Crystallographic characterizations and new high-yield synthetic routes for the complete series of 6-X-B10H13 halodecaboranes (X = F, Cl, Br, I) via superacid-induced cage-opening reactions of closo-B10H10(2-)

The high-yield syntheses of 6-X-B 10H 13 [X = Cl (88%), Br (96%), I (84%)] resulted from the cage-opening reactions of the (NH 4 (+)) 2B 10H 10 (2-) salt with ionic-liquid-based superacidic hydrogen halides, while both the previously unknown 6-F-B 10H 13 (77%) derivative and 6-Cl-B 10H 13 (90%) were synthesized in high yields via the reactions of (NH 4 (+)) 2B 10H 10 (2-) with triflic acid in the presence of 1-fluoropentane and dichloromethane, respectively. Structural characterizations of 1- 4 confirm the predicted structures and indicate strong halogen back-bonding interactions with the B6 boron. The reaction of 6-Br-B 10H 13 with Bu 3SnH produced the parent B 10H 14 in 70% yield, and thus, this reaction, in conjunction with the haloacid-induced closo-B 10H 10 (2-) cage-opening reactions, has the potential to provide an alternative to the traditional diborane pyrolysis route to decaborane.     

GaCl3-assisted [2 + 3] cycloaddition: a route to tetrazaphospholes

The GaCl3-assisted [2 + 3] cycloaddition of Mes*-N=P-Cl (Mes* = 2,4,6-tBu3C6H2) with trimethylsilylazide (TMS-N3) results in the formation of the first tetrazaphosphole, stabilized as a GaCl3 adduct in high yields (>96%).     

Fast tin-free hydrodehalogenation and reductive radical cyclization reactions: a new reduction process

The photostimulated reactions of several aryl and alkyl chlorides and bromides with the monoanion of reduced ethyl benzoate 5H furnish the reduced products in high yields. If the aryl moieties have suitable double bonds, the cyclized reduced products are obtained in high yields. The photostimulated reaction of 1-allyloxy-2-bromobenzene (1a) with 5H affords 3-methyl-2,3-dihydro-benzofuran (2a) in 97% yield. When 1-allyloxy-2-chlorobenzene (1b) is used, the yield of 2a is only 55%, which increases up to 91% when acetone enolate ion is added to the reaction mixture as entrainment reagent. With diallyl-(2-bromophenyl)amine (3a), and 2-allyloxy-1-halonaphthalenes (chloro, 4b, and bromo, 4a) the cyclized reduced products are obtained in yields above 96%. By competition experiments, 5H reacts ca. 5 times faster with 1-naphthyl radicals than benzenethiolate ions do, which is near the diffusion limit rate.     

Selective n,n-dimethylation of primary aromatic amines with methyl alkyl carbonates in the presence of phosphonium salts

In the presence of onium salts, at 140-170 degrees C, methyl alkyl carbonates [1a-c, ROCO2Me, R = MeO(CH2)2[O(CH2)2]n; n = 2-0, respectively] react with primary aromatic amines (XC6H4NH2, X= p-OMe, p-Me, H, p-Cl, p-CO2Me, o-Et, and 2,3-Me2C6H3NH2) to yield the corresponding N,N-dimethyl derivatives (ArNMe2) with high selectivity (up to 96%) and good isolated yields (78-95%). Phosphonium salts (e.g., Ph3PEtI and n-Bu4PBr) are particularly efficient catalysts. Overall, a solvent-free reaction is coupled with safe methylating agents (1a-c) made from nontoxic dimethyl carbonate.     

Ultra-deep desulfurization of diesel: oxidation with a recoverable catalyst assembled in emulsion

A [(C(18)H(37))(2)N(+)(CH(3))(2)](3)[PW(12)O(40)] catalyst, assembled in an emulsion in diesel, can selectively oxidize the sulfur-containing molecules present in diesel into their corresponding sulfones by using H(2)O(2) as the oxidant under mild conditions. The sulfones can be readily separated from the diesel using an extractant, and the sulfur level of the desulfurized diesel can be lowered from about 500 ppm to 0.1 ppm without changing the properties of the diesel. The catalyst demonstrates high performance (>/=96 % efficiency of H(2)O(2), is easily recycled, and approximately 100 % selectivity to sulfones). Metastable emulsion droplets (water in oil) act like a homogeneous catalyst and are formed when the catalyst (as the surfactant) and H(2)O(2) (30 %) are mixed in the diesel. However, the catalyst can be separated from the diesel after demulsification.     

