• <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 ?

    Photoactive Naphthalene Diimide Functionalized Titanium-Oxo Clusters with High Photoelectrochemical Responses

    2023-12-28 08:47:46YANGYuZHAOQixin趙啟新ZHENGQiXUANWeimin宣為民

    YANG Yu(楊 雨), ZHAO Qixin(趙啟新), ZHENG Qi(鄭 琦), XUAN Weimin(宣為民)*

    1 College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China

    2 College of Materials Science and Engineering, Donghua University, Shanghai 201620, China

    3 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China

    Abstract:Photoactive functionalized titanium-oxo clusters (TOCs) are regarded as an important model compound for dye-sensitized titanium dioxide solar cells. However, the dyes used for sensitizing TOCs are still limited. Herein, two cyclic TOCs are reported, namely, [Ti6(μ3-O)2(Oi-Pr)8)(LA)2]·i-PrOH (S1) and [Ti6(μ3-O)2(Oi-Pr)8)(LV)2]·i-PrOH (S2), which are functionalized by photoactive naphthalene diimide (NDI) chromophores. Their molecular structures and photophysical and photochemical properties were systematically studied. As shown by ultraviolet-visible (UV-vis) spectra and photocurrent study results, the band gap and the photocurrent response of S1 and S2 were derived from NDI ligands which extend the absorption edge of S1 and S2 approaching 500 nm and afford high photocurrent densities of 2.12 μA/cm2 and 1.95 μA/cm2 for S1 and S2, respectively, demonstrating the significance of the photoactive ligand in modulating photoresponse of TOCs. This work is expected to enrich the structural library of photoactive TOCs and provide insights into understanding the structure-property relationships of sensitized clusters.

    Key words:titanium-oxo cluster; naphthalene diimide; photoactive; photoelectrochemical response

    0 Introduction

    Titanium-oxo clusters (TOCs) have aroused increasing interest owing to their critical role as structural and reactivity models to elucidate the structure-property relationship of nano TiO2at the atomic level[1-5]. The last two decades have witnessed the rapid development of TOCs regarding their structural diversity and promising applications in catalysis, dye-sensitized solar cells (DSSCs),etc.[6-22]. Along with the remarkable progress, rational tuning of the photophysical and photochemical properties of TOCs via structural design has been extensively studied since these are closely related to their employment as photoactive materials[23-24]. So far, functionalization with organic chromophores, hetero metal doping and Ti-O core tuning have emerged as the main strategies to endow TOCs with desirable photoresponsive properties[15,25-31]. This has led to the discovery of a number of functional TOCs which show high efficiency for photo-driven energy conversion and organic transformation[32-35], wide band gap covering the whole visible region and even the near-infrared (NIR) region[36-37], and excellent optical performance[38-39].

    In general, TOCs are composed of central Ti-O cores encapsulated by organic ligands on the outer sphere. This inherent structure feature, coupled with the almost unlimited structure library of ligands, renders it quite facile and effective in modulating the photoresponsive properties with ligand functionalization[25]. Based on the milestone work initialized by Coppens’s group[40], usingp-nitrophenyl acetylacetone and coumarin 343 as photoactive ligands, Dai’s group[41-44]further extended this strategy and expanded the ligand scope to a vast variety, including anthracene, tetrathiafulvalene, ferrocene and triphenylamine derivatives. Later on, Zhang’s group[36]conducted the systematic tuning of the band gap by varying the electron-withdrawing effect of the organic ligands. Moreover, Zhang’s group[45]demonstrated the efficiency of using a catechol ligand to reduce the band gap, and this finally resulted in black TOCs with an ultralow band gap of 1.51 eV, a tremendous breakthrough reported very recently by Zhang’s group[39]. With the functionalization of photoactive ligands, the as-synthesized TOCs usually exhibit enhanced photocurrent response, broadened light absorption with modulated band gaps, and better photoluminescence as compared with the pristine TOCs.

    Naphthalene diimide (NDI) derivatives are a class of electron-deficient and redox-active dyes that can be used for a variety of applications ranging from biomedicine to electronics[46]. Upon coordination with metal centers, NDI derivatives have been proven to be good organic chromophores for the construction of organic-inorganic hybrid materials such as metal-organic frameworks (MOFs) and metal-organic polyhedral[47-49], showing interesting optical properties[50-51]. However, NDI is rarely used to build metal-oxo clusters despite its excellent photophysical and photochemical properties. In this context, we envision that functionalization with NDI may result in photoactive TOCs showing high photoelectrochemical responses, which is expected to facilitate the discovery of functional TOCs as photoactive materials.

    Herein, we report the synthesis of two cyclic TOCs, namely, [Ti6(μ3-O)2(Oi-Pr)8)(LA)2]·i-PrOH (S1) and [Ti6(μ3-O)2(Oi-Pr)8)(LV)2]·i-PrOH (S2), functionalized by photoactive NDI chromophores (Scheme 1). S1 and S2 are synthesized facilely via one-pot reaction and their structures are fully characterized by a variety of spectroscopies and techniques. Both of the compounds adopt the same architecture of [Ti6(μ3-O)2(Oi-Pr)8)] in which two triangular {Ti3(μ3-O)} units are connected by two NDI ligands. As revealed by solid-state ultraviolet-visible (UV-vis) absorption spectra, the introduction of NDI ligands extends the absorption edge of S1 and S2 to the visible-light region, with band gaps of 2.85 eV and 2.91 eV, respectively. Moreover, owing to the presence of NDI ligands, S1 and S2 exhibit excellent photocurrent density up to 2.12 μA/cm2and 1.95 μA/cm2, respectively.

