• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Facile construction of aggregation-induced emission molecular liquids via Piers-Rubinsztajn reaction for green fluorescent ink

    2022-06-20 06:20:48RongFuLongyueYuJunyingZhngHuidongYuShengyuFengXingDongXu
    Chinese Chemical Letters 2022年4期

    Rong Fu,Longyue Yu,Junying Zhng,Huidong Yu,Shengyu Feng,Xing-Dong Xu,*

    a Key Laboratory of Special Functional Aggregated Materials of Ministry of Education,Shandong Key Laboratory of Advanced Silicone Materials and Technology,School of Chemistry and Chemical Engineering,National Engineering Research Center for Colloidal Materials,Shandong University,Ji’nan 250100,China

    b Shandong Qilu Zhonghe Technology Co.,Ltd.,Ji’nan 250100,China

    ABSTRACT Solvent-free luminescent molecular liquids(LMLs),which exhibit nonvolatile fluidic nature and active optoelectronic properties,were widely used.For further development,we introduced siloxane units into AIE molecules,designed and synthesized TPE derivatives with siloxane side chains via facile Piers-Rubinsztajn reaction.The obtained AIE molecular liquids exhibit unique photophysical properties.Compared with the obtained alkyl TPE-solids,siloxane TPE show liquid state,which proves that the siloxane units have stronger liquefaction effect than alkyl.Viscosity test shows that siloxane TPE-liquids has far more lower viscosity and better fluidity than the long-chain alkyl molecular liquids in previous research.All those properties are attributed to the weak interaction between flexible molecular chains of siloxane.Besides,fluorescence test shows temperature responsiveness of siloxane TPE-liquids.We developed this lowviscosity nonvolatile AIE molecular liquid as green fluorescent ink.

    Keywords:TPE derivatives Piers-rubinsztajn reaction Molecular liquids Aggregation-induced emission Green fluorescent ink

    Soft matter such as hydrogels,ionic liquids,foams and liquid crystals is a class of innovative smart materials,which have had a significant impact in various fields such as chemistry,physics and material sciences in recent years[1–5].In the past decade,with the positive requirement for advanced soft chromophores,a new generation of soft matter termed as solvent-free luminous molecular liquids(LMLs)have caught the spotlight[6–9].LMLs exhibit nonvolatile,environmentally friendly,tunable optoelectronic,superior stability and excellent processability.In general,LMLs are synthesized by attaching aπ-conjugated chromophore with large,flexible,and low-melting side chains.The wrapping of the side chains appreciably suppresses the intermolecularπ-πinteractions and obtain free-flowing or amorphous states with strong emission,thus giving unparalleled photophysical properties in the solventfree state.Due to their unique characteristic,LMLs have been attracting growing research interest and giving impetus to many new applications of LMLs such as optoelectronic devices recently[10].

    As a suitableπ-conjugated chromophore for solvent-free LMLs,tetraphenylethylene(TPE)has attracted considerable interest due to its typical aggregation induced emission(AIE)properties and its handy modification[11–18].However,there are only a few successful cases to liquefy AIE chromophore as LMLs.For example,some TPE-based materials with large and flexible side chains such as alkyl[19]and ethylene glycol[20]have been reported with extensive application prospects.In contrast,molecules with short alkyl or ethylene glycol chains show solid state[21–23].Therefore,in order to obtain the LMLs,rather large chains are required for modification[24–27],which can isolate the core unit and lead to the melting point(Tm)far below room temperature,and such LMLs exhibit high viscosity.

    Inspired by the use of siloxane liquefied triarylamine for the optoelectronic devices[28],the performance of siloxane liquefied AIE molecules is worth exploring.Siloxane has a flexible molecular main chain composed of Si-O-Si bonds,and the interaction between chains is weak,therefore they exhibit low viscosity.Apart from its distinctive merits of inherent flexibility and thermal stability,siloxane is really convenient to modify,so they have shown great activity from material preparation to commercial-scale application[29–33].In the past few decades,the Piers-Rubinsztajn reaction has been proven to be an effective method in many different types of siloxane chemistries[34–41].The reaction is taken place under fairly mild and ambient conditions with low catalyst(tris(pentafluorophenyl)borane(BCF))loadings,and the substitution proceeds without metathesis or redistribution of the siloxane component,ending up with a high yield and the only byproduct is hydrogen or methane.In this study,the Piers-Rubinsztajn reaction was chosen as a powerful way to decorate chromophores with siloxane side chains,then obtain AIE molecular Liquids with unique properties.

    Fig.1.Structures of AIE-active TPE derivatives.

