Structure and Fluorescence Property of a 2D Bilayer Cd(Ⅱ) Coordination Polymer Induced by H-bonding and π-π Interaction

Solvothermal reactions of 4,4＇-oxybis（benzoic acid） （H2oba） with 1,3-dipyridyl benzene （1,3-dpb） produced a two-dimensional （2D） cadmium（Ⅱ） coordination polymer {[Cd（oba）（dpb）]·H2O}n （1）. The complex was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group C2/c with a = 13.6692（9）, b = 25.9647（17）, c = 8.7912（6） , α = 125.0370（10）, γ = 2544.7（3）°, V = 2544.7（3） 3, C30H22N2O6Cd, Mr = 618.91, Dc =1.609 g/cm3, F（000） = 1248, μ = 0.904 mm-1 and Z = 4. The neighboring Cd（Ⅱ） ions are linked by oba2-anions and 1,3-dpb to form an infinitely 2D wavelike sheet, and two such 2D sheets are interlocked with each other by H-bonding to form a 2D → 2D structure. The adjacent two groups of interlocked structures are further linked to form a bilayer 2D supramolecular network by π-π interactions. In addition, the fluorescence property of 1 was also studied.

CONCERTED H-BONDING TEMPLATE SYNTHESIS OF AN ORDERED LADDER POLYSILSESQUIOXANE

A novel soluble regular ladder poly（benzoyl-3-aminopropyl） silsesquioxane （LPBAS） was facilely prepared under effective assistance of concerted H-bonding self-assembly of amido groups of side chains and silanol groups, respectively, of a new template monomer [1,3-bis（benzoyl-3-aminopropyl）-1,1,3,3-tetraethoxydisiloxane] （M）. The ordered ladder structure of LPBAS is manifested in： （1） the presence of two Bragg peaks representing the ladder width （d） and ladder thickness （t） in X-ray diffraction （XRD） pattern; （2） narrow base-line width （w = 6） of resonance absorption for -CH2SiO3/2 moiety in 29Si-NMR and （3） high glass transition temperature Tg = 1 12℃ in differential scanning calorimetry （DSC） analysis.

An intravenous clarithromycin lipid emulsion with a high drug loading, H-bonding and a hydrogen-bonded ion pair complex exhibiting excellent antibacterial activity

The aim of this study was to develop an intravenous clarithromycin lipid emulsion(CLE)with good stability and excellent antibacterial activity. The CLE was prepared by the thinfilm dispersed homogenization method. The interaction between clarithromycin(CLA) and cholesteryl hemisuccinate(CHEMS) was confirmed by DSC, FT-IR and^1H NMR analysis. The interfacial drug loading, thermal sterilization, freeze–thaw stability, and in vitro and in vivo antibacterial activity were investigated systematically. DSC, FT-IR and^1H NMR spectra showed that CHEMS(CLA: CHEMS, M ratio 1:2) could interact with CLA through H-bonding and a hydrogen-bonded ion pair. The CHEMS was found necessary to maintain the stability of CLE.Ultracentrifugation showed that almost 88% CLA could be loaded into the interfacial layer.The optimized CLE formulation could withstand autoclaving at 121 °C for 10 min and remain stable after three freeze–thaw cycles. The in vitro susceptibility test revealed that the CLA–CHEMS ion-pair and CLE have similar activity to the parent drug against many different bacterial strains. The in vivo antibacterial activity showed that the ED50 of intravenous CLE was markedly lower than that of CLA solution administrated orally. CLE exhibited pronounced antibacterial activity and might be a candidate for a new nanocarrier for CLA with potential advantages over the current commercial formulation.

H-BONDING SELF-ASSEMBLED TEMPLATE-CONTROLLED SYNTHESIS OF A NOVEL SOLUBLE AND REACTIVE AMIDE-BRIDGED LADDERLIKE POLYHYDROSILOXANE

A novel soluble and reactive amide-bridged ladderlike polyhydrosiloxane （ALPHS） was first synthesized by an amido H-bonding self-assembled template. ALPHS with molecular weight M^-a = 18300 has very highly ordered ladderlike structure, which was confirmed by a sharp resonance absorption peak of [-Si（H）O2/2 ] moiety with the half peak width △1/2 〈 0.5 in^29Si-NMR spectrum. Presence of the reactive Si-H groups gives ALPHS an opportunity to further derive a variety of functional polymers by versatile Si-H reactions such as hydrosilylation, condensation, and so on.