    *——indicating the structural frames that omit the isopropyl group.

    1 Experiments

    1.1 Materials and characterization methods

    Reagents and solvents were commercially available and employed without further purification.

    Powder X-ray diffraction (PXRD) results were recorded on a diffractometer (DX-2700B, Dandong Haoyuan Instrument Company Limited, China) with monochromatized Cu-Kα radiation (λ=0.154 0 nm) and a scanning rate of 0.02(°)/s. Thermogravimetric Analysis (TGA) was performed on a thermogravimetric analyzer (TG8000, Mettler Toledo Instruments (Shanghai) Company Limited, China) under nitrogen flow at a typical heating rate of 10 ℃/min. Element analyses for C, N and H mass fractions were determined by an elemental analyzer (VARIDEL III, Elementar Trading (shanghai) Company Limited, China). The samples were prepared as a KBr pellet and the Fourier transform infrared (FTIR) spectra were collected in the transmission mode in a range of 500 to 4 000 cm-1using a spectrometer (NEXUS-670, Thermo Electron Corporation, USA). All compounds were prepared into powders which were tested for solid-state UV-vis spectra in the wavelength mode by integrating sphere attachment in a UV-Vis spectrometer (UV3600, Shanghai Titan Technology Company Limited, China). All photoelectrochemical measurements (photocurrent, the Mott-Schottky plots and electrochemical impedance spectra (EIS)) were carried out by using an electrochemical workstation (CHI660E, Shanghai Chenhua Instrument Company Limited, China) in a three-electrode system, with the sample-coated indium tin oxide (ITO) glass as the working electrode, a Pt wire as the counter electrode, and a saturated Ag/AgCl electrode as the reference electrode. The electrolyte was Na2SO4(0.2 mol/L) aqueous solution. For the preparation of working photo-electrodes, the crystal sample (about 5 mg) was dispersed in a mixed solution of 1 mL ethanol and 100 μL Nafion, which was then dropped onto a precleared ITO glass (1 cm×2 cm). The working photoelectrode was obtained after evaporation. The Mott-Schottky plots were also measured over an alternating current frequency of 1 000, 1 500 and 2 000 Hz. Electrochemical impedance spectra measurements were recorded over a frequency range of 1 000 kHz to 0.1 Hz with an amplitude of 20 mV at 0 V.

    1.2 Synthesis of ligands H2LA and H2LV

    The ligands 2,2′-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)dipropionic acid(H2LA) and 2,2′-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8] phenanthroline-2,7-diyl)bis(3-methylbutanoic acid) (H2LV) were synthesized according to the reported procedure based on the condensation of naphthalene dianhydride and the related amino acids[49].

    1.3 Synthesis of S1

    H2LA(0.063 6 mmol, 26.1 mg) was dissolved in a mixed solution ofi-PrOH (1.1 mL) and dimethylformamide(DMF) (1.1 mL). The solution was stirred for 5 min, and then Ti(Oi-Pr)4(1.2 mmol, 0.368 mL) was added to the glass vial and mixed at room temperature. The resultant solution was heated at 80 ℃ for 2 d. After the solution cooled to room temperature, the pale-yellow crystal S1 was obtained (yield: 35.25 mg, 8.23% based on Ti(Oi-Pr)4). The calculated mass fractions of C, H and N were 51.04%, 6.78% and 2.62%, respectively. According to elemental analysis, the mass fractions of C, H and N were 51.32%, 6.96% and 2.53%, respectively.

    1.4 Synthesis of S2

    H2LV(0.063 6 mmol, 29.7 mg) was dissolved in a mixed solution ofi-PrOH (1.0 mL) and DMF (1.2 mL). The solution was stirred for 5 min, and then Ti(Oi-Pr)4(1.2 mmol, 0.368 mL) was added and mixed in the solution at room temperature. The resultant solution was heated at 80 ℃ for 2 d. After the solution being cooled to room temperature, the pale-yellow crystal S2 was obtained (yield: 33.75 mg, 7.48% based on Ti(Oi-Pr)4). The calculated mass fractions of C, H and N were 52.76%, 7.16% and 2.49%, respectively. According to elemental analysis, the mass fractions of C, H and N were 53.02%, 7.03% and 2.53%, respectively.

