Synthesis of Alkylene-linked Dimers of (-)-Huperzine A

Six alkylene-linked dimers of (-)-huperzineA (6) were prepared. All these dimers are less potent than (-)-Hup A in inhibition of AChE.

A New Cadmium(Ⅱ) Dimer Constructed by 1,10-Phenanthroline Derivative and Chlorine Anions: Syntheses, Crystal Structure and Photoluminescence

In this work, a new Cd（Ⅱ） dimeric compound, [Cd（Cl）2（L）（H2O）]2 （1, L = 2-（4- fluorophenyl）-lH-imidazo[4,5-f][1,10]phenanthroline）, has been achieved under hydrothermal conditions. The structure of compound 1 was determined by single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P21/c with a = 8.944（2）, b = 18.781（5）, c = 10.904（3） A, β = 91.392（4）°, V = 1831.2（8） A^3, Z = 2, C3sH26Cd2F2C14Cl4N8O2, Mr = 1031.27, Dc = 1.870 g/cm3, F（000） = 1016, μ（MoKα） = 1.513 mm^-1, R = 0.0532 and wR = 0.1407. Each Cd（ll） atom is in an octahedral coordination sphere, completed by two nitrogen atoms from one L ligand, two chlorine anions, and one water oxygen atom. Two chlorine anions bridge two Cd（Ⅱ） atoms to give a dimer [Cd（Cl）2（L）（H2O）]2. Adjacent dimers are stacked by one type of π…π interactions among L ligands to generate a 1D supramolecular chain. Further, the 1D supramolecular chains are stacked by another type of π…π interactions among L ligands to give a 2D supramolecular layer. Finally, the luminescent property of 1 has been studied in solid state at room temperature.

Crystal Structure,Thermal Behavior and Luminescence of a New Dimeric Manganese(Ⅱ) Complex Constructed with 3-Carboxy-1-carboxymethyl-2-oxidopyridinium

A new dimeric Mn（Ⅱ） complex,namely,[Mn（L）（PIP）]_2·H_2O（1）,was synthesized under hydrothermal condition（H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-（pyridin-3-yl）-1H-imidazo[4,5-f][1,10]phenanthroline）.It crystallizes in triclinic,space group P1 with a = 9.2037（13）,b = 9.6794（13）,c = 14.649（3） A,α = 94.858（3）,β = 94.928（3）,γ = 114.468（2）o,V = 1172.9（3） A^3,Z = 1,C_（52）H_（34）Mn_2N_（12）O_（11）,Mr = 1112.79,Dc = 1.575 g/cm^3,F（000） = 568,μ（Mo Ka） = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn（Ⅱ） atoms to give a dimeric [Mn（L）（PIP）] unit with the Mn···Mn distance of 3.009（2） A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.

Assessment of Some Density Functional Theory Methods and Force Field Models in Describing Various Interaction Modes of Benzene Dimer

Benzene dimer （bz2） is the simplest prototype of the π-π interactions. Such interactions are ubiquitous in diverse areas of science and molecular engineering. In the present work, we have made assessment on some modern density functional methods including B97-D, BLYP-D3, M06-2X, XYG3, and force field models including CHARMM, AMBER, MM3, AMOEBA on six important interaction modes of bz2. Our results not only highlight the usefulness of these cost-effective methods, which can be used as economic substitutes of the expensive CCSD（T） for complex real-world systems, but also indicate their weakness in the description of the π-π interactions, which points to the future direction for further improvements.

Effects of temperature on UV-B-induced DNA damage and photorepair in Arabidopsis thaliana

DNA damage in the form of cyclobutane pyrimidine dimers(CPDs) and (6-4) photoproducts(6-4PPs) induced by UV-B radiation in Arabidopsis thaliana at different temperatures was investigated using ELISA with specific monoclonal antibodies. CPDs and 6-4PPs increased during 3 h UV-B exposure, but further exposure led to decreases. Contrary to the commonly accepted view that DNA damage induced by UV-B radiation is temperature-independent because of its photochemical nature, we found UV-B-induction of CPDs and 6-4PPs in Arabidopsis to be slower at a low than at a high temperature. Photorepair of CPDs at 24℃ was much faster than that at 0℃ and 12℃, with 50% CPDs removal during 1 h exposure to white light. Photorepair of 6-4PPs at 12℃ was very slow as compared with that at 24℃, and almost no removal of 6-4PPs was detected after 4 h exposure to white light at 0℃. There was evidence to suggest that temperature-dependent DNA damage and photorepair could have important ecological implications.

