Vanadium(Ⅳ)dimer complexes containing [V(o-C_6H_4OS)_3]~(2-)fragment and caged sodium ions

Tris[o-mercaptophenolato]vanadium(IV)dimer complexes(A)_2[V(mp)_3NaLL']_2(A=Ph_4P~+,H_2mp=o-mercaptophenol,L=MeCN,L'=EtOH,(1);L'=MeOH,(2))were prepared bythe reaction of anhydrous VCl_3 and Na_2mp in the molar ratio 1:3.Complex(3)(A=Et,N~+,L=L'=MeOH)was prepared by the reaction of VCl_3,Na_2mp and Li_2S in the molar ratio 1:2:1.The com-plexes were characterized by X-ray diffraction crystallography,infrared spectra,magnetic suseepti-bility,and cyclic voltammetric measurements.Complex 2 crystallizes in the triclinic space groupP1 with a=12.813(6),b=14.199(4),c=12.790(5),α=112.72(2),β=104.24(4).γ=88.68(4)°,V=2073.6,and Z=1.The structure was refined to R=0.058.Complex 3 crystallizes in the mono-clinic space group P2_1/n with a=12.359(3),b=17.452(6),c=14.829(13),β=96.51(5)°,V=3177.8,and Z=2.The final R factor is 0.067.Both of the anions of 2 and 3 contain two[V(rap)3]~(2-) fragmentslinked by sodium ions through the μ_3-O bridges with a crystallographic center of symmetry.The V(IV)atom is in a coordination environment intermediate between a trigonal prism and an ideal octahedron.     

Studies on Cytochrome c Modified by [PtdienNO_3]Cl

For the first time, [PtdienNO_3]Cl was used as a stable reagent to modify ferricytochrome c and the reaction products were separated and purified with the CM-52 cation exchange chromatography. Five components were obtained, corresponding to the native cytochrome c single-labeled, dual-labeled, and triple-labeled derivatives as shown by the analysis of the molar ratio of the two metal atoms (Pt and Fe). The reduction potentials of these proteins were measured by differential pulse voltammetry. His-33 and Trp-59 were identified by~1HNMR as the binding sites of the platinum complex in the modified cytochrome c derivatives. Trp-59 was a conserved amino acid connected with the heme through hydrogen bond, which had not been modified by other transition metal complexes. The platinummodified cytochrome c derivatives might be valuable in exploring the role of the aromatic amino acids, especially Trp-59, in electron transfer.     

Design, Synthesis, and Hypnotic Activity of Pyrazolo [1,5-a]pyrimidine Derivatives

On the basis of the Zaleplon structure, novel pyrazolo[1,5-a]pyrimidines were designed and prepared for studies on their hypnotic activity. This paper reported the synthesis of twelve new 5-methyl-7-substituted-pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives by using simple starting materials such as propane dinitrile and triethyl orthoformate. The structures of the derived target compounds were confirmed by their IR and ^1H-NMR spectroscopic data. The preliminary pharmacological evaluations indicated that some compounds showed hypnotic activity, whilc derivative 1c was the most potent one.     

Synthesis and Crystal Structure of 2-Benzylsulefnyl-3-cyano-5,7-dimethyl-pyrazolo[1,5-a]pyrimidine

1 INTRODUCTION The pyrazolo[1,5-a]pyrimidines are the active compositions in many pesticides and medicines. A new class of KDR (tyrosine kinase VEGFR-2) ki- nase inhibitors is discovered and found to have affi- nity for the human CRF-1 (Corticotrophin re…     

Synthesis and reactivity of 3-(trichlorogermyl)propanoic acid and 3-(triphenylgermyl) propanoic acid

3-(Trichlorogermyl)propanoic acid (la) reacts with phenylmagnesium bromide in malar ratio 1:4 to give 3-(triphenylgermyl)propanoic acid (2a).In the compounds la and 2a theβ-carboxylic functional group shows some unusual properties when they react with excess of phenylmagnesium bromide.The compound la reacts with phenylmagnesium bromide in molar ratio 1:5 to give phenyl 2-(triphenylgermyl)ethylketone (3a) and in molar ratio 1:6 to give l,l-diphenyl-3-(triphenylgermyl)propanol (4a).The compound 2a reacts with phenylmagnesium bromide in molar ratio 1:2 to give 3a and in molar ratio 1:3 to give 4a also.Dehydration of the compound 4a with dilute hydrochloric acid seems especially easy.Moreover,the compound la reacted with phenylmagnsium bromide in molar ratio 1:6,then the mixture was treated with dilute hydrochloric acid to give 1,1-diphenyl-3-(triphenylgermyl)-1-propene (5a) in one pot reaction.Alkyl Ge-C bond in the compound 5a can be cleaved selectively by lithium aluminium hydride ( LiAlH4) in good yiel     

Synthesis of Schiff Base Calix [4] arene Crowns

This letter reports the synthesis of Schiff base calix [4] arene crowns containing m-xylylene phenol subunit, in which calix [4] arene Schiff base crowns 2a,2b and 2c were formed by 1:1 condensation of calix [4] arene diamine 1 with dialdehydes (2,6-diformyl-4-chlorophenol 3a,2,6-diformyl-4-methylphenol 3b,2,6-diformyl-4-tert-butylphenol 3c)under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.     