    1.5 X-ray crystallography

    The crystallographic data of S1 and S2 were collected using synchrotron radiation (λ=0.067 0 nm) on beamline 17B1 at National Facility for Protein Science Shanghai (NFPS) in Shanghai Synchrotron Radiation Facility, China. Then the diffraction data reduction and integration were performed by the APEX3 program, which converted the format into sfrm files. The empirical absorption correction was conducted by using the SADABS program. The structures were solved by intrinsic phasing with the software ShelXT and refined with a full-matrix least-squares technique of ShelXL interpreted by the software Olex2. Anisotropic thermal parameters were applied to all non-hydrogen atoms except the isolated guest molecules. The hydrogen atoms were generated by the riding mode. The X-ray crystallographic data for structures reported in this article were deposited at Cambridge Crystallographic Data Centre, under deposition number CCDC-2239929-2239930. These data can be obtained free of charge from Cambridge Crystallographic Data Center (www.ccdc.cam.ac.uk/data_request/cif).

    2 Results and Discussion

    2.1 Description of crystal structures

    Single-crystal X-ray diffraction structural analysis reveals that S1 crystallizes in the orthorhombic Pnna space group. S1 features a cyclic [Ti6(μ3-O)2(Oi-Pr)8)(LA)2] structure in which two {Ti3(μ3-O)} units are connected by two LA. The outer surface of each {Ti3(μ3-O)} unit is surrounded by two carboxylate groups from two NDI ligands and eight isopropoxy groups. Two isopropoxy groups act as bridging ligands while the others as terminal ligands (Figs. 1(a) and 1(b)). Interestingly, one of the terminal isopropoxy is located within the cavity defined by the cyclic architecture, and the weak intra C—H…π interaction (0.304 9 nm) could be identified between hydrogen atoms on methyl groups and the NDI ring (Fig.1(c)). The {Ti3(μ3-O)} unit is a versatile building block that can be easily transferred to build cyclic, triangular and rectangular TOCs[52-55]. In contrast to reported cyclic PCT-71[52]where two cyclohexane groups on ligands adopt almost parallel orientation, two NDI rings in S1 twist towards each other owing to the increasing steric hindrance, with the dihedral angle of 68.57° (Figs. 1(b) and 2(a)). S2 shares the same framework as S1 except for the different substituents on NDI ligand H2LV(Fig.1(d)). The presence of bulky isopropyl exerts more steric hindrance, which pushes the NDI rings to twist outward, giving a larger dihedral angle of 71.19° for S2 (Fig.2(b)).

    Fig.1 Structural representations of S1 and S2: (a) {Ti3(μ3-O)} unit; (b) and (d) ball-and-stick representations of molecular structures of S1 and S2; (c) C—H…π interaction between isopropoxy group and NDI in S1

    Fig.2 Dihedral angles of two NDI rings in different compounds: (a) S1; (b) S2

    In crystallography, crystal structure is described in terms of lattice and cell. The lattice is the periodic arrangement of atoms or molecules, which can be viewed as a three-dimensional(3D) coordinate system consisting of three mutually perpendicular coordinate axes, usually denoted bya,bandc. The neighboring NDI rings of S1 adopt two kinds of π-π interactions with centroid-centroid distances of 0.367 6 nm and 0.376 8 nm (Fig.3(a)), resulting in a one-dimensional (1D) superamolecular chain alongbaxis (Fig.3(b)). Moreover, weak hydrogen bonds are found between the methyl substituent on ligands and O atoms on the NDI rings (0.321 6 nm and 0.349 6 nm), which further assist the formation of 1D superamolecular chain (Fig.3). The introduction of peripheral isopropyl substituent in S2 diminishes the π-π interactions, and the shortest centroid-to-centroid distance between neighboring NDIs is 0.516 6 nm. Instead, C—H…π contacts of 0.271 0 nm and 0.276 0 nm arise from aromatic protons and the planar NDI rings. Also, the weak hydrogen bonds (0.312 7 nm) form among adjacent NDI moieties (Fig.4). It is well known that π-π stacking plays an important role in charge transport[56]. Indeed, a series of conductive MOFs operate on the π-π stacking between a diverse set of organic cores, such as anthracene, naphthalene and NDI[57-59]. Based on the packing modes of S1 and S2, it can be therefore reasonably concluded that S1 will in principle provide a more favorable pathway than S2 for charge transfer.

    Fig.3 Structures of S1: (a) π-π interactions; (b) packing structure

    Fig.4 Structures of S2: (a) C—H…π contacts and weak hydrogen bonds; (b) packing structure

    2.2 Structural characterization of S1 and S2

    The experimental PXRD patterns of S1 and S2 match well with the simulated ones (Fig.5), confirming their high phase purity. The TGA curves show that clusters S1 and S2 have good thermal stability with the onset temperature of thermal decomposition at about 150 ℃ (Fig.6). For S1 (Fig.6(a)), the first mass loss of 4.08% in the range of 30 to 120 ℃ is attributed to the removal of isopropanol guest molecules. Then the isopropoxy ligands are lost between 120 ℃ and 300 ℃, corresponding to a mass loss of 31.31%. Further mass loss (10.12%) at 300-460 ℃ is attributed to the decomposition of carboxylate ligands. Afterward, the whole framework of S1 collapses and transforms into TiO2. A similar mass loss profile for S2 is shown in Fig.6(b).

