Trigonal Prismatic Structure Research Articles

Synthesis, Structural Features and Fluorescent Properties of Terbium Acylpyrazolone Complexes

AbstractThree 8‐coordinated terbium acylpyrazolone complexes [Tb(DMBPMP)3(H2O)2] (Tb1), [Tb(DMBMCPMP)3(H2O)2] (Tb2), and [Tb(DMBPTMP)3(H2O)2] (Tb3) with a distorted bicapped trigonal prismatic structure were synthesized (where, 3,5‐dimethylbenzoyl 1‐(phenyl = DMBPMP/m‐chlorophenyl = DMBMCPMP/p‐tolyl = DMBPTMP) 3‐methyl 5‐pyrazolone). The structures of the complexes were comprehensively analyzed using mass ESI, FTIR, UV–vis, powder XRD, and TG‐DTA methods. Single‐crystal analysis of Tb3·H2O confirmed an eight‐coordinate structure (TbO8) with a distorted bicapped trigonal prismatic geometry. In the on‐state emission spectrum, the 5D4 → 7F5 transition exhibits hypersensitivity in the green region of the visible spectrum (∼540–560 nm). The differences between electric dipole (ED) and magnetic dipole (MD) transitions indicate a small degree of asymmetry. The examination of solid‐state emission spectra included the assessment of intensity, G/B ratio, green color purity, and the antenna effect energy diagram.

Engineering the electronic and magnetic properties of monolayer TiS[formula omitted] through systematic transition-metal doping

Despite substantial interest, most of the two-dimensional (2D) materials are not magnetic in their pristine form. Several standard approaches, such as adsorption of atoms, introduction of point defects, and edge engineering, have been developed to induce magnetism in two-dimensional materials. In this way, we investigate the electronic and magnetic properties of monolayer TiS2 doped with 3d transition metals (TMs) atoms in both octahedral 1T and trigonal prismatic 1H structures using first-principles calculations. In its pristine form, TiS2 is a non-magnetic semiconductor. The bands near the Fermi energy primarily exhibit d orbital characters, and due to the presence of ideal octahedral and trigonal arrangements, they are well separated from other bands with p character. Upon substituting 3d-TM atoms in both structures, a variety of electronic and magnetic phases emerge, including magnetic semiconductor, magnetic half-metal, and magnetic metal. Chromium exhibits the largest magnetic moment in both the 1T and 1H structures. The 1T structure shows a slightly higher magnetic moment of 3.4 μB compared to the 1H structure 3.1 μB, attributed to the distorted octahedral structure of the 1T structure. Unlike pristine TiS2, the deficiency in saturation of neighboring S atoms in the presence of impurities leads to the proximity of energy levels of d and p states, resulting in unexpectedly sizeable magnetic moments. Another interesting case is Cobalt, which leads to a magnetic moment of approximately 0.8 μB in the 1H structure, while the Co exhibits a non-magnetic state in the 1H structure. These materials demonstrate a high degree of tunability and can be optimized for various magnetic applications.

Neutral Adducts of Molybdenum Hexafluoride: Structure and Bonding in MoF6(NC5H5) and MoF6(NC5H5)2.

The first Lewis acid base adducts of MoF6 and an organic base have been synthesized, i. e., MoF6(NC5H5) and MoF6(NC5H5)2. These adducts are structurally characterized with X-ray crystallography, showing that both adducts adopt capped trigonal prismatic structures. The MoF6(NC5H5) and MoF6(NC5H5)2 adducts are fluxional on the NMR time scale at room temperature. Two different fluorine environments could be resolved by 19F NMR spectroscopy at -80 °C for the 1 : 2 adduct, MoF6(NC5H5)2, whereas MoF6(NC5H5) remains fluxional at that temperature. Density functional theory (DFT) calculations aide the assignment of the infrared and Raman spectra. Natural Bond Order and Molecular Electrostatic Potential analyses elucidate the structures and properties of the MoF6 pyridine adducts. Regions of significantly higher molecular electrostatic potential, i. e., σ-holes, in trigonal prismatic compared to octahedral MoF6 rationalize the capped trigonal prismatic geometry of the adducts. Whereas MoF6(NC5H5) is stable at room temperature under exclusion of moisture, MoF6(NC5H5)2 decomposes at 60 °C in pyridine solvent, and the solid slowly decomposes at room temperature after 24 h.