Synthesis of （p-Formylphenyl）azo Calix[4]arenes

Five novel azo calix[4]arenes were reported. The p-aminobenzaldehyde was diazotized with sodium nitrite in aqueous hydrochloride solution. Mono-, bis-, tris- and tetrakis(p-formylphenyl)azo calix[4]arenes (including proximal and distal isomers) were obtained respectively by diazo-coupling in different molar ratio to calix[4]arene(1) under pH=7.5--8.5 at 0-5℃. All (p-formylphenyl)azo calix[4]arenes were characterized by ^1H NMR, ^13C NMR, IR, MS (ESIMS) spectroscopies and elemental analysis.     

Preparation,Characterization and Thermal Decomposition Kinetics of the Complexes [Dy(p-NBA)_3Phen]_2·3H_2O and [Dy(m-NBA)_3Phen]_2·4H_2O

The title complexes [Dy(p-NBA)3Phen]2·3H2O(I) and [Dy(m-NBA)3Phen]2·4H2O(Ⅱ) were synthesized, in the two molecular formulas of which NBA is nitrobenzoate and Phen is 1,10-phenanthroline. The characterizations of the complexes were carried out by means of elemental analysis, UV, IR, XRD and molar conductivity. The thermal decomposition of the two complexes were studied under the non-isothermal condition by DSC, TG-DTG and IR methods in detail. The kinetic parameters of the dehydration process were also obtai...     

Synthesis of （p—Substituted phenyl）azo Calix[4] arenes

A novel method for the preparation of chromogenic calixarenes with azo groups was reported.p-Substituted(-NO2,-CH3,-Cl)amilines were diazotized with isoamyl nitrite in EtONa/EtOH under refluxing condition.Fifteen mono-,bis-,tris-and tetrakis(p-substituted phenyl)azo calix[4]arenes (including proximal and distal isomers) were obtainged respectively by diazo-coupling in different molar ratio to calix[4]arenes(1) under pH=7.5-9.0 in non-aqueous solution at 0-5℃.^1H NMR and ^13C NMR spectra of (p-substtituted phenyl)azo calix[4]-arenes indicated that they existed in cone conformation in solution.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of a New Dinuclear Copper Complex [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]

The hydrothermal reaction of copper chloride dihydrate and 5,5-dimethyl-imidazolidine,-2,4-dione with a mole ratio of 1：1 in acetonitrile resulted in the formation of a new acetate-bridged dinuclear copper complex, [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]. Protonated acetamide in eaolie form and acetic acid were yielded by the hydrolysis of acetonitrile under hydrothennal condition. The rifle complex （C12H24Cl2Cu2N2O10） was characterized by X-ray single-crystal diffraction, IR spectrum, elemental and electrochemical analysis. It crystallizes in the monoclinic system, space group P21/c with a = 8.298004）, b = 14.358（2）, c = 12.0010（2） A^°, β= 130.620（3）°, V = 1085.3（2） A^°^3, Dc = 1.696 g/cm^3, 34, = 554.31, Z = 2, F（000） = 564 and μ = 2.254 mm^-1. The crystal structure consists of a tetraacetate-bridging dinulcear copper complex anion [Cu2Cl2（μ-CH3COO）4]^2-, with the chlorine anions in the axial positions, and two protonated acetamide cations [C2H6ON]^＋, which were connected through hydrogen bonds to form a three-dimensional infinite network.     

