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On the basis of the higher order perturbation formulas of g-factors for a 4d1 group in tetragonally compressed octahedra, the g-factors, optical absorption, local structure and their concentration dependences of pentavalent molybdenum in 40PbO-(10-x)Y2 O3 -50P2 O5 :xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq, covalent factor N and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8-4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2 O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems.

A series of cobalt complexes, stabilized by a monoanionic tridentate NCN pincer ligand, was synthetized and characterized. Preparation of the paramagnetic 15 VE complex [Co(NCNCH2−Et)Br] (1) was accomplished by transmetalation of Li[2,6‐(Et2NCH2)2C6H3] with CoBr2 in THF. Treatment of this air‐sensitive compound with NO gas resulted in the formation of the diamagnetic Co(III) species [Co(NCNCH2−Et)(NO)Br] (2) as confirmed by X‐ray diffraction. This complex features a strongly bent NO ligand (Co−N−O∠135.0°). The νNO is observed at 1609 cm−1 which is typical for a bent metal‐N−O arrangement. Coordinatively unsaturated 1 could further be treated with pyridine, isocyanides, phosphines and CO to form five‐coordinate 17 VE complexes. Oxidation of 1 with CuBr2 led to the formation of the Co(III) complex [Co(NCNCH2−Et)Br2]. Treatment of [Co(NCNCH2−Et)Br2] with TlBF4 as halide scavenger in acetonitrile led to the formation of the cationic octahedral complex [Co(NCNCH2−Et)(MeCN)3](BF4)2. A combination of X‐ray crystallography, IR‐, NMR‐ and EPR‐spectroscopy as well as DFT/CAS‐SCF calculations were used to characterize all compounds., The preparation of several Co(II) and Co(III) NCN pincer complexes is described. A combination of X‐ray diffraction, EPR‐, IR‐ and NMR spectroscopy together with computational methods was used to characterize and study the properties of all products.

Mononuclear chelates of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II) and Cd(II) resulted from new tridentate Schiff base ligand, 4‐((1‐(5‐acetyl‐2,4‐dihydroxyphenyl)ethylidene)amino)‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one, were synthesized. Metal to ligand ratio was found to be1 : 1, which was revealed via elemental analysis and characterized via various spectroscopic tools. IR has point out that the coordination of the ligand towards the metal ions was carried out via NOO donor atoms. UV‐Vis, 1H NMR spectral data, molar conductivity measurements, BET surface area, melting points and theoretically through density function theory were used such as characterizing techniques in supporting further interpretation of the complexes structures. The complexes were octahedral except Cu(II) and Ni(II) complexes were tetrahedral as suggested from the magnetic moment measurement. The complexes were found to have surface area, pore volume and particle radius of 23–176 m2 g−1, 0.02‐0.33 cc/g and 8.71‐4.32 nm, respectively, as pointed out from BET measurement. Schiff base ligand and metal complexes were tested in vitro to estimate their antimicrobial activity opposed to Gram‐negative and Gram‐positive bacterial and fungal organisms. MOE 2008 was used headed for screen potential drugs with molecular docking by the protein sites of new coronavirus and the study was constructed to molecular docking without validation through MD simulations.

Herein, we report, four new mixed ligand complexes of Cobalt(II) and Iron(III), viz., [Co(L1 )(L2 )(H2 O)2 ]Cl2 (1), [Co(L1 )(L2 )(L3 )(H2 O)]Cl2 (2), [Fe(L1 )(L2 )(H2 O)2 ]Cl3 (3), and [Fe(L1 )(L2 )(L3 )(H2 O)]Cl3 (4), where L1 = 1,10-phenanthroline (C12 H8 N2 ), L2 = 2,2'-bipyridine (C10 H8 N2 ), and L3 = acetamide (C2 H5 NO)). They were synthesized and characterized using spectroscopic analysis (ESI-MS, ICP-OES, FT-IR, and UV-Vis), elemental analysis, melting point determination, and conductance measurement. The in vitro antibacterial activity was tested on two Gram-positive Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) and two Gram-negative Escherichia coli (E. Coli)and Klebsiella pneumoniae (K. pneumoniae) bacteria using the disc diffusion method. Based on the analytical and spectroscopic data, octahedral geometries are assigned to the complexes. Co(II) complexes were found more active against K. pneumoniae than the corresponding Fe(III) complexes which indicated that antibacterial activities of metal complexes have tuned with the nature of the metal. The results provide an insight to design and readily prepare task-specific metal-based drugs for interaction with particular bacterial strains.

Herein, we report a detailed structural, electric, thermal and optical analysis of a titanium and tantalum phosphate LiNaTiTa2 P2 O13 . The title compound is comprised of typical ReO3 -type layers constituted by corner-sharing TiO6 and TaO6 octahedra, bridged by PO4 tetrahedra, and the structure is closely related to monophosphate niobium bronzes. The existence of pentagonal tunnels, hosting the Li+ and Na+ ions, endows LiNaTiTa2 P2 O13 a moderate ion transportation behavior (4.67×10-4 S/cm at 823 K). In addition, the successful substitution of Nb for Ta in LiNaTiTa2 P2 O13 results in the optical absorption red-shift towards visible range with a narrowing band gap, which may provide a route of isomorphic replacement to band engineering for photo-catalysis.

