Alkylene-functionality in bridged and fused nitrogen-rich poly-cyclic energetic materials:Synthesis,structural diversity and energetic properties

From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.

Synthesis and Crystal Structure of the Ladder-like Organotin Complex: μ-pentaoxygen bridged penta(bis-benzyltin) bis-salicylate

A novel organotin complex of μ-pentaoxygen bridged penta（bis-benzyltin） bissalicylate has been synthesized by the reaction of bis-benzyltin oxide and salicylic acid and its structure has been determined by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 1.7206（5）, b = 2.1401（6）, c = 2.1488（6）nm, β= 93.325（5）°, V = 7.899（4） nm^3, Z = 4, Dc = 1.564 g/cm^3,μ（MoKα） = 16.17cm^-1, Mr = 1859.94, F（000） = 3692, R1= 0.0755 and wR2= 0.1557. According to structural analysis, the coordination geometry of tin is a distorted trigonal bipyramid, and the ladder-like structure is shaped by four Sn2O2 planar four-membered rings.

Comparison Between the Effects of 2-Selenium Bridged β-Cyclodextrin and Ebselen on Treating SHRsp Stroke

A glutathione peroxidase（GPX） mimic, 2-selenium bridged β-cyclodextrin（2-SeCD）, was synthesized. In order to examine its role and mechanism in treating stroke we chose stroke-prone spontaneously hypertensive rats（SHRsp） as animal model. 56 SHRsps of 8-week olds were randomly divided into several groups： test groups （low, moderate, high dose of 2-SeCD） and control groups（positive and negative）. After onset of the stroke, the rats in test groups were orally administrated with different amounts of 2-SeCD, the positive control group with ebselen, and the negative control group with drinking water. The treatment lasted two weeks, followed by observation of the rats for 10 days, meanwhile blood pressure, biochemical parameters of plasma, and the contents of nitric oxide（NO） and malondialdehyde（MDA） in plasma and brain were determined. The results show that there were significant differences in contents of NO and MDA in plasma and brain between the test groups（high, moderate dose of 2-SeCD） and negative control group. The NO contents of the test groups were obviously higher than that of the negative control group （P〈0.01）. The MDA contents of the test groups（high, moderate dose of 2-SeCD） were obviously lower than that of the negative control group（P〈0.01）. The mechanism of 2-SeCD in treating stroke was discussed, which maybe related to the increase of NO and the decrease of MDA in plasma and brain tissue, but the exact mechanism should be further studied. Moreover, the tendencies of changes in systolic blood pressure, contents of NO and MDA, and other physiological parameters for the test groups were shown to be much better than the corresponding parameters for the positive group（the group with ebselen）（P〈0.05）, indicating that the treatment effect of 2-SeCD is better than that of ebselen.

Synthesis of a Novel Aromatic Diamino-bridged Bis(β-cyclodextrin) and its Inclusion Complexation with Dyes Molecules

A novel brideed bis（β-cvclodextrin）, 4, 4＇-diaminodiphenyl ether-bfiged-bis （6-aimino-6-deoxv-β-cyclodextrin） 3, has been synthesized and its inclusion complexation behavior with three linear＇guest dyes （AR, NR and MB ） has been investigated by. means of fluorescence spectrometry. The-result obtained demonstrated that the novel bridged bis（β-cyclodextnn） showed much higher affinities towards guest dyes than native β-cyclodextrin.

Synthesis, Characterization and Application of A Novel Carbon Bridged Half-metallocene Chromium Catalyst for Methyl Methacrylate Polymerization

