Two new compounds, 1-deoxy-1-[2'-oxo-1'-pyrrolidinyl]-2-n-butyl-α-fructofuranoside (1) and isoarvenin III (2), were isolated from the fruits of Trichosanthes kirilowii Maxim, and their structures were established on the basis of spectroscopic methods.

Further investigation on the stems of Artocarpus nitidus subsp. lingnanensis led to the isolation and characterization of a new flavan-3-ol, named artoflavanocoumarin (1), along with three known compounds (+)-catechin (2), (+)-afzelechin 3-O-α-l-rhamnoside (3), and (+)-catechin 3-O-α-l-rhamnoside (4). Their structures were elucidated on the basis of spectroscopic data.

Two new C(21) steroidal glycosides were isolated from the EtOAc fraction of Cynanchum amplexicaule. Their structures were elucidated as amplexicogenin d-3-O-β-d-cymaropyranoside (1) and stauntogenin -3-O-α-l-oleandropyranosyl-(1 → 4)-O-β-d-digitoxopyranosyl-(1 → 4)-O-β-d-oleandropyranoside (2) by spectroscopic analysis including 1D and 2D NMR experiments.

Spiraeamide (1), a new sphingolipid, has been isolated from the ethyl acetate-soluble fraction of the methanolic extract of the whole plant of Spiraea brahuica, along with marrubiin (2), 19-acetylmarrubenol (3), and 6-acetylmarruenol (4). Their structures were elucidated by (1)H and (13)C NMR spectra, and COSY, NOESY, HMQC, HMBC, EI-MS, and ...

The 1,3-dipolar cycloaddition of azides and active internal alkynes has been well studied, but is rarely utilized as a tool for polymer preparation. In this work, an efficient polymerization route is developed. Polycycloaddition of diazide (4) and bis(benzoylethynyl)-benzenes and -butane (3) at elevated temperature has produced the first examples of ...

A new pyrimidinedione derivative, 9-acetyl-1,3,7-trimethyl-pyrimidinedione (1), was isolated from the gorgonian coral Verrucella umbraculum, together with two known compounds, caffeine (2) and 1,3-dimethylpyrimidine-2,4(1H,3H)-dione (3). The structure of 1 was elucidated by the aid of 1D, 2D NMR and MS experiments. The structures of the known compounds were identified by comparison ...

One new cytochalasan alkaloid, chaetoglobosin V(b) (1), together with two structurally related known compounds, chaetoglobosin V (2) and chaetoglobosin G (3), was isolated from the ethyl acetate extract of a culture of the endophytic fungus Chaetomium globosum, associated with the leaves of Ginkgo biloba tree. The structures of the isolated ...

We report the remarkable stability of di-substituted organo-Zintl deltahedral clusters in the presence of water. This has been exploited in a reaction at the organic substituents of the cluster which produces water as a by-product. Also reported are the synthesis, characterization, and crystal structure of [K-krypt](2)[Ge(9)-(CH[double bond, length as m-dash]CH-CH(2)NH(2))(2)] ...

Two novel α,β-unsaturated γ-lactono-hydrazides, geralcin A (2) and geralcin B (3), were isolated from Streptomyces sp. LMA-545. This unusual scaffold consists of the condensation of alkyl-hydrazide with an α,β-unsaturated γ-lactone, 3-(5-oxo-2H-furan-4-yl)propanoic acid (1), which was isolated from the same broth culture. Amberlite XAD-16 solid-phase extraction was used during the cultivation ...

Single-crystal-to-single-crystal (SCSC) transformations represent some of the most fascinating phenomena in chemistry. They are not only intriguing from a basic science point of view but also provide a means to modify or tune the properties of the materials via the postsynthetic introduction of suitable guest molecules or organic functional groups ...

In this Communication, we present the synthesis and use of [Ru(bpy)(2)(bpy-CCH)](2+), a versatile synthon for the construction of more sophisticated dyads by means of click chemistry. The resulting chromophore-acceptor or -donor complexes have been studied by flash photolysis and are shown to undergo efficient electron transfer to/from the chromophore. Additionally, ...

A facile two-step hydrothermal method is developed for the large-scale preparation of lithium nickel manganese oxide spinel as a cathode material for lithium ion batteries. In the reaction, nickel is introduced in a first step at neutral pH, followed by lithium insertion under base to form a product having composition ...