Oxidative amide synthesis and N-terminal alpha-amino group ligation of peptides in aqueous medium

A new method for oxidative synthesis of amides from alkynes and amines in high yields (up to 96%) using [Mn(2,6-Cl2TPP)Cl] 1 as a catalyst and Oxone/H2O2 as an oxidant in aqueous medium has been developed. This method could be used for N-terminal alpha-amino group ligation of unprotected peptides with aryl, aliphatic, and internal alkynes under mild conditions.     

在三乙基苄基氯化铵相转移催化下水相中(E)-3-亚苄基-2,3-二氢吲哚-2-酮衍生物的合成

以芳醛和2,3-二氢吲哚为原料, 以水为溶剂, 在室温以三乙基苄基氯化铵为催化剂合成了一系列的(E)-3-亚苄基-2,3-二氢吲哚-2-酮衍生物. 该方法具有反应条件温和、立体选择性好、产率高(72%～96%)和环境友好等优点. 产物的结构通过熔点, IR, ¹H NMR和元素分析表征.     

Asymmetric synthesis of tetrahydropyran[3,2-c]quinolinones via an organocatalyzed formal[3 + 3] annulation of quinolinones and MBH 2-naphthoates of nitroolefin

An efficient asymmetric and enantio-swithchable organocatalytic[3+3]annulation reaction using MBH-2-naphthoates of nitroalkenes and 4-hydroxyquinolin-2(1H)-ones has been developed.Densely substituted tetrahydropyrano[3,2-c]qui noli nones scaffolds with two adjacent stereogenic centers are obtained with high yield(up to 95%yield)and good stereoselectivities(up to>20:1 dr and 96%ee)in an enantio-switchable manner.Furthermore,gram scale synthesis was achieved and the nitro group could easily transform into an amino group without any appreciable loss in the diastereo-and enantioselectivity.     

新型镍催化体系合成Cis-1,4聚丁二烯的研究

本文研究了以加氢汽油为溶剂的Ni(Naph)_2-Al(i-Bu)_2OR-BP_3·OEt_2及Ni(NaPh)_2-Al(i-Bu)_2OAr-BF3·OEt_2两体系对丁二烯的催化聚合活性、聚合物分子量、微观结构等。各种Al(i-Bu)_2OR或Al(i-Bu)_2OAr为助催化剂组成的新型镍催化体系对丁二烯聚合都有较高的催化活性,所得聚合物Cis-1,4含量在96％以上。磁化率和紫外可见光谱研究证明,在Al(i-Bu)_2OR体系中以Ni(Ⅰ)为主及小量未还原的Ni(Ⅱ);Al(i-Bu)_2OAr中Ni(Ⅰ)及Ni(O)共存。     

Water clusters on graphite: methodology for quantum chemical a priori prediction of reaction rate constants

The properties, interactions, and reactions of cyclic water clusters (H(2)O)(n=1-5) on model systems for a graphite surface have been studied using pure B3LYP, dispersion-augmented density functional tight binding (DFTB-D), and integrated ONIOM(B3LYP:DFTB-D) methods. Coronene C(24)H(12) as well as polycircumcoronenes C(96)H(24) and C(216)H(36) in monolayer, bilayer, and trilayer arrangements were used as model systems to simulate ABA bulk graphite. Structures, binding energies, and vibrational frequencies of water clusters on mono- and bilayer graphite models have been calculated, and structural changes and frequency shifts due to the water cluster-graphite interactions are discussed. ONIOM(B3LYP:DFTB-D) with coronene and water in the high level and C(96)H(24) in the low level mimics the effect of extended graphite pi-conjugation on the water-graphite interaction very reasonably and suggests that water clusters only weakly interact with graphite surfaces, as suggested by the fact that water is an excellent graphite lubricant. We use the ONIOM(B3LYP:DFTB-D) method to predict rate constants for model pathways of water dissociative adsorption on graphite. Quantum chemical molecular dynamics (QM/MD) simulations of water clusters and water addition products on the C(96)H(24) graphite model are presented using the DFTB-D method. A three-stage strategy is devised for a priori investigations of high temperature corrosion processes of graphite surfaces due to interaction with water molecules and fragments.     

Cobalt-mediated, enantioselective synthesis of C(2) and C(1) dienes

The asymmetric C-H functionalization of norbornene and norbornadiene with five-, six-, and seven-membered cyclic enones mediated by the reactive intermediate [{η(5)-((t)BuMe(2)Si)C(5)H(4)}Co(NO)(2)] is reported. A novel base mixture derived from enantiopure ammonium salts and NaHMDS was used as a source of chirality, and this enantioselective desymmetrization of C(s) alkenes has been applied to the asymmetric synthesis of C(2)- and C(1)-symmetric diene ligands in high regioselectivity (3.7-20:1 anti/syn), near perfect diastereoselectivity (>99:1 dr), and high enantioselectivity (90-96% ee).     