    Fig.2.Fluorescence spectra of(a)solvent-free 1a,1b supported on quartz plate and 1a,1b solution in THF(c = 2.0 × 10-5 mol/L),(b)1a in mixed solvents of THF/H2O(c = 2.0 × 10-5 mol/L,λex = 370 nm),and(c)a plot of fluorescence intensity of 1a at 490 nm in THF/H2O mixtures with different H2O fractions(c = 2.0 × 10-5 mol/L,λex = 370 nm).(d)Picture of 1a,1b,2a and 2b in natural light and UV light.(All the ex slit:5 nm,em slit:5 nm).

    Herein,based on our previous work[42–45],we designed siloxane TPE(1a and 1b)to obtain AIE molecular liquids,as shown in Fig.1.As a contrast,we synthesized alkyl TPE(2a and 2b)with similar side chain lengths.Furthermore,straight and branched chains are also set as an affect of the different properties.The synthesis of 1a,1b,2a and 2b are carried out according to Scheme 1.The detailed synthetic procedures and characterization data of1H NMR and13C NMR,or MS are shown in the Supporting information(Figs.S1-S14 in Supporting information).In the synthesis process,through mild and efficient Piers-Rubinsztajn reaction,the molecules 1a and 1b with siloxane chains were found to be lowviscous liquids,while 2a and 2b with alkyl chains are solids at room temperature(Fig.2d).Combined with Takashi’s previous research[19],this interesting phenomenon indicates the awesome liquefaction ability of the siloxane chains.

    Scheme 1.Synthesis of 1a,1b,2a and 2b.

    To assess the optical affect of different kinds of side chains on the TPE derivatives,the synthesized molecules were characterized by fluorescence emission spectra(Fig.2).According to Fig.2a,the fluorescence of siloxane TPE-liquids 1a and 1b were highly emissive in solvent-free state,although they are liquids,and on the contrary,nearly quenched in good solvents such as THF.Further analysis of the absorption and emission spectra are shown in Fig.S15(Supporting informaiton).As shown in Fig.S15b,different from the alkyl TPE-solids 2a and 2b,of whichλemappeared at around 440 nm,those of siloxane TPE-liquids 1a and 1b appeared at around 490 nm.Theλemof siloxane TPE-liquids 1a and 1b redshifted to longer wavelength was owing to the extended effective conjugated length,roughly due to the better coplanarity of the liquid molecules.In aggregated state,compared with 2a and 2b,1a and 1b have lower emission intensity due to the low-viscosity siloxane side chains,according to Figs.S15b and c.And in good solvent,they show similar low emission intensity(Fig.S15f).In addition,the difference in fluorescence performance between straight and branched chains under such short chain length is not obvious.

    Furthermore,the fluorescence emission spectra were carried out in a THF/H2O solution mixture with various ratios at a fixed concentration(2.0 × 10-5mol/L),as shown in Fig.2b and Fig.S16(Supporting information).With the addition of the poor solvent H2O,the fluorescence intensity slightly increased at first and then showed a sharp increase upon the water fraction(fw)increasing to beyond around 80%.Uponfwincreasing up to 90%,the intensity reached a maximum.This is due to the effect of the restricted intramolecular rotation(RIR)effects,exhibiting typical AIE behavior.It can be clearly observed from Fig.2c that the fluorescence intensity at 490 nm showed a trend of increase.Moreover,the molecules 1b,2a and 2b showed similar emission spectrum(Fig.S16),which exhibits typical AIE behavior as well.

    The photophysical properties for all compounds are included in Table 1.The siloxane TPE-liquids with straight chains 1a and branched chains 1b exhibited the quantum yield(ΦF)values of 0.11 and 0.21,respectively.The alkyl TPE-solids 2a and 2b showed theΦFvalues of both 0.47.The time constant(τ)was larger for the alkyl TPE-solids(2–3 ns)than that for the siloxane TPE-liquids(<1 ns).According to the calculation results of the rate constant of the radiative(kr)and nonradiative processes(knr),krwere roughly identical in both liquid and solid molecules(0.1–0.3 ns-1),while solid molecules showed smallerknr(<0.3 ns-1)compared to that of liquid molecules(>0.9 ns-1).In the case where thekrof liquid and solid molecules are similar,the higherknrof the liquid molecules is the main reason for the lowerΦFandτ.Furthermore,viscosity measurements for siloxane TPE-liquids 1a and 1b revealed the intrinsic viscosity to be merely 302.5 cP and 104.4 cP,respectively.As a contrast,according to Machida’s previous report[19],their long-chain alkyl TPE-liquids show relatively highΦF(>0.65)and lowknr(<0.091)due to the high viscosity(ca.6000 cP).Therefore,for siloxane TPE-liquids,the intramolecular motion is not so restricted due to low viscosity,causing higherknrand weak-AIE behavior.

