• <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 ?

    Effect of Fluorination on the Crystal Structure, Stability and Gas Adsorption Property in Zinc(II)Metal-organic Frameworks①

    2022-03-08 02:31:06ZHANGXinCHENZhenXiaYANGYongTaiDENGMingLiWENGLinHong
    結(jié)構(gòu)化學(xué) 2022年1期

    ZHANG Xin CHEN Zhen-Xia YANG Yong-Tai DENG Ming-Li WENG Lin-Hong

    (Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Department of Chemistry, Fudan University, Shanghai 200433, China)

    ABSTRACT Three zinc(II) metal-organic frameworks (xF-MAC-3) have been synthesized by using Zn(II) salts,3,5-dimethyl-1H-1,2,4-triazole (Hdmtrz) and different fluorination degree carboxylate ligands, which are analogic structures and can be described as (6,6)-connected pcu-b net. We find that the fluorine atoms have structural regulation effect on xF-MAC-3, which can not only enlarge the torsion angle of carboxylate ligands but also elevate the space group of structures. Besides, the CO2-273 K uptake increased from 23.21 cm3·g-1 (MAC-3) to 36.13 cm3·g-1 (4F-MAC-3) and H2-77 K uptake increased from 24.33 cm3·g-1 (MAC-3) to 59.79 cm3·g-1(4F-MAC-3), which means fluorination can enhance the gas adsorption uptake of xF-MAC-3 analogues.Furthermore, the results of fluorination in xF-MAC-3 analogues offer a potential way to study the ligand pre-functionalization effect on the structures and properties of MOFs analogues.

    Keywords: metal-organic frameworks, fluorine functionalization, X-ray crystallography, gas adsorption;

    1 INTRODUCTION

    Metal-organic frameworks (MOFs) are porous crystalline materials which are constructed by secondary building units(SBUs) and organic ligands[1-3]. In the last two decades, due to their permanent porosity, structural stability and easily functionalization, MOFs have been widely studied in the fields of applications such as gas adsorption and purification[4-6], catalysis[7-9], molecule sensing and recognition[10-12].

    Since fluorine atoms have the strongest electronegativity and small electron polarization, introducing fluorine-containing functional groups into MOFs can change the pore channel properties and lead to various applications[13-15], such as hydrocarbon separation[16-19], ionic conductivity[20]and,mostly important, H2and CO2adsorption[21-23]. Nevertheless,fluorination will largely change the acidity and coordination ability of the carboxylate ligand, so that fluorinated analogues of MOFs constructed by carboxylate ligands can hardly be synthesized[24-26]. In recent years, some fluorinated analogues of MOFs have been synthesized and the effects of fluorination on MOFs have been studied[27-29]. However, there are still some challenges to figure out the effect of fluorination in MOFs for crystal structures, stabilities, H2and CO2adsorption properties, which arouses our interests.

    Cheetham and co-workers investigated that a series of 3D fluorinated-MOFs can be synthesized by using perfluorinated carboxylates in combination with nonfluorinated nitrogen heterocyclic ligands such as imidazole[30], triazole[31], and both bipyridine[32]. Inspired by this, we synthesized three analogic structures (xF-MAC-3) based on our previous work[33]by using Zn(II) salts, 3,5-dimethyl-1H-1,2,4-triazole(Hdmtrz) and different fluorination degree carboxylate ligands.We also discuss the effects of fluorination on MOFs structure,thermal and chemical stability, H2and CO2adsorption properties in detail.

    2 EXPERIMENTAL

    2. 1 General materials and methods

    All reagents were purchased from commercial sources and used without further purification, except for 3,5-dimethyl-1H-1,2,4-triazole (HDmtrz) and 2,5-difluoroterephthalic acid(H2DFBDC), which were synthesized according to the references[34,35]. Fourier Transform Infrared Spectra (FT-IR)were performed on a ThermoFisher Nicolet iS10 FT-IR spectrometer in the range of 4000~400 cm-1with KBr pellets.Elemental analyses of C, N and H were tested on the Elementar Vario EL III. Powder X-ray diffraction (PXRD)was measured by using a Bruker D8 Advance diffractometer with Cu-Kαradiation (λ= 1.5406 ?). Thermogravimetric analyses (TGA) were carried out on SDT Q600 with the temperature range of 30~900 °C under N2flow at a heating rate 10 °C·min-1. Gas adsorption analyses were tested on the Micromeritics ASAP 2020 surface area analyzer. Before gas sorption, the as-made MOF samples (about 100 mg) were exchanged with dichloromethane (10 mL for three times) and then degassed at 140 °C for 10 hours.