    Fig.5 Experimental and simulated PXRD patterns: (a) S1; (b) S2

    Fig.6 TGA curves: (a) S1; (b) S2

    Fig.7 FTIR spectra of samples before and after photoelectrochemical experiments: (a) S1; (b) S2

    As shown by the solid-state UV-vis spectra (Fig.8(a)), the absorption bands of S1 and S2 mainly derive from the π-π transition of the NDI ligand, with the absorption edge approaching 500 nm. Owing to the similar structure, the maximum absorption wavelengths of S1 and S2 are also close to each other,i.e., 385 nm for S1 and 383 nm for S2. The small shoulder peaks observed at 450-510 nm for S1 and 425-500 nm for S2 could be tentatively assigned to the charge transfer bands from NDI to Ti(IV) metal, which overlapped with the NDI absorption band. This phenomenon has been observed in photoactive ferrocene and triphenylamine-anchored TOCs[19,60-61]. According to the Kubelka-Munk function, the band gaps for S1 and S2 are 2.85 eV and 2.91 eV, respectively (Figs. 8(b) and 8(c)). In Figs.8(b) and 8(c),F(R) is the variable in the Kubelka-Munk formula. Compared with the nonphotoactive cyclohexanedicarboxylate-functionalized PCT-71[52], the π conjugation in the NDI ligands can effectively reduce the transition energy, broaden the light absorption, and narrow the band gap of S1 and S2.

    Fig.9 Mott-Schottky plots of samples in 0.2 mol/L Na2SO4 aqueous solution: (a) S1; (b) S2

    2.3 Photoelectrochemical properties

    The Mott-Schottky measurement of the TOC-treated photoelectrodes was conducted at the frequencies of 1 000, 1 500 and 2 000 Hz to explore the lowest unoccupied molecular orbital (LUMO). Figure 9 shows the Mott-Schottky plots of the samples, whereCdenotes the capacitance. The positive slopes in the plots confirm that S1 and S2 are n-type semiconductor materials. According to the Mott-Schottky plots, the LUMO potential levels vs. the normal hydrogen electrode (NHE) of S1 and S2 are -0.14 V and -0.27 V, respectively. Based on the band gaps of S1 and S2, the highest occupied molecular orbital (HOMO) potential levels (vs. NHE) of S1 and S2 are evaluated as 2.71 V and 2.64 V, respectively.

    The photoelectrochemical activities of S1 and S2 were investigated under cyclic irradiation with Xe light (300 W). The photoelectrodes treated with S1 and S2 show reversible transient short-circuit photocurrent responses (Fig.10(a)), indicating rapid photoinduced electron-hole separation in the photoelectrodes. It is worth noting that the photoelectrodes treated with S1 and S2 exhibit excellent photocurrent response, with values of 2.12 and 1.95 μA/cm2, respectively. These values are relatively high and comparable with those of other TOCs functionalized by photoactive ligands such as ferrocene[32,60-61], which could be ascribed to the effective charge transfer derived from NDI. Electrochemical impedance spectroscopy was also carried out. As impedance is a vector, it is represented in the plane in the form of a complex number, where the horizontal and vertical coordinatesZ′ andZ″ are the real and imaginary parts of the complex number, denoting resistance and reactance, respectively. It is clearly seen from Fig.10(b) that the electrochemical impedance of the photoelectrodes treated with S1 is slightly lower than that of the photoelectrode treated with S2, indicating that the surface charge transfer rate of S1 is faster than that of S2. Therefore, the charge separation efficiency of S1 is better than that of S2, which is also consistent with the photocurrent responses.

    Fig.10 Photoelectrochemical measurements to investigate the charge separation efficiency: (a) photocurrent responses of S1 and S2; (b) electrochemical impedance spectroscopy of S1 and S2

    3 Conclusions

    In summary, two cyclic TOCs S1 and S2 are successfully synthesized and functionalized by photoactive NDI ligands bearing different substituents. S1 and S2 show quite similar cyclic structures consisting of two {Ti3(μ3-O)} units linked by NDI chromophores. The incorporation of NDI endows S1 and S2 the photophysical and photochemical properties. As reflected by solid-state UV-vis spectra and the Kubelka-Munk function, the band gaps of S1 and S2 exhibit n-type semiconductor characteristics of 2.85 eV and 2.91 eV, respectively. In particular, S1 and S2 exhibit excellent photocurrent responses with photocurrent densities of 2.12 and 1.95 μA/cm2, respectively. This work provides valuable models for investigating the relationship between the structure and photochemical properties of TOCs using photoactive ligands.