    To investigate the influence of the branched or straight chain on the solvent-free molecules,compounds 2a and 2b were employed to carry out single crystal X-ray analysis(Fig.3 and Table S1 in Supporting information).Single crystals of 2a and 2b were obtainedviaa common recrystallization process,which can be seen in Figs.3a and b.It is shown in Figs.3c and d that themolecular packing natures of 2a and 2b were extremely different.For 2a,theπ–πinteractions on the phenyl group withca.2.8 ?A were observed,in addition,there are C···H–H···C interactions between the hydrogens on the terminal alkyl groups withca.2.2–2.9 ?A.And for 2b,C···H-πinteractions between the alkyl group and phenyl group withca.2.9 ?A and C···H–O interactions between the Oxygen atom and phenyl group with 2.5 ?A were observed.However,the different molecular packing properties of 2a and 2b did not show obvious difference in macroscopic properties.

    Each solvent-free state compound was characterized by differential scanning calorimetry(DSC)to evaluate the effect of molecular chains branching and silicone substitution on the glass transition temperatures(Tg)and melting point(Tm)of the materials.Upon heating,solvent-free liquid compounds 1a and 1b illustratedTgat-81.5 °C and-73.8 °C,respectively(Table 1 and Fig.S17b in Supporting information),and there is no obviousTm.These lowTgsuggested that the siloxane TPE 1a and 1b are amorphous molecules with a temperature-stable liquid state.On the other hand,the alkyl TPE 2a and 2b showedTmat 86 °C and 92.8 °C,respectively(Table 1 and Fig.S17a in Supporting information)upon the heating process.At the same time,by comparing the branched and straight chains molecules(Tgof 1a<1b,Tmof 2a<2b),it is found that the movement of branched chains molecules requires more energy,it probably because the viscosity of 1b(302.5 cp)is greater than that of 1a(104.4 cp).Besides,although supercooling liquid behavior is often observed in alkyl-substituted liquid[8],siloxane TPE-liquids shows to be completely liquids in spite of short side chains,which is obvious in DSC thermogram.This is come from the fluidic nature of siloxane chain.

    Table 1 Summary of photophysical and thermal properties of TPE derivatives in the solvent-free statea.

    Fig.3.X-ray single crystal structures of 2a(a),2b(b),and crystal packing of 2a(c)and 2b(d).Solvent molecules and most hydrogen atoms are omitted for clarity.

    To further explore the affect of temperature on the fluorescence of the solvent-free TPE derivatives,the synthesized molecules were characterized by emission spectra(Fig.4).According to Figs.4a and e,siloxane TPE-liquids 1a and 1b both shows much higher fluorescence intensity at-196 °C(both>4000 a.u.)than either at room temperature or at 100 °C(both<500 a.u.),and theλemblueshifted to lower wavelength at-196 °C.At-196 °C,far below theTgof 1a(-81.5 °C)and 1b(-73.8 °C),the freezing of TPE siloxane side chains leads to the RIR effects,which causes the enhancement of fluorescence emission.Futhermore,freezing will deteriorate the coplanarity of the molecules[15],leading to the blue-shift of the emission wavelength.Besides,as shown in Fig.S18(Supporting information),alkyl TPE-solids 2a and 2b both shows much lower fluorescence intensity at 100 °C(both<500 a.u.)than either at-196°C or room temperature(both>2500 a.u.).When heated to 100°C,the temperature is above theTmof 2a and 2b(86.0 °C and 92.8°C),then 2a and 2b change to liquid state,causing weaker RIR effects.Meanwhile,the better coplanarity of the molecules cause the red-shift of the emission wavelength.

    Inspired by the unique fluorescence performance and lowviscosity of solvent-free siloxane TPE-liquids,we tried to pack compound 1a and 1b as green fluorescent ink in a ballpoint pen refill or use them as inkpads to make the fluorescence pattern on paper substrate that can only be seen under the UV light(Figs.4bd and Figs.4f-h).As shown in Figs.4b-d,a black panda and fluorescent bamboos are painted with normal ink and 1a fluorescent ink,respectively,and a stamp is covered with 1a fluorescent ink.Under natural light,only a panda can be seen(Fig.4b).While,a bright fluorescent stamp and bamboos can be observed under UV light.During the process of returning to room temperature after freezing in liquid nitrogen(Figs.4c and d),the stamp and bamboos gradually changed from blue(λem= 449.6 nm)to green(λem= 492.8 nm)under UV light(λex= 365 nm).The result is consistent with the fluorescence spectrum in Fig.4a.As shown in Figs.4e-h,using 1b as the fluorescent ink,the painting showed similar results to 1a.Therefore,we successfully developed a facile green fluorescent ink,which is a solvent-free siloxane TPE-liquids.Different from traditional ink,the new fluorescent ink use UV light to identify patterns on the paper substrates,and due to its solventfree characteristics,it is stable and environmentally friendly.

