Tetravalent Terbium Chelates: Stability Enhancement and Property Tuning.

Coordination chemistry of rare-earth elements has been dominated by the +3 oxidation state. Complexes with higher-valence lanthanide ions are synthetically challenging but are of fundamental research interest and significance as advanced molecular materials. Herein, four tetravalent terbium complexes (-) of the common formula [Tb(OSiPh)L] (L = ethylene glycol dimethyl ether (DME), 2,2-bipyridine (bpy), 2,2-bipyrimidine (bpym), and 1,10-phenanthroline (phen)) are reported.

Improved Gaussian basis sets for norm-conserving 4f-in-core pseudopotentials of trivalent lanthanides (Ln = Ce-Lu).

The first-principles quantum chemical computations often scale as Nk (N = basis sets; k = 1-4 for linear scaling, Hartree-Fock or density functional theory methods), which makes the development of accurate pseudopotentials and efficient basis sets necessary ingredients in modeling of heavy elements such as lanthanides and actinides. Recently, we have developed 4f-in-core norm-conserving pseudopotentials and associated basis sets for the trivalent lanthanides [Lu et al., J.

Synthesis and characterization of iron clusters with an icosahedral [Fe@Fe] Core.

Iron-metal clusters are crucial in a variety of critical biological and material systems, including metalloenzymes, catalysts, and magnetic storage devices. However, a synthetic high-nuclear iron cluster has been absent due to the extreme difficulty in stabilizing species with direct iron-iron bonding. In this work, we have synthesized, crystallized, and characterized a (Tp*)WS(Fe@Fe) cluster (Tp* = tris(3,5-dimethyl-1-pyrazolyl)borate(1-)), which features a rare trideca-nuclear, icosahedral [Fe@Fe] cluster core with direct multicenter iron-iron bonding between the interstitial iron (Fe) and peripheral irons (Fe), as well as Fe···Fe ferromagnetic coupling.

4f/5d Hybridization Induced Single-Electron Delocalization in an Azide-Bridged Dicerium Complex.

Dilanthanide complexes with one-electron delocalization are important targets for understanding the specific 4f/5d-bonding feature in lanthanide chemistry. Here, we report an isolable azide-bridged dicerium complex [{(Trapen)Ce}(μ-N)] [Trapen = tris (2-aminobenzyl)amine; TMS = SiMe], which is synthesized by the reaction of tripodal ligand-supported (Trapen)CeCl complex with NaN. The structure and bonding nature of are fully characterized by X-ray crystal diffraction analysis, electron paramagnetic resonance (EPR), magnetic measurement, cyclic voltammetry, X-ray absorption spectroscopy, and quantum-theoretical studies.

Pd Nanocluster with Nonmetal-to-Metal- Ring Coordination and Promising Photothermal Conversion Efficiency.

Constructing ambient-stable, single-atom-layered metal-based materials with atomic precision and understanding their underlying stability mechanisms are challenging. Here, stable single-atom-layered nanoclusters of Pd were synthesized and precisely characterized through electrospray ionization mass spectrometry and single-crystal X-ray crystallography. A pseudo-pentalene-like Pd unit was found in the nanocluster, interacting with two syn PPh units through nonmetal-to-metal -ring coordination.

Structural characterization and immunomodulatory activity of a novel polysaccharide from .

Polysaccharides are important components of Panax notoginseng that contribute to its immunomodulatory ability. This study aimed to isolate polysaccharides from notoginseng and investigate the structural feature and potential immunomodulatory activity. The polysaccharide was isolated from notoginseng by anion exchange and gel permeation chromatography.

Stereoelectronic Modulation of a Single-Molecule Junction through a Tunable Metal-Carbon dπ-pπ Hyperconjugation.

Conjugated molecules play a critical role in the construction of single-molecule devices. However, most conventional conjugated molecules, such as hydrocarbons, involve only a pπ-pπ conjugation of light elements. While the metal d-orbitals can introduce abundant electronic effects to achieve novel electronic properties, it is very scarce for the charge transport study of dπ-pπ conjugated pathways with a metal involved.

Qualitative and quantitative analysis of major components of Renshen-Yangrong Pill by UPLC-LTQ/Orbitrap/MS and UPLC-MS/MS.

Renshen-Yangrong Pill (RYP) is a classical traditional Chinese medicine (TCM) preparation for the treatment of asthenic symptoms, while its multiple herbal compositions bring a wide variety of unclear chemical components which seriously hinder the effective quality control and clinical practice. The present study aimed to investigate the overall chemical profile of RYP by UPLC-LTQ/Orbitrap/MS, and further obtain the quantitative distributions of representing components in the preparations. A total of 132 components in RYP including flavonoids, triterpenoid saponins, phenylpropanoids, and monoterpenoid glycosides were identified or tentatively characterized by authentic compounds or accurate masses and fragmentation, in which 52 characteristic components were selected for further quantitation by UPLC-MS/MS.

Norm-Conserving 4f-in-Core Pseudopotentials and Basis Sets Optimized for Trivalent Lanthanides (Ln = Ce-Lu).