A new natural product, 10-hydroxyrutaecarpine (1), and a rarely new glycosidic alkaloid, rutaecarpine-10-O-rutinoside (2), along with the known compounds rutaecarpine (3), evodiamine, wuzhuyuamide-I, and dehydroevodiamine were isolated from the butanol fraction of 70% ethanol aqueous extract of the dried and nearly ripe fruits of Euodia rutaecarpa (Juss.) Benth. Their structures ...

Presented herein is the design of a dinuclear Ni(II) synthetic hydrolase [Ni(2)(HBPPAMFF)(μ-OAc)(2)(H(2)O)]BPh(4) (1) (H(2)BPPAMFF = 2-[(N-benzyl-N-2-pyridylmethylamine)]-4-methyl-6-[N-(2-pyridylmethyl)aminomethyl)])-4-methyl-6-formylphenol) to be covalently attached to silica surfaces, while maintaining its catalytic activity. An aldehyde-containing ligand (H(2)BPPAMFF) provides a reactive functional group that can serve as a cross-linking group to bind the complex to an ...

Through specific molecular shapes and repeating polymeric sequences, biomacromolecules encode information about both structure and function. Inspired by DNA molecules, we have conceived a strategy to encode linear molecular strands with sequences that specify intermolecular association, and we and our collaborators have supported this idea through our experimental work. This ...

[2]Pseudorotaxanes, [2]rotaxanes and metal-organic rotaxane framework materials that utilise as the wheel component are well known and structural variations based on changing the axle component are common. Studies in which the wheel is structurally modified are much more limited. Herein, is described the synthesis of symmetrical analogues containing four CH(2)OR ...

Two new epipolythiodioxopiperazines, named chetracins B and C (1 and 2), and five new diketopiperazines, named chetracin D (4) and oidioperazines A-D (5, 10, 12, and 13), were isolated from the fungus Oidiodendron truncatum GW3-13, along with six known compounds (3, 6, 7, 8, 9, and 11). Their structures were ...

Frustrated Lewis pairs (FLPs) has been applied to catalytic metal-free hydrogenation. Can the FLP reactivity be used for catalytic hydroamination? Using density functional theory (DFT) calculations, we have explored whether the molecules , which were previously designed by integrating the dearomatization-aromatization effect and the FLP reactivity, can catalyze the intramolecular ...

We characterized and determined the crystal structure of a putative glucokinase/hexokinase from Thermus thermophilus that belongs to the ROK (bacterial repressors, uncharacterized open reading frames, and sugar kinases) family. The protein possessed significant enzymatic activity against glucose and mannose, with V(max) values of 260 and 68μmol·min(-1)·mg(-1) protein, respectively. Therefore, we ...

Catalytically inactive phospholipase A(2) (PLA(2)) homologues play key roles in the pathogenesis induced by snake envenomation, causing extensive tissue damage via a mechanism still unknown. Although, the amino acid residues directly involved in catalysis are conserved, the substitution of Asp49 by Arg/Lys/Gln or Ser prevents the binding of the essential ...

GTP-bound Ras adopts two interconverting conformations, "inactive" state 1 and "active" state 2. However, the tertiary structure of wild-type (WT) state 1 remains unsolved. Here we solve the state 1 crystal structures of H-Ras WT together with its oncogenic G12V and Q61L mutants. They assume open structures characterized by impaired ...

Metathesis reaction of LLnCl(THF)(2) [L = (Me(3)SiNC(C(6)H(5))N)(2)(CH(2))(3)] with NaBH(4) in a 1 : 1.5 molar ratio in THF (THF = tetrahydrofuran) at 60 °C afforded the monoborohydride LLn(BH(4))(DME) [Ln = Y (), Nd (), Sm() and Yb()] crystallized from DME solution (DME = dimethoxyethane). Crystal structure analyses revealed are monomers, in which ...

The TiNiSi-type structure, antiferromagnetic ordering and divalent state of europium in EuPdSn have been confirmed by neutron powder diffraction. The Néel temperature is 16.2(3) K. The magnetic diffraction peaks can be indexed with a propagation vector k = [0, 0.217, q(z)] (q(z) ≤ 0.02) at 13.2 K, and k = [0, 0.276, 0] at 3.6 K, indicating an incommensurate antiferromagnetic structure at both ...

We introduce a facile and robust methodology for the aggregation-free, aqueous phase synthesis of hierarchically complex metal-semiconductor heterostructures. By encapsulating semiconductor nanostructures within a porous SiO2 shell with a hollow interior, we are able isolate each individual particle while allowing it access to metal precursors for subsequent metal growth. We ...