    In summary,we reported two kinds of siloxane TPE-liquids(1a with straight side chains and 1b with branched side chains)as members of AIE molecular liquids,which were synthesized using short siloxane chainsviafacile Piers-Rubinsztajn reaction,and they exhibited room-temperature liquid state.With similar chain lengths,alkyl TPE-solids(2a with straight chains,2b with branched chains)were synthesized as a comparison,which exhibited roomtemperature solid state.This indicates that the siloxane chain has a stronger liquefaction effect to construct LMLs than the alkyl chain.Besides,viscosity test shows that siloxane TPE-liquids has much lower viscosity(302.5 cp and 104.4 cp)than the long-chain alkyl molecular liquids(ca.6000 cp)in previous research.That is due to the flexible molecular chains of siloxane and weak interaction between chains.Furthermore,siloxane TPE-liquids also shows completely liquids,longer emission wavelength and weaker-AIE behavior than alkyl TPE.Due to the low viscosity,which makes them easy to be packed in the refill,and other characteristic such as fluorescence temperature responsiveness,nonvolatile,environmental friendly,stable and room-temperature liquids,siloxane TPE-liquids 1a and 1b can be developed as environmentally friendly fluorescent inks.Therefore,the current platform broadens the avenue for the preparation and application of AIE molecular liquids.

    Declaration of competing interest

    The authors declared that they have no conflicts of interest to this work.We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.

    Acknowledgments

    This work was supported by the National Natural Science Foundation of China(No.21602124),Natural Science Foundation of Shandong Province(No.ZR2016BQ11),and the Young Scholars Program of Shandong University(No.2018WLJH40)

    Fig.4.Fluorescence spectra of solvent-free 1a(a)and 1b(e)in the bulk state at different temperatures(λex = 370 nm),ex slit:2.5 nm,em slit:2.5 nm.(b-d)Schematic diagram of painting and stamp with 1a as ink from-196 °C to room temperature under natural light or UV light.(f-h)Schematic diagram of painting with 1b as ink from-196 °C to room temperature under natural light or UV light.

    Supplementary materials

    Supplementary material associated with this article can be found,in the online version,at doi:10.1016/j.cclet.2021.10.018.