Given the strong influence of surface structure on the reactivity of heterogeneous catalysts, understanding the mechanisms that control crystal morphology is an important component of designing catalytic materials with targeted shape and functionality. Herein, we employ density functional theory to examine the impact of growth media on NiO crystal faceting in line with experimental findings, showing that molten-salt synthesis in alkali chlorides (KCl, LiCl, and NaCl) imposes shape selectivity on NiO particles. We find that the production of NiO octahedra is attributed to the dissociative adsorption of H2 O, whereas the formation of trapezohedral particles is associated with the control of the growth kinetics exerted by ordered salt structures on high-index facets. To our knowledge, this is the first observation that growth inhibition of metal-oxide facets occurs by a localized ordering of molten salts at the crystal-solvent interface. These findings provide new molecular-level insight on kinetics and thermodynamics of molten-salt synthesis as a predictive route to shape-engineer metal-oxide crystals.

Two new imidazophenanthroline derivatives, namely 2-(4-bromo-(2,1,3)-benzothiadiazol-7-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (btdip), 2-(dibenzofuran-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (dbfip) and their octahedral nickel complexes [Ni(phen)(2)(btdip)](2+) (1) and [Ni(phen)(2)(dbfip)](2+) (2) have been synthesized and characterized by CHN analysis, ESI-MS, NMR and UV-vis spectra. Their DNA binding abilities were spectrophotometrically, hydrodynamically and electrophoretically studied and found that while btdip binds DNA externally, dbfip binds in the grooves and both of their nickel complexes also bind DNA through grooves giving severe DNA damage in the presence of peroxide. The compounds were screened against four different human cancer cell lines using MTT assay method. The results obtained showed that both ligands are active against DLD-1, and further dbfip is found to be more active than positive control drugs against DLD-1 and HepG2 cell lines. The complex 2 has more antiproliferative effect than 1 against MCF-7 and HepG2 cells. On the other hand, complex 2 was found to have more toxic effect on HepG2 cells than the standard drugs cisplatin and ploxal-S.

Multinary transition metal nitrides and oxonitrides are a versatile and intriguing class of compounds. However, they have been investigated far less than pure oxides. The compounds Sc5 P12 N23 O3 and Ti5 P12 N24 O2 have now been synthesized from the binary nitrides ScN and TiN, respectively, by following a high-pressure high-temperature approach at 8 GPa and 1400 °C. NH4 F acts as a mineralizing agent that supports product formation and crystallization. The starting materials ScN and TiN are seemingly an uncommon choice because of their chemical inertness but, nevertheless, react under these conditions. Sc5 P12 N23 O3 and Ti5 P12 N24 O2 crystallize isotypically with Ti5 B12 O26 , consisting of solely vertex-sharing P(O/N)4 tetrahedra forming two independent interpenetrating diamond-like nets that host TM(O/N)6 (TM=Sc, Ti) octahedra. Ti5 P12 N24 O2 is a mixed-valence compound and shows ordering of Ti3+ and Ti4+ ions.

[H7 O3 ]4 [Tc20 O68 ] ⋅ 4H2 O [1] was prepared from an aqueous Tc2 O7 solution concentrated over anhydrous H2 SO4 . [Tc20 O68 ]4- is the first polyanionic species to be reported for Tc. The unit cell contains one centrosymmetric [Tc20 O68 ]4- polyanion as well as hydronium ions and water molecules. The core of the structure consists of four Tc(V)O6 octahedra that form a square Tc4 O4 ring. The four Tc(V)O6 octahedra are decorated by sixteen Tc(VII)O4 tetrahedra. Calculations show the bonding within the Tc4 O4 ring to consist of a 3-center bond formed between each neighboring pair of Tc atoms and their bridging oxygen. Calculations also indicate that a strong d→d electronic transition at 513 nm is the origin of the red color of [1]. The characterization of red HTcO4 solutions by X-ray absorption spectroscopy has complemented the description of this compound in aqueous solution. The formation mechanisms in solution, including the possible role of technetium's radioactivity in the formation of [1], are discussed.

It is critical to assemble nanoparticles (NPs) into superlattices with controlled symmetries and spacings on substrates for metamaterials applications, where such structural parameters dictate their properties. Here, we use DNA to assemble anisotropic NPs of three shapes-cubes, octahedra, and rhombic dodecahedra-on substrates and investigate their thermally induced reorganization into two-dimensional (2D) crystalline films. We report two new low-density 2D structures, including a honeycomb lattice based on octahedral NPs. The low-density lattices favored here are not usually seen when particles are crystallized via other bottom-up assembly techniques. Furthermore, we show that, consistent with the complementary contact model, a primary driving force for crystallization is the formation of directional, face-to-face DNA bonds between neighboring NPs and between NPs and the substrate. Our results can be used to deliberately prepare crystalline NP films with novel morphologies.

