The (Bu4N)2[{Mo6I8}(CN)5(OEt)]·2H2O and (Bu4N)2[{W6I8}(CN)4(OEt)2]·H2O·EtOH cluster complexes are prepared by the reaction of (Bu4N)2[{M6I8}I6] (M = Mo, W) with NaCN in ethanol and subsequent recrystallization from an aqueous ethanol solution. The structure of both compounds is determined by XRD. The external ligand environment of the anions contains CN– and OEt– ligands. The behavior of the complexes in an aqueous solution is studied by electron spectroscopy.
The addition of tartrate, oxalate and citrate anions during the one-pot synthesis of 12-MC-4 metallacrown based on β-alaninehydroximate ligands leads, respectively, to dimeric complex Cu10(β-alaha)8 (tartrate)2·10H2O (1) and two one-dimensional coordination polymers, Cu5(β-alaha)4Cu(oxalate)2·8H2O (2) and Cu10(β-alaha)8Cu(citrate)2·19H2O (3). According to X-ray diffraction data for 2 and 3, in the presence of oxalate and citrate anions, infinite chains containing alternating molecules of cationic copper (II) 12 –MC-4 metallacrown and polycarboxylate cuprate anion are formed in crystals. The distance between the metallacrown molecules in the crystal depends significantly on the choice of the initial polycarboxylate anion. In contrast to the oxalate and citrate anions, the dibasic tartrate guest anion does not lead to the formation of endless one-dimensional chains in the crystal. In this case, dimeric complex 1 is formed, for which short Cu–O contacts occur between neighboring 12-MC-4 metallamacrocycles.
The machine learning potential (MLP) is proposed based on the representation of the environment through moment tensors to model the diamond phase nucleation in misoriented bilayer graphene. MLP is trained on a set of graphene structures, 2D diamond, and their hydrogenated modifications obtained by density functional theory computations. Learned MLP accurately reproduces energies and strengths of these structures and correctly describes hydrogenation of bilayer graphene and the formation of interlayer bonds. Growth of the diamond phase in bigraphene with a 5° misorientation of layers is studied using MLP. It is found that the formation energy increases with an increase in the number of hydrogen atoms, which indicates hydrogen cluster nucleation on the surface of bilayer graphene. Hydrogenation of the system leads to the growth of the cubic diamond region up to the AA′ stacking promoting the formation of lonsdaleite with the ((10bar{1}0)) surface. This fact allows us to draw the conclusion about the adequacy of the potential obtained.
Thiocyanate bridged homometallic Ni(II) chains have potential applications in areas such as molecular magnetism and spintronics due to their tunable magnetic properties. The magnetic properties of these chains are of particular interest and can lead to intriguing magnetic behaviors, such as antiferromagnetic or ferromagnetic interactions. In this context, we have successfully synthesized a (text{Ni(NCS)}_{text{6}}^{text{4}-}) bridge Ni(II) chain complex [Ni2(H2L)2(μ1,3-NCS)2(NCS)4]n∙2nCH3CN (1), derived from a tetradentate N3O donor Schiff base ligand (HL). It has been thoroughly characterized by the help of elemental analysis and IR spectroscopy. Single crystal X-ray crystallography has confirmed the geometry of the chain complexes. Both Ni1 and Ni2 centers exhibit hexa-coordination with slightly distorted octahedral geometries, and their coordination environments differ significantly (NiN2O2S2 for Ni1 and NiN6 for Ni2). Within the solid-state structure of the complex, a noteworthy two-dimensional network of hydrogen bonding is observed. The present complex showing a unique example in the realm of single thiocyanato-bridged Ni(II) chains.
The Sr3B2O6–YbBO3 diagram was constructed based on samples obtained by the solid-state synthesis. In the system YbBO3, Sr3Yb(BO3)3, Sr3Yb2(BO3)4 and Sr3B2O6 phases were identified by XRD analysis. Diffusion experiments showed formation of solid solutions between all compounds. These solid solutions demonstrate typical near-infrared luminescence in the range of 960-1020 nm, characteristic of Yb3+ and related to 2F5/2 → 2F7/2 transitions in ytterbium ions.
SiBCN films are synthesized by plasma-enhanced chemical vapor deposition at a reduced pressure and 500-600 °C. Organoelement silicon and boron compounds are selected as precursors, namely, hexamethyldisilazane HN(SiMe3)2 and triethylaminoborane Et3N·BH3 that were not used previously in the synthesis of SiBCN films. Vapor flows of initial compounds and additional gas (ammonia) were separately supplied to the reactor without premixing. The chemical bonding structure, elemental composition, surface morphology, and film deposition rate are studied by FTIR, XPS, wave dispersive X-ray spectroscopy, SEM, and Raman spectroscopy techniques. The surface morphology analysis of the samples shows that the films are smooth, homogeneous, and uniform without features. Variation of precursor concentrations in the initial mixture allows changes in the film composition in a wide range. The boron concentration in four-component coatings reaches 45 at.%. The study of chemical bonding structures of the films reveals the occurrence of Si–C, Si–N, B–N, C–H bonds along with the hybrid BCnN3–n bond.