A new carbon bridged cyclopentadienyl chromium complex of the type [（C5H4）C（CH3）2 CH2（C5H4N）]CrCl2 was prepared by treatment of CrCl3·（THF）3 in THF solution with the lithium salt of ligand containing cyclopentadienyl and pyridyl groups. The chromium complex was characterized by 1H NMR and elemental analysis（EA）, and the crystal structure was determined by X-ray diffraction analysis. Activated by Al（i-Bu）3, the chromium complex displayed a very high activity for methyl methacrylate（MMA） polymerization. After 24 hours,more than 95.5% MMA was converted to polymethyl methacrylate（PMMA） with a viscosity average molecular weight（Wη） of 416000 g·mol-1 at 60 ℃ for MMA/ Al（i-Bu）3 /chromium catalyst molar ratio of up to 2000：20：1. Effects of temperature, molar ratios of MMA/catalyst and catalyst/cocatalyst on the polymerization have been studied. The high conversion of MMA and high molecular weight of PMMA with narrow molecular weight distribution is caused by the unique stable active site formed by the new chromium complex and aluminum cocatalyst.

Safety and efficacy of transpapillary bridged bilateral side-by-side stenting for unresectable malignant hilar biliary obstruction

To the Editor:Biliary drainage is most frequently performed among endoscopic procedures using pancreatobiliary endoscopy.A large-diameter metallic stent can significantly extend the patency period rather than a plastic stent for extrahepatic biliary stricture.;However,the optimal drainage for the hilar biliary obstruction is still controversial.

Cyanide-bridged One-dimensional Heterobimetallic Complex cis-[Fe^Ⅱ(phen)2(CN)2Mn^Ⅲ(salen)](PF6):Synthesis,Crystal Structure and Magnetic Properties

Dicyanide building block cis-Fe（phen）2（CN）2 and [MnⅢ（salen）]（ClO4） have been used to design and synthesize a cyanide-bridged complex, resulting in a heterobimetallic one-dimensional（1D） zigzag chain complex 1, [cis-Fe（phen）2（CN）2Mn（salen）]（PF6）（phen =1,10-phenanthroline, salen=N,N-ethylenebis-（salicylideneaminato） dianion）. Single-crystal X-ray diffraction analysis shows complex 1 crystallizes in the monoclinic P2（1/c） space group and the asymmetric unit contains one [-NC-Fe（phen）2（μ-CN）-MnⅢ-（salen）-]＋ cation and one PF6- anion. In the cationic structure of 1, each FeⅡ（phen）2（CN）2 connects two [MnⅢ（salen）]＋ with two cyanide groups in a cis-conformation, and in turn each [MnⅢ（salen）]＋ unit links two FeⅡ（phen）2（CN）2 building blocks in a trans-conformation, resulting in a 1D [-NC-FeⅡ-CN-MnⅢ-]n chain. Furthermore, the electronic absorption spectra and electrochemical and magnetic properties of complex 1 have also been studied.

Effect of 2-Selenium Bridged β-Cyclodextrin,Glutathione Peroxidase Mimic on Stroke of Stroke-prone Spontaneously Hypertensive Rats

To investigate the treatment effect of 2-selenium bridged β -cyclodextrin(2-SeCD),a GPX mimic,on the stroke of stroke-prone spontaneously hypertensive rats(SHRSP),fifty-two SHRSP of 8-week old were randomly divided into four groups A,B,C and control group D. The rats of groups A,B,C and D were given 1.0%-1.5% NaCl mass fraction as drinking fluid. After onset of stroke,groups A,B and C were given \{orally\} 16.05,160.5 and 1605 mg·kg -1 ·day -1 of 2-SeCD,respectively,and group D was given water for \{2 weeks.\} The clinical score of stroke,systolic blood pressure(SBP),survival time of rats were recorded and the histopathologic examinations of their brain and carotid artery were made after decapitation. The clinical scores of stroke after treatment with 160.5 mg·kg -1 ·day -1 (Group B) and 1605 mg·kg -1 ·day -1 (Group C) of 2-SeCD are 2.55±0.98 and 1.98±0.79,respectively,those are obviously lower than that of group D(3.41±0.83,p<0.01). The survival days in group B(10.0±8.6) and group C(14.4±7.9) are longer than that for group D(4.7±2.9,p<0.01). The electron microscope study showed that the endothelium of carotid artery was near to normal in group B and group C,while it was seriously injured in control group D and mildly injured in group A. 2-SeCD may effectively be used to treat the stroke for SHRSP.