    一区二区三区高清视频在线| 别揉我奶头~嗯~啊~动态视频| 色吧在线观看| 国产精品免费一区二区三区在线| 日韩 欧美 亚洲 中文字幕| 一区二区三区高清视频在线| 精品国产美女av久久久久小说| 日韩欧美国产一区二区入口| 久久精品人妻少妇| 精华霜和精华液先用哪个| 国产成年人精品一区二区| 亚洲av美国av| 日韩欧美一区二区三区在线观看| 香蕉av资源在线| 97超视频在线观看视频| 99国产综合亚洲精品| 久久天躁狠狠躁夜夜2o2o| 一本一本综合久久| 最新在线观看一区二区三区| 精品国产乱子伦一区二区三区| 日本熟妇午夜| 欧美精品啪啪一区二区三区| 人妻夜夜爽99麻豆av| 国产成人系列免费观看| АⅤ资源中文在线天堂| cao死你这个sao货| 别揉我奶头~嗯~啊~动态视频| 国产单亲对白刺激| 老司机午夜福利在线观看视频| 老司机午夜福利在线观看视频| 真人做人爱边吃奶动态| 国产伦一二天堂av在线观看| 成年版毛片免费区| 真人一进一出gif抽搐免费| 精品久久久久久久末码| 午夜福利在线观看吧| 十八禁人妻一区二区| 国产精品美女特级片免费视频播放器 | 露出奶头的视频| 天堂动漫精品| 国产精品精品国产色婷婷| 一级a爱片免费观看的视频| 小说图片视频综合网站| 国产精品98久久久久久宅男小说| 精品国产乱码久久久久久男人| 日韩欧美一区二区三区在线观看| 国产欧美日韩精品亚洲av| 国产精品精品国产色婷婷| 一本一本综合久久| 亚洲男人的天堂狠狠| 国产欧美日韩精品一区二区| 国产精品1区2区在线观看.| 欧美又色又爽又黄视频| 久久久久久久久久黄片| 久久中文字幕人妻熟女| 午夜免费激情av| 美女 人体艺术 gogo| 97碰自拍视频| av国产免费在线观看| 床上黄色一级片| 夜夜爽天天搞| 午夜激情欧美在线| 欧美日韩亚洲国产一区二区在线观看| 精品国内亚洲2022精品成人| 亚洲色图av天堂| 久久人人精品亚洲av| 亚洲成人精品中文字幕电影| www.自偷自拍.com| 久久亚洲精品不卡| 哪里可以看免费的av片| 免费观看人在逋| 18美女黄网站色大片免费观看| 首页视频小说图片口味搜索| 首页视频小说图片口味搜索| 欧美国产日韩亚洲一区| 日日夜夜操网爽| 色综合婷婷激情| 日韩精品中文字幕看吧| 国产精品99久久久久久久久| 又黄又粗又硬又大视频| 一二三四在线观看免费中文在| 12—13女人毛片做爰片一| 1000部很黄的大片| 亚洲国产看品久久| 男女床上黄色一级片免费看| 亚洲欧美日韩卡通动漫| aaaaa片日本免费| 午夜久久久久精精品| 亚洲国产欧美网| 国产精品1区2区在线观看.| 老熟妇仑乱视频hdxx| 伊人久久大香线蕉亚洲五| 美女免费视频网站| 岛国视频午夜一区免费看| 一夜夜www| 国产亚洲精品久久久com| 老司机午夜福利在线观看视频| 一级毛片精品| 黄色日韩在线| 国产精品影院久久| 免费av毛片视频| 宅男免费午夜| 十八禁网站免费在线| 琪琪午夜伦伦电影理论片6080| av视频在线观看入口| 高清毛片免费观看视频网站| 国产淫片久久久久久久久 | 亚洲最大成人中文| 亚洲成人久久性| 五月伊人婷婷丁香| 亚洲无线在线观看| 嫩草影院入口| 夜夜夜夜夜久久久久| 亚洲在线自拍视频| 此物有八面人人有两片| 久久亚洲真实| 啦啦啦韩国在线观看视频| 999久久久国产精品视频| 久久天堂一区二区三区四区| 久9热在线精品视频| 亚洲av中文字字幕乱码综合| 亚洲国产看品久久| 1024手机看黄色片| 超碰成人久久| 88av欧美| 久久中文字幕人妻熟女| 亚洲av电影不卡..在线观看| 日韩中文字幕欧美一区二区| 俄罗斯特黄特色一大片| 伦理电影免费视频| 97碰自拍视频| 麻豆av在线久日| 国产在线精品亚洲第一网站| 国产野战对白在线观看| a在线观看视频网站| 淫妇啪啪啪对白视频| 男人舔奶头视频| 岛国在线免费视频观看| 丰满人妻熟妇乱又伦精品不卡| 长腿黑丝高跟| aaaaa片日本免费| 欧美精品啪啪一区二区三区| 久久精品影院6| 国产成人一区二区三区免费视频网站| 又黄又粗又硬又大视频| 国产精品久久久久久精品电影| 美女cb高潮喷水在线观看 | 国产高清有码在线观看视频| 99热这里只有是精品50| 久久久国产欧美日韩av| 高清毛片免费观看视频网站| 天堂av国产一区二区熟女人妻| 亚洲乱码一区二区免费版| 欧美激情在线99| 