The construction of three-dimensional (3D) covalent organic frameworks (COFs) remains challenging due to the limited types of organic building blocks. With octahedral Ti(IV) complex as the building unit, this study reports on the first 3D anionic titanium-based COF ( Ti-COF-1 ) with an edge-transitive (6, 4)-connected soc topology. Ti-COF-1 exhibits high crystallinity, superior stability, and large specific surface area (1000.4 m 2 g -1 ). Moreover, Ti-COF-1 has a broad absorption band in the UV spectrum with an optical energy gap of 1.86 eV, and exhibits high photocatalytic activity toward Meerwein addition reactions. This research demonstrates an attractive strategy for the design of 3D functional COFs.

Separation of C2 hydrocarbons, C2 H6 , C2 H4 , and C2 H2 , remains significant challenges in chemical industry. However, there are only few adsorbents that can effectively isolate C2 hydrocarbons from their mixtures particularly at a high temperature. Herein, we design a zeolitic octahedral metal oxide based on ϵ-Keggin polyoxometalates with metal ion linkers. Single gas adsorption of the material shows the different adsorption performances for the C2 hydrocarbons and the strong interaction of the material with the C2 hydrocarbons. Dynamic competitive adsorption experiments show that the material efficiently separates each of the binary C2 hydrocarbon mixtures and even the ternary C2 hydrocarbon mixtures with high selectivity. The material keeps high separation performance even the temperature was increased to 85 °C. The material is stable and is able to be reused without loss of the separation performance.

Renewable energy-powered methane (CH4 ) conversion at ambient conditions is an attractive but highly challenging field. Due to the highly inert character of CH4 , the selective cleavage of its first C-H bond without over-oxidation is essential for transforming CH4 into value-added products. In this work, we developed an efficient and selective CH4 conversion approach at room temperature using intermediate chlorine species (*Cl), which were electrochemically generated and stabilized on mixed cobalt-nickel spinels with different Co/Ni ratios. The lower overpotentials for *Cl formation enabled an effective activation and conversion of CH4 to CH3 Cl without over-oxidation to CO2 , and Ni3+ at the octahedral sites in the mixed cobalt-nickel spinels allowed to stabilize surface-bound *Cl species. The CoNi2 Ox electrocatalyst exhibited an outstanding yield of CH3 Cl (364 mmol g-1 h-1 ) and a high CH3 Cl/CO2 selectivity of over 400 at room temperature, with demonstrated capability of direct CH4 conversion under seawater working conditions.

Metal-organic frameworks (MOFs) have attracted increasing attention as a promising electrode material for the oxygen evolution reaction (OER). Comprehending catalytic mechanisms in the OER process is of key relevance for the design of efficient catalysts. In this study, two types of Co based MOF with different organic ligands (ZIF-67 and CoBDC; BDC=1,4-benzenedicarboxylate) are synthesized as OER electrocatalysts and their electrochemical behavior is studied in alkaline solution. Physical characterization indicates that ZIF-67, with tetrahedral Co sites, transforms into α-Co(OH)2 on electrochemical activation, which provides continuous active sites in the following oxidation, whereas CoBDC, with octahedral sites, evolves into β-Co(OH)2 through hydrolysis, which is inert for the OER. Electrochemical characterization reveals that Co sites coordinated by nitrogen from imidazole ligands (Co-N coordination) are more inclined to electrochemical activation than Co-O sites. The successive exposure and accumulation of real active sites is responsible for the gradual increase in activity of ZIF-67 in OER. This work not only indicates that CoMOFs are promising OER electrocatalysts but also provides a reference system to understand how metal coordination in MOFs affects the OER process.

Herein, we report the self-assembly of an anionic homochiral octahedral cage by condensing six Ga3+ cations and four trisacylhydrazone ligands. The robust nature of the hydrazone bond renders the cage stable in water, where it can take advantage of the hydrophobic effect for host-guest recognition. In addition to the internal binding site, namely, the inner cavity, the octahedral cage possesses four "windows", each of which represents an external binding site allowing peripheral complexation. These internal and external binding sites endow the cage with the capability to bind a broad range of guests whose sizes could either be smaller than or exceed the volume of the cage's inner cavity. Upon accommodation of a chiral guest, one of the two cage enantiomers becomes more favored than the other, producing circular-dichroism (CD) signals. The CD signal intensity of the cage is observed to be proportional to the ee value of the chiral guest, allowing a quantitative determination of the latter.

The Jahn-Teller (JT) theorem constitutes one of the most fundamental concepts in chemistry. In transition-element chemistry, the 3d4 and 3d9 configurations in octahedral complexes are particularly illustrative, where a distortion in local geometry is associated with a reduction of the electronic energy. However, there has been a lasting debate about the fact that the octahedra are found to exclusively elongate. In contrast, for Na9 Bi5 Os3 O24 , the octahedron around Os6+ (5d2 ) is heavily compressed, lifting the degeneracy of the t2g set of 5d orbitals such that in the sense of a JT compression a diamagnetic ground state results. This effect is not forced by structural constraints, the structure offers sufficient space for osmium to shift the apical oxygen atoms to a standard distance. The relevance of these findings is far reaching, since they provide new insights in the hierarchy of perturbations defining ground states of open shell electronic systems.