H-bonding template-directed synthesis of a complete m-PDA-bridged ladder polyhydrosiloxane (OLPHS)

A highly ordered m-phenylenediimino-bridged ladder polyhydrosiloxane （abbr. OLPHS） with Mn = 1.24 × 10^4 was synthesized stoichiometric hydrolysis and dehydrochlorination condensation reaction between Si-Cl and Si-OH bonds. The complete ladder structure of OLPHS has been confirmed by the following three data. Two characteristic Bragg＇s peaks representing the ladder width （w = 0.94 nm） and ladder thickness （t = 0.42 nm） were observed in XRD analysis, which are consistent with those calculated by molecular simulation. The very sharp absorption with a small half-peak width （w1/2 = 0.5 ppm） for [（-HN）HSiO2/2]n moiety of OLPHS in ^29Si NMR spectrum indicated presence of the complete ladder structure. As collateral evidence, a higher glass transition temperature （Tg = 105 ℃） is also recorded in the DSC measurement, implying the high stiffness of ladder chain of OLPHS.

H-Bonding Self-assembled Template-directed Synthesis of a Reactive Amide-bridged Ladder Polyvinylsiloxane

A novel, reactive amide-bridged ladder polyvinylsiloxane （abbr. LP） with Mn= 2.4×10^4 was synthesized for the first time by means of aryl amide H-bonding self-assembled template. The regularity of LP was characterized by the XRD, ^29Si NMR and DSC methods. XRD analysis demonstrated the ladder width w = 9.09A and the ladder thickness t = 3.89A, respectively, which are approximately consistent with the molecular simulation-calculated ones： w＇= 10.60A and t＇= 3.06A. ^29Si NMR displayed a resonance peak with small half peak width, △1/2 - 4 ppm, for the moiety [=Si（Vi）O2/2-]n of LP. Besides, as a collateral evidence, DSC measurement revealed a high glass transition temperature Tg = 225℃, suggesting high stiffness of the ladder main chain of LP.

Self-healed microcracks in polymer bonded explosives via thermoreversible covalent bond and hydrogen actions

Polymeric materials used for the polymer bonded explosive(PBX)or other energetic composite materials(ECMs)that simultaneously possess excellent mechanical properties and high self-healing ability,convenient healing,and facile fabrication are always a huge challenge.Herein,self-healing linear polyurethane elastomers(PTMEG2000-IPDI-DAPU,denoted as 2I-DAPU)with high healing efficiency and mechanical properties were facilely fabricated by constructing reversible covalent bonds and dynamic hard domains into polymer chains.Furthermore,a TATB-based PBX using as-prepared 2I-DAPU polymer as the binder was constructed,disclosing an excellent self-healing property to heal cracks generated during fabrication,transportation and storage.The damage healing manner of such a PBX sample was investigated by means of prefabricated damage through mechanical load,heal treatment via heating at high temperature,and CT-scanning the inner structure and mechanical property characterization via Brazilian test.The self-healing mechanism of internal damage in PBX was preliminarily explored.We propose that this 2I-DAPU binder with Diels-Alder bonds could generate plentiful active surface groups resulting from damage and drive self-healing at fitting temperature and increase the slightly packed hard phase via incorporating a small amount of hydrogen bonds.This work may offer a novel strategy for improving mechanical property and healing ability in the field of self-healing material which could help expand its applications with enhanced versatility in mechanical-enhanced functional materials.

A TD-DFT Study for the Excited State Calculations of Microhydration of N-Acetyl-Phenylalaninylamide (NAPA)