Both the ionic and covalent bonds stabilize the W@Si12 cluster

Si is an important semiconductor material in the development of modern industry. With the miniaturization trend of semiconductor devices, the size of Si has reached the cluster size. The search for stable Si clusters is an important issue. In this work, the electronic structures and stability mechanism of the W@Si12 cluster are calculated by the first-principle calculations. Different from a C2v hexacapped trigonal prism structure of Si12, the W@Si12 cluster presents an embedded hexagonal prism structure with D6h symmetry. The addition of W atom leads to a higher stability. The molecular orbitals show obvious superatomic characteristics for the W@Si12 cluster, and their energy levels are more degenerate than that of the Si12 cluster. The population analysis indicates that a total charge of 2.21e is transferred from Si atoms to the center W atom, which suggests an ionic bond for W-Si. The electron localization function further proves a covalent bond for Si–Si. The enhanced stability of the W@Si12 cluster is attributed to the combination of the ionic and covalent bonds.

Fabrication of Ni–Mo–Nb metallic glass/micro-nano lattice composite for nonenzymatic glucose sensing

The rising global diabetic population has ignited significant interest in enzyme-free electrochemical glucose sensors. However, their widespread usage has been severely impeded by the lack of sensing probes with both high sensitivity and stability. In this work, we present a novel approach for conformally depositing a Ni–Mo–Nb metallic-glass film onto a three-dimensional printed polymer skeleton for glucose detection. The printing template is designed based on a six-membered tricapped trigonal prism (6M-TTP) structure, which is derived from a medium-range order structure motif observed in amorphous alloys. The fabricated composite combines the high electrochemical activity of Ni–Mo–Nb amorphous alloy with the stability afforded by the micro-nano lattice structure, resulting in a high sensitivity (482 ​μA mM−1cm−2), a wide linear range (0–1 ​mM and 1–5 ​mM), a low detection limit (2.94 ​μM), and good long-term stability and selectivity in alkaline solution. Our work has proposed a new avenue to fabricate complex micro-nano electrodes, potentially offering significant versatility and great promise for widespread applications in the field of electrochemistry.

Anionic Templates Drive Conversion between a ZnII9L6 Tricapped Trigonal Prism and ZnII6L4 Pseudo-Octahedra.

This work introduces the use of 8-aminoquinoline subcomponents to generate complex three-dimensional structures. Together with a tris(formylpyridine), 8-aminoquinoline condensed around ZnII templates to produce a tris(tridentate) ligand. This ligand is incorporated into either a tricapped trigonal prismatic ZnII9L6 structure or a pair of pseudo-octahedral ZnII6L4 diastereomers, with S4 and D2 symmetries. Introduction of a methyl group onto the aminoquinoline modulated the coordination sphere of ZnII, which favored the ZnII9L6 structure and disfavored the ZnII6L4 assembly. The tricapped trigonal prismatic ZnII9L6 architecture converted into a single ZnII6L4 cage diastereomer following the addition of a dianionic 4,4'-dinitrostilbene-2,2'-disulfonate guest. Four of these guests clustered tightly at the four windows of the ZnII6L4 cage, held in place through electrostatic interactions and hydrogen bonding, stabilize a single diastereomeric configuration with S4 symmetry.

Controlling the Assembly of Tantalum Oxyfluoride Anions by Organic Amine Cations: From Molecular Cluster, Molecular Cage to Polymeric Chain

Three tantalum oxyfluorides, with structures ranging from molecular cluster, molecular cage to polymeric chain, were synthesized by using organic cations as structure-directing agents in the presence of aqueous hydrofluoric acid. Single-crystal X-ray analysis reveals that compound [C7H13NH]6[Ta2OF10][Ta4O4F16]·(H2O)2 (1, C7H13NH = quinuclidinium) contains binuclear [Ta2OF10]2– and tetranuclear [Ta4F12O6]4– anions, compound [NH(C2H4)2NH2CH3][Ta6O9F18]·(H2O)3 (2, NH(C2H4)2NH2CH3 = doubly protonated 1- methyl-piperazine) contains the hexagonal cages of [Ta6O9F18]6–, and compound [C6H5NH3][TaOF4] (3, C6H5NH3 = anilinium) features a one-dimensional polymeric chain of [TaOF4]nn– in which oxygen atoms act as bridging ligands. Notably, compound 1 is the first tantalum oxyfluoride comprising mixed discrete anionic tantalum oxyfluoride clusters, while compound 2 features a rare molecular cage with a Ta6 trigonal prism structure.