Two-dimensional (2D) hybrid perovskites are recently emerging as a potential family of semiconductors for versatile optoelectronic applications. Currently, the "perovskitizer" moieties are rigidly limited to small-size cations, while few 2D metal-halides containing guanidinium cations inside perovskite cages have been studied for photodetection. Herein, we present a new 2D hybrid perovskite, (i-BA)2 (G)Pb2 I7 (where G is guanidinium and i-BA is isobutylammonium), which adopts a bilayered framework of {GPb2 I7 }. Single-crystal structure analyses disclose that G cations act as the perovskitizer, confined in the flexible perovskite cages formed by the distorted PbI6 octahedra. Such inorganic sheets are crucial to the superior semiconducting properties and optical bandgap, as verified by the density functional theory calculation. Furthermore, its planar crystal-array photodetector shows fascinating photoelectric performance, including a quite low dark current (∼4.6×10-11 A), a large current switching ratio (∼1.0×103 ), and a notable photo-responsivity of ∼0.72 A W-1 , suggesting great potential of (i-BA)2 (G)Pb2 I7 for photodetection.

As a consequence of the static Jahn-Teller effect of the 5 E ground state of MnIII in cubic structures with octahedral parent geometries, their octahedral coordination spheres become distorted. In the case of six fluorido ligands, [MnF6 ]3- anions with two longer and four shorter Mn-F bonds making elongated octahedra are usually observed. Herein, we report the synthesis of the compound K3 [MnF6 ] through a high-temperature approach and its crystallization by a high-pressure/high-temperature route. The main structural motifs are two quasi-isolated, octahedron-like [MnF6 ]3- anions of quite different nature compared to that met in ideal octahedral MnIII Jahn-Teller systems. Owing to the internal electric field of Ci symmetry dominated by the next-neighbour K+ ions acting on the MnIII sites, both sites, the pseudo-rhombic (site 1) and the pseudo-tetragonally elongated (site 2) [MnF6 ]3- anions are present in K3 [MnF6 ]. The compound was characterized by single-crystal and powder X-ray diffraction, and magnetometry as well as by FTIR, Raman, and ligand field spectroscopy. A theoretical interpretation of the electronic structure and molecular geometry of the two Mn sites in the lattice is given by using a vibronic coupling model with parameters adjusted from multireference ab-initio cluster calculations.

Two-dimensional hybrid halide perovskites with single chiral and ferroelectricity together with various structural phase transitions provide the possibility for more diverse functional properties. Here, we present a 2D chiral hybrid halide perovskite ferroelectric, [C6 H5 (CH2 )4 NH3 ]2 CdCl4 (4PBA-CdCl4 , 4PBA=4-phenylbutylamine) that experiences two continuous phase transitions from centrosymmetric triclinic P 1‾ to polar chiral monoclinic P2 and then to another centrosymmetric tetragonal P4/mmm with increasing temperature, accompanied by symmetry breaking, due to the prominent octahedral distortion and disorder transformation of organic 4PBA cations. In the polar chiral phase, 4PBA-CdCl4 gives a significant CD signal and has a moderate ferroelectric polarization of 0.35 μC/cm2 . In addition, 4PBA-CdCl4 occupies a wide band gap of 4.376 eV that is chiefly contributed by the inorganic CdCl6 octahedron. This finding offers an alternative pathway for designing new phase transitions and related physical properties in hybrid halide perovskites and other hybrid crystals.

Supramolecular coordination cages show a wide range of useful properties including, but not limited to, complex molecular machine‐like operations, confined space catalysis, and rich host–guest chemistries. Here we report the uptake and release of non‐covalently encapsulated, pharmaceutically‐active cargo from an octahedral Pd cage bearing polymer chains on each vertex. Six poly(ethylene glycol)‐decorated bipyridine ligands are used to assemble an octahedral PdII 6(TPT)4 cage. The supramolecular container encapsulates progesterone and ibuprofen within its hydrophobic nanocavity and is activated by shear force produced by ultrasonication in aqueous solution entailing complete cargo release upon rupture, as shown by NMR and GPC analyses., An octahedral PdII 6(TPT)4 cage with polymer chains on each vertex is activated by shear force from ultrasonication in aqueous solution. The metal–organic cage encapsulates progesterone or ibuprofen within its hydrophobic nanocavity and shows complete cargo release upon rupture.

The new coordination polymer Cr(en)2As2VO7 (en=ethylenediamine) was synthesized under solvothermal conditions as deep red crystals. In the crystal structure VO4 tetrahedra and As2O5 handles formed by corner-sharing of two AsO3 pyramidal units are joined by common oxygen atoms into an undulated chain that is directed along the crystallographic b-axis. The chain is decorated by [Cr(en)2]3+ complexes with the Cr3+ cation having bonds to two terminal O2− anions of the As2O5 moiety thus generating a CrN4O2 octahedron, which displays a cis-configuration. The connection mode between Cr3+ and As2O5 leads to formation of a six-membered CrAs2O3 ring. The chains are arranged in a layer-like fashion in the (001) plane and these layers are stacked along [001]. A large number of N−H⋅⋅⋅O and C−H⋅⋅⋅O hydrogen bonds generate a three dimensional network. A Hirshfeld surface analysis was performed for visualizing the extended interchain interactions. The hydrogen bonding interactions are clearly detected in the IR spectrum. The UV-Vis spectrum shows an absorption at 2.3 eV which is in agreement with the red color of the sample.

