Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

酸枣仁中三萜皂苷的分离和结构研究

从酸枣仁(Zizyphus jujuba Mill. Var. spinosa Hu)中分离得到四个三萜皂苷, 分别鉴定为酸枣仁皂苷G (1, jujuboside G), 酸枣仁皂苷A (2, jujuboside A), 酸枣仁皂苷B (3, jujuboside B)和酸枣仁皂苷A₁ (4, jujuboside A₁). 其中酸枣仁皂苷G与其它酸枣仁皂苷不同, 为新的酮基达玛烷型三萜皂苷. 运用现代波谱技术, 包括二维核磁共振谱和高分辨质谱, 对上述化合物的结构进行了确证.     

Exploratory syntheses,structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse Pb^II coordination complexes, [Pb₃O(OH)(4-sphth)]₂(H₂O) (1), [Pb(3,5-Hdhb)]H₂O (2), and [Pb₃(4-nphth)₂(OH)₂] (3) (4-H₃sphth, 4-sulfophthalic acid; 3,5-H₂dhb, 3,5-dihydroxybenzoic acid; 4-H₂nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb₄O₄] cubanes, based on which ladder-shaped structure is built via 4-H₃sphth bridge. This is the first Pb₄O₄-containing polymer. The Pb₂O₂ units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb₃O units, which are linked through Pb corners to form a hexagonal unit. Each PbO₆ polyhedron is connected to three polyhedra (Pb₃O) via sharing an edge (two μ ₃-oxygen atoms) and two faces (three μ ₃-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.     

Synthesis,structural characterization and catalytic potential of oxidovanadium(IV) and dioxidovanadium(V) complexes with thiazole-derived NNN-donor ligand

Reaction between the tridentate NNN donor ligand, (E)-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)benzo[d]thiazole (HL), and V₂O₅ in ethanol gave a new vanadium(V) complex, [VO₂L] (1), while the similar reaction by using [V^IVO(acac)₂] as the metal source gave two different types of crystals related to compounds [VO₂L] (1) and [V^IVO(acac)L] (2). The molecular structures of the complexes were determined by single-crystal X-ray diffraction and spectroscopic characterization was carried out by means of FT-IR, UV–vis and NMR experiments as well as elemental analysis. The oxidovanadium(IV) and dioxidovanadium(V) species were used as catalyst precursors for olefin oxidation in the presence of hydrogen peroxide (H₂O₂) as an oxidant. Under similar experimental conditions, the presence of 1 resulted in higher oxidation conversion than 2.     

Two new linear acetogenins from the fruits of Goniothalamus gracilipes

Two new linear acetogenins, gracilipin A (1) and methylsaccopetrin A (2) along with seven known compounds, saccopetrin A (3), 7,3′,4′-trimethylquercetin (4), rhamnazin (5), casticin (6), isokanugin (7), melisimplexin (8) and 5-hydroxy-3,7-dimethoxy-3′,4′-methylenedioxyflavone (9) were isolated from the fruits of Goniothalamus gracilipes Bân. Their structures were established by spectral analysis, such as mass spectrometry, 1D-NMR, 2D-NMR and circular dichroism (CD). Compounds 1 and 3 showed cytotoxic activity against KB cell line with IC₅₀ values of 14.6 and 15.3 μM, respectively.     

Four new dammarane-type triterpenes derivatives from hydrolyzate of total Gynostemma pentaphyllum saponins and their bioactivities

Phytochemical investigation of hydrolysate of total G. pentaphyllum saponins led to the isolation of four novel triterpenes, Gypensapogenin U (1), Gypensapogenin V (2), Gypensapogenin W (3) and Gypensapogenin X (4). The structures of these compounds were identified by 1D, 2D-NMR and HR-ESI-MS evidences. Additionally, the protective activity of these new compounds against cardiomyocytes injury induced by H₂O₂ and their cytotoxic activity against t-HSC/Cl-6 cells were evaluated.     

New sesquiterpenoid derivatives from Solanum septemlobum with cytotoxicities

Two new sesquiterpenoid derivatives, attributable to eudesmane-type (1–2, named septemlobin D and 11,12-O-isopropylidenesolajiangxin F), were isolated from the whole plant of Solanum septemlobum. Their structures were elucidated on the basis of integrated spectroscopic techniques, mainly HR-FAB-MS, 1D and 2D-NMR (¹H–¹H COSY, HMQC, HMBC and ROESY). In vitro, two sesquiterpenoid derivatives were found to show significant cytotoxicity against three cancer cell lines (P-388, HONE-1 and HT-29), and gave IC₅₀ values in the range of 3.0–7.3 μM.     