    人妻夜夜爽99麻豆av| 男女午夜视频在线观看| 男女下面进入的视频免费午夜| 亚洲精品粉嫩美女一区| 午夜老司机福利剧场| 很黄的视频免费| 国产又黄又爽又无遮挡在线| 亚洲va日本ⅴa欧美va伊人久久| 国产高潮美女av| 日本 av在线| 黄色视频,在线免费观看| 亚洲av免费高清在线观看| 一卡2卡三卡四卡精品乱码亚洲| 最近最新中文字幕大全电影3| 国产在线精品亚洲第一网站| 蜜桃亚洲精品一区二区三区| 亚洲一区高清亚洲精品| 欧美3d第一页| 欧美一级毛片孕妇| 亚洲av不卡在线观看| 老司机福利观看| 国产久久久一区二区三区| 法律面前人人平等表现在哪些方面| 欧美一级毛片孕妇| 日本在线视频免费播放| 日韩欧美国产在线观看| 哪里可以看免费的av片| 久久精品人妻少妇| 亚洲av成人不卡在线观看播放网| 2021天堂中文幕一二区在线观| 搡老岳熟女国产| avwww免费| 色吧在线观看| 欧美日韩中文字幕国产精品一区二区三区| 免费观看人在逋| 亚洲国产精品成人综合色| 成年人黄色毛片网站| 最新在线观看一区二区三区| 日韩欧美国产在线观看| 国产亚洲精品综合一区在线观看| 成年版毛片免费区| 亚洲一区二区三区色噜噜| 午夜福利18| 美女黄网站色视频| 国产欧美日韩精品亚洲av| 十八禁网站免费在线| 叶爱在线成人免费视频播放| 亚洲五月天丁香| 熟女人妻精品中文字幕| 中出人妻视频一区二区| 亚洲在线观看片| 国产精品亚洲美女久久久| 三级男女做爰猛烈吃奶摸视频| 亚洲国产高清在线一区二区三| 此物有八面人人有两片| 国产免费av片在线观看野外av| 欧美性猛交黑人性爽| 一夜夜www| 亚洲成av人片免费观看| 狂野欧美激情性xxxx| 男女那种视频在线观看| 欧美乱码精品一区二区三区| 99视频精品全部免费 在线| 伊人久久大香线蕉亚洲五| 3wmmmm亚洲av在线观看| 五月玫瑰六月丁香| 日本a在线网址| 久久九九热精品免费| 国产精品久久久久久久久免 | 日韩欧美精品免费久久 | 国产精华一区二区三区| av片东京热男人的天堂| 午夜久久久久精精品| 好看av亚洲va欧美ⅴa在| 少妇高潮的动态图| 亚洲一区二区三区色噜噜| 丁香欧美五月| 十八禁网站免费在线| 搡老妇女老女人老熟妇| 午夜免费激情av| 欧美色欧美亚洲另类二区| 日韩欧美在线二视频| 少妇的逼水好多| 精品福利观看| 97碰自拍视频| 久久久久久久久大av| 一个人免费在线观看电影| 欧美色视频一区免费| 两人在一起打扑克的视频| 九色国产91popny在线| 国产探花极品一区二区| 三级国产精品欧美在线观看| 中文字幕人成人乱码亚洲影| 有码 亚洲区| 久久亚洲真实| 99久久精品国产亚洲精品| xxx96com| 婷婷亚洲欧美| 男人舔奶头视频| 88av欧美| 日本 欧美在线| 免费在线观看亚洲国产| 久久久精品大字幕| 色老头精品视频在线观看| 每晚都被弄得嗷嗷叫到高潮| 欧美bdsm另类| 舔av片在线| 久久午夜亚洲精品久久| 欧美日韩亚洲国产一区二区在线观看| 国产精品电影一区二区三区| 波野结衣二区三区在线 | 亚洲av第一区精品v没综合| 精品熟女少妇八av免费久了| 亚洲男人的天堂狠狠| 在线国产一区二区在线| 一个人看的www免费观看视频| 午夜福利在线在线| 久久久久久久久久黄片| 母亲3免费完整高清在线观看| 18禁裸乳无遮挡免费网站照片| aaaaa片日本免费| 99久久综合精品五月天人人| 国产激情偷乱视频一区二区| 欧美区成人在线视频| 欧美在线黄色| 中文字幕熟女人妻在线| 日韩亚洲欧美综合| 亚洲不卡免费看| 伊人久久精品亚洲午夜| 好男人电影高清在线观看| 国产精品一及| 69人妻影院| 国产视频内射| 亚洲中文日韩欧美视频| 麻豆久久精品国产亚洲av| 国产精品久久久人人做人人爽| 久久久久亚洲av毛片大全| 日韩欧美免费精品| 两个人看的免费小视频| 国产成人系列免费观看| 亚洲成av人片免费观看| 99国产精品一区二区三区| 久久精品国产亚洲av香蕉五月| 桃红色精品国产亚洲av| 国产成+人综合+亚洲专区| 国产真人三级小视频在线观看| 岛国在线免费视频观看| 国产综合懂色| 欧美日本亚洲视频在线播放| 天天添夜夜摸| 久久性视频一级片| 99久久综合精品五月天人人| 欧美日韩综合久久久久久 | 国产免费一级a男人的天堂| xxx96com| 又黄又爽又免费观看的视频| 亚洲国产欧洲综合997久久,| 亚洲av不卡在线观看| 