Intercalation on Transition Metal Trichalcogenides via a Quasi‐Amorphous Phase with 1D Order (Adv. Funct. Mater. 10/2023)

Transition Metal Trichalcogenides In article number 2208702, Masaya Fujioka and co-workers successfully intercalate ions into 1D structural transition metal trichalcogenides with a trigonal prismatic structure, leading to a 1D structural intercalation compound with an octahedral structure through a quasi-amorphous phase. This unique amorphous phase with 1D order has the potential to exhibit various functions depending on the ion concentration. Here they show that the two crystal phases with trigonal prismatic and octahedral structures are connected via a quasi-amorphous phase.

Intercalation on Transition Metal Trichalcogenides via a Quasi‐Amorphous Phase with 1D Order

AbstractIntercalation into 1D transition metal trichalcogenides (TMTs) in which fibers are bonded by a weak van der Waals force can be expected to create various intercalation compounds and develop unique physical properties according to the combination of the host materials and guest ions. However, structural changes via intercalation into 1D TMTs are not as simple as those in 2D transition metal dichalcogenides (TMDs) and are still not understood comprehensively. ZrTe3: a typical compound with a 1D trigonal prismatic structure, belongs to TMTs. Herein, through the Ag introduction to ZrTe3 via solid‐state intercalation, a novel crystal phase with a 1D octahedral structure and a quasi‐amorphous (QA) phase during the structural transition are discovered; the QA phase is a novel state of matter in which long‐range order is lost while retaining 1D order. Based on the Ag concentration, the transport properties are flexibly modulated from superconductivity to semiconductivity. Density functional theory calculations indicate the attraction between Ag ions and the pair diffusion due to their attraction. Furthermore, judging the attraction or repulsion between guest ions predicts whether to induce a QA phase or simple lattice expansion like the intercalation into 2D TMDs.

Fabricating polymer/HEA-hybrid topological lattice structure for enhanced mechanical properties

Metamaterials such as architected lattice structures have aroused broad interest in being applied as mechanical supports for their lightweight and custom-shaped capabilities. Although various prior efforts have been devoted, a multiscale fabrication of micro-nano lattice structures without penalizing the mechanical properties is still a challenging but highly desirable task. Here we put forward a strategy to produce a mechanically enhanced micro-nano lattice structure by conformally depositing a CoCrFeNiTi high-entropy alloy (HEA) coating layer onto a three-dimensional (3D) printed polymer skeleton. The template for the 3D printing employs a six-membered tricapped trigonal prism (6M-TTP) structure derived from a medium-range order structure motif in amorphous alloys. The topological complexity of the 6M-TTP can substantially avoid the stress concentration by offering stress-release channels, while the HEA film incorporating with amorphous and nanocrystalline constituents can further reinforce the lattice architecture through its size hardening effect. Benefitting from the above, the fabricated polymer/HEA-hybrid lattice exhibits a high specific compressive strength (∼0.055 ​MPa ​kg-1 m3 at a density below 500 ​kg ​m-3), a superior elastic recoverability (∼70% recovery rate under >30% compression), an enhanced plasticity (40% strain) and a high specific modulus (0.135 ​MPa ​kg-1 m3). Our strategy initiates a perspective way to fabricate multiscale micro-nano lattice structures with improved mechanical properties, which could be extended to widespread metamaterial research.