观看免费一级毛片| 丁香欧美五月| 好男人在线观看高清免费视频| 国产成人精品久久二区二区免费| 一a级毛片在线观看| a在线观看视频网站| 国产激情偷乱视频一区二区| avwww免费| 欧美一区二区国产精品久久精品| a级毛片在线看网站| 丁香六月欧美| 小说图片视频综合网站| 国产精品久久久人人做人人爽| 99久久无色码亚洲精品果冻| 欧美大码av| 午夜视频精品福利| 成年女人永久免费观看视频| 嫩草影院入口| 国产久久久一区二区三区| 成人永久免费在线观看视频| 久久人人精品亚洲av| 成在线人永久免费视频| 又爽又黄无遮挡网站| 不卡av一区二区三区| 叶爱在线成人免费视频播放| 18禁裸乳无遮挡免费网站照片| 最新在线观看一区二区三区| 韩国av一区二区三区四区| 国产av在哪里看| 精品免费久久久久久久清纯| 最新在线观看一区二区三区| 午夜日韩欧美国产| 亚洲美女黄片视频| a在线观看视频网站| 欧美日韩一级在线毛片| 一区二区三区国产精品乱码| 九九在线视频观看精品| 欧美午夜高清在线| a在线观看视频网站| 日韩欧美在线二视频| 一二三四在线观看免费中文在| www日本黄色视频网| 伦理电影免费视频| 精品国产超薄肉色丝袜足j| 久久久精品欧美日韩精品| 99热这里只有精品一区 | 亚洲精品国产精品久久久不卡| 欧美3d第一页| 午夜福利高清视频| 免费看十八禁软件| 天天一区二区日本电影三级| 九九热线精品视视频播放| 成熟少妇高潮喷水视频| 精品电影一区二区在线| 这个男人来自地球电影免费观看| 国产亚洲精品av在线| 在线永久观看黄色视频| 国产麻豆成人av免费视频| 两性午夜刺激爽爽歪歪视频在线观看| 床上黄色一级片| 校园春色视频在线观看| 久久欧美精品欧美久久欧美| 俺也久久电影网| 亚洲av成人一区二区三| 亚洲熟妇中文字幕五十中出| 国产成人啪精品午夜网站| 好男人电影高清在线观看| 日韩av在线大香蕉| 国产亚洲精品av在线| 宅男免费午夜| 日日夜夜操网爽| 天天躁狠狠躁夜夜躁狠狠躁| 欧美色视频一区免费| 亚洲自偷自拍图片 自拍| 国产成年人精品一区二区| 亚洲第一欧美日韩一区二区三区| 日韩人妻高清精品专区| 青草久久国产| 一级黄色大片毛片| 亚洲av第一区精品v没综合| 天堂网av新在线| 午夜福利欧美成人| aaaaa片日本免费| 全区人妻精品视频| 色播亚洲综合网| 日韩欧美在线乱码| 亚洲精品粉嫩美女一区| 无限看片的www在线观看| 香蕉av资源在线| 久久久国产成人精品二区| 动漫黄色视频在线观看| 亚洲国产欧美一区二区综合| 亚洲最大成人中文| 叶爱在线成人免费视频播放| 一区二区三区国产精品乱码| 亚洲精品美女久久av网站| 在线免费观看不下载黄p国产 | 午夜福利欧美成人| 精品久久久久久久毛片微露脸| 90打野战视频偷拍视频| 成年女人毛片免费观看观看9| 久久久久久人人人人人| 国产精品久久久久久人妻精品电影| 免费观看精品视频网站| 午夜精品在线福利| 中文字幕久久专区| 91麻豆精品激情在线观看国产| 夜夜夜夜夜久久久久| 我的老师免费观看完整版| cao死你这个sao货| 欧美精品啪啪一区二区三区| 免费观看人在逋| 成人欧美大片| 亚洲av成人av| 老熟妇仑乱视频hdxx| 99久久精品一区二区三区| 在线观看午夜福利视频| 亚洲国产精品合色在线| 亚洲狠狠婷婷综合久久图片| 一级毛片精品| 亚洲av成人av| 天堂网av新在线| 精品国产三级普通话版| 精品日产1卡2卡| av天堂在线播放| av女优亚洲男人天堂 | 免费观看的影片在线观看| 亚洲欧美日韩东京热| 90打野战视频偷拍视频| 精品久久久久久久人妻蜜臀av| 亚洲,欧美精品.| 国产精品久久电影中文字幕| 色在线成人网| 麻豆国产av国片精品| h日本视频在线播放| 欧美日韩乱码在线| 久久精品国产综合久久久| 成人性生交大片免费视频hd| 国产99白浆流出| 91在线精品国自产拍蜜月 | 亚洲专区字幕在线| 成人三级黄色视频| 九九热线精品视视频播放| cao死你这个sao货| 级片在线观看| 老熟妇仑乱视频hdxx| 综合色av麻豆| 色哟哟哟哟哟哟| 搡老岳熟女国产| 老司机午夜十八禁免费视频| 国产三级中文精品| 女警被强在线播放| 国产99白浆流出| 中国美女看黄片| 国产毛片a区久久久久| 国产精品av久久久久免费| 精品国内亚洲2022精品成人| 长腿黑丝高跟| 亚洲 欧美一区二区三区| 美女黄网站色视频| 久久热在线av| 美女高潮喷水抽搐中文字幕| 中文在线观看免费www的网站| 97人妻精品一区二区三区麻豆| 美女 人体艺术 gogo| 悠悠久久av| 毛片女人毛片| 日韩中文字幕欧美一区二区| 禁无遮挡网站| 日韩中文字幕欧美一区二区| 美女cb高潮喷水在线观看 | 麻豆成人午夜福利视频| 色哟哟哟哟哟哟| 男人的好看免费观看在线视频| 国产精品1区2区在线观看.