forming the anionic part of both complexes. Additionally, weak argentophilic Ag…Ag interactions were observed within the structures.

The discussion has revolved around the derivatives of amino acids and peptides containing carbocycles and their potential antiviral activity in vitro against influenza A, hepatitis C viruses, and coronavirus. Studies conducted on cell cultures reveal that aminoadamantane amino acid derivatives exhibit the capacity to hinder the replication of viruses containing viroporins. Furthermore, certain compounds demonstrate potent virucidal activity with respect to influenza A/H5N1 and hepatitis C virus particles. A conceptual framework for viroporin inhibitors has been introduced, incorporating carbocyclic motifs as membranotropic carriers in the structure, alongside a functional segment comprised of amino acids and peptides. These components correspond to the interaction with the inner surface of the channel's pore or another target protein.

Silver(I) complexation with boron cluster anions [BnHn]2- (n = 10, 12) and chelating 1-substituted-2-aldiminebenzimidazoles 1-(1-methylbenzimidazol-2-yl)-N-phenylmetanimine (L1) and 1-(1-benzylbenzimidazol-2-yl)-Ncyclohexylmethanimine (L2) in systems AgNO3/[BnHn]2- /L and {Ag2[BnHn]}m/L, as well as with azaheterocyclic ligands 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen) in the system AgNO3/[BnHn]2- /L has been first studied. The effect of the organic ligand on the composition and structures of the resulting compounds has been shown. As a result, binuclear complexes [Ag2L2[mu-BnHn]] with bridging boron cluster anions with various combinations of coordination modes (edge-edge and edge-face for the [B10H10]2- anion, edge-atom and nontrivial asymmetric for the [B12H12]2- anion) have been synthesized and structurally characterized for benzimidazole derivatives L1 and L2. When using bipy or phen as ligands, polymeric complexes {Ag2L[B10H10]}m or {Ag2L2[mu-B12H12]}m have been obtained.