Synthesis, Crystal Structure, Physical Properties, and Application of a Series of Functional Dibenzo[d,f][1,3]dioxepine Derivatives

The twisted aromatics, functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5＇-dibromo-2,2＇-biphenol with corresponding ketal or ketone compounds under acid catalysis. The structures of these compounds were characterized by ^1H NMR, elemental analysis, UV-Vis absorption spectrum and X-ray diffraction analysis. The conformation of O--C--O bridged biphenyl derivatives with varied substitute groups on 6,6＇-position was studied by X-ray crystallography and force-field simulation. The result of calculations by UNIVERSAL 1.02 force field in Cerius2 package（4.6） indicates that dibenzo[d,f][1,3]dioxepine derivatives show twisted conformations and the twisted angle between the phenyl rings is about 40°, which is accordant with the result from crystal structure determination, though the obtained angles in the crystal of dibenzo[d,f][1,3]dioxepine derivatives with the varied substitute groups on 6,6＇-position are shown to be slightly shifted to 40° owing to intermolecular interactions in crystal stacking. DSC studies exhibit that the substitute groups on 6,6＇-position can induce a large variation of endothermic peaks ranging from 80 to 135 ℃. The conjugated polymers based on dibenzo[d,f][1,3]dioxepine derivatives, which have ultraviolet emitting with a quantum efficiency of 10%, were obtained by Yamamoto coupling.

Mechanistic Aspects of Monomer, Polymer Formation, and Synthesis of PQ-Alt-Dialkyl-fluorene Conjugated Copolymer

Suzuki coupling reaction is widely used in the construction of conjugated polymers; however, there is still no report describing the mechanism and coupling of 9,10-phenanthrenequinone（PQ） building blocks via Suzuki reaction because PQ is sensitive to bases and light. Herein is reported the efficient Suzuki coupling of PQ with 9,10-dialkylfluorene with Na2CO3 as basic species and high molecular weight PQ-Alt-Dialkyl-Fluorene conjugated copolymer obtained in an yield of 42%. Based on the characterization data and well-accepted literature, we proposed a step-by-step mechanistic explanation for the formation of the PQ containing alternating conjugated copolymer.

Synthesis and Non-linear Optical(NLO) Properties of a Series of Alkoxysilane Derivative Chromophores

1 Introduction Nonlinear optical materials（NLO） have drawn a great intrest of some scholars and scientists in the last dacades because of their tremendous potential application in optoelectronic. The fabrication of efficient optoelectron devices is a challenging task because such systems need to meet the stringentable requirements for high optical quality and large and sustainable electro-optical（EO） response. In pursuit of NLO materials with excellent optoelectronic property,

Synthesis,GC-EIMS,~1H NMR,^(13)C NMR,Mechanistic and Thermal Studies of o-Xylylene-α,α'-bis (triphenylphosphinebromide)

Organophosphorous compounds containing phosphorus as an integral part have been widely used in industry, organic synthesis and optoelectronics, o-Xylylene-a,a＇-bis（triphenylphosphinebromide）（OXBTPPB） is a facile reagent to convert o-quinones（e.g., 9,10-phenanthrenequinone） into polycyclic aromatic hydrocarbons（PAHs）. Herein lies an improved synthetic route to OXBTPPB. The resultant was carefully characterized with GC-EIMS, ^1H NMR, ^13C NMR, spectroscopic techniques. The EIMS shows characteristic peaks at m/z=262.4, 183.3, 108.2, 77.1 attributed to the [C18H15P]^＋, [C12H8P]^＋, [C6H8P]^＋, [C6H5]^＋ ions, respectively. The ^1H and ^13C NMR spectrum shows well resolved peaks and all the hydrogens and carbons were well-assigned via a combined study of ^1H-^1H COSY, HMBC, and HMQC experiments. The mechanism for the formation of OXBTPPB was proposed based on literature and obtained experimental data. Meanwhile, the thermal stability of OXBTPPB was evaluated with TGA analysis, and an onset decomposition temperature（Td） was recorded at 323.6 ℃.

Molecular Properties of 9,10-Phenanthrenequinone and Benzil

9,10-Phenanthrenequinone（PQ） and benzil are important a-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used 1H NMR, 13C NMR, 1H-IH COSY, HMBC, HMQC, UV-Vis absorption and emission, CV and TGA experiments to study PQ and benzil that provided the following novel results. （1） The 1H NMR（CDC13） of PQ show δ 8.19（H1）, 8.02（H4）, 7.72（H3）, 7.47（H2） instead of an earlier reported 8.25（H4）, 8.08（H1）, 7.80（H2）, 7.55（H3）; （2） in the 13C NMR（CDCl3）, the C9/C10（C=O） signal of PQ appears upfield（6 180.3） compared to C9/Cl0（C=O） signal of benzil（6 194.5）, which shows higher electrophilic character（more attractive for nucleophiles） of C9/C10（C=O） of benzil; （3） the first 2max for the UV-Vis absorption and emission of PQ are blue-shifted compared to benzil despite increased conjugation attributed to the different symmetries（C2v for PQ and C2h for Benzil） of the two molecules; （4） the emission spectrum of benzil is broader compared to that of PQ due to slower relaxation of the excited state; （5） The CV study shows that PQ and benzil are good electron acceptors and PQ shows a better reduction process than benzil due to an extra ring that provides stability for the reduced species（mono or diradical anions）; （6） TGA shows the higher thermal stability of PQ than benzil attributed to the presence of phenanthrene unit in PQ.