International audience; Tetranuclear Zn(II) complexes, [Zn4(L)4(µ3-OCH3)2(X)2] (L = 2-((benzyloxy)carbonyl)-6-methoxyphenolate; X = Cl ⎻ (1), Br ⎻ (2), I ⎻ (3), N3 ⎻ (4), or NCS ⎻ (5)), have provided "defective" double-cubane core [Zn4O6], which were bridged by two µ3-methoxo and four µ2-phenolato oxygens in each discrete complex. In halide complexes 1, 2 and 3, two Zn(II) ions are in slightly distorted octahedral coordinations and the other two in geometries close to the severely distorted trigonal bipyramid, respectively, while all four Zn(II) in pseudo halide complexes 4 and 5 show slightly distorted octahedral geometries. Each complex exhibited blue fluorescence (λmax = 415-428 nm) with high photoluminescence quantum yields (PLQYS, Φem) in the range of 0.22-0.53 at room temperature in the solid state, of which 5 showed the highest Φem among the alkoxo-bridged multinuclear Zn(II) clusters ever reported.

Fabrication of 3d metal-based core@shell nanocatalysts with engineered Pt-surfaces provides an effective approach for improving the catalytic performance. The challenges in such preparation include shape control of the 3d metallic cores and thickness control of the Pt-based shells. Herein, we report a colloidal seed-mediated method to prepare octahedral CuNi@Pt-Cu core@shell nanocrystals using CuNi octahedral cores as the template. By precisely controlling the synthesis conditions including the deposition rate and diffusion rate of the shell-formation through tuning the capping ligand, reaction temperature, and heating rate, uniform Pt-based shells can be achieved with a thickness of

Addition of the bipyridyl-embedded cycloparaphenylene nanohoop bipy[9]CPP to [Fe{H2 B(pyz)2 }] (pyz=pyrazolyl) produces the distorted octahedral complex [Fe(bipy[9]CPP){H2 B(pyz)2 }2 ] (1). The molecular structure of 1 shows that the nanohoop ligand contains a non-planar bipy unit. Magnetic susceptibility measurements indicate spin-crossover (SCO) behaviour with a T1/2 of 130 K, lower than that of 160 K observed with the related compound [Fe(bipy){H2 B(pyz)2 }2 ] (2), which contains a conventional bipy ligand. A computational study of 1 and 2 reveals that the curvature of the nanohoop leads to the different SCO properties, suggesting that the SCO behaviour of iron(II) can be tuned by varying the size and diameter of the nanohoop.

We report a carbon-boron clathrate with composition 2 La@B6 C6 (LaB3 C3 ). Like recently reported SrB3 C3 ,[1] single-crystal X-ray diffraction and computational modelling indicate that the isostructural La member crystallizes in the cubic bipartite sodalite structure (Type-VII clathrate) with La atoms encapsulated within truncated octahedral cages composed of alternating carbon and boron atoms. The covalent nature of the B-C bonding results in a hard, incompressible framework, and owing to the balanced electron count, La3+ [B3 C3 ]3- exhibits markedly improved pressure stability and is a semiconductor with an indirect band gap predicted near 1.3 eV. A variety of different guest atoms may potentially be substituted within Type-VII clathrate cages, presenting opportunities for a large family of boron-stabilized, carbon-based clathrates with ranging physical properties.

The local structure, d-d transition band as well as spin Hamiltonian parameters (SHPs) are theoretically studied for the V4+ probe in 10Na2 O-30PbO-10Bi2 O3 -(50-x)SiO2 (NPBS) glass ceramics containing V2 O5 dopant with various concentration x (0 ≤ x ≤ 5 mol %) by using the perturbation formulas of the SHPs for tetragonally compressed octahedral 3d1 clusters. The first decreasing (or increasing) and then increasing (or decreasing) d-d transition band (= 10 Dq ) and hyperfine structure constants A// and A⊥ (or g factors g// and g⊥ ) with x can be suitably simulated with the similarly varying Fourier type concentration functions of cubic field parameter Dq , covalence factor N, core polarization constant κ and reduction factor H (or relative tetragonal compression ratio ρ), with the minima (or maxima) at the middle concentration x = 3 mol %, respectively. The above concentration variations of SHPs and the related quantities may originate from the modifications of local crystal-field strength, tetragonal compression and electron cloud distribution near the impurity V4+ with x, corresponding to the highest [V4+ ]/[V5+ ] ratio at 3 mol %. Present studies would be helpful to explore novel sodium lead bismuth silicate glass ceramics by modifying the concentration of V2 O5 dopant.