CRYSTAL STRUCTURE OF A 2D SHEET－LIKE μ－CYANIDO－OXAMIDATO BRIDGED Fe（III）－Cu（II） HETERNUCLEAR COMPLEX

The synthesis is and crystal structure are reported for the sheet-like compourd [CU2(oxpn)Fe(CN )5(NO)]. there oxpn is the dianion of M, M'-bis(3-aminopropyl)oxamide. This compound crustallizes in the orthogonal space group Puma. with a=11 .413(4), b=22.242(5), c=7.736(2) A, and Z=4.The structure was refined to conventionat discrepancy factors R=0.047 and Pw=0.054. The Cu(II ) and Fe(III)centers are bridged by oxpn and cyanide, the formal behaves as a his-terdentate tigand bound to cooper(II)ion to form (II) dimers. whereas the latter bridges Cu(II) and Fe(III) centers in both symmetric and asymetric end- to-end bis-monodentate fashions, spreading out along be plane to form a 20 network. The Structure is made up of CuFe unit with Cu(II) and Fe(III) ions locating in a distorted square-based pyramid and a compressed octahedron, respectively.

STRUCTURAL EVIDENCE FOR THE METAL ION BRIDGED LIGANDLIGAND INTERACTION：THE X－RAY CRYSTAL STRUCTURE OF ［（2，2＇－BIPYRIDYL）（PHENYLMALONATE）COPPER（Ⅱ）］ TRIHYDRATE

The crystal structure of the ternary complex [Cu (L)(2, 2'-bipy)H2 O]·2H2O(L=phenylmalonate) has been determined by X-ray diffraction methods. The copperf(II) centerin five-coordinate Square-pyramidal structure.It is of interest in this structure that the complexinvolves a metal ion bridge ligand-ligand aromatic ring stacking interaction

One and Two-dimensional Structures of a New Oxamido Copper(II) Complex with Phthalato Bridged

A new o-phthalato-bridged oxamide copper（Ⅱ） complex 1, {[Cu2（oxap）]（pht）. 4H2O}n （oxap=N, N＇-bis（2-aminopropyl）oxamide, pht= phthalate dianion）, has been prepared and structurally characterized. It crystallizes in monoclinic, space group C2/c with a=23.424（4）, h=7.9696（14）, c=15.727（3）A°,β=129.617（2）°, C16H28Cu2N4O10, Mr=563.50, V=2261.6（7） A°, Z=4, Dc=1.655 g/cm^3, μ（MoKα）=1.939 mm^-1, F（000） = 1160, the final R=0.0393 and wR=0.0928 for 1707 observed reflections with I〉2σ（1）. Single-crystal X-ray analysis reveals that 1 displays a one-dimensional zigzag chain structure, in which each Cu（oxap） moiety adopting trans-conformation is connected by ,μ1,6-phthalate anion bridges, and these zigzag chains are further linked by another ,μ1,6-phthalate anion bridge to form a 2D sheet structure. The polar guest water molecules reside in the inter-and intrasheets to stabilize the whole crystal structure.

The Synthesis of Bridged Purine Dinucleoside

Two bridged purine dinucleosides, bis(2-N-acetyl-6-N-alkylylene-2,6-diaminopurine-2',3',5'-triacetyl-beta-D-ribofuranoside), were synthesized fi om the reaction of the key medium 3, 2-acetylamino-6-[1-(1,2,4-triazolyl)]-purine-2',3',5'-triacetyl-beta-D-ribofuranoside with dialkylamine.