邻甲基苯磺酸铜催化"一锅法"合成3,4-二氢嘧啶-2(1H)-酮

二氢嘧啶酮(DHPMs)及其衍生物具有广泛的生物活性,如抗病毒、抗肿瘤、抗癌、抗高血压及消炎等作用[1].此外,DHPMs及其衍生物作为钙通道阻滞剂、α1a-对抗剂和神经肽Y的对抗剂,显示出良好的药理活性[2].更重要的是,最近几种含二氢嘧啶酮-5-羧酸盐的海洋生物碱被成功分离出来,并表现出重要的生物学性质[3],某些可以阻止HIVgp-120-CD4键的形成,是一种潜在的HIV抑制剂[4].因此,对DHPMs及其衍生物的研究成为生物活性有机杂环化合物的研究热点之一.     

High-throughput screening system for catalytic hydrogen-producing materials

A high-throughput screening system and methodology were developed for libraries of hydrogen (H(2)) producing catalytic materials. The system is based on the chemo-optical properties of WO(3), which give rise to reflectance changes in the presence of H(2). Pd-coated WO(3) sensors were synthesized and examined for their hydrogen sensitivity, wavelength-dependent reflectance, and performance in the presence of water vapor. For high-throughput screening, a polypropylene reactor block was designed and constructed to house 8 x 12 catalyst libraries deposited as thin films. When the library and reactor block are assembled together, 96 independent microreactor units are formed. A large-area Pd/WO(3) sensor film covers and seals all microreactors, forming a 96-element 2-D H(2) sensor array. As H(2) is produced differentially across the library, the reflectance changes of the Pd/WO(3) film are monitored by reflectivity sensors that scan the surface every 30 s. The time-dependent changes in reflectance indicate relative rates of H(2) production. A library of cathode electrocatalysts was synthesized from Ti, Pt, Ni, Au, Pd, Al, Ag, Ge, and mixtures thereof to demonstrate the H(2) high-throughput screening system. The results of the electrolytic screening are in agreement with expected literature trends: mixtures of Ni and samples containing Pt and Pd generated H(2) at the greatest rates, while Ge- and Ti-based materials were the least effective electrocatalysts. A mixture of 80% Al and 20% Pt was found to have the highest rate of H(2) production. This high-throughput screening system is applicable in a variety of catalytic screening applications where hydrogen is the desired product.     

A VUV photoionization study of the combustion-relevant reaction of the phenyl radical (C6H5) with propylene (C3H6) in a high temperature chemical reactor

We studied the reaction of phenyl radicals (C(6)H(5)) with propylene (C(3)H(6)) exploiting a high temperature chemical reactor under combustion-like conditions (300 Torr, 1200-1500 K). The reaction products were probed in a supersonic beam by utilizing tunable vacuum ultraviolet (VUV) radiation from the Advanced Light Source and recording the photoionization efficiency (PIE) curves at mass-to-charge ratios of m/z = 118 (C(9)H(10)(+)) and m/z = 104 (C(8)H(8)(+)). Our results suggest that the methyl and atomic hydrogen losses are the two major reaction pathways with branching ratios of 86 ± 10% and 14 ± 10%. The isomer distributions were probed by fitting the recorded PIE curves with a linear combination of the PIE curves of the individual C(9)H(10) and C(8)H(8) isomers. Styrene (C(6)H(5)C(2)H(3)) was found to be the exclusive product contributing to m/z = 104 (C(8)H(8)(+)), whereas 3-phenylpropene, cis-1-phenylpropene, and 2-phenylpropene with branching ratios of 96 ± 4%, 3 ± 3%, and 1 ± 1% could account for the signal at m/z = 118 (C(9)H(10)(+)). Although searched for carefully, no evidence of the bicyclic indane molecule could be provided. The reaction mechanisms and branching ratios are explained in terms of electronic structure calculations nicely agreeing with a recent crossed molecular beam study on this system.     