Co- and Ni-based layered hydroxides constitute a unique class of two-dimensional inorganic materials with exceptional chemical diversity, physicochemical properties and outstanding performance as supercapacitors and overall water splitting catalysts. Recently, the occurrence of Co(III) in these phases has been proposed as a key factor that enhance their electrochemical performance. However, the origin of this centers and control over its contents remains as an open question. We employed the Epoxide Route to synthesize a whole set of α-NiCo layered hydroxides. The PXRD and XAS characterization alert about the occurrence of Co(III) as a consequence of the increment in the Ni content. DFT+U simulation suggest that the shortening of the Co−O distance promotes a structural distortion in the Co environments, resulting in a double degeneration in the octahedral Co 3d orbitals. Hence, a strong modification of the electronic properties leaves the system prone to oxidation, by the appearance of Co localized electronic states on the Fermi level. This work combines a microscopic interpretation supported by a multiscale crystallochemical analysis, regarding the so-called synergistic redox behavior of Co and Ni, offering fundamental tools for the controllable design of highly efficient electroactive materials. To the best of our knowledge, this is the first computational–experimental investigation of the electronic and structural details of α-NiCo hydroxides, laying the foundation for the fine tuning of electronic properties in layered hydroxides. Fil: Hunt, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Constituyentes | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Constituyentes; Argentina Fil: Oestreicher, Víctor Santiago Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Mizrahi, Martin Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Requejo, Felix Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Jobbagy, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina

Photoreduction of CO2 into solar fuels is usually regarded as one of the promising solutions to overcome environmental pollution and the energy crisis. The main challenge in CO2 photoreduction (CO2 PR) is the low efficiency and poor selectivity. Layered double hydroxides (LDHs) are a class of 2D materials, consisting with M(OH)6 octahedra in the host layers and intercalated anions. Owing to the tuneable composition, particle size, morphology, and virtue coordinatively unsaturated active sites, a series of efficient strategies (morphology control, heterostructure, defect control, etc.) in LDH-based photocatalysts have been efficiently developed to enhance the photocatalytic selectivity and activity for CO2 PR. This review summarizes recent progress on the LDH-based photocatalysts for CO2 PR.

In order to maximize the performance of nanocrystals in a specific application, it is necessary to control both their size and shape. Here we report a one-pot protocol that allows us to separate growth from nucleation for achieving better control over the size and shape of Pd nanocrystals. The two processes are temporally separated from each other, although the synthesis is carried out in the same reaction container. Size control is achieved by simply varying the ratio between the amounts of precursor allocated to the growth and nucleation processes. With the involvement of seeds at a fixed number, increasing the amount of precursor for growth leads to increasingly larger nanocrystals. Shape control is made possible by varying the capping agent, with bromide leading to a cubic shape and citrate inducing the formation of an octahedral shape. The synthesis can also be scaled up by at least tenfold without compromising the quality.

The reactions of MnII (O2 CCH3 )2 with NEt3 Me+ CN- and NEt2 Me2 + CN- form (NEt3 Me)2 MnII 5 (CN)12 (1) and (NEt2 Me2 )2 MnII 5 (CN)12 (2), respectively. Structure model-building and Rietveld refinement of high-resolution synchrotron powder diffraction data revealed a cubic [a=24.0093 A (1), 23.8804 A (2)] 3D extended structural motif with adjacent tetrahedral and octahedral MnII sites in a 3:2 ratio. Each tetrahedral MnII site is surrounded by four low-spin octahedral MnII sites, and each octahedral MnII site is surrounded by six high-spin tetrahedral MnII sites; adjacent sites are antiferromagnetically coupled in 3D. Compensation does not occur, and magnetic ordering as a ferrimagnet is observed at Tc =13 K for 2 based on the temperature at which remnant magnetization, Mr (T)→0. The hysteresis has an unusual constricted shape with inflection points around 50 and 1.2 kOe with a 5 K coercivity of 16 Oe and remnant magnetization, Mr , of 2050 emuOe mol-1 . The unusual structure and stoichiometry are attributed to the very ionic nature of the high-spin N-bonded MnII ion, which enables the maximization of the attractive van der Waals interactions through minimization of void space via a reduced ∠ MnNC. This results in an additional example of the Ax MnII y (CN)x+2y (x=0, y=1; x=1, y=3; x=2, y=1; x=2, y=2; x=2, y=3; x=3, y=5; and x=4, y=1) family of compounds possessing an unprecedented stoichiometry and lattice motif that are cation adaptive structured materials.

Redox reactions, substitutions, and metalations are reported for the iron carbido sulfide [Fe(6)C(CO)(14)(S)](2−) ([1](2−)). Dianion [1](2−) oxidized to [Fe(6)C(CO)(16)(S)](0) ([2](0)) upon treatment with of [Fe(C(5)H(5))(2)]BF(4) or HBF(4) (H(2) formation) under an atmosphere of CO. Reaction of [2](0) with tBuNC gave [Fe(6)C(S)(CO)(13)(tBuNC)(5)], consisting of Fe(5)C(CO)(13) and [Fe(tBuNC)(5)](2+) subunits linked by a μ(3)-S(2−). The Fe(7)CS cluster [Fe(7)C(CO)(17)(S)](2−) formed upon treatment of (Ph(4)P)(2)[1] with Fe(benzylideneacetone)(CO)(3). The Fe(7) species is an edge-fused cluster with [Fe(6)C(CO)(10)(μ-CO)(4)] and Fe(CO)(3) subunits joined by μ(3)-S and two Fe–Fe bonds. The analogous reaction using Mo(CO)(4)(norbornadiene) gave [MoFe(6)C(CO)(18)(S)](2−). In this cluster, the Mo center is located in the octahedral subunit. Treatment of [1](2−) with SO(2) afforded [Fe(6)C(S)(SO(2))(CO)(13)](2−). This cluster features an Fe(6)C core decorated with μ(3)-S and μ(2)-SO(2) ligands. These experiments were undertaken in an effort to connect organometallic clusters to FeMoco.

