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.

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.

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.

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-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 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.

H-bonding interactions enable a 3D pillared cobalt(Ⅱ) coordination polymer for touchless finger moisture detection

Coordination polymers(CPs) are emerging as the next generation of macromolecule materials in many industrial and technological applications,e.g.gas/humidity sensing.The design of CP-based sensors with high performance and low cost is of significance,but this work is still in the infancy stage.In this contribution,a new one dimensional(1D) CP has been successfully synthesized by a simple solvent evaporation method at room temperature,namely [Co(DPP)(H_(2)O)_(2)]n·(TCA)2(H_(2)O)_(4)(named as Co-1,HTCA=3-thiophenezoic acid,DPP=1,3-di(4-pyridyl)propane).The Co-1 structure contains abundant H-bonding interactions,weaving it from 1D chain structure into three dimensional(3D) pillared-layer structure.As an impedimetric humidity sensing material,this CP exhibits short response time,small hysteresis,excellent repeatability,and good stability in the working range of 11%-97% relative humidity(RH).Furthermore,it also shows excellent performance in monitoring the moisture content of human finger skin.By analyzing the complex impedance spectra,the humidity sensing mechanism of Co-1 sensor was expounded at different RH ranges.

Phototriggered Formation of a Supramolecular Polymer Network Based on Orthogonal H-Bonding and Host-Guest Recognition

Supramolecular polymer networks(SPNs)have gained increasing research attention due to their reversible and tunable nature in the preparation of adaptive materials.The use of hierarchical self-assembly techniques is an emerging strategy for the fabrication of smart supramolecular polymer networks,but corresponding study is still rare.Herein,we have reported a novel supramolecular polymer network through complementary host-guest interactions and phototriggered quadruple H-bonding cross-linking.Specifically,we design and synthesize an H1G1-type monomer consisting of a benzo-21-crown-7(B21C7)host(H1),a dialkylammonium salt guest(G1)and a photolabile o-nitrobenzyl ether protected ureidopyrimidinone(Upy)moiety.B21C7 and ammonium moieties can first form a linear supramolecular polymer through complementary host-guest interactions.Under photoirradiation,the Upy groups on the SP side chains were released,and the obtained linear supramolecular polymer could be further transformed into SPN through a quadruple H-bonding cross-linking.Meanwhile,the in situ transformation in the solid state is also accompanied by pronounced enhancement in mechanical properties,which provides foundation for further application of materials in different scenarios.

Highly Ordered Supramolecular Assembled Networks Tailored by Bioinspired H-Bonding Confinement for Recyclable Ion-Transport Materials

Controlling dynamic molecular self-assembly to finely tune macroscopic properties offers chemical solutions to rational material design.Here we report that combining disulfide-mediated ring-opening polymerization withβ-sheet-like H-bonding self-assembly can drive a direct small-molecular assembly into a layered ionic network with precise architectural tunability and controllable functions as ion-transport membranes.This strategy enables a one-step evaporationinduced self-assembly from discrete small molecules to layered ionic networks with high crystallinity.The interlayer distances can be readily engineered with nanometer accuracy by varying the length of the oligopeptide side chain.The synergy of the layered structure and hydrophilic terminal groups facilitates the formation and ordering of interlayer water channels,endowing the resulting membranes with high efficiency in transporting ions.Moreover,the inherent dynamic nature of poly(disulfide)s allows chemical recycling to monomers under mild conditions.We foresee that the robust strategy of combining dynamic disulfide chemistry and noncovalent assembly can afford many opportunities in designing smart materials with unique functions and applications.

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.

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.

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。

Homopolymerization of N-pyrimidinyl acrylamide

Homopolymerization of N-pyrimidinyl acrylamide (NPA) was reported for the first time. The polymer (polyNPA) was soluble only in acidic media and fluoroalcohols, and only in fluoroalcohol was homogeneous polymerization of NPA feasible. 1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA and α,α-bis(trifluoromethyl)phenyl propan-2-ol (BTMP). Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer (RAFT) polymerization of NPA in BTMP was carried out. 1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion. The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced.

Crystal Structures and Magnetic Properties of Two New Schiff Base Complexes

Two new Schiff base complexes, [NiL]ClO4 1 and [CuL]ClO40.5H2O 2, were synthesized and characterized, where L is the 1:1 condensation product of salicylaldehyde and diethylenetriamine. Their crystal structures and magnetic properties were determined and investigated. The H-bonding interactions concern just in neighbor cation and anion, do not extend into network for both 1 and 2. The temperature dependence of the magnetic susceptibilities (2-300K) showed that 1 is diamagnetism and 2 is paramagnetism with weak antiferromagnetic exchange interactions between adjacent spin carriers, no magnetic ordering taking place in these two complexes.