A sol-gel technique allowing the single-pot synthesis of a carbon gel-templated, Ca-based, Al(2) O(3) -stabilized CO(2) sorbent is reported. Upon removal of the carbon gel template via calcination in air, hollow microspheres, comprised of a nanostructured shell are obtained. The new material possesses an excellent CO(2) uptake of 0.56 g(CO(2) ...

Flame silica was surface-labeled with 17O, through isotopic enrichment of both siloxanes and silanols. After heat treatment at 200 and 700°C under vacuum, the resulting partially dehydroxylated silica materials were investigat-ed by high-field solid-state 1H and 17O NMR. More specifically, MQ MAS and HMQC sequences were used to probe 17O ...

Partial labeling by deuterium may be quantified through simple integrations of those (1) H (200 or 400 MHz) and (13) C (100.6 MHz) NMR resonances that are split into pairs by chemical shifts (n) Δ=δ(deuterated)-δ(nondeuterated) as induced by deuterium across n>2 chemical bonds. The relative intensities of the two components of a ...

A new approach to synthesize 3D structures through a [2+2] photodimerization process has been carried out by transforming two isostructures of 1D staggered-sculls chain [M(1,2-chdc)(bpe)(2) (H(2) O)(2) ]⋅H(2) O (M=Zn, Mn) into 3D NbO-type metal-organic frameworks through UV irradiation in single-crystal-to-single-crystal mode. (see figure; bpe=trans-1,2-(bis(4-pyridyl)ethene, chdc=cyclohexanedicarboxylate).

A common perception of many chemists is that non-biological chiral crystals comprise a small fraction of all crystals, as is the case of chiral non-biological molecules (∼10%). We show that the proportion of non-biological chiral crystals is as high as 23%; and only ∼6% of these are labelled as chiral.

Atmospheric organic aerosols (OA) represent a significant fraction of airborne particulate matter and can impact climate, visibility, and human health. These mixtures are difficult to characterize experimentally due to their complex and dynamic chemical composition. We introduce a novel Computational Brewing Application (COBRA) and apply it to modeling oligomerization chemistry ...

Solid humic acid (HA) particles were dissolved and subsequently coated on a type of multiwalled carbon nanotubes (MWCNTs). Pb(2+) sorption from water by the solid HA, the MWCNTs and the obtained HA-MWCNT complexes was compared. The underlying mechanism of the difference in the sorption was discussed with the data at ...

Halogenation at a semi-conductor surface follows simple dynamics characterized by 'localized reaction' along the direction of the halide bond being broken. Here we extend the study of halide reaction-dynamics to the important environment of a smooth metal surface, where greater product mobility would be expected. Extensive examination of the physisorbed ...

ABSTRACT: Two new monocyclic monoterpenoid glycosides, rel-(1R,2S,3R,4R) p-menthane-1,2,3-triol 3-O--D-glucopyranoside (1) and rel- (1S,2R,3S) terpinolene-1,2,3-triol 3-O--D-glucopyranoside (2) were isolated from aqueous acetone extract of the aerial parts of Mentha haplocalyx. Their structures were elucidated through spectral analysis using MS and NMR spectrometers.

Porous molecular crystals are accessible by a directed self-assembling of a molecular organic precursor by hydrogen bonding. As M. Mastalerz and I. M. Oppel describe in their Communication (DOI: 10.1002/anie.201201174), enclosed solvent molecules were removed from the pores, leading to a permanently porous material with a specific surface area of ...

Surface-hydrogenated anatase TiO(2) (TiO(2)-H) nanowire-microspheres were prepared by converting protonated titanate nanotube to TiO(2)-H under a hydrogen atmosphere. We show that TiO(2)-H nanowire-microspheres have Ti-H and O-H bonds on their surface and exhibit improved visible-light absorption and highly enhanced photocatalytic activity.

Effective methodology to functionalize C-H bonds requires overcoming the key challenge of differentiating among the multitude of C-H bonds that are present in complex organic molecules. This Account focuses on our work over the past decade toward the development of site-selective Pd-catalyzed C-H functionalization reactions using the following approaches: substrate-based ...

Three new clerodane-type diterpenoids with a rare sulfoxide group, cleidbrevoids A-C (1-3), were isolated from the twigs and leaves of Cleidion brevipetiolatum. Their structures were elucidated on the basis of spectroscopic methods and the absolute configuration of compounds 1 and 3 was determined by X-ray analysis. Compound 3 showed weak ...

Using molecular dynamics simulations on the microsecond timescale, we investigate the nucleation and growth mechanisms of CO2 hydrates in a water/CO2/silica three-phase system. Our simulation results indicate that CO2 hydrate nucleates near the three-phase contact line rather than at the two-phase interfaces, and then grows along the contact line to ...