Silver Ion-Induced Formation of Unprecedented Thorium Nonamer Clusters via Lacuna-Construction Strategy

Silver Ion-Induced Formation of Unprecedented Thorium Nonamer Clusters via Lacuna-Construction Strategy

Structure of Aqueous Scandium(III) Nitrate Solution by Large-Angle X-ray Scattering Combined with Empirical Potential Refinement Modeling, X-ray Absorption Fine Structure, and Discrete Variational Xα Calculations

Abstract Large-Angle X-ray scattering (LAXS) and Sc K X-ray absorption near-edge structure (XANES) measurements are made at room temperature on a 1 M (= mol dm−3) Sc(NO3)3 aqueous solution. The X-ray interference function is subjected to an empirical potential structure refinement (EPSR) modeling to extract the site-site pair correlation functions, the coordination number distribution, and the spatial density functions (three-dimensional structure). The LAXS analysis combined with EPSR reveals that Sc3+ is surrounded by six or seven water molecules and one oxygen atom of NO3− with an Sc3+-Ow (H2O) and Sc3+-ON (NO3−) distance of 2.14 Å. NO3− has a weak solvation shell with a broad distribution of coordination numbers with the highest population of nine at an N-Ow distance of 3.66 Å. Solvent water forms the tetrahedral network structure. The XANES spectrum is compared with simulated spectra on various coordination geometries of an ScO7 moiety with a discrete variational Xα (DV-Xα) molecular orbital (MO) method. A distorted monocapped trigonal prism structure of Sc3+ best reproduced the experimental pre-peak due to the Sc 1s → 3d transition in the XANES spectrum.

Template-Free Synthesis of an Interlocked Covalent Organic Molecular Cage.

An interlocked covalent organic molecular cage with a trigonal-prismatic structure based on anthracene units and imine bonds was synthesized by a template-free and one-pot reaction in a relatively good yield. By comparing the single-crystal structures of the interlocked cage and two additional monomeric cages as reference compounds, a cause of weak supramolecular interaction-induced synthesis was proposed; π···π interactions induce the triphenylbenzene units as the core and anthracenes as side parts close to each other, which provides a possibility of the preorganization for the formation of the interlocked structure.

Toward Heteronuclear Molecular Re(I)-Cu(II) Boxes: Structural, Luminescent, and Magnetic Properties.

The bifunctional ligands of isonicotinic acid (Py-4-COOH) and 4-pyrid-4-ylbenzoic acid (Pybz-4-COOH) instead of polypyridines were therefore reacted with (Re(CO)4)3(C3N3S3) (C3N3S3 = cyanurate trianion), resulting in the formation of two trinuclear [(Re(CO)3)3(C3N3S3)(Py-4-COOH)3] (1) and [(Re(CO)3)3(C3N3S3)(Pybz-4-COOH)3] (2), respectively. In the meantime, both complexes 1 and 2 are connected by three bifurcated hydrogen bonds between their carboxylic acid moieties Py-4-COOH and Pybz-4-COOH to form the supramolecular trigonal-prismatic and -antiprismatic structures, respectively. It is noted that complex 1 can further react with copper(II) nitrate upon deprotonation to give nonanuclear [(Re(CO)3)3(C3N3S3)(Py-4-COO)3]2Cu3(H2O)9 (3), where two trinuclear [(Re(CO)3)3(C3N3S3)(Py-4-COO)3] moieties are connected by three penta-coordinate copper(II) ions, each coordinating to two carboxylates and three water molecules, to form the trigonal-prismatic structure. Surprisingly, addition of pyrazine (pz) in the synthetic process of complex 3 resulted in serendipitous isolation of a rare example of octadecanuclear {[(Re(CO)3)3(C3N3S3)(Py-4-COO)3]2Cu3(H2O)6(pz)2}2 (4), which can be regarded as a dimer of complex 3, connected by two bridging pz ligands. Interestingly, both complexes 3 and 4 are heteronuclear molecular Re(I)-Cu(II) boxes, constructed by a complex-as-a-ligand strategy. Furthermore, complexes 1 and 2 can exhibit respective low-energy luminescence at ca. 561 and 534 nm at room temperature upon photoexcitation, and complex 3 is found to display antiferromagnetic coupling of −127.68 and −134.70 cm–1, possibly due to multiple hydrogen bonds inducing significant Cu(II)···Cu(II) coupling.