| 成人午夜高清在线视频| 99国产精品一区二区三区| 俄罗斯特黄特色一大片| 久久精品亚洲精品国产色婷小说| 久久久国产精品麻豆| 看免费av毛片| 草草在线视频免费看| 久9热在线精品视频| 亚洲欧美精品综合一区二区三区| 亚洲黑人精品在线| 成人国产综合亚洲| 69av精品久久久久久| 男女那种视频在线观看| 村上凉子中文字幕在线| xxxwww97欧美| 老熟妇仑乱视频hdxx| 51午夜福利影视在线观看| 丁香六月欧美| 午夜福利免费观看在线| 国产成人精品久久二区二区免费| or卡值多少钱| 亚洲成av人片在线播放无| 成年女人永久免费观看视频| 成人欧美大片| АⅤ资源中文在线天堂| 一级毛片精品| 一个人免费在线观看的高清视频| 91九色精品人成在线观看| 国产一区二区三区在线臀色熟女| 好看av亚洲va欧美ⅴa在| 一个人免费在线观看的高清视频| 久久久久免费精品人妻一区二区| 偷拍熟女少妇极品色| 国产成人精品久久二区二区免费| 黄色视频,在线免费观看| 亚洲国产欧美网| 露出奶头的视频| 色综合婷婷激情| 露出奶头的视频| 中文字幕av在线有码专区| 天堂动漫精品| 99久久精品一区二区三区| 国产午夜精品久久久久久| 午夜精品一区二区三区免费看| 五月玫瑰六月丁香| 怎么达到女性高潮| 亚洲精品国产精品久久久不卡| 美女被艹到高潮喷水动态| 久久久久久久久久黄片| 脱女人内裤的视频| 欧美日韩中文字幕国产精品一区二区三区| 人人妻人人看人人澡| 90打野战视频偷拍视频| 一本综合久久免费| 亚洲欧美日韩卡通动漫| 三级男女做爰猛烈吃奶摸视频| 色精品久久人妻99蜜桃| 精品国产亚洲在线| 午夜精品久久久久久毛片777| 免费在线观看影片大全网站| 熟女人妻精品中文字幕| 波多野结衣高清无吗| 老司机午夜十八禁免费视频| 丁香欧美五月| 久久伊人香网站| 精品国产美女av久久久久小说| 99久久成人亚洲精品观看| 91麻豆精品激情在线观看国产| 久久午夜综合久久蜜桃| 国产成年人精品一区二区| 亚洲欧美日韩高清在线视频| 久久久久久国产a免费观看| 小蜜桃在线观看免费完整版高清| 国产精品自产拍在线观看55亚洲| 亚洲va日本ⅴa欧美va伊人久久| av在线天堂中文字幕| 久久久久免费精品人妻一区二区| 最近最新中文字幕大全免费视频| 国产黄片美女视频| 给我免费播放毛片高清在线观看| 亚洲专区中文字幕在线| 国产亚洲欧美98| 亚洲成人中文字幕在线播放| 在线播放国产精品三级| 宅男免费午夜| 丁香六月欧美| 日韩欧美免费精品| 成年版毛片免费区| 免费观看的影片在线观看| 两个人的视频大全免费| 国产成人一区二区三区免费视频网站| 在线视频色国产色| 丰满人妻熟妇乱又伦精品不卡| 97超视频在线观看视频| 天堂av国产一区二区熟女人妻| 精品久久久久久久毛片微露脸| 国产精品亚洲美女久久久| 最近最新中文字幕大全免费视频| 日本成人三级电影网站| 99精品久久久久人妻精品| 91字幕亚洲| 国产97色在线日韩免费| 午夜a级毛片| 一本精品99久久精品77| 麻豆国产97在线/欧美| 黑人巨大精品欧美一区二区mp4| 日本一二三区视频观看| 午夜视频精品福利| 欧美3d第一页| 丰满的人妻完整版| 夜夜躁狠狠躁天天躁| 国产三级黄色录像| 无限看片的www在线观看| 91久久精品国产一区二区成人 | www.