A Porous 3D Supramolecular Architecture of Cd(II) Complex with Water Clusters as Pillars

A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.

Synthesis, Structure and Thermal Stability of [Tm(TBTA)_(1.5)(bipy)(H_2O)_2]_n

The complex [Tm（TBTA）1.5（bipy）（H2O）2]n （H2TBTA = 2,3,5,6-tetrabromoterephthalic acid, bipy = 2,2-bipyridyl） has been synthesized in water-methanol solution at ambient temperature and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectrum and thermogravimetric analysis. The crystal belongs to triclinic, space group P1 with a = 11.1429（2）, b = 11.485（2）, c = 12.872（2）, V = 1498.1（5）3 , Z = 2, C22H14Br6N2O9Tm, Mr = 1098.74, Dc = 2.436 g/cm3 , μ（MoKα） = 11.013 mm-1 , F（000） = 1022, T = 296.15 K, the final R （I 〉2σ（I）） = 0.0494 and wR （all data） = 0.1246. The asymmetric unit of the complex is composed of one Tm ion, one and a half of coordinated TBTA 2-anions, one bipy, two coordinated and one lattice water molecules. The adjacent metal ions are bridged by TBTA 2- anions to form a 2D wave-like layer.

Syntheses, Crystal Structures and Thermal Stability of Two Complexes of La(Ⅲ)/Ce(Ⅲ) Assembled by H_2TBTA and Phen

Two 2D layer complexes {[La（TBTA）1.5（phen）2H2O].3H2O}n （1） and {[Ce（TBTA）l.5（phen）2H2O]-3H2O}n （2） （H2TBTA = 2,3,5,6-tetrabromoterephthalic acid, phen = 1.10-phenanthroline） have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric analyses. Both crystals belong to monoclinic, space group P21/n. Crystal data for 1： a = 8.7097（11）, b = 34.276（4）, c = 13.7281（17） A, β = 95.397（2）°, V= 4080.1（9） A3, Z = 4, LaC36H24Br6N4O10, Mr= 1290.96, Dc = 2.102 g/cm3,μ（MoKa） = 6.983 mm-1, F（000） = 2460.0, T = 296（2） K, the final R （I 〉 2σ（I）） = 0.0478 and wR （all data） = 0.0985 for 10127 independent （Rint = 0.0775） and 7137 observed reflections with I 〉 2σ（I）. Crystal data for 2： a = 8.709（2）, b = 34.202（9）, c = 13.685（4） A, β = 95.714（4）, V= 4055.9（19） A3, Z = 4, CeBr6C36H24O10N4, Mr = 1292.17, Dc = 2.116 g/cm3, μ（MoKa） = 7.094 mm-1, F（000） = 2464.0, T= 296（2） K, the final R（I 〉 2σ（I）） = 0.0590 and wR（all data） = 0.1453 for 10014 independent （Rint = 0.1253） and 6081 observed reflections with I 〉 2σ（I）. Both complexes are allomerism with the general molecular formula of {[M（TBTA）1.5（phen）2H2O].3H2O}n. In the structures, the H2TBTA ligands adopt a monodentate coordination mode. Both the 2D layer frameworks are further extended to be 3D layers via H-bonding interactions.

Space Group Distribution in Substituted Phenols

Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristics of intermolecular H-bondsformed by two OH groups,the space group distribution could be rationalized well.

A 3D Hydrogen-bonded 2-Fold Interpenetrated Supramolecular Structure of Cyclen Derivative

The title compound 1,4,7,10-tetrakis（2-（4-methoxyphenoxy）ethyl）-1,4,7,10-tetraazacyclododecane hydrobromide derivated from cyclen has been synthesized by 4-methoxyphenol via two steps and characterized by ^1H NMR and X-ray single-crystal diffraction. The crystal belongs to the orthorhombic system, space group Pbcn with a = 17.3174（15）, b = 12.9891（11）, c = 19.3379（17） A, V = 4349.8（7） ？3, Z = 4, Dc = 1.304 g/cm3, Mr = 853.87, F（000） = 1808, μ = 1.001 mm^-1, Mo Ka radiation（λ = 0.71073 A）, R = 0.0467 and w R = 0.1045 for 2774 observed reflections with I 〉 2σ（I）. X-ray structural analysis reveals that the molecular structure of the title compound is stabilized by intramolecular C–H···O and C–H···Br hydrogen-bonding interactions, and a 3D 2-fold interpenetrated supramolecular framework is constructed by intermolecular C–H···O and C–H···Br hydrogen-bonding interactions.

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.