This work reports the ambient temperature synthesis and structural characterisation of six new first row transition metal acetylenedicarboxylate coordination polymers. The Co and two Ni compounds adopt structures in which the octahedral metals are connected into 1D chains via the acetylenedicarboxylate ligand. In contrast the Mn and two Zn compounds adopt 3D metal-organic frameworks; while the Mn compound is non-porous the two Zn structures contain dimeric or trimeric clusters connected into frameworks that are potentially porous. These two anionic metal-organic frameworks are, however, charged balanced by cations siting in their pores which greatly reduces the ability to access their porosity.

Liquid state self‐assembly is important for the understanding of the complex structures developed in abiogenesis and biogenesis as well as for numerous potential technological applications. Herein we report the first body‐centered cubic liquid crystalline phase with 8‐connected network topology and open octahedral network structure. It is formed by dynamic soft self‐assembly of X‐shaped polyphiles with oligo(para‐phenylene‐ethynylene) cores. The π‐conjugated rods with perfluorinated inner benzene rings form networks conjoined by eight‐way junctions, which are formed by nano‐segregated spheres involving hydrogen‐bonded polar end groups, while the branched aliphatic chains at opposite sides of the cores fill the continuum. This novel cubic phase is based on the I‐WP minimal surface separating the frameworks of polyaromatic cores from the most disordered chain segments. It can also be considered as a dense sphere packing. Such liquid organic frameworks, representing hybrids of sphere packings and networks could be of interest for organic photonics and other technologies., The first 8‐connected network based on the I‐WP minimal surface is formed by dynamic soft self‐assembly of X‐shaped polyphiles with oligo(para‐phenylene‐ethynylene) cores. This Im 3‾ m cubic liquid‐crystalline phase is one of a new kind of cubic phases combining a network structure of rod‐bundles interconnected by polar spheres.

Following the recent discovery of stable octa‐coordinated alkaline earth metals with N2 and CO, the role of group II metals in the catalytic reduction of these ligands by means of density functional theory (DFT) calculations and conceptual DFT‐based reactivity indices is investigated. Cubic group IV and octahedral group VI transition metal complexes as well as the free ligands are computed for reference. The outer and most accessible atoms of N2 and CO become much more nucleophilic and electrophilic in all complexes, relevant for N2 fixation, as probed by the Fukui function and local softness. Within one row of the periodic table, the alkaline earth complexes often show the strongest activation. On the contrary, the electrostatic character is found to be virtually unaffected by complexation. Trends in the soft frontier orbital and hard electrostatic character are in agreement with calculated proton affinities and energy decomposition analyses of the protonated structures, demonstrating the dominance of the soft (HOMO–LUMO) orbital interactions., Alkaline earth complexes: The viability of alkaline earth metal‐based N2 fixation is investigated. It is shown that the activation of N2 through complexation originates from the d–π back‐donation. Within one row of the periodic table, the alkaline earth metal shows the strongest nucleophilic activation of the N2 ligand, confirming clear trends in proton affinities.

Supramolecular systems hold great potential as ferroelectric materials because they are easy to prepare and do not require toxic and environmentally damaging elements. However, directing the self-assembly process of a supramolecular array to yield polarizable solids is still challenging. Here, we describe induced ferroelectricity in a supramolecular framework of metal-organic cages that are supported by a flexible tripodal ligand (NHCH2 -(3-Py))3 PO (TPPA). Ferroelectric responses on the discrete cage [Cu6 (H2 O)12 (TPPA)8 ](NO3 )12 ⋅ 45H2 O (1) and its 2D-connected framework [{Cu6 Cl4 (H2 O)6 (TPPA)8 }(NO3 )8 ⋅ 60H2 O]n (2) yielded well-resolved rectangular hysteresis loops at room temperature with remnant polarization values of 27.27 and 29.09 μC/cm2 , respectively. Thermal hysteresis measurements (THM) and capacitance-voltage (C-V) plots further corroborate the ferroelectric behavior in these compounds. The polarization in them is due to the displacements of solvated molecules and nitrate ions in the pockets of these frameworks.