First example of a Zr(IV) complex with an aromatic carboxyamidate ligand, Zr(mba)4 (mba = N-methoxybenzamidate), is prepared. Its structures in the solution (1H, 13C{1H} NMR) and in the crystal phase (single-crystal XRD) are determined and compared with those of the initial N-methoxybenzamide Hmba. During the complexation, mba– ligands exhibit a bidentate cyclic function through oxygen atoms. The coordination polyhedron of the metal atom is a distorted square antiprism, the lengths of Zr–O bonds with carbonyl and methoxy groups fall within 2.08-2.09 Å and 2.29-2.33 Å, respectively. Despite the presence of available phenyl rings, the Zr(mba)4 and Hmba crystals contain no intermolecular π–π-interactions, but exhibit C–H⋯π and N–H⋯O contacts, respectively. According to the DSC data, Hmba undergoes no phase transitions from 130 K up to the melting point (335.0±0.5 K, ΔH = 15.1±0.1 kJ/mol, ΔS = 45.2±0.2 J/(mol·K)), while Zr(mba)4 exhibits a reversible solid-phase transition (Tonset = 177.4±0.5 K, ΔH = 0.68±0.20 kJ/mol, ΔS = 3.8±0.1 J/(mol·K)). Studying the Zr(mba)4 crystals at 150 K and 200 K shows that this transition is not accompanied by the crystal deformation and is apparently caused by the rotation of phenyl groups. Due to this conversation, the space group changes from P21/c to P21/n, and one of the unit cell parameters increases by 3 times.
1,2,4-Oxadiazole based unsymmetric bidentate ligand, 3,5-bis-(4-pyridyl)-1,2,4-oxadiazole has been employed for complexation with silver nitrate; this ligand has been used for the first time for preparation of any coordination complex. A polymeric array of one-dimensional silver-ligand complex is formed where each metal ion is coordinated to two 4-pyridyl groups of two different ligands and two O-atoms of a nitrate ion. Single crystal X-ray data shows presence of hydrogen bonding and π–π stacking between each one-dimensional array which leads to formation of channels in its solid state. The hydrogen bonding interactions have also been verified by Hirsfeld surface analysis plots. Antimicrobial property study of ligand 3,5-bis-(4-pyridyl)-1,2,4-oxadiazole has been performed with Lactobacillus plantarum and it inhibits the growth at 12.5 μg/mL.
Supramolecular adducts of lanthanide complexes with cucurbituril, [{Eu(1–x)Nd(1+x)(H2O)5(NO3)}2 CB[6]](NO3)4·HNO3·6H2O (x = 0.5, –0.5), are prepared by heating a mixture of dissolved lanthanide nitrates and cucurbit[6]uril. According to the single-crystal XRD data for 1 and 2, the metal is connected to the macrocycle through the bidentate coordination of oxygen atoms of cucurbit[6]uril portals to the lanthanide(III) cations, thus leading to the formation of a molecular complex. In the crystal, the [{Ln(H2O)5(NO3)}2(CB[6])]4+ cations are interconnected by a system of hydrogen bonds. The compounds are shown to be isostructural and are characterized by a number of physicochemical methods: IR spectroscopy, powder XRD, and elemental analysis. Their luminescence spectra are recorded.
In this study, experimental methods X-ray single crystal analysis, UV-Vis spectroscopy and FTIR spectroscopy, and theoretical method Density Functional Theory (DFT) were used to study the structure of the new Schiff base (E)-N-(2,6-dichlorophenyl)-1-(5-nitro-2-(piperidin-1-yl)phenyl) methanamine. Theoretical calculations of the title compound and FTIR harmonic vibration frequencies were carried out using B3LYP methods with the 6-31G(d,p) basis set. The optical properties have been studied by DFT calculation and the experimental UV-Vis spectrum presents its contribution to the HOMO‒LUMO boundary. The molecular electrostatic potential map (MEP-ESP), analysis of frontier molecular orbitals (FMO), and determination of thermodynamic properties for the title compound were conducted using identical levels of theory. Besides, the structural state and crystal packing of the title compound were analyzed using molecular structure, Hirshfeld surfaces, interactions energies, energy frameworks and electrophilicity-based charge transfer (ECT) with DNA bases.
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