Investigating the impact of microhydration on the excited-states and electronic excitation properties of biomolecules has remained one of the important yet challenging aspects of science because of the complexity of developing models. However, with the advent of computational chemistry methods such as TD-DFT, many useful insights about the electronic excitation energy and excited-state nature of biomolecules can be explored. Accordingly, in our study, we have incorporated the TD-DFT/wB97XD/cc-pVTZ method to study the excited state properties of N-acetyl phenylalanine amide (NAPA-A(H2O) n) (n = 1 to 4) clusters from ground to the tenth lowest gaseous singlet excited state. We found that the C=O bond length gradually increases both in N-terminal amide and C-terminal amide after the sequential addition of water molecules because of intermolecular H-bonding and this intermolecular H-bonding becomes weaker after the sequential addition of H2O molecules. The UV absorption maxima of NAPA-A (H2O)n (n = 1 - 4) clusters consisted of two peaks that are S5←S0 (1st absorption) and S6←S0 (2nd absorption) excitations. The first absorption maxima were blue-shifted with the increase in oscillator strength. This means that strong H-bonds reduce the charge transfer and make clusters more rigid. On the other hand, the second absorption maxima were red-shifted with the decrease in oscillator strength. In the ECD spectra, the negative bands indicate the presence of an amide bond and L-configuration of micro hydrated NAPA-A clusters. Finally, our calculated absorption and fluorescence energy confirm that all the NAPA-A (H2O) n (n = 0 - 4) clusters revert to the ground state from the fluorescent state by emitting around 5.490 eV of light.

3-X-2(1H)-吡啶酮互变异构体系的理论计算

The geometries of 3 X 2(1H) pyridones(X=NO 2, NH 2, COOH) and their tautomers in the gas phase and DMSO solution(SCRF) have been obtained at HF/6 31G ** and MP2/6 31G ** levels. The influences of intramolecular hydrogen bond on the tautomeric equilibrium have also been investigated. In the gas phase, the calculated results show that the enol form is more stable than the keto form for 3 NO 2 2(1H) pyridone, and the ketoenol equilibrium shift right due to the formation of intramolecular hydrogen bond between 3 nitro and 2 hydroxyl group, while for the amino and carboxyl derivatives, the keto forms are favored over the enol forms because of the stronger intermolecular hydrogen bonds in keto tautomers. However, owing to the polarization effects of solvent, it can be predicted that the keto tautomers are dominant for all of the title compounds in DMSO solution, which are in good agreement with the experimental results.

手性膦酸二酯类化合物的合成与结构

手性呋喃酮 1 a,1 b与亚磷酸三酯 2 a,2 b通过串联的不对称 Michael加成 /分子内 Michalis-Arbazov重排反应 ,得到含磷官能团的新手性化合物 5 -( S) -( 1 S) -冰片氧基 -4 -膦酸二酯基 -3-卤素 -2 ( 5 H) -呋喃酮 ( 3a～ 3d) .该反应具有条件温和 ,产率高 ( 69%～ 93% ) ,光学纯度单一 ( d.e.≥ 98% )等特点 .通过元素分析 ,IR,UV,1 H NMR,1 3C NMR,MS,[α]2 0D 等分析数据以及

Two-dimensional ATR-FTIR Spectroscopic Study on the Water Diffusion Behavior in Polyimide/Silica Nanocomposite

To consider the reliability and performance of electronic devices based on polyimide derivatives, dynamic water sorption and diffusion behavior in a polyimide derivative： poly（4＇4 oxydiphenylene pyromellitimide） （PMDA-ODA）/silica nanocomposite was investigated by two-dimensional ATR-FTIR spectroscopy, by which three states of water molecules owning different H-bonding strength were distinguished. The amounts and strength of H-bonding also played a significant role in determining the diffusion rate of the different states of water molecules. The type of aggregated water molecules which also formed H-bonding with silicic acid （residues） or polyimide system was the last one diffusing to the polymer side in contact with the ATR crystal element because the polymeric matrix blocked their diffusion to a great extent. The diffusion coefficient was also estimated to gain the information of the dynamic diffusion behavior.

N-苯甲酰基-N’-4-甲基苯基硫脲的结构研究

The crystal structure of N-benzoyl-N’-4-methylphenylthiourea（BMPT）was determined by x-ray diffraction with erystallographic data as p21/c,a=12.948（8）*!,b=5.398（3）*!,c=19.790（12）*!,β=80.923（7）O,V=1365.9（14）*!3,Z=4.The intromolecular hydrogen bond of N-benzoyl-N’-（4-methyl）phenylthiourea was discussed.The results of the extended MO calculations using density functional theory（DFT）with a hybrid B3LYP density functional were qualitatively supported by experimental X-ray diffraction stueies on the title compound at the level of 6-311G*.