Model cobalt catalysts for CO2 hydrogenation were prepared using colloidal chemistry. The turnover frequency at 6 bar and at 200-300 °C increased with cobalt nanoparticle size from 3 to 10 nm. It was demonstrated that near monodisperse nanoparticles in the size range 3 - 10 nm could be generated without ...

A new spirostanol saponin (1), along with four known saponins, dioscin (2), protodioscin (3), methyl-protodioscin (4), and indioside D (5), and one known steroid glycoalkaloid solamargine (6) were isolated from the two synonymous species, Solanum incanum and S. heteracanthum. The structure of the new saponin was established as (23S,25R)-spirost-5-en-3β,23-diol 3-O-{β-d-xylopyranosyl-(1→2)-O-α-l-rhamnopyranosyl-(1→4)-[O-α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranoside}, ...

Two new quaternary protoberberine alkaloids, namely corydayanine (1) and yanhusuine (2), were isolated from the tubers of Corydalis yanhusuo. On the basis of extensive chemical and spectroscopic evidences, especially 1D and 2D NMR and HRMS experiments, their structures were elucidated as 5,6-dihydro-3,9-dihydroxy-2,10-dimethoxy-13-methyl-dibenzo[a,g] quinolizinium alkaloid and 5,6-dihydro-12-hydroxy-2,3,9-trimethoxy-13-methyl-dibenzo[a,g] quinolizinium alkaloid, respectively.

A new megastigmane glycoside, grasshopper ketone 3-O-primveroside (1), was isolated from the methanolic extract of the whole herbs of Sinocrassula indica (Crassulaceae). Its structure was elucidated on the basis of spectral and chemical evidence.

Chelate stabilization of a titanium(iv)-salan alkoxide by ligand exchange with 2,6-pyridinedicarboxylic acid (dipic) resulted in heptacoordinate complex which is not redox-active, stable on silica gel and has increased aqueous stability. is highly toxic in HeLa S3 and Hep G2 and has enhanced antitumor efficacy in a mouse cervical-cancer model.

We report a uniquely high yielding, general and practical ortho-bromination and iodination reaction of different classes of aromatic compounds. This reaction occurs by Rh(III)-catalyzed C-H bond activation methodology and is therefore the first example of the application of this cationic catalyst for C-Br and C-I bond formation.

2-Phenylpyridine-5,4'-dicarboxylic acid (1, dcppy), a derivative of 4,4'-biphenyldicarboxylic (2, bpdc) was used as the organic linking component for several metal-organic frameworks (MOFs). The pyridine component of 1 does not interfere with the solvothermal synthetic procedure, and hence both 1 and 2 form similar isoreticular MOFs. Zr(4+)-based UiO-67-dcppy, Al(3+)-based DUT-5-dcppy, Zn(2+)-based ...

We investigated driven crystal formation events in thin layers of sedimented colloidal particles under low salt conditions. Using optical microscopy, we observe particles in a thermodynamically stable colloidal fluid to move radially converging towards cation exchange resin fragments acting as seed particles. When the local particle concentration has become sufficiently ...

Two isomers of Sm@C92 and four isomers of Sm@C94 were isolated from carbon soot obtained by electric arc vaporization of carbon rods doped with Sm2O3. Analysis of the structures by single crystal X-ray diffraction on cocrystals formed with NiII(octaethylporphyrin) reveals the identities of two of the Sm@C92 isomers: Sm@C92(I), which ...

Within the three-dimensional architectures of RNA molecules, divalent metal ions populate specific locations, shedding their water molecules to form chelates. These interactions help the RNA adopt and maintain specific conformations and frequently make essential contributions to function. Defining the locations of these site-bound metal ions remains challenging despite the growing ...

Parameters are derived for a molecular mechanics type dispersive correction to solid-state density functional theory calculations on molecular crystals containing iodine and phosphorous. The molecular C(6) coefficients are derived from photoabsorption differential oscillator strength spectra determined from accurate (e,e) dipole spectra. The cross-over parameters, which ensure correct behavior at short ...

CuO/ZnO nanocomposites were synthesized on Al(2) O(3) substrates by a hybrid plasma-assisted approach, combining the initial growth of ZnO columnar arrays by plasma-enhanced chemical vapor deposition (PE-CVD) and subsequent radio frequency (RF) sputtering of copper, followed by final annealing in air. Chemical, morphological, and structural analyses revealed the formation of ...