Synthesis and Crystal Structures of New Strontium Complexes with Aminoalkoxy and β-Diketonato Ligands

New heteroleptic strontium complexes were synthesized using substitution reaction of bis(trimethylsilyl)amide of Sr(btsa)2·2DME with aminoalkoxide and β-diketonate ligands. The complexes [Sr(bdmp)(btsa)]2·2THF (1), [Sr(bdeamp)(btsa)]2 (2), [Sr(dadamb)(btsa)]2 (3), [Sr(bdmp)(hfac)]3 (4), [Sr(bdeamp)(hfac)]3 (5), [Sr(dadamb)(hfac)]3 (6), and [Sr3(dadamb)4(tmhd)2] (7) were prepared and characterized by means of various analysis techniques such as Fourier transform infrared, NMR, thermogravimetric analysis, and elemental analysis. Complexes 1–3 were further structurally confirmed by single-crystal X-ray crystallography, and they displayed dimeric structures in which strontium atoms were connected by alkoxide oxygen atoms of the μ2 type. Compound 1 has a trigonal prismatic structure, whereas 2 and 3 have a distorted square pyramidal structure. In complexes 5–7, trimeric structures were obtained with strontium atoms connected by μ3–O bonds of alkoxide oxygen atoms and μ2–O bonds of alkoxide and β-diketonate oxygen atoms. The crystal structures of 5, 6, and 7 showed distorted capped octahedral geometry, while 7 (middle Sr atom) displayed a distorted trigonal prism geometry. Complexes 5–7 displayed ∼70% mass loss in the temperature range from 25 to 315 °C.

Heterometallic Ni-Pt Chini-Type Carbonyl Clusters: An Example of Molecular Random Alloy Clusters.

The direct reactions of homometallic [Ni6(CO)12]2– and [Pt6(CO)12]2– Chini carbonyl clusters result in heterometallic Ni–Pt Chini-type clusters of the general formula [Pt6–xNix(CO)12]2– (x = 0–6). Their molecular structures have been determined by single-crystal X-ray diffraction (SC-XRD), showing a common octahedral (staggered, D3d) structure analogous to that of [Ni6(CO)12]2–, whereas [Pt6(CO)12]2– displays a trigonal-prismatic (eclipsed, D3h) structure. This structural change after replacing one single Pt with Ni may be classified as an alloying effect, and it has been theoretically investigated by DFT methods. Spectroscopic (IR and 195Pt and 13C NMR) and ESI-MS studies indicate that mixtures of [Pt6–xNix(CO)12]2– (x = 0–6) clusters are actually present in solution, whose compositions may be varied in an almost continuous way. Thus, they may be viewed as random alloy clusters whose overall compositions depend on the stoichiometry of the reagents.

Synthesis, spectroscopic characterization, and SC-XRD study of one privileged heteronuclear Ni(II)/Hg(II)-Salen complex: An exclusive DFT outlook

A novel heteronuclear Salen complex, [NiHgCl2(L)] (1) (H2L = N,N′-bis(3-methoxysalicylidene)-2,2-dimethylpropane-1,3-diamine) has been integrated using two different synthetic lines. The complex is characterized by various spectroscopic techniques, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and single-crystal X-ray diffraction (SC-XRD). Powder X-ray diffraction (PXRD) confirms complex phase purity and crystallinity. The scanning electron microscope and energy-dispersive X-ray analysis (SEM-EDX) identified the element’s chemical composition, morphology, and crystal size. X-ray diffraction revealed ligand released phenoxide-type deprotonated form [L]2− and had spent two pockets, N2O2 pocket occupied by Ni(II) comprises square planar geometry (NiN2O2). In contrast, Hg(II) occupies a large open O4 compartment accompanied by two chloride ions (HgO4Cl2), switching to achieve a trigonal prismatic structure. The close surveillance of the crystal structure discloses various non-covalent interactions like H-bonding, CH⋯π, and π⋯π. The complex’s geometry was fully optimized, employing the quantum chemistry method at the DFT/B3LYP with the 6-31G (d, p) basis set to divine the vibrational spectra, NMR chemical shifts, and solvent effect on the electronic properties. Natural Bond Orbital (NBO) dissected the stability of the molecular structure and the intermolecular orbital interactions. The highest stabilizing energy was 132.84 kcal/mol between the lone pair C12 and the antibonding of N7-C17 atoms. The Hirshfeld Surface (HS) is detectable that the H⋯N input is maximum than H⋯O. The electrophilic-nucleophilic sites, non-covalent interactions, and reactivity were investigated based on Molecular Electrostatic Potential (MESP), Reduced Density Gradient (RDG), atoms in a molecule (AIM), and the HOMO-LUMO difference. Eventually, a significant correlation was anticipated between theoretical and experimental spectroscopic criteria.