亚洲 欧美 日韩 在线 免费| 乱人视频在线观看| 亚洲人成网站高清观看| 日韩精品青青久久久久久| 欧美成人性av电影在线观看| 99精品在免费线老司机午夜| 国产野战对白在线观看| 久久久国产精品麻豆| 午夜老司机福利剧场| 久久精品国产99精品国产亚洲性色| 美女被艹到高潮喷水动态| 日本黄色视频三级网站网址| 男女下面进入的视频免费午夜| 国内毛片毛片毛片毛片毛片| 国产精品美女特级片免费视频播放器| 久久人妻av系列| 日本黄色视频三级网站网址| 国产免费av片在线观看野外av| 久久久久久久精品吃奶| 又爽又黄无遮挡网站| 9191精品国产免费久久| 国产精品久久久久久亚洲av鲁大| 一二三四社区在线视频社区8| 俺也久久电影网| 久久伊人香网站| 国内精品一区二区在线观看| 欧美日本亚洲视频在线播放| 90打野战视频偷拍视频| 在线观看日韩欧美| 亚洲av成人精品一区久久| 在线a可以看的网站| 在线观看一区二区三区| 免费看美女性在线毛片视频| 国内精品久久久久久久电影| a级一级毛片免费在线观看| 亚洲精品一卡2卡三卡4卡5卡| 97人妻精品一区二区三区麻豆| 久久久精品欧美日韩精品| 狂野欧美白嫩少妇大欣赏| 日日摸夜夜添夜夜添小说| 亚洲成人免费电影在线观看| 亚洲精品在线观看二区| 欧美日韩中文字幕国产精品一区二区三区| 欧美黑人巨大hd| 日韩欧美在线二视频| 岛国在线观看网站| 亚洲乱码一区二区免费版| 久久久久久久午夜电影| 午夜福利视频1000在线观看| 高清在线国产一区| 国语自产精品视频在线第100页| 国产一区二区在线观看日韩 | 国产日本99.免费观看| 欧美高清成人免费视频www| 一级黄色大片毛片| 一级a爱片免费观看的视频| 免费大片18禁| 国产亚洲欧美98| 国产亚洲精品一区二区www| 女人高潮潮喷娇喘18禁视频| 美女高潮喷水抽搐中文字幕| 精品久久久久久久末码| 99久国产av精品| 国产探花极品一区二区| 美女大奶头视频| 日韩欧美免费精品| 特大巨黑吊av在线直播| 少妇熟女aⅴ在线视频| 丁香欧美五月| 成人午夜高清在线视频| 色综合欧美亚洲国产小说| 亚洲国产精品合色在线| 搡老岳熟女国产| 成人午夜高清在线视频| 精品久久久久久成人av| 欧美不卡视频在线免费观看| eeuss影院久久| 偷拍熟女少妇极品色| e午夜精品久久久久久久| 国产伦在线观看视频一区| 欧美在线黄色| 一夜夜www| 成人鲁丝片一二三区免费| 久久久久免费精品人妻一区二区| 亚洲乱码一区二区免费版| 香蕉丝袜av| 欧美日韩亚洲国产一区二区在线观看| 亚洲色图av天堂| 搡女人真爽免费视频火全软件 | 欧美在线一区亚洲| 精品久久久久久成人av| 一级黄色大片毛片| 深夜精品福利| 亚洲成人久久爱视频| 免费av观看视频| 午夜福利高清视频| 国产一区二区在线av高清观看| 国产真实乱freesex| 日韩欧美在线乱码| 在线观看av片永久免费下载| 久久久精品欧美日韩精品| 性欧美人与动物交配| 亚洲人成电影免费在线| 国产 一区 欧美 日韩| 亚洲精品一卡2卡三卡4卡5卡| 国内揄拍国产精品人妻在线| 一区二区三区免费毛片| 亚洲av成人精品一区久久| 国产精品综合久久久久久久免费| 亚洲精品国产精品久久久不卡| 欧美日韩福利视频一区二区| 少妇的逼水好多| 久久国产乱子伦精品免费另类| 18禁美女被吸乳视频| 蜜桃久久精品国产亚洲av| 三级男女做爰猛烈吃奶摸视频| 91麻豆精品激情在线观看国产| 嫩草影院入口| 精品久久久久久久久久久久久| 757午夜福利合集在线观看| 免费看a级黄色片| 国产高清有码在线观看视频| 国产精品 欧美亚洲| 亚洲 欧美 日韩 在线 免费| 久久精品影院6| 国产淫片久久久久久久久 | x7x7x7水蜜桃| 亚洲欧美日韩东京热| 啦啦啦免费观看视频1| 免费观看人在逋| 亚洲不卡免费看| 色哟哟哟哟哟哟| 高清毛片免费观看视频网站| 精品乱码久久久久久99久播| 久久久精品欧美日韩精品| 国产成人av教育| 看免费av毛片| 女同久久另类99精品国产91| 国产国拍精品亚洲av在线观看 | 99久久99久久久精品蜜桃| 91av网一区二区| 国产精品 国内视频| 国产色爽女视频免费观看| 亚洲专区中文字幕在线| 搡老妇女老女人老熟妇| 99久久成人亚洲精品观看| 精品一区二区三区视频在线观看免费| 国产成人福利小说| 欧美中文日本在线观看视频| 在线观看66精品国产| 