    2. 2 X-ray crystallographic study

    Single-crystal X-ray diffraction (SC-XRD) of all compounds was performed on a Bruker D8 Venture MetalJet with Ga-Kαradiation (λ= 1.3414 ?) at 173 K. Data collection and reduction were performed with APEX III, and empirical absorption corrections were applied by the SADABS program.Structures were solved by direct methods using the SHELXS program and refined with the SHELXL program[36].Non-hydrogen atoms and N-bondedHatoms were directly obtained from a difference Fourier map.C-bonded H atoms were placed geometrically and refined as riding modes. Final refinements were carried out by full-matrix least-squares methods with anisotropic thermal parameters for all non-hydrogen atoms onF2. SQUEEZE method was used to consider the disorder in the channel of the structures[37].

    2. 3 Syntheses

    2. 3. 1 3,5-Dimethyl-1H-1,2,4-triazole (HDmtrz)

    Acetamide (60 g, 1 mol) and 80 wt% hydrazine hydrate (30 g, 0.5 mol) were added into a 250 mL flask and heated at 120 °C for 3 h, when the reaction solution first turned pink and then became colorless. After that, the reaction temperature was increased to 180 °C for 3 h and about 30 mL of liquid was distilled. Finally, the temperature was further increased to 240 °C and colorless liquid was distilled, which was condensed on the tube as white solid product (8.98 g, 0.09 mol). Yield: 9%.1H NMR (DMSO-d6) showedδ= 13.13 (s,1H), 2.20 (s, 6H).

    2. 3. 2 2,5-Difluoroterephthalic acid (H2DFBDC)

    2,5-Difluoro-4-methylbenzoic acid (5.6 g, 33.5 mmol),N-bromosuccinimide (NBS, 29.5 g, 165 mmol) and benzoyl peroxide (BPO, 0.4 g) were added into 100 mL CCl4and refluxed at 120 °C for 48 h and the reaction system changed into orange color. The hot mixture was filtered and washed successively with hot CCl4, and the organic solution was extracted with 1 M HCl by three times, dried over anhydrous MgSO4, filtered and evaporated. The remaining orange solid was the intermediate product with the mess of 9.14 g.1H NMR (DMSO-d6):δ= 7.71 (q, 1H), 7.61 (q, 1H), 7.41 (s, 1H).

    The intermediate product (9.14 g) and sodium periodate(7.17 g, 33.5 mmol) were added into 50 mL 2% H2SO4and refluxed at 90 °C for 24 h. The product was subsequently cooled to room temperature and the cold mixture was filtered,then the precipitate was washed with water. The solids were recrystallized from acetic acid to gain white powder 3.47 g(17.5 mmol). Yield: 52.2%.1H NMR (DMSO-d6):δ= 7.68 (t, 2H).

    2. 3. 3 Zn2(BDC)2(Dmtrz)]·(CH3NH3)·2H2O (MAC-3)

    Zn(OAc)2·2H2O (75 mg, 0.2 mmol), terephthalic acid(H2BDC, 33 mg, 0.2 mmol) and HDmtrz (10 mg, 0.1 mmol)were added to 10 mLN,N-dimethylformamide (DMF) and stirred for 10 min. Then the solution was sealed in a Teflon-lined stainless-steel autoclave (15 mL) and heated at 140 °C for 3 days, followed by cooling down to room temperature. Colorless block crystals were collected by filtration. Yield: 75% based on the Zn(OAc)2·2H2O. Elemental analysis calculated for MAC-3 (Zn2C21H24N4O10, 623.19):C, 40.41; N, 8.98; H, 3.85%. Found: C, 40.50; N, 9.41; H,3.78%. FT-IR (cm-1): 3426m, 3059m, 2963m, 2794m, 2484w,1952w, 1632vs, 1599vs, 1492s, 1393vs, 1253w, 1136w,1099m, 10118m, 875w, 816m, 753s, 694w, 592w, 514m (Fig. 1b).