Novel smart supramolecular metallo-hydrogel that could selectively recognize and effectively remove Pb2+ in aqueous solution

A series of novel and simple ligands based on a biscarboxyl-functionalized benzimidazole derivative were synthesized.The experiments showed that the ligand L2 as a low molecular weight(LMW) hydrogelator could form stable metallo-hydrogels in the presence of up to 0.3 equiv.of lead ions.The metallo-hydrogels were characterized using powder X-ray diffraction,scanning electron microscopy(SEM),and Fourier transform infrared(FT-IR) spectroscopic techniques.When the molar ratio of L2:Pb2+ was in the range of 1:0.3 to 1:0.5 a translucent gel was produced.When the L2:Pb2+ molar ratio was higher than 1:0.5 the resulting gel tended to be opaque.The morphologies of these metallo-hydrogels were L2/Pb ratio dependent,ranging from worm-like to rod-shaped and nanofibrous.The FT-IR and X-ray diffraction(XRD) studies revealed that L2-Pb complexation was the main driving force for the formation of the metallo-hydrogels.In addition,these metallo-hydrogels exhibited outstanding thermostability and thermoreversibility,and displayed a reversible sol-gel transition induced by changes in pH and EDTA concentration.Importantly,ligand L2 showed an excellent capacity for the removal of Pb 2+ in aqueous solution through the formation of metallo-hydrogels.At a L2:Pb molar ratio of 1:0.5 and below,the concentration of residual Pb2+ was as low as 7.6×10-5 mol/L in aqueous solution,and the removal ratio was as high as 95.4%.These results demonstrate that multi-channel responsive smart metallo-hydrogels have the potential to be widely applied in materials science,and might provide the basis for lead pollution capture and removal.     

Synthesis,Bioactivity and Crystal Structure Analysis of Novel Benzo[d]isothiazol-3（2H）-ones

Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BIT) and characterized by 1 H NMR,IR and elemental analysis,respectively.The single crystals of compounds 1 and 2 were obtained and determined by X-ray diffraction analysis.The preliminary results of biological activity experiment show that some of the title compounds exhibited a favorable antimicrobial activity.     

Synthesis and nitration of calix[4] (aza)crowns

Calix[4] (aza) crowns containing amide groups 3a-d were synthesized by the reactions of calix[4]arene (1a) or p-tert-butylcalix[4]arene (1b) with N, N'-ethylenebis(2-chloroac-etamide) (2a) or N, N'-1,2-phenylenebis(2-chloroacetamide) (2b) by one step procedure in yields of 85-90% . Calix[4]-(aza) crowns 4a-b could be obtained by the reduction of 3a-b with LiAlH4 in yields of 51 and 67% , respectively. The nitration of 3a or 3c afforded new chromogenic calix[4]arenes 5a bearing two nitrophenol moieties and 5c bearing one nitro-phenol and one quinone moiety, respectively. The ipso-nitrations of 3b and 3d were also studied. Both gave the products containing one nitrophenol and one quinone moiety. Moreover, a very interesting calix[4]arene derivative 5d containing one cyclohexadienone moiety was also separated as the main product when 3d was ipso -nitrated.     

Syntheses, Structural Characterization of Fe and Ni Complexes with Polypyrazolyl Borate Ligand ： Fe [ HB （pz） 3 ] 2 and Ni [ HB （pz） 3 ] 2

Fe(Ⅱ) complex Fe[HB(pz)3]2(compound 1, pz=pyrazole) and Ni(Ⅱ) complex Ni[HB(pz)3]2(compound 2) have been obtained by the reaction of MCI2(M=Fe and Ni) with NaHB(pz)3 in MeOH. The two complexes(compounds 1 and 2) were characterized by IR, NMR, elemental analysis and X-ray diffraction. Compound 1 crystallizes in space group P21/c with a=1.224(3) nm, b=1.161(2) nm, c=1.648(3) nm, β=107.62(15)°, V=2.233(8) nm3, Z=2. Compound 2 crystallizes in space group P21/c with a=0.97926(18) nm, b=1.7423(3) nm, c=1.3156(2) nm, β=97.055(16)°, V=2.2277(7) nm3, Z=4. The results of X-ray structural analyses show that both compounds 1 and 2 are monomeric neutral, possessing a similar coordination mode and a similar structure around the metal centers. The related spectral characterizations, steric effects and binding properties are discussed.     

SYNTHESIS OF FUNCTIONAL MACROMOLECULE INTERMEDIATE THROUGH ACYLATION CATALYZED BY [Emim]Cl-AlCl3 IONIC LIQUID

Acylation reaction of anthracene with oxalyl chloride in the presence of [Emim]Cl-AlCl3 ionic liquid has been investigated. Pure 1,2-aceanthryenedione, which is used as intermediate of functional aromatic polymer material, was obtained by recrystalling the reaction mixture with aether and was determined by GC/MS, 1↑HNMR and FTIR analysis. The influences of various parameters, such as the contents of AlCl3 in [Emim]Cl-AlCl3, the amount of acylation agent, amount of [Emim]Cl-AlCl3, reaction temperature and reaction time were investigated. The optimum conditions were as follows： the molar fraction of AlCl3 in ionic liquid [x（AlCl3）] being 0.67, molar ratio of ionic liquid to anthracene being 2：1, molar ratio of oxalyl chloride to anthracene being 2：1, reaction temperature being 40℃ and reaction time being 6h. Under above conditions, the yield and selectivity of 1,2-aceanthrylenedione can reach 91.5% and 98.3% respectively. Further more, [Emim]Cl-AlCl3 ionic liquid, compared with metal halides such as AlCl3, was found to catalyze the reaction as a novel environmental friendly catalyst and solvent and can be reused.     