Replacing the Pb-X octahedral building unit of AI PbX3 perovskites (X=halide) with a pair of edge-sharing Pb-X octahedra affords the expanded perovskite analogs: AII Pb2 X6 . We report seven members of this new family of materials. In 3D hybrid perovskites, orbitals from the organic molecules do not participate in the band edges. In contrast, the more spacious inorganic sublattice of the expanded analogs accommodates larger pyrazinium-based cations with low-lying π* orbitals that form the conduction band, substantially decreasing the band gap of the expanded lattice. The molecular nature of the conduction band allows us to electronically dope the materials by reducing the organic molecules. By synthesizing derivatives with AII =pyridinium and ammonium, we can isolate the contributions of the pyrazinium-based orbitals in the band gap transition of AII Pb2 X6 . The organic-molecule-based conduction band and the inorganic-ion-based valence band provide an unusual electronic platform with localized states for electrons and more disperse bands for holes upon optical or thermal excitation.

Ti silicates, and in particular, titanium silicalite-1 (TS-1), are nowadays important catalysts for several partial oxidation reactions in the presence of aqueous H2 O2 as an oxidant. Despite the numerous studies dealing with this material, some fundamental aspects are still unclear. In particular, the structure and the catalytic role of defective Ti sites, other than perfect tetrahedral sites recognized as the main active species, has not been quantitatively discussed in the literature. We assess the structural features of defective Ti sites on the basis of outcomes of electronic spectroscopies, as interpreted through quantum mechanical simulation. Strong evidence is disclosed to support the fact that the most common defective Ti sites, often reported in the TS-1 literature, are monomeric Ti centers that are embedded in the zeolite framework, and which have a distorted octahedral local symmetry.

The lead-free halide perovskite A3 Sb2 Br9 is utilized as a photocatalyst for the first time for C(sp3 )-H bond activation. A3 Sb2 Br9 nanoparticles (A3 Sb2 Br9 NPs) with different ratios of Cs and CH3 NH3 (MA) show different photocatalytic activities for toluene oxidation and the photocatalytic performance is enhanced when increasing the amount of Cs. The octahedron distortion caused by A-site cations can change the electronic properties of X-site ions and further affect the electron transfer from toluene molecules to Br sites. After the regulation of A-site cations, the photocatalytic activity is higher with A3 Sb2 Br9 NPs than that with classic photocatalysts (TiO2 , WO3 , and CdS). The main active species involved in photocatalytic oxidation of toluene are photogenerated holes (h+ ) and superoxide anions (. O2 - ). The octahedron distortion by A-site cations affecting photocatalytic activity remains unique and is also a step forward for understanding more about halide-perovskite-based photocatalysis. The relationship between octahedron distortion and photocatalysis can also guide the design of new photocatalytic systems involving other halide perovskites.

Precise atomic structure of metal nanoclusters (NCs) is fundamental for elucidating the structure-property relationships and the inherent size-evolution principles. Reported here is the largest known FCC-based (FCC=face centered cubic) silver nanocluster, [Ag100 (SC6 H3 3,4 F2 )48 (PPh3 )8 ]- : the first all-octahedral symmetric nesting Ag nanocluster with a four-layered Ag6 @Ag38 @Ag48 S24 @Ag8 S24 P8 structure, consistent symmetry elements, and a unique rhombicuboctahedral morphology distinct from theoretical predictions and previously reported FCC-based Ag clusters. DFT studies revealed extensive interlayer interactions and degenerate frontier orbitals. The FCC-based Russian nesting doll model constitutes a new platform for the study of the size-evolution principles of Ag NCs.

[N,N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L1) and [N,N-bis(2-quinolylmethyl)-N-bis(2-pyridyl)methylamine] (L2) were employed to prepare CuII and CuI complexes for spectroscopic and structural characterization. [L1CuII(H2O)](NO3)2 and [L2CuII(NO3)]NO3 have Jahn–Teller distorted octahedral geometries and give rise to isotropic EPR spectra in frozen solution. [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf have distorted trigonal bipyramidal and tetrahedral solid-state structures, respectively. The N-donors display labile behavior in solution, based on variable-temperature 1H NMR studies. Addition of trimethylamine N-oxide (Me3NO) to solutions of [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf resulted in diamagnetic species tentatively assigned as the corresponding adducts upon replacement of coordinated acetonitrile, based on 1H NMR spectroscopy. Heating [L1CuI(CH3CN)]OTf to 50–60 °C in the presence of Me3NO resulted in its cupric analogue [L1CuII(CH3CN)]2+, as well as a small amount of 2-dipyridylketone, along with other oxidation by-products. In the case of [L2CuI(CH3CN)]OTf, the reaction with Me3NO resulted in the cupric complex bis(2-quinolinecarboxamidato)copper(II), along with 2-dipyridylketone as oxidation products.

Low-dimensional ns2 -metal halide compounds have received immense attention for applications in solid-state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb2+ or unstable Sn2+ , and a stable inorganic luminescent material has yet to be found. Here, the zero-dimensional Rb7 Sb3 Cl16 phase, comprised of isolated [SbCl6 ]3- octahedra and edge-sharing [Sb2 Cl10 ]4- dimers, shows room-temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature-dependent PL lifetime rivals that of previous low-dimensional materials with a specific temperature sensitivity above 0.06 K-1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi3+ in the Rb7 Bi3-3x Sb3x Cl16 (x≤1) family, we present the edge-shared [Sb2 Cl10 ]4- dimer as a design principle for Sb-based luminescent materials.