卤代乙烯与氟化氢二聚体g-C_2H_2X_2-HF(X=F,Cl)的结构和氢键性质的理论研究

本文作者使用了Counterpoise(CP)校正方法,在MP2/aug cc pVDZ水平,计算得到了实频的C2H4HF和g C2H2X2HF(X=F,Cl)的优化结构。由于X原子的作用,二聚体g C2H2X2HF(X=F,Cl)的πH键被延长,并且在结构中发生了倾斜和弯曲。X原子的作用降低了πH键相互作用能,而电子相关效应增加了πH键相互作用能。g C2H2X2HF(X=F,Cl)结构中存在着πtypeH bond。

2-取代-1,7-二氧螺[4.4]壬-8-酮的合成研究

分别用K2CO3、1，5-二氮双环[4．3．0]壬-5-烯（DBN）和四丁基氟化铵（TBAF）等碱催化3－（3-羟基丙基）－r-丁烯酸内酯的分子内Micheal加成反应合成了2-取代-1，7-二氧螺[4．4]壬-8-酮．

A robust self-healing polyurethane elastomer: From H-bonds and stacking interactions to well-defined microphase morphology

Self-healing materials have attracted considerable attention because of their improved safety, lifetime, energy efficiency and environmental impact. Supramolecular interactions have been extensively considered in the field of self-healing materials due to their excellent reversibility and sensitive responsiveness to environmental stimuli. However,development of a polymeric material with good mechanical performance as well as self-healing capacity is very challenging. In this study, we report a robust self-healing polyurethane(PU) elastomer polypropylene glycol-2-amino-5-(2-hydroxyethyl)-6-methylpyrimidin-4-ol(PPG-mUPy) by integrating ureidopyrimidone(UPy) motifs with a PPG segment with a well-defined architecture and microphase morphology.To balance the self-healing capacity and mechanical performance, a thermal-triggered switch of H-bonding is introduced. The quadruple H-bonded UPy dimeric moieties in the backbone induce phase separation to form a hard domain as well as enable further aggregation into microcrystals by virtue of the stacking interactions, which are stable in ambient temperature. This feature endows the PU with high mechanical strength. Meanwhile, a high healing efficiency can be realized, when the reversibility of the H-bond was unlocked from the stacking at higher temperature. An optimized sample PPG1000-mUPy50%with a good balance of mechanical performance(20.62 MPa of tensile strength) and healing efficiency(93% in tensile strength) was achieved. This strategy will provide a new idea for developing robust self-healing polymers.

Synthesis and Crystal Structure of Zinc(II) Complex with Isonicotinate Containing a Three-dimensional Hydrogen-bond Network

A zinc complex, [Zn(iso)_2(H_2O)_4](iso=C_6H_4NO_2^-), was synthesized and characterized by elemental analysis, thermal analysis and IR spectrum studies. The crystal structure of the complex was determined by X-ray diffraction. The crystal crystallizes in the triclinic system, molecular formula ZnC12H16N2O8, Mr=381.64, space group P with a = 6.338(1), b =6.919(1), c=9.277(1), α=96.28(1), β=104.91(1), γ=112.85(1)°, V=352.12(9)?3, Z=1, Dc=1.80g?cm-3 and F(000)=196, μ =1.791mm-1. The crystal structure was solved by direct methods for final R=0.0204 and Rw=0.0542 for 1258 observed reflections with [Fo>4σ(Fo)]. The crystal structure reveals that zinc ion is trans-octahedral with two pyridyl nitrogens and two aque oxygens at the equational positions and two aqua oxygens at the axial positions. The complex forms a three-dimensional network through intermolecular hydrogen bonds.

Design and Synthesis of a Highly Stable Six-hydrogen-bonded Serfassembly Yellowish Green Electroluminescent Molecular Duplex

This paper describes the design, synthesis and characterization of a hydrogen-bonded molecular duplex with 1,8-naphthalimide fluorescent pendants. The two oligoamide molecular strands, with complementary hydrogen bond sequences of DDADAA and AADADD, can form an ultra stable self-assembly duplex. Its molecular structure was confu-med by ^1H NMR and ESI-MS, and its photoluminescence properties were determined. The resulting duplex exhibited a dramatically enhanced photoluminescence （PL） quantum efficiency of 63.7% compared to the corresponding 1,8-naphthalimide segment （32.4%）, suggesting that the formation of the duplex with larger molecular weight could successfully inhibit the quenching of the fluorescent pendant. This novel duplex is a prospective candidate for new electroluminescent emitter.