Synthesis and Crystal Structure of N-Benzyl-N'-(2-pyridyl)urea and Its Mononuclear Cu(Ⅱ) Complex

A new ligand of N-benzyl-N＇-（2-pyridyl）urea L and its self-assembly product with CuCl2, [Cu（Ⅱ）LCl2]∞ 1, have been synthesized and structurally characterized by IR, 1H NMR and single-crystal X-ray diffraction analysis. In the structure of L, the urea groups adopt Z,E conformation to form dimers through intermolecular hydrogen bonds; while in complex 1, it assumes Z,Z conformation to fit for the coordination sphere of the Cu（Ⅱ） ions. The coordinated units are connected through intermolecular N-H...Cl hydrogen bonds to form an extended 2D framework. Finally, a 3D structure is obtained via π-π stacking interactions between pyridyl rings

A New Diterpenoid Dimer from Annona glabra

A new diterpenoid dimer annonebinide A has been isolated from the stems of Annona glabra. Its structure was determined to be ent-16a-hydroxykauran-17-yl ent-16b-kauran-17-oate on the basis of spectroscopic and chemical evidence.

Curing Behaviors and Thermal Properties of Dimer Fatty Acid （DFA） Modified Multifunctional Epoxy Resin

In order to improve the toughness of the cured aromatic tetrafunctional epoxy resins, a dlmer rarboxylic acid named dlmer fatty acid （DFA） was used to modify an aromatic tetrafunctional epoxy, N, N, N＇, N＇-tetraglycidyl-2,2-bis [ 4-（ 4-aminophcuoxy ） phenyl ] propane （TGBAPP）. The curing behaviors of DFA- TGBAPP/MNA （ methyl nadic anhydride） systems were studied by differential scanning calorimetry （DSC） method. And the thermal properties of the cured epoxy resin were investigated with the thermo-gravimetric analysis （TGA） and dynamic mechanical analysis （DMA）. Besides, the toughness was characterized with the impact strength tested by charpy impact testing. The results indicated that the modification would improve the curing reactions, and the curing temperatures were decreased with the increasing content of DFA. The thermal properties were not influenced obviously, and the toughness could be improved when the epoxy resin was modified with DFA.

π-Pimer,π-Dimer,π-Trimer,and 1Dπ-Stacks in a Series of Benzene Triimide Radical Anions:Substituent-Modulated π Interactions and Physical Properties in Crystalline State

We herein present the efficient syntheses,crystal structures,and physical properties of a series of novel benzene triimide(BTI)radical anions,emphasizing the relationship between molecular structure with spin–spin intermolecular interactions and physical properties in the crystalline state.BTI radical crystals were preparedby reducingvarious substitutedBTIs(1)with cobaltocene(CoCp2),followed by sequential crystallization processes.Two isolable radical species,that is,neutral molecule-radical anion pair(2)and monoradical species(3),were obtained from BTIs bearing small substituents(ethyl and propyl),while for those bearing larger substituents(butyl,hexyl,and benzyl)sole monoradicals(3)were produced.The radical species showed diverse intermolecular stackings in the crystalline state referred to asπ-pimer,π-dimer,alternatingπ-trimer,and one-dimensional(1D)slippedπ-stacks depending on the length and size of the substituents.Different spin–spin interactions arising from the substituent-tuned radical packings were demonstrated by electron spin resonance(ESR)spectra.The structure–property relationshipwas studied in terms of magnetism and conductivity.The radicalπ-pimers andπ-stacks with effective charge transport exhibited paramagnetic property and conductivity feasibly at room temperature,whileπ-dimers andπ-trimers featuring thermally populated spin-triplet stateswere antiferromagnetic and nonconductive due to their strong radical–radical pairing effect.

从瘀论治肺癌简况

肺癌可归属"肺积""息积""息贲"等范畴,为正气内虚,瘀毒、血瘀、痰瘀等集聚成瘤,总属本虚标实。乃"瘀"与"毒"结合,有不同侧重,瘀具有重要地位。肿瘤细胞产生促凝物质或分泌细胞因子、血浆D-二聚体、血栓素B2(TXB2)、一氧化氮(NO)、活性氧(ROS)及6-酮前列环F1α(6Keto-PGF1α)异常,均可致血液处于高度浓、黏、聚、凝状态,舌像异常。血府逐瘀汤、补阳还五汤、鸦胆子油乳注射液、艾迪注射液、华蟾素注射液、榄香烯注射液、复方苦参注射液、康艾注射液、康莱特注射液等活血化瘀法治疗血瘀为主肺癌具有重要意义。