A new phenanthropyran and a new biphenanthrene from the rhizomes of Dioscorea septemloba and their antioxidant activities

Abstract

A new phenanthropyran, dioscorone B (1), and a new phenanthrene (2), together with seven known compounds (3–9), were isolated from the 75% ethanol extract of Dioscorea septemloba rhizomes. The chemical structures of these compounds were elucidated by comprehensive spectroscopic methods including NMR, HRESIMS, IR, and UV spectra. Compounds 1–5 were first isolated from genus Dioscorea. The proton and carbon chemical shifts of compounds 1–9 were unambiguously assigned based on the 1D-NMR and 2D-NMR data. Compounds 1–5 and 8–9 were first tested for their antioxidant activities. Compounds 1 and 2 showed excellent activities with IC₅₀ values of 0.07?±?0.10?μM and 0.13?±?0.09?μM, respectively.     

Isolation and structure elucidation of two new compounds from artemisia Ordosica Krasch

Abstract

Two new compounds, namely arteordoyn A (1) and arteordoyn B (2), together with four known compounds, were isolated from the petroleum ether extract of Artemisia ordosica Krasch. The structures elucidation of 1 and 2 were carried out by 1D-NMR (¹H and ¹³C NMR), 2D-NMR (COSY, HSQC, HMBC and NOESY) and HR-ESI-MS spectral analysis.     

Hydrothermal synthesis,characterization, and luminescence of two new arsenic–vanadium compounds with a γ-[As8V14O42(H2O)]4− anion

Two new compounds, [Zn(phen)₃]₂[γ-As₈V₁₄O₄₂(H₂O)]?·?4H₂O (1) and [Cd(phen)₃]₂[γ-As₈V₁₄O₄₂(H₂O)]?·?2H₂O (2) (phen?=?1,10′-phenanthroline), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, infrared spectrum, and thermogravimetric analysis. Compound 1 crystallizes in the triclinic space group P 1 with a?=?11.429(4)?Å, b?=?15.760(5)?Å, c?=?15.952(5)?Å, α?=?108.825(5)°, β?=?92.194(5)°, γ?=?104.155(5)°, V?=?2615.6(15)?ų, Z?=?1; 2 crystallizes in the triclinic space group P 1 with a?=?11.450(4)?Å, b?=?15.629(6)?Å, c?=?16.302(6)?Å, α?=?109.177(5)°, β?=?92.628(5)°, γ?=?104.251(4)°, V?=?2644.8(17)?ų, Z?=?1. Single-crystal structural analysis shows that both 1 and 2 consist of a new type of [γ-As₈V₁₄O₄₂(H₂O)]^4? cluster anion.     

Isomeric organic ligand dominating polyoxometalate-based hybrid compounds: synthesis and as electrocatalysts and pH-sensitive probes

By introducing isomeric organic ligands into polyoxometalate (POM) systems, two new POM-based hybrid compounds, [Cu₆(m-pyttz)₂(H₂O)][HPMo₁₂O₄₀] (1) and [Ag₃(p-H₂pyttz)(p-Hpyttz)Cl][H₂PMo₁₂O₄₀]·6H₂O (2) (m-/p-H₂pyttz = 3-(pyrid-3/4-yl)-5(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl), have been hydrothermally synthesized and characterized. Single-crystal structural analysis shows the m-pyttz ligands link Cu^I ions to generate a two-dimensional layer with hanger-like rhombus, which is pillared by the PMo₁₂ anions in 1. Compound 2 exhibits a three-dimensional supramolecular framework, in which PMo₁₂ anions are building blocks facilitating the extension of the whole structure. The influence of the coordination modes of m-/p-H₂pyttz on the structures is discussed in detail. Furthermore, electrochemical properties of 1 and 2 have been studied and they display excellent electrocatalytic activities toward the reduction of nitrite and hydrogen peroxide and pH-dependent electrochemical behaviors.     