Synthesis, spectral characterization, density functional theory studies, and biological screening of some transition metal complexes of a novel hydrazide–hydrazone ligand of isonicotinic acid

Novel Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes (1–7) of hydrazide–hydrazone ligand (H2L) derived from the condensation of isonicotinic acid hydrazide with (Z)‐N′‐(2‐nitrobenzylidene)‐3‐oxobutanehydrazide have been prepared. The ligand and its chelates were characterized based on elemental analysis, spectral, thermal analysis, molar conductance, and magnetic moment measurements. Besides, density functional theory (DFT) computations have been conducted to study structures and energetics of the ligand and its complexes. The IR spectra showed that the ligand was chelated with the metal ion in a monobasic tridentate manner using ONO donors in all complexes except Zn(II) complex (5) where the ligand binds with Zn(II) ion as a dibasic tridentate utilizing ONO donors. The magnetic moment and electronic spectral data revealed octahedral and square pyramidal geometries for complexes (1, 7) and (2, 4, 5), respectively, whereas a square planar geometry was suggested for 3. DFT studies show that the Cd(II) center reveals interesting structural deviations from regular octahedral geometry in the resulting hexa‐coordinated complex [Cd(H2L)2].2H2O (6) assumes a trigonal prismatic (TP) structure for this complex. The antibacterial and antifungal activities of the ligand and its complexes have been investigated with different bacterial and fungal strains. The data revealed that Hg(II) complex (7) demonstrated a very good antibacterial and antifungal activity than others.Highlights A new hydrazide–hydrazone ligand of isonicotinic acid was synthesized. Seven mononuclear Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes of the new ligand were prepared and characterized by different tools. DFT studies have been carried out to study the structure of the ligand and its complexes. Antimicrobial activities of the ligand and its complexes were studied against a variety of bacterial and fungal strains by using disk diffusion method and results were compared with standard drugs.

First-principles study on the stability and electronic structure of monolayer GaSe with trigonal-antiprismatic structure

The structural stability and electronic states of GaSe monolayer with trigonal-antiprismatic (AP) structure, which is a recently discovered new polymorph, were studied by first-principles calculations. The AP phase GaSe monolayer was found stable, and the differences in energy and lattice constant were small when compared to those calculated for a GaSe monolayer with conventional trigonal-prismatic (P) structure which was found to be the ground state. Moreover, it was revealed that the relative stability of P phase and AP phase GaSe monolayers reverses under tensile strain. These calculation results provide insight into the formation mechanism of AP phase GaSe monolayers in epitaxially-grown GaSe thin films.

Temperature Dependent Structural Evolution of WSe2: A Synchrotron X-ray Diffraction Study

A thorough investigation of the structural parameters of micromechanically exfoliated multilayer WSe2 flakes was undertaken between 400 K to 110 K. Crystal structure of WSe2 remains in the trigonal prismatic structure in this temperature range, however, with a clear difference in the temperature dependence of the in-plane a, and the out-of-plane c, lattice parameters. The linear coefficients of thermal expansion of a and c are 5.132 × 10−6/K and 8.105 × 10−6/K, respectively. The temperature dependence of the unit-cell volume is analyzed using zero-pressure equation-of-state which yielded the Debye temperature of the WSe2 to be 160 K. Following the temperature dependence of the W-Se and W-W bond distances, a nonlinear behavior is observed in the former in contrast to a rather regular behavior of the later. This significant difference in the temperature dependence of the a and c lattice parameters can have consequences in the macroscopic physical properties of the system. A good correlation between the temperature dependence of the W-Se bond distance and Raman E2g1 mode has been observed.