Synthesis of 2-Arylimidazo[1, 2-a]pyrimidines in Ionic Liquids

Room temperature ionic liquids were used as a “green“ recyclable alternative to conventional solvents in the synthesis of pharmaceutically useful compounds 2-arylimidazo[1, 2-a]pyrimidines through Tschotschibabin reaction of a-bromoacetophenones with 2-aminopyrimidine in good yields.     

Preparation, Curing Reactivity and Thermal Properties of Titanium-doped Silicone Resins

Novel titanium-doped silicone resins were synthesized from low-cost silane monomers and tetrabutyl titanate as raw materials and hydrochloric acid as catalyst, with titanium element as dopant into principal chain of Si-O-Si. The resins were characterized by means of FTIR, 1 H NMR and 13 C NMR spectra, their thermal properties and curing properties were investigated and their corresponding films were determined. The results show that the thermal stability and storage stability of the resins were influenced by the types of silane monomers containing different carbon atomicities of organic group. The thermal stability of the titanium-doped silicone resin with a molar ratio of silane monomer B(n-propyl triethoxysilane) to silane monomer C(n-octyl triethoxysilane) being 1:1 is superior to that of the resin with a molar ratio of silane monomer B to silane monomer C being 1:3. However, the storage stability of the former is inferior to that of the latter.This work also showed that the synthesized titanium-doped silicone resins have the highest thermal stability up to 450―500 °C with an atomicity molar ratio of 1:4 of titanium to silicon in the reactants. But the best storage stability of the resin prepared from the reactants with an atomicity molar ratio of 1:6[n(Ti):n(Si)] was obtained. The effect of the type and content of curing agent on the curing properties of the resin was also studied. Moreover, thermal mechanism and curing mechanism were proposed in this work.     

Synthesis and Crystal Structure of 2-(4’-Methylphenoxy)-5,8,9-trimethyl-3-phenyl Thieno[3′,2′:5,6]pyrido[4,3-d]pyrimidin-4-(3H)-one Hydrochloride

1 INTRODUCTION Pyrido[4,3-d]pyrimidine derivatives have pharma- ceutical activity and germicidal action[1~3]. So far, hundreds of tetrahydro- and octahydro-pyrido[4,3- d]pyrimidines have been synthesized as potential diuretic, antirheumatic and bacteriostatic drugs, but only a few of fully aromatic pyrido[4,3-d] pyrimi- dines are known. An important synthetic route to synthesize fully aromatic pyrido[4,3-d]pyrimidines is the condensation reaction of 4-aminonicotinic acid and amines[4]. Ho…     

Crystal structure and single crystal EPR of (NH4)2(15-crown-5)3[Cu(mnt)2] and (NH4)2(benzo-15-crown-5)4[Cu(mnt)2]·0.5H2O

The X-ray crystal structures of (NH4)2(15-crown-5)3[Cu(mnt)2] (1) and (NH4)2(benzo-15-crown-5)4- [Cu(mnt)2]·0.5H2O (2) were determined. Two single crystals are composed of distinct structures of ammonium-crown ether supramolecular cation and [Cu(mnt)2]2- anion. The triple-decker dication in complex 1 and a sandwich dimmer in complex 2 were observed. X-Band EPR studies on the single crystals of both complex 1 and complex 2 have been carried out at room temperature, which revealed that complex 2 showed a perfect hyperfine structure of Cu whereas that of complex 1 could not be observed. The principal values and direction cosines of the principal axes of the g and A tensors were computed by a least-squares fitting procedure. The spin density of Cu(Ⅱ) was estimated according to the principal values of the A tensors and compared well with the results calculated based on DFT method.     

新型取代硅桥联茂稀土化合物的合成及在纳米级氢化钠助催化剂作用下高活性催化甲基丙烯酸甲酯聚合的研究

The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me2Si(C5H3CMe2C6H5)2LnC1]2 [Ln=Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [MeESi(C5H3CMe2C6H5)2LnC1]2/NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 105. The activity reached that of organolanthanide hydride as a single-component catalyst. In ]MeESi(C5H3CMe2C6H5)2ErC1]2/Nail (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.