New α-glucosidase inhibiting anthracenone from the barks of Harungana madagascariensis Lam

Two new 10-hydroxy-9(10H)-anthracenone, madagascenone A (1) and B (2), were isolated from the barks of Harungana madagascariensis Lam. The structures of the compounds were determined using 1D- and 2D-NMR and mass spectroscopic techniques. Both of the compounds showed an in vitro α-glucosidase inhibition with IC₅₀ = 69.9 ± 4.21 and 122.3 ± 1.13 μM, respectively, more potent than the standard acarbose (IC₅₀ = 840 ± 1.23 μM).     

Syntheses and structural determination of binuclear nine-coordinate (NH4)4[SmIII2(Httha)2]·16H2O and 2-D ladder-like binuclear nine-coordinate (NH4)4[SmIII2(dtpa)2]·10H2O

Two rare-earth metal coordination compounds, (NH₄)₄[Sm^III₂(Httha)₂]·16H₂O (1) (H₆ttha?=?triethylenetetramine-N,N,N′,N′′,N′′′,N′′′-hexaacetic acid) and (NH₄)₄[Sm^III₂(dtpa)₂]·10H₂O (2) (H₅dtpa?=?diethylenetriamine-N,N,N′,N′′,N′′-pentaacetic acid), have been synthesized through reflux and characterized by FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction techniques. Sm^III of (NH₄)₄[Sm^III₂(Httha)₂]·16H₂O (1) is nine-coordinate, forming tricapped trigonal prismatic coordination with three amine nitrogens and six oxygens, in which four oxygens are from one ttha and two from the other ttha. (NH₄)₄[Sm^III₂(Httha)₂]·16H₂O (1) crystallizes in the monoclinic crystal system with P2(1)/c space group. The crystal data are: a?=?13.9340(13) Å, b?=?22.890(3) Å, c?=?20.708(2) (14) Å, β?=?99.521(2)°, and V?=?6513.7(13) ų. There are two –NH⁺– groups in the [Sm^III₂(Httha)₂]^4?. The polymeric (NH₄)₄[Sm^III₂(dtpa)₂]·10H₂O (2) also is nine-coordinate with tricapped trigonal prismatic conformation and crystallizes in the triclinic crystal system with P–1 space group. The cell dimensions are: a?=?9.8240(8) Å, b?=?10.0329(9) Å, c?=?13.0941(11) Å, β?=?77.1640(10)°, and V?=?1227.30(18) ų. In (NH₄)₄[Sm^III₂(dtpa)₂]·10H₂O, there are two types of ammonium cations, which connect [Sm^III₂(dtpa)₂]^4? and lattice water through hydrogen bonds, leading to a 2-D ladder-like layer structure.     

Synthesis, crystal structure and spectroscopic properties of two new complexes containing azido or dicyanamido bridges

Two new complexes, [Cu(L₁){N(CN)₂}]·ClO₄ (1) (L₁ is 1,8-dimethyl-1,3,6,8,10,13-hexa-azacyclotetradecane) and [Co(L₂)(N₃)₂]·ClO₄ (2) (L₂ is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane) have been synthesized and characterized. The compounds crystallize in the monoclinic system P2₁ space group for 1 and P2₁/n for 2. Single crystal X-ray analysis reveals that the compound 1 assumes a one-dimensional structure via hydrogen-bonding interactions, in which each Cu(II) ion is coordinated by four nitrogen atoms from ligand L₁ and one nitrogen atom from [N(CN)₂]⁻ anion. For compound 2, each Co(III) ion is coordinated by four nitrogen atoms of ligand L₂ and two nitrogen atoms from N₃ ⁻ anion.     

Fading of a novel colorimetric receptor after recognizing H2PO4−

A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H₂PO₄^? ion was reported. Fancifully, the recognition process of receptor 1 to H₂PO₄^? was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H₂PO₄^? that H₂PO₄^? ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV–vis, fluorescence, ¹H NMR titrations and ESI-MS experiments.     