Syntheses and Crystal Structures of Four Cobalt Supramolecular Architectures with Hmtyaa Ligand

Four cobalt supramolecular architectures with Hmtyaa（2-（5-methyl-1,3,4-thiadiazol-2-ylthio）acetic acid） ligand have been synthesized.[Co（mtyaa）2（H2O）4]·4（H2O）（1）：triclinic,space group P1 with a = 6.7537（18）,b = 8.591（2）,c = 10.615（3） ,α = 96.495（4）,β = 99.955（5）,γ = 103.615（5）°,V = 581.9（3） 3,Z = 1,Mr = 581.52,Dc = 1.659 g/m3,μ = 1.158 mm-1,F（000） = 301,Rint = 0.0557,R = 0.0377 and wR = 0.1056 for 1854 observed reflections with Ⅰ 〉 2σ（Ⅰ）;{[Co（4,4＇-bipy）（H2O）4]·2（mtyaa）·2（H2O）}n（2）：triclinic,space group P1 with a = 7.669（2）,b = 8.840（3）,c = 11.521（4） ,α = 79.912（5）,β = 73.954（5）,γ = 86.612（6）°,V = 738.9（4） 3,Z = 1,Mr = 701.67,Dc = 1.577 g/m3,μ = 0.924 mm-1,F（000） = 363,Rint = 0.0636,R = 0.0498 and wR = 0.1311 for 2155 observed reflections with Ⅰ 〉 2σ（Ⅰ）;{[Co（4,4＇-bipy）（mtyaa）（H2O）3]（mtyaa）·2（H2O）}（3）：monoclinic,space group Pc with a = 7.7832（17）,b = 11.527（3）,c = 31.483（7） ,β = 91.952（4）°,V = 2822.9（11） 3,Z = 4,Mr = 683.65,Dc = 1.609 g/m3,μ = 0.963 mm-1,F（000） = 1412,Rint = 0.0758,R = 0.0609 and wR = 0.1095 for 5841 observed reflections with I 〉 2σ（I）;{[Co（bpe）（mtyaa）2（H2O）2]}n（4）：monoclinic,space group C2/c with a = 19.290（11）,b = 12.027（7）,c = 14.865（8） ,β = 125.648（8）°,V = 2802（3）3,Z = 4,Mr = 657.66,Dc = 1.559 g/m3,μ = 0.959 mm-1,F（000） = 1356,Rint = 0.0456,R = 0.0332 and wR = 0.0985 for 2299 observed reflections with Ⅰ 〉 2σ（Ⅰ）.

Novel four-hydrogen-bond assembled oligoamide dimer with pyrazoline moieties and its photoluminescent properties

In this paper, the synthesis and characterization of a triarylpyrazoline modified four-H-bonded molecular duplex are described. Its molecular structure has been confirmed by ^1H NMR and ESI-MS. The duplex emits strong pure blue light peaking at 448 and 452 nm under UV photoexcitation in solution and solid state, respectively, and its relative photoluminescence quantum efficiency in solution is determined as 0.778 using quinine sulfate as reference. In concentration of 〉40 mmol/L, the duplex can gelate DMSO, and the organogel formed shows good pure blue photoluminescence too. This novel duplex, for its well-defined structure and efficient photoluminescence property, is a prospective candidate for pure blue electroluminescent emitter.

FTIR STUDIES ON THE MODEL POLYURETHANE HARD SEGMENTS BASED ON A NEW WATERBORNE CHAIN EXTENDER DIMETHYLOL BUTANOIC ACID (DMBA)

Three model polyurethane hard segments based on dimethylol butanoic acid (DMBA) and 1,6-hexane diisocyanate (HDI), toluene diisocyanate (TDI) and 4,4'-diphenylmethane diisocyanate (MDI) were prepared by the solution method. Fourier Infrared (FTIR) spectroscopy was employed to study the H-bonds in these model polyurethanes. The model polyurethane hard segment prepared from HDI and 1,4-butanodiol (BDO) was used for comparison. It was found that the incorporation of the pendent carboxyl through DMBA into the model hard segments weakens the original NH…O = C H-bond but gives more H-bond patterns based on the two H-bond donors, urethane NH and carboxylic OH. The carboxylic dimer is one of the main H-bond types and is stronger than another main H-bond type NH…O=C. In addition, the H-bond in aromatic model hard segments is stronger than that of aliphatic hard segments. The appearance of the free C=O and the fact that almost all N—H is H-bonded suggest that there possibly exist either the third H-bond acceptor or the H-bond formed by one acceptor with two donors.