FERROMAGNETIC INTERACTION BETWEEN GADOLINIUM（Ⅲ） AND COPPER （Ⅱ）IONS IN N，N＇－BIS（2－AMINOPROPYL）OXAMIDO COPPER（Ⅱ） BRIDGED BINUCLEAR Gd（Ⅲ）－Cu（Ⅱ） COMPLEX

The heterobinuclear complex of formula Cu (oxap )Gd(phen)2 (CIO4 )3 has been synthesized, where oxap denotes the N, N'-bis (2-aminopropyl )oxamido dianion and phen represents 1,10-phenanthroline. The complex was characterized with ESR and variable temperature magnetic susceptibility (4- 300K). The least-squares fit of the experimental sosceptibilities yielded J=2. 25cm-1. The observed Gd (Ⅲ)-Cu (Ⅱ) coupling is ferromagnetic.One Plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅱ) and Cu (Ⅱ) is discussed in terms of spin-polarization.

Preparation and Characterisation of Cyclopentadienyl Tetramethylethene－bridged Dicyclopentadienylsamarium（Ⅲ）Tetrahydrofuranate Complexes

The complexes of cyclopentadienyl tetramethylethenebridsied dicyclopentadienylsamarium (Ⅲ) tetrahydrofuranates, Me4C2(C5H4)2LnC5H5 (THF) (Ln = Nd, Sm, Gd, Yb) were synthesized and characterized by elemental analysis, IR, 1HNMR, thermogravimetry and MS. The crystal structure of Me4C2(C5H4)2SmC5H5 was determined by X-ray diffraction method. The crystal belongs orthorhombic space group Cc2a. with a =1 . 1696(6) nm, b =1 .2539(5) nm, c = 2.9432(15) nm, V= 4.316 (4) nm3, Z= 8 and Dc = 1 . 54 g . cm-3.

Crystal Structure of Bridged Dimer Complex of [Yb (H_2O)) (acac)_2 (Ac)]_2

The title complex C24H38O14Yb2(Mr=896. 62 ) crystallized in orthorhombic system, space group Pbcn with unit cell dimensions a=13. 478 (4), b=16. 161(7), c=15. 110(5); V=3291. 2(2); Z=4; F(000) = 1736; Dc=1. 810g. cm-3;μ= 17. 5 cm-1 (MoKa). The final R and Rw are 0.061 and 0.058 respectively. The title complex is a bridged dimer. The ligands that bridge two Yb(Ⅲ) centerions are the two acetatos in the complex and every Yb(Ⅲ) ion is eight-coordinated, being bonded to one O atom of one H,O molecule, four O atoms of two acetylacetonatos,two O atoms of an acetato and one O atom of another acetato. The coordination polyhedron of the Yb(Ⅲ) ion in the title complex is a dodecahedron.

SYNTHESIS OF NOVEL THIOPHENEDIMETHYLENE BRIDGED HOMOBINUCLEAR METALLOCENES AND THEIR CATALYTIC PROPERTIES FOR ETHYLENE POLYMERIZATION

By treating disodium（thiophenedimethylene）dicyclopentadienide C4H2S（CH2C5H4Na）2 with two equivalent of CpTiCl3 or CpZrC13 DME at 0℃ in THF, two new thiophenedimethylene bridged binuclear metallocenes [Cl2MC5H5][C5H4CH2C4H2SCH2C5H4][C5H5MCl2] （M = Ti 3, M = Zr 4） were synthesized in high yield and their structures were characterized by ^1H-NMR. These complexes were used as catalysts for ethylene polymerization in the presence of methylaluminoxane （MAO）. The effects of polymerization temperature, time, concentration of catalyst, molar ratio of MAO/Cat on polymerization were studied in detail. The catalytic activities of thiophenedimethylene bridged binuclear metallocene catalysts （3, 4） reached 2.44 × 10^5 g PE mol^-1 cat^-1· h^-1, 9.61 × 10^5 g PE mol^-1 · cat^-1· h^-1 respectively, which are higher than that of pheneyldimethylene bridged binuclear metallocene catalysts and much higher than that of corresponding mononuclear metallocenes （Cp2TiCl2 and Cp2ZrCl2）. The molecular weight distribution curves of polyethylenes produced by binuclear metallocene catalysts （3, 4） and by mononuclear metallocene catalyst have only single peak, but the former （MWD = 3.5-4.7） is obviously broader than the latter （MWD = 2.0-2.2）.