国产欧美日韩精品亚洲av| 首页视频小说图片口味搜索| 天天一区二区日本电影三级| 美女黄网站色视频| 1024手机看黄色片| 国产亚洲精品av在线| 一区福利在线观看| 国产精品嫩草影院av在线观看 | 亚洲内射少妇av| 女人被狂操c到高潮| 女同久久另类99精品国产91| 久久香蕉国产精品| 女人被狂操c到高潮| 精品不卡国产一区二区三区| 久久香蕉国产精品| 色av中文字幕| 欧美三级亚洲精品| 久久久精品欧美日韩精品| 亚洲男人的天堂狠狠| 悠悠久久av| а√天堂www在线а√下载| 制服人妻中文乱码| 亚洲精品亚洲一区二区| 欧美zozozo另类| 天堂网av新在线| 亚洲欧美日韩无卡精品| 午夜免费激情av| 国产亚洲精品综合一区在线观看| 国产真人三级小视频在线观看| 日本一二三区视频观看| 韩国av一区二区三区四区| 热99在线观看视频| 成人性生交大片免费视频hd| 成人高潮视频无遮挡免费网站| 黄片小视频在线播放| 99久久精品国产亚洲精品| 亚洲专区国产一区二区| 亚洲av日韩精品久久久久久密| 亚洲avbb在线观看| 久久久久久九九精品二区国产| 国产伦人伦偷精品视频| 真实男女啪啪啪动态图| 日本五十路高清| 性色avwww在线观看| 在线播放无遮挡| 亚洲,欧美精品.| 午夜激情福利司机影院| 黄色日韩在线| 色综合站精品国产| 精品久久久久久成人av| 国内少妇人妻偷人精品xxx网站| 亚洲aⅴ乱码一区二区在线播放| 啦啦啦韩国在线观看视频| eeuss影院久久| 可以在线观看的亚洲视频| www日本在线高清视频| 日本精品一区二区三区蜜桃| 亚洲精品456在线播放app | 丰满人妻熟妇乱又伦精品不卡| 91字幕亚洲| 欧美zozozo另类| 丁香六月欧美| 搡女人真爽免费视频火全软件 | 99久国产av精品| 午夜两性在线视频| 深爱激情五月婷婷| 真实男女啪啪啪动态图| 美女大奶头视频| 99精品久久久久人妻精品| 欧美日韩瑟瑟在线播放| 国产av不卡久久| 亚洲一区高清亚洲精品| 成年女人看的毛片在线观看| 51午夜福利影视在线观看| 精品久久久久久久久久免费视频| 18禁黄网站禁片免费观看直播| 久久九九热精品免费| 欧美精品啪啪一区二区三区| 19禁男女啪啪无遮挡网站| 国产精品 欧美亚洲| 婷婷精品国产亚洲av在线| 黄片大片在线免费观看| 两性午夜刺激爽爽歪歪视频在线观看| 国产一区二区在线av高清观看| 亚洲久久久久久中文字幕| 亚洲一区二区三区色噜噜| 天美传媒精品一区二区| 热99re8久久精品国产| 午夜两性在线视频| 狠狠狠狠99中文字幕| 成人精品一区二区免费| 午夜精品在线福利| svipshipincom国产片| 亚洲 国产 在线| 一本久久中文字幕| 久久久久国产精品人妻aⅴ院| 久久精品综合一区二区三区| 日本三级黄在线观看| 国产精品综合久久久久久久免费| 夜夜爽天天搞| 国产精品亚洲美女久久久| 国产国拍精品亚洲av在线观看 | 亚洲电影在线观看av| 51午夜福利影视在线观看| 看片在线看免费视频| 久久99热这里只有精品18| 国产亚洲欧美98| 久久久久久人人人人人| 午夜免费激情av| 亚洲国产精品合色在线| 嫩草影院精品99| 夜夜躁狠狠躁天天躁| av欧美777| 国产69精品久久久久777片| 三级国产精品欧美在线观看| 久久天躁狠狠躁夜夜2o2o| 国产午夜精品论理片| 99热只有精品国产| 亚洲人成网站在线播| 人人妻人人澡欧美一区二区| 欧美日韩福利视频一区二区| 在线观看免费视频日本深夜| 性色av乱码一区二区三区2| 亚洲av中文字字幕乱码综合| 午夜免费观看网址| 一卡2卡三卡四卡精品乱码亚洲| av中文乱码字幕在线| 欧美日韩一级在线毛片| 日韩中文字幕欧美一区二区| 欧美在线一区亚洲| 一本综合久久免费| 欧美性猛交黑人性爽| 夜夜躁狠狠躁天天躁| 国产精品久久久久久精品电影| 成年女人毛片免费观看观看9| 日韩免费av在线播放| 禁无遮挡网站| 亚洲av二区三区四区| 日本免费a在线| 可以在线观看毛片的网站| 高清日韩中文字幕在线| 欧美一级毛片孕妇| 最好的美女福利视频网| 亚洲成人久久爱视频| 不卡一级毛片| 99riav亚洲国产免费| 精品福利观看| 最近最新中文字幕大全免费视频| 91九色精品人成在线观看| 成年女人永久免费观看视频| 精品久久久久久久久久免费视频| 日韩欧美一区二区三区在线观看| 久久草成人影院| 村上凉子中文字幕在线| 亚洲成人久久爱视频| 