自偷自拍.com| 99久久综合精品五月天人人| 国产91精品成人一区二区三区| 夜夜躁狠狠躁天天躁| 综合色av麻豆| 久久久久国产精品人妻aⅴ院| 久久久久国内视频| 国产高清视频在线播放一区| 99久久精品国产亚洲精品| 90打野战视频偷拍视频| 韩国av一区二区三区四区| 日日干狠狠操夜夜爽| 精品福利观看| 男人和女人高潮做爰伦理| ponron亚洲| 99热6这里只有精品| 18禁黄网站禁片免费观看直播| 精品久久久久久成人av| 波多野结衣高清作品| 一级毛片高清免费大全| 国产黄色小视频在线观看| 亚洲精品一卡2卡三卡4卡5卡| 久久久久九九精品影院| 久久久久久九九精品二区国产| 最新在线观看一区二区三区| 在线永久观看黄色视频| 免费一级毛片在线播放高清视频| 精品国产乱码久久久久久男人| 国产黄片美女视频| 别揉我奶头~嗯~啊~动态视频| 亚洲精品一区av在线观看| 特大巨黑吊av在线直播| 免费电影在线观看免费观看| 日韩欧美在线乱码| 老鸭窝网址在线观看| 三级国产精品欧美在线观看 | 国内揄拍国产精品人妻在线| 中文字幕久久专区| 一个人免费在线观看电影 | 在线观看日韩欧美| 丁香欧美五月| 黑人欧美特级aaaaaa片| 欧美性猛交黑人性爽| 成人高潮视频无遮挡免费网站| 欧美成人一区二区免费高清观看 | 日韩欧美免费精品| 国产亚洲av高清不卡| 女警被强在线播放| 男女下面进入的视频免费午夜| 一本精品99久久精品77| 国产精品爽爽va在线观看网站| 亚洲va日本ⅴa欧美va伊人久久| 18禁裸乳无遮挡免费网站照片| 成人国产一区最新在线观看| 国产精品久久电影中文字幕| 国产黄a三级三级三级人| 一本综合久久免费| 午夜免费激情av| 好男人电影高清在线观看| 成熟少妇高潮喷水视频| 老汉色av国产亚洲站长工具| 成人永久免费在线观看视频| 嫁个100分男人电影在线观看| 大型黄色视频在线免费观看| 欧美日韩亚洲国产一区二区在线观看| АⅤ资源中文在线天堂| 成人高潮视频无遮挡免费网站| 久久性视频一级片| 亚洲自拍偷在线| 高清在线国产一区| 淫秽高清视频在线观看| 免费无遮挡裸体视频| 99精品久久久久人妻精品| 巨乳人妻的诱惑在线观看| 黑人欧美特级aaaaaa片| 少妇裸体淫交视频免费看高清| 亚洲熟女毛片儿| 日本撒尿小便嘘嘘汇集6| 日韩欧美一区二区三区在线观看| 中文字幕av在线有码专区| 国产精品久久久久久人妻精品电影| 免费在线观看影片大全网站| 老司机福利观看| 长腿黑丝高跟| 亚洲国产精品合色在线| 午夜精品久久久久久毛片777| av国产免费在线观看| 国内精品久久久久精免费| 亚洲av第一区精品v没综合| 不卡一级毛片| 老司机福利观看| 日韩三级视频一区二区三区| 色老头精品视频在线观看| 国产真实乱freesex| 精华霜和精华液先用哪个| 精品国产乱子伦一区二区三区| 免费大片18禁| 国产极品精品免费视频能看的| 成年免费大片在线观看| 国产私拍福利视频在线观看| 欧美乱码精品一区二区三区| 高清毛片免费观看视频网站| 亚洲自拍偷在线| 淫妇啪啪啪对白视频| 51午夜福利影视在线观看| 老汉色∧v一级毛片| 国产单亲对白刺激| 国产欧美日韩精品亚洲av| 成人高潮视频无遮挡免费网站| 国产淫片久久久久久久久 | 国产精品1区2区在线观看.| bbb黄色大片| 99久久精品热视频| 少妇的逼水好多| 成人无遮挡网站| 精品人妻1区二区| 久久国产精品人妻蜜桃| 国产精品av久久久久免费| 久久精品91蜜桃| 国产成人欧美在线观看| 国产精品一区二区三区四区久久| 国产免费男女视频| 亚洲国产色片| 国产伦精品一区二区三区视频9 | av天堂中文字幕网| 精品无人区乱码1区二区| 草草在线视频免费看| 9191精品国产免费久久| 久久久久国内视频| 亚洲自拍偷在线| 中文字幕久久专区| 母亲3免费完整高清在线观看| 国产乱人视频| 中文在线观看免费www的网站| 免费观看人在逋| 成人av一区二区三区在线看| 午夜福利成人在线免费观看| 成人特级av手机在线观看| 一级黄色大片毛片| 首页视频小说图片口味搜索| 99在线人妻在线中文字幕| h日本视频在线播放| 99久久精品国产亚洲精品| 中文字幕人妻丝袜一区二区| 曰老女人黄片| 国产探花在线观看一区二区| 最近最新中文字幕大全免费视频| 国产乱人视频| 国产aⅴ精品一区二区三区波| 搡老妇女老女人老熟妇| 欧美一区二区精品小视频在线| 高清在线国产一区| 观看美女的网站| 国产爱豆传媒在线观看| 午夜久久久久精精品| 亚洲欧美一区二区三区黑人| 日韩欧美 国产精品| 精品久久久久久久久久久久久| 天天添夜夜摸| 黄色 视频免费看| 亚洲男人的天堂狠狠| 欧美性猛交╳xxx乱大交人| 三级国产精品欧美在线观看 | 麻豆国产97在线/欧美| 精品不卡国产一区二区三区| 亚洲精品456在线播放app | 免费无遮挡裸体视频| 国产视频内射| 天堂√8在线中文| 日本成人三级电影网站| 国产v大片淫在线免费观看| 长腿黑丝高跟|