Hydrothermal Synthesis and Crystal Structure of Binuclear Copper(Ⅱ) Complex Bridged by 1,2,4,5- Benzenetetracarboxylato Trivalent Anion

The title complex [(phen) 2Cu(Htcb)Cu(phen) 2]H 3tcb(tcb=1,2,4,5-benzenetetracarboxylato tetravalent anion; phen=1,10-phenanthroline) was synthesized by the hydrothermal synthesis method. The crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic system with space group P1, a=1.04174(8) nm, b=1.07119(8) nm, c=1.26360(10) nm, α=98.169(2)°, β=99.679(10)°, γ=93.658(10)°, V=1.37031(18) nm3, Z=1. The two copper(Ⅱ) cations are bridged by Htcb in the monodentate fashion, and have the same five-coordinated environment completed by the four N atoms from the two phen molecules and one O atom from the carboxylic group of Htcb respectively, which can be best described as distorted trigonal-bipyramid geometry. Moreover, the three dimensional network is formed by H-bonding interactions [O…O distance from 0.2506(10) nm to 0.3176(11) nm] and π-π stacking interactions between the phen rings of adjacent binuclear entities with a face-to-face separation of ca. 0.354 nm.

TRIPLY BRIDGED BINUCLEAR COMPLEX OF OXOMOLYBDENUM(Ⅴ)WITH MERCAPTOPHENOLATE LIGANDS

Reaction of(n-Bu_4N)_xNa_(4-x)[a-Mo_8O_(26)](x=1-4)and mpH_2(mpH_2=o-mercaptophenol) leads to the formation of compound(n-Bu_4N)[Mo_2O_3(mp)_3Na(EtOH)_2(MeOH)],It crystallizes in the space group P2_1/n with four molecules per unit cell.The cell dimension is a=12.776(3),b=14.154(5),c=26.281(7)(?)=95.50(2)°,V=4730.5 (?),d_c=1.407 g/cm^3.Full-matrix refinement of 496 parameters on 3348 reflection data gave final R(R_w) value of 0.072(0.072).The two oxomolybdenum-mercaptophenolate,units are triply bridged by an inorganic oxygen atom and a doubly bridging mp^(2-)ligand.

Synthesis and Characterization of Novel Bridged Porphyrins

The reaction of 5-(4-hydroxyphenyl)-10,15,20-triphenyl porphyrin with 2,6-dibromomethylpyridine and 4,4′-dicarboxyl-2,2′-bipyridine respectively gave 2,6-bis-[5,10,15-triphenyl-20-(4-phenoxymethyl)-porphyrin-yl]-pyridine(3) and 4,4′-di-[5,10,15-triphenyl-20-(p-phenoxycarbonyl)-porphyrin-yl]-2,2′-bipyridine (4). 5-[4-(4′- Bromobutoxy) phenyl]-10,15,20-triphenyl porphyrin reacted with 2,6-dihydroxymethylpyridine to give 2,6-bis-[5,10,15-triphenyl-20-(4-(p-phenoxy)-butoxymethyl)-porphyrin-yl]-pyridine(5). Those new compounds have been identified by1H NMR, IR, MS and UV-visible spectra, and elemental analysis. Key words bridged porphyrin - synthesis - structure characterization CLC number O 626.13 Foundation item: Supported by the National Natural Science Foundation of China (29972035)Biography: FU Shi-tao (1979-), male, Ph. D candidate, research direction: porphyrin chemistry.

The Assembly and Molecular Structure of a Novel One-dimensionalCyanide-bridged [Ni(pn)_2Ni(CN)_4]_n·nH_2 O Complex

The synthesis, structure and characterization of a new one-dimensional cyanide-bridgedcomplex [Ni(pn)_2Ni(CN)4]n'nH2O (where pn = 1,2-diaminopropane) are described. The structure ofthis complex consists of a one-dimensional polymeric chain-Ni(pn)2-NC-Ni(CN)2-CN-Ni(pn)2- inwhich the Ni(II) centers are linked by two CN groups.