老汉色∧v一级毛片| 午夜福利视频1000在线观看| 热99在线观看视频| 日本撒尿小便嘘嘘汇集6| 12—13女人毛片做爰片一| 国产亚洲精品久久久com| 麻豆成人av在线观看| 免费搜索国产男女视频| 熟妇人妻久久中文字幕3abv| 噜噜噜噜噜久久久久久91| 99久久精品一区二区三区| 亚洲激情在线av| 欧洲精品卡2卡3卡4卡5卡区| 亚洲国产精品999在线| 国产97色在线日韩免费| 亚洲美女黄片视频| 老司机午夜十八禁免费视频| 亚洲电影在线观看av| 亚洲精品影视一区二区三区av| 欧美日韩瑟瑟在线播放| 天美传媒精品一区二区| 国产精品亚洲美女久久久| 九九热线精品视视频播放| 国产精品野战在线观看| 99在线人妻在线中文字幕| 国产高清三级在线| 精品乱码久久久久久99久播| av黄色大香蕉| 国产蜜桃级精品一区二区三区| 国产成人啪精品午夜网站| 亚洲片人在线观看| 欧美一级毛片孕妇| 丁香欧美五月| 91麻豆av在线| 久久亚洲精品不卡| 国产av麻豆久久久久久久| 亚洲欧美一区二区三区黑人| 999久久久精品免费观看国产| e午夜精品久久久久久久| 丰满的人妻完整版| 亚洲国产欧美网| 欧美在线一区亚洲| ponron亚洲| 亚洲欧美精品综合久久99| 97超视频在线观看视频| 国产熟女xx| 午夜老司机福利剧场| 男人舔奶头视频| 亚洲不卡免费看| 女生性感内裤真人,穿戴方法视频| 在线十欧美十亚洲十日本专区| 久久久久九九精品影院| 国产三级在线视频| 九色国产91popny在线| 欧美性猛交╳xxx乱大交人| av福利片在线观看| 99热6这里只有精品| 久久99热这里只有精品18| 国产精品一区二区免费欧美| 国产高清视频在线观看网站| 啦啦啦观看免费观看视频高清| 国产高清视频在线观看网站| 高潮久久久久久久久久久不卡| 欧美黄色片欧美黄色片| 黑人欧美特级aaaaaa片| 日韩欧美三级三区| 夜夜躁狠狠躁天天躁| 国产成人福利小说| 午夜视频国产福利| 精品久久久久久久毛片微露脸| 国产熟女xx| 日日干狠狠操夜夜爽| 老司机在亚洲福利影院| 一边摸一边抽搐一进一小说| 夜夜看夜夜爽夜夜摸| 国产亚洲精品久久久com| 成人av一区二区三区在线看| 国产精品美女特级片免费视频播放器| 亚洲精品亚洲一区二区| 亚洲一区高清亚洲精品| 中文字幕人成人乱码亚洲影| 成人18禁在线播放| 亚洲精品色激情综合| 国产激情偷乱视频一区二区| 极品教师在线免费播放| 亚洲欧美日韩东京热| 亚洲精品影视一区二区三区av| 在线a可以看的网站| 亚洲欧美激情综合另类| 在线免费观看的www视频| 国产精品99久久久久久久久| 真人一进一出gif抽搐免费| 中文字幕人成人乱码亚洲影| 国产激情偷乱视频一区二区| 午夜福利在线观看吧| 波多野结衣高清无吗| 国内久久婷婷六月综合欲色啪| 嫩草影院精品99| 一区二区三区激情视频| 女人被狂操c到高潮| 亚洲av成人av| 老司机在亚洲福利影院| 国产日本99.免费观看| 欧美黄色片欧美黄色片| 国内精品一区二区在线观看| 18禁黄网站禁片午夜丰满| 色综合亚洲欧美另类图片| 欧美日韩国产亚洲二区| 欧美色视频一区免费| 最新中文字幕久久久久| 亚洲中文日韩欧美视频| 午夜免费激情av| 18禁黄网站禁片免费观看直播| 人人妻人人看人人澡| 极品教师在线免费播放| 国产精品国产高清国产av| 欧美成人性av电影在线观看| 99视频精品全部免费 在线| 最近在线观看免费完整版| 国产av在哪里看| 中出人妻视频一区二区| 九九久久精品国产亚洲av麻豆| 日韩欧美国产在线观看| 哪里可以看免费的av片| 亚洲一区二区三区不卡视频| 岛国在线免费视频观看| 99视频精品全部免费 在线| 在线观看日韩欧美| 色在线成人网| 国产av一区在线观看免费| 国产精品一区二区三区四区久久| 中文字幕av在线有码专区| 午夜亚洲福利在线播放| 一个人看的www免费观看视频| a在线观看视频网站| 一进一出抽搐gif免费好疼| 国产97色在线日韩免费| 国产伦精品一区二区三区视频9 | 在线观看66精品国产| 可以在线观看的亚洲视频| 亚洲国产精品sss在线观看| 在线播放国产精品三级| 亚洲精品粉嫩美女一区| 香蕉久久夜色| 免费看十八禁软件| 亚洲专区中文字幕在线| 午夜福利成人在线免费观看| 99热只有精品国产| 欧美高清成人免费视频www| 两个人视频免费观看高清| 亚洲人成网站在线播放欧美日韩| 操出白浆在线播放|