A fluorescent 3-D metal-organic framework with unusual tetranuclear zinc secondary building units

A 3-D metal-organic framework (MOF) {Zn₄(μ₃-OH)₂(bdc)₃(pad)₂}·2H₂O (1, H₂bdc = 1,4-benzenedicarboxylic acid, pad = 1,10-phenanthroline-5,6-dione) with unusual Zn₄(μ₃-OH)₂(COO)₆(N₂)₂ secondary building units (SBUs) has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis, and infrared spectroscopy. The tetranuclear Zn₄ SBU was formed through two dinuclear Zn₂ clusters by sharing two μ₃-OH bridges. Considering this Zn₄ SBU as a six-connected node, the overall framework of 1 has a pcu topology. This tetranuclear Zn₄ SBU can be used as a node in construction of MOFs.     

Crystal structures and luminescence of two cadmium(II) polymers constructed from aromatic polycarboxylate and bis(1,2,4-triazol-1-yl)methane ligands

Two new coordination compounds, {[Cd₂(btrm)(ip)₂(H₂O)₂]?·?2H₂O} _n (1) and {[Cd₂(btrm)(hip)₂(H₂O)₄]?·?3H₂O} _n (2) (btrm?=?bis(1,2,4-triazol-1-yl)methane, H₂ip?=?isophthalic acid, H₂hip?=?5-hydroxy isophthalic acid), have been synthesized and structurally characterized. Compound 1 is a 3-D network with CdSO₄ topology. Compound 2 contains 1-D ladder structures, which are interconnected by classical hydrogen-bonding interactions (O–H?···?O) to lead to 3-D supramolecular architectures. Luminescence was performed on 1 and 2, both of which showed strong fluorescent emissions in the solid state at room temperature.     

New triterpenoid saponins from the steaming treated roots of Panax notoginseng

Further phytochemical investigation of the steaming treated roots of Panax notoginseng (Araliaceae) led to the identification of two new dammarane-type triterpenoid saponins, notoginsenoside SP20 (1) and SP21 (2). In addition, a pair of new phenolic glycosides (3a and 3b) was also isolated together with two known compounds. Their structures were elucidated by HRESIMS, 1D- and 2D-NMR spectra. Compounds 1 and 2 showed no in vitro cytotoxicity against five human cancer cell lines (HL-60, SMMC-7712, A-549, MCF-9 and SW480).     

New members of the [Mn6/oxime] family and analogues with converging [Mn3] planes

The synthesis, structural, and magnetic characterization of five new members of the hexanuclear oximate [Mn^III₆] family are reported. All five clusters can be described with the general formula [Mn^III₆O₂(R-sao)₆(R′-CO₂)₂(sol)_x(H₂O)_y] (where R-saoH₂ = salicylaldoxime substituted at the oxime carbon with R = H, Me and Et; R′ = 1-naphthalene, 2-naphthalene, and 1-pyrene; sol = MeOH, EtOH, or MeCN; x = 0–4 and y = 0–4). More specifically, the reaction of Mn(ClO₄)₂·6H₂O with salicylaldoxime-like ligands and the appropriate carboxylic acid in alcoholic or MeCN solutions in the presence of base afforded complexes 1–5: [Mn₆O₂(Me-sao)₆(1-naphth-CO₂)₂(H₂O)(MeCN)]·4MeCN (1·4MeCN); [Mn₆O₂(Me-sao)₆(2-naphth-CO₂)₂(H₂O)(MeCN)]·3MeCN·0.1H₂O (2·3MeCN·0.1H₂O); [Mn₆O₂(Et-sao)₆(2-naphth-CO₂)₂(EtOH)₄(H₂O)₂] (3); [Mn₆O₂(Et-sao)₆(2-naphth-CO₂)₂(MeOH)₆] (4) and [Mn₆O₂(sao)₆(1-pyrene-CO₂)₂(H₂O)₂(EtOH)₂]·6EtOH (5·6EtOH). Clusters 3, 4, and 5 display the usual [Mn₆/oximate] structural motif consisting of two [Mn₃O] subunits bridged by two O_oximate atoms from two R-sao^2? ligands to form the hexanuclear complex in which the two triangular [Mn₃] units are parallel to each other. On the contrary, clusters 1 and 2 display a highly distorted stacking arrangement of the two [Mn₃] subunits resulting in two converging planes, forming a novel motif in the [Mn₆] family. Investigation of the magnetic properties for all complexes reveal dominant antiferromagnetic interactions for 1, 2, and 5, while 3 and 4 display dominant ferromagnetic interactions with a ground state of S = 12 for both clusters. Finally, 3 and 4 display single-molecule magnet behavior with U_eff = 63 and 36 K, respectively.