高速逆流色谱与硅胶柱色谱结合分离制备高纯度芦荟素异构体

芦荟素是芦荟叶中主要的蒽醌类成分,通常以芦荟素A和B两种非对映异构体形式并存,目前已成为许多芦荟产品质量控制指标之一。采用高速逆流色谱和硅胶柱色谱结合的方法,从老芦荟干粉中分离制备了高纯度的芦荟素A(纯度为98%)和芦荟素B(纯度为96%)样品,并采用快原子轰击质谱(FAB-MS)和核磁共振氢谱(1H NMR)以及GOESY(gradient-enhanced nuclear Overhauser effect spectroscopy)等方法对所得的两个芦荟素异构体的立体构象进行了确认。该法具有制备量大和分离效率高的特点。     

溶胶-凝胶法制备高取向Bi4Ti3O12/SrTiO3(100)薄膜

Bi4Ti3O12具有良好的铁电、电光等性能山、特别是Bi4Ti3O12薄膜很适合作永久性存储材料，也可用于电光器件问．在微电子学、光电子学、集成光学、集成铁电学等领域均有广泛开发和应用前景，国外已用溅射法、激光沉积法制备出c轴取向Bi。Ti3Ol。薄膜【’，＼山东大学用MOCVD法制     

Synthesis of two pentaarylated [60]fullerene derivatives Ar_5C_(60)-H (Ar = p-MeC_6H_4, m-MeC_6H_4) and their novel electrochemical properties

Through one pot reaction of C60 with organocopper/magne-sium reagent ( p - MeQ H4 )2 CuMgBr or ( m - MeC6 H )2 -CuMgBr prepared from CuBr-Me2S and p-MeC6H4MgBr or m-MeC6H4MgBr and subsequent quenching with aqueous NH4Cl, two pentaarylated [60] fullerene derivatives (p-MeC6H4)5C60H (1) and (m-MeC6H4)5C60H (2) have been synthesized in 94% and 96% yields, respectively. While known compound 1 prepared via this improved method is unambiguously identified, new compound 2 is fully characterized by elemental analysis, IR, UV-vis, 1H NMR and 13C NMR spectroscopies. Additionally, electrochemical study shows that the two [60] fullerene derivatives 1 and 2 in dichloromethane solution display two sequential one-electron reductions which are shifted by about 0.4V towards more negative potential values with respect to free C60. Such remarkable cathodic shift is attributed to the multiple breakage of the double-bond conjugation within the fullerene core.     

Bifunctional hydrogen-bond donors that bear a quinazoline or benzothiadiazine skeleton for asymmetric organocatalysis

Hydrogen-bond (HB)-donor catalysts that bear a 2-aminoquinazolin-4-(1H)-one or a 3-aminobenzothiadiazine-1,1-dioxide skeleton have been developed, and it has been shown that these catalyst motifs act similarly to other HB-donor catalysts such as thioureas. The highly enantioselective hydrazination of 1,3-dicarbonyl compounds was realized even at room temperature with up to 96% ee for 2-aminoquinazolin-4-(1H)-one-type catalysts, which were more effective than the corresponding urea and thiourea catalysts. In addition, benzothiadiazine-1,1-dioxide-type catalysts were shown to promote the isomerization of alkynoates to allenoates with high enantioselectivity. To overcome the problem that the products were obtained as mixtures with the starting alkynoates, we developed the tandem isomerization and cycloaddition of alkynoates for the synthesis of advanced chiral compounds such as bicyclo[2.2.1]heptenes and 3-alkylidene pyrrolidine without a significant loss of enantioselectivity.     

Ru-Catalyzed asymmetric hydrogenation of alpha-ketoesters with CeCl3.7H2O as additive

[reaction: see text] An efficient asymmetric hydrogenation of alpha-ketoesters is reported with use of a catalyst prepared from [Ru((S)-3)(benzene)Cl]Cl and CeCl(3).7H(2)O. Alpha-hydroxy esters are obtained in up to 96% ee. The addition of CeCl(3).7H(2)O not only improves the enantioselectivity, but also enhances the stability of the catalyst. As a result, the hydrogenation of methyl benzoylformate affords the product with 92% ee with a substrate/catalyst ratio of 10 000. Hydrolysis of 2 provides the final compound with 83% yield at 99% ee after a single recrystallization from 1,2-dichloroethylene.     

From phenylalkylcyanamides to heterocyclic selenazadiphospholaminediselenides and carbamidoyl(phenyl)phosphinodiselenoic acids

The reaction of 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide (Woollins' Reagent, WR) with phenylalkylcyanamides (RR'NC[triple bond, length as m-dash]N, R = PhCH2CH2, R' = CH3 and R = PhCH2CH2CH2, R' = H) in refluxing toluene led to novel heterocyclic selenazadiphospholaminediselenides and (43% and 42% yields), the latter being hydrolyzed to the unusual zwitterionic carbamidoyl(phenyl)phosphinodiselenoic acids and in excellent yields (96% and 98%).