Molecular Recognition Based on Hydrogen-bonding in the Coliposomes of Phosphatidylcholine and Amphiphiles Using Nucleobases

A functional amphiphile, N^6 -myristoyl-9-[ 8-（ 1-trimethylamino） octyl ] adenine bromide （MTOAB）, was used to form coliposomes of phosphatidyleholine（PC）, PC/thymine, and PC/TOTB using sonication . The morphologies of the coliposomes were characterized using TEM （transmission electron microscopy）. The UV-Vis spectroscopic behavior of PC/MTOAB/thymine （molar ratio = 5： 1： 1 ） and PC/MTOAB/TOTB （molar ratio = 5： 1： 1 ） of coliposomal solutions showed that as a result of base pairing, absorption intensity showed a decrease at 263 nm with increase of time. The decrease of absorption intensity is ascribed to the hypochromic effect, which is because of the formation of hydrogen bonds between adenine and thymine in the coliposomes. The same effect was also observed for the mixture of aqueous PC/MTOAB liposomes and PC/TOTB liposomes after fusion, whereas the nocomplementary coliposomcs formed from PC/MTOAB and PC/TOTB did not show these spectroscopic changes. The molecular recognition through hydrogen interactions between adenine and thymine is very slow because of the possible occurrence of molecular lateral diffusion and exchange of amphiphile before recognition progresses in coliposomes. These results provide useful information for the design of supramolecular devices such as vesicles and liposomes,which can be used to mimic primitive recognition processes observed in biological systems.

Poly(meta-phenylene) Derivative with Rigid Twisted Biphenyl Units in Backbone:Synthesis,Structural Characterization,Photophysical Properties and Electroluminescence

A soluble poly（meta-phenylene） derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named ＂conformers＂ exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π^＊ transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore, the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 run. The ultraviolet-emitting electroluminescence（EL） device with the single layer structure shows EL λmax of the derivative at 370 nm.

Developing TPA Polymers to Expand Opto—electronic Applications

TPA phenomenon has been paid more and more attention because of a number of emerging applications, including 3D optical data storage, 3D microfabrication, upconverted lasing, photodynamic therapy, and so on. Some strategies have been used to enhance cross sections. Specially innovated donors or acceptors have been screen se-lected and focused in building new chromophore with some applications. The paper summarizes four potential applications of TPA polymers, and reviews several design strategies that have successfully been used to enhance the TPA cross-section.

NIR Emission Nanoparticles Based on FRET Composed of AIE Luminogens and NIR Dyes for Two-photon Fluorescence Imaging

Near-infrared(NIR) nanoparticles(NPs) based on fluorescence resonance energy transfer(FRET) were prepared by coencapsulation of a red aggregation-induced emission(AIE) molecule, 2-(4-bromophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl)fumaronitrile(TB), and a commercial NIR fluorescence dye, silicon 2,3-naphthalocyanine bis(trihexylsilyloxide)(NIR775) with an amphiphilic polymer poly(styrene-co-maleic anhydride)(PSMA). The surface of the NPs, PSMA@TB/NIR775, was modified with poly(ethylene glycol)(PEG) to increase the in vivo biocompatibility of the NPs. The PSMA@TB/NIR775 NPs showed a strong NIR(780 nm) narrow emission and excellent two-photon absorption property. Moreover, the NPs exhibited good monodispersity, stability, and low cytotoxicity.Under the excitation of a 1040 nm femtosecond(fs) laser, the emission peaks at 680 nm of TB and 780 nm of NIR775 excited by FRET were obtained. We utilized PSMA@TB/NIR775 NPs as fluorescent contrast agents for two-photon excited NIR microscopic imaging, and good NIR imaging effect of mouse brain vasculature was obtained with the imaging depth of about 150 μm. The FRET strategy by coencapsulating AIE molecule and NIR dye will be helpful in preparing more narrow emission NIR probes for deep-tissue biological imaging.

Self-assembling Behavior of Amphiphilic Copolymer Containing Cross-linked Hydrophilic Block in Ethanol

The self-assembly behavior of the amphiphilic block copolymer poly（ methyl methacrylate） -block-poly（ lead dimethacrylate） （PMMA-b-PLDMA） with cross-linked hydrophilic block（PLDMA） in ethanol was investigated. The results show that the size and morphology of the resulting micelle or micellar aggregates are ascribed to the content of ethanol and the nature of the solvent mixture. PbS nanoparticles were formed in the micelle by in situ reaction with H2S gas. The morphology and size of the self-assembly objects were investigated using scanning electron microscopy （SEM） and transmission electron microscopy（TEM）.

Dendritic tellurides acting as antioxidants

We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the pe- riphery which act as glutathione peroxidase (GPx) mimics. These series of compounds were well characterized by H-NMR, 1 13C-NMR and ESI-MS. Using different ROOH (H2O2, cumene hydroperoxide) for testing the antioxidizing properties of these com- pounds, we have found that from generation 0 to 2, the activity of the dendritic GPx mimics first de- creased and then increased. This can be explained on the basis of a greater steric hindrance, going from generation 0 to 1, and stronger binding interactions going from generation 1 to 2. In other words, there exists a balance between binding interactions and steric hindrance that may optimize the GPx activity.