We present here a set of scalar-relativistic norm-conserving 4f-in-core pseudopotentials, together with complementary valence-shell Gaussian basis sets, for the lanthanide (Ln) series (Ce-Lu). The Goedecker, Teter, and Hutter (GTH) formalism is adopted with the generalized gradient approximation (GGA) for the exchange-correlation Perdew-Burke-Ernzerhof (PBE) functional. The 4f-in-core pseudopotentials are built through attributing 4f-subconfiguration 4f ( = 1-14) for Ln (Ln = Ce-Lu) into the atomic core region, making it possible to circumvent the difficulty of the description of the open 4f valence shell.

The smallest 4f-metalla-aromatic molecule of cyclo-PrB with Pr-B multiple bonds.

The concept of metalla-aromaticity proposed by Thorn-Hoffmann (. 1979, 3, 39) has been expanded to organometallic molecules of transition metals that have more than one independent electron-delocalized system. Lanthanides, with highly contracted 4f atomic orbitals, are rarely found in multiply aromatic systems.

Cis- and trans-binding influences in [NUO·(N)].

Uranium nitride-oxide cations [NUO] and their complexes with equatorial N ligands, [NUO·(N)] (n = 1-7), were synthesized in the gas phase. Mass-selected infrared photodissociation spectroscopy and quantum chemical calculations confirm [NUO·(N)] to be a sterically fully coordinated cation, with electronic singlet ground state of A, linear [NUO] core, and C structure. The presence of short N-U bond distances and high stretching modes, with slightly elongated U-O bond distances and lowered stretching modes, is rationalized by attributing them to cooperative covalent and dative [ǀN≡U≡Oǀ] triple bonds.

Bonding Nature of "Ionic Carbenes" in [M(μ-CH)]-Containing Compounds: The Covalent Interaction.

While a series of trinuclear rare-earth metal methylene (divalent >CH) complexes with the so-called "ionic carbene" have been known for decades, the nature of metal-carbene interactions in this class of compounds remains elusive. Herein, a quantum chemical investigation has been performed to reveal the bonding nature in typical trimetallic "ionic carbene" species with the [M(μ-CH)] (M = Sc, Y, La, and Ac) cluster core. Through various chemical bonding analyses, we have demonstrated that there exists a non-negligible covalent interaction between μ-CH and M moieties, and the chemical bonding can be accounted for with two three-center two-electron (3c-2e) bonds.

On the highest oxidation states of the actinoids in AnO molecules (An = Ac - Cm): A DMRG-CASSCF study.

Actinoid tetroxide molecules AnO (An = Ac - Cm) are investigated with the ab initio density matrix renormalization group (DMRG) approach. Natural orbital shapes are used to read out the oxidation state (OS) of the f-elements, and the atomic orbital energies and radii are used to explain the trends. The highest OSs reveal a "volcano"-type variation: For An = Ac - Np, the OSs are equal to the number of available valence electrons, that is, Ac , Th , Pa , U , and Np .

Electronic Structure and Spectroscopic Properties of Group-7 Tri-Oxo-Halides MOX (M = Mn-Bh, X = F-Ts).

The 24 trioxide halide molecules MOX of the manganese group (M = Mn-Bh; X = F-Ts), which are iso-valence-electronic with the famous MnO ion, have been quantum-chemically investigated by quasi-relativistic density-functional and ab initio correlated approaches. Geometric and electronic structures, valence and oxidation numbers, vibrational and electronic spectral properties, energetic stabilities of the monomers in the gas phase, and the decay mode of MnOF have been investigated. The light Mn-3d species are most strongly electron-correlated, indicating that the concept of a closed-shell Lewis-type single-configurational structure [Mn(d) O(p) F(p)] reaches its limits.

The elements of human cyclin D1 promoter and regulation involved.

Cyclin D1 is a cell cycle machine, a sensor of extracellular signals and plays an important role in G1-S phase progression. The human cyclin D1 promoter contains multiple transcription factor binding sites such as AP-1, NF-қB, E2F, Oct-1, and so on. The extracellular signals functions through the signal transduction pathways converging at the binding sites to active or inhibit the promoter activity and regulate the cell cycle progression.

Resonance Raman intensity analysis of the excited-state proton-transfer dynamics of 2-hydroxybenzaldehyde in the charge-transfer/proton-transfer absorption band.

Resonance Raman spectra were obtained for 2-hydroxybenzaldehyde (OHBA) in cyclohexane solution with excitation wavelengths in resonance with the first charge-transfer/proton-transfer (CT/PT) band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion predominantly along the nominal C=CH in-plane bend+ring deformation modes (nu9, nu10, nu14, nu16, nu18, nu19, nu20, nu26, nu30, nu31, and nu35) accompanied by a smaller amount of motion along the nominal C=O stretch mode (nu7), the nominal C=C-C(=O) in-plane bend modes (nu33 and nu37), and the nominal ring C-O-H in-plane bend modes (nu9 and nu14). A preliminary resonance Raman intensity analysis was done, and these results for the OHBA molecule were compared to results previously reported for the 2-hydroxyacetophenone (OHAP) molecule.

[Experimental study on Rhizoma sparganii and Radices zedoariae treating hepatic fibrosis].

Objective: To study the effects of rhizoma sparganii and radices zedoariae on hepatic fibrosis.

Method: The rat immunohepatic fibrosis model was made by intraperitoneal injection of porcine serum and treated with rhizoma sparganii and radices zedoariae. The ALT, GGT, TP, ALb, A/G, IVC, LN, HA and the pathological change of the liver were observed.