Resolvable polymorphism in an intergrowth of two modifications of tris(diethyldithiocarbamato)antimony

Tris(diethyldithiocarbamato-κS)antimony(III), [Sb(C5H10NS2)3], is tentatively presumed to comprise a triclinic and a monoclinic polymorph intergrown into each other. The geometry in the triclinic phase is a ψ-capped octahedron and that in the monoclinic phase is a ψ-pentagonal bipyramid. The study also identifies the polyhedral symbols for a reported pair of polymorphs of another SbIII coordination compound, as well as for those of published polymorphic modifications of other BiIII and PbII coordination compounds; the symbols in the pair differ in most of these examples. When differentiating related structures of such classes of coordination compounds, lone-pair stereochemistry may be another informative variable, as stereochemical activity is not always apparent from bond distances and angles only.

STUDY THE STABLE STRUCTURES OF ScGe6 BY GA-DFT AND THE CO ADSORPTION ON ScGe6− CLUSTER

The structures of ScGe6 and ScGe6− clusters were investigated by a combination of genetic algorithm with quantum chemical calculations (GA-DFT and DLPNO-CCSD(T)). Results show that the two most stable isomers of the ScGe6 cluster have a pentagonal bipyramid structure with a Sc atom at the vertex and a Ge atom capping the face of tetragonal bipyramid with a Sc atom at the vertex with Cs symmetry. The pentagonal bipyramid with the scandium atom at the vertex with C5v symmetry is the most stable ScGe6− cluster. The CO adsorption on the most stable isomer of the anionic cluster was studied by PBE functional. The isomer A1 of ScGe6− cluster can adsorb CO molecule as well. The most stable structure has CO along with the Sc-Ge bond. In two adsorption models at the Sc atom along the main axis, the Sc-CO adsorption model is more favorable than the Sc-OC model.

Study the structure, stability and CO2 adsorption of the ScVB5 cluster

A combination of genetic algorithm and density functional theory (GA-DFT) was used to calculate the minimum structures of ScVB5 clusters. The thirteen isomers of ScVB5 cluster were investigated at the level of PBE/def2-TZVPP, TPSSh/def2-TZVPP, and TPSSh/def2-QZVP levels. The relative energies, the structural geometry, ionization energy, affinity energy of neutral isomers were reported. The ScVB5 cluster can be formed by adding atom into smaller clusters. The proposed structure of ScVB5 cluster for CO2 treatment is a pentagonal bipyramid in the Cs symmetry with vanadium atom at one of the vertices and scandium atom in the base of bipyramid. The favor position for adsorp CO2 by the ScVB5 cluster were at around of Sc and V atoms. The dual transition metal-doped boron clusters can interact with CO2 molecules stronger than pure boron clusters.

Synthesis, crystal structure, and quantum mechanical studies regarding a new metal–organic complex based on Cd (II)

A novel metal-organic complex formulated as [Cd (phen)(dipic) (H2O)2]. 3 H2O (phen = 1, 10-phenanthroline; dipic2−= pyridine-2,6-dicarboxylate) has been hydrothermally synthesized at 150°C for 48h. The structure of Cd complex was characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and single-crystal X-ray diffraction (SC-XRD). The crystal system of Cd complex is monoclinic with space group C 2/c. The pentagonal bipyramid (seven coordinate) around Cd2+ center filled by two terminal water ligands, one 1,10-phenanthroline, and one pyridine-2,6-dicarboxylate anion. Extensive O–H···O hydrogen bonding interactions involving all coordinated water molecules, dipicolinate oxygens, and crystallization water molecules further stabilize the complex units by linking them to form three-dimensional polymeric networks. Indeed, quantum mechanical studies were performed to understand effective factors on stability of the Cd(II) complex.

Revealing 3D atomic packing in liquid-like solids

Liquids and solids are two fundamental states of matter. However, due to the lack of direct experimental determination, our understanding of the 3D atomic structure of liquids and amorphous solids remained speculative. Here we advance atomic electron tomography to determine for the first time the 3D atomic positions in monatomic amorphous materials, including a Ta thin film and two Pd nanoparticles. We observe that pentagonal bipyramids are the most abundant atomic motifs in these amorphous materials. Instead of forming icosahedra, the majority of pentagonal bipyramids arrange into a novel medium-range order, named the pentagonal bipyramid network. Molecular dynamic simulations further reveal that pentagonal bipyramid networks are prevalent in monatomic amorphous liquids, which rapidly grow in size and form icosahedra during the quench from the liquid state to glass state. The experimental method and results are expected to advance the study of the amorphous-crystalline phase transition and glass transition at the single-atom level.

First-Principles Study on Optic-Electronic Properties of Charge-Ordered Indium Halide Perovskite Cs2In(I)In(III)Cl6 at High Pressure

Using the first principle method we studied, theoretically and in detail, the structural, optical, and electronic properties of a charge-ordered indium halide perovskite Cs2In(I)In(III)Cl6 at high pressure. In this structure, In1, In2, and In3 are octahedrally coordinated, whereas In4 is at the center of a pentagonal bipyramid. The charge of In on In1 and In2 sites can be assigned to 3+, while In+ occupies In3 and In4 sites. The results indicated that the band gap decreases, and the electron excitation produces the red-shift of peak value of optical absorption coefficient in visible and infrared regions with increasing pressure, and the reflectivity decreases in visible and infrared regions with increasing pressure. These theoretical results provide a basis for designing related inorganic halide perovskites.

Hepta-coordinated Ni(ii) assemblies – structure and magnetic studies

HF-EPR and magnetometric studies show high magnetic anisotropy of Ni(ii) ions imposed by pentagonal bipyramid coordination geometry.

Synthesis, structures and magnetic properties of dysprosium(III) complexes based on amino-bis(benzotriazole phenolate) and nitrophenolates: influence over the slow relaxation of the magnetization.

We report the synthesis and crystal structures of four dysprosium(III) complexes based on the amino-bis(benzotriazole phenolate) ligand (C1NNBiBTP-H2). Whereas a pentagonal bipyramid complex [Dy(C1NNBiBTP-H)Cl2DMF]•THF (1•THF) is obtained in the absence...

Attainment of Pentagonal-Bipyramidal LnIII Complexes from a Planar Pentadentate Ligand

The search for mononuclear lanthanoid-based single-ion magnets (SIMs) has increased the interest in some coordination environments with low coordination numbers, in combination with an axial symmetry, as they could maximize the anisotropy of complexes of oblate lanthanoid ions, such as dysprosium(III). In this sense, the pentagonal–bipyramid geometry can have ground-state doublets with perfect axiality, and therefore such complexes can be good candidates for SIMs. In our particular case, we have used a well-known open planar pentadentate chelating Schiff base ligand as 2,6-bis(1-salicyloylhydrazonoethyl)pyridine) (H4daps) for the synthesis of air-stable pentagonal–bipyramidal LnIII complexes (these being Ln: Dy and Er, oblate and prolate, respectively), in order to compare their structures. Thus, the reaction of H4daps with (CH3)4NOH·5H2O and the corresponding LnCl3·hexahydrate has yielded heptacoordinate [(CH3)4N][LnIII(H2daps)Cl2] complexes, where the tetramethylammonium cation is acting as the counterion of pentagonal–bipyramidal LnIII complexes, which are bearing two chloride atoms in apical positions. As both complexes could be crystallized as single crystals, we can compare their crystal structures, as well as with some other related complexes in the literature, which contain different counterions, trying to see their influence on other properties of the compounds, such as their magnetic behavior.