    2. 3. 4 Zn3(H2O)2(MeO)2(DFBDC)2(Dmtrz)]·(CH3)2NH2(2F-MAC-3)

    [Zn(NO3)2·6H2O (87 mg, 0.3 mmol), H2DFBDC (40 mg,0.2 mmol) and HDmtrz (10 mg, 0.1 mmol) were added to the mixture solution of DMF (2 mL) and methanol (MeOH, 8 mL), and the mixture was stirred for 10 min. Subsequently,the mixture was sealed in a Teflon-lined stainless-steel autoclave (15 mL) and heated at 90 °C for 12 h, followed by cooling down to room temperature. Colorless block crystals were collected by filtration. Yield: 60% based on the Zn(NO3)2·6H2O. Elemental analysis calculated for 2F-MAC-3 (Zn3C24H28N4O12F4, 836.61): C, 34.42; N, 6.69; H,3.35%. Found: C, 34.45; N, 6.65; H, 3.30%. FT-IR (cm-1):3411m, 3073w, 2978m, 2927w, 2878w, 2448w, 2033w,1646vs, 1588vs, 1486m, 1419vs, 1356s, 1264m, 1213m,1183s, 1121m, 1026w, 988w, 945w, 900m, 853m, 808s, 774s,706w, 657w, 529m (Fig. 1b).

    2. 3. 5 [Zn2(TFBDC)2(Dmtrz)]·H2O (4F-MAC-3)

    Zn(NO3)2·6H2O (87 mg, 0.3 mmol), 2,3,5,6-tetrafluoroterephthalic acid (H2TFBDC, 48 mg, 0.2 mmol) and HDmtrz (10 mg, 0.1 mmol) were added to the mixture solution ofN,N-diethylformamide (DEF, 2 mL) and MeOH (8 mL), and the mixture was stirred for 10 min. Then the mixture was sealed in a Teflon-lined stainless-steel autoclave (15 mL) and heated at 90 °C for 12 h, followed by cooling down to room temperature. Light purple block crystals were collected by filtration. Yield: 65% based on Zn(NO3)2·6H2O. Elemental analysis calculated for 4F-MAC-3 (Zn2C20H9N3O9F8, 718.04):C, 33.42; N, 5.84; H, 1.24%. Found: C, 33.50; N, 5.94; H,1.20%. FT-IR (cm-1): 3422m, 2921w, 2941w, 2874w, 2361w,1639vs, 1474m, 1419vs, 1356s, 1264m, 1213m, 1183s,1121m, 1026w, 988w, 945w, 900m, 853m, 808s, 774s, 706w,657w, 529m (Fig. 1b).

    3 RESULTS AND DISCUSSION

    3. 1 Synthesis and general characterization

    Zn2(BDC)2(Dmtrz)]·(CH3NH3)·2H2O (MAC-3) was synthesized by solvothermal method in DMF with the raw material ratio of Zn(OAc)2·2H2O:H2BDC:HDmtrz as 3:2:2 after referring to the previously reported method[33]. However,we failed to acquirexF-MAC-3 (x= 2 or 4) under the same synthesis conditions, which we believed that was mainly due to the introduction of fluorine atoms[38]. Due to the strongest electronegativity and electron polarization of the fluorine atom, the electronic density on the benzene ring and the ligand acidity would change after the introduction of the fluorine atom into the carboxylate ligand. As the number of fluorine atoms increases, the electronic density of the benzene ring would decrease while the ligand acidity would increase,which changed the coordination ability of the carboxylate ligand and affected the synthesis of MOF materials. Therefore,we used zinc nitrate with stronger coordination ability as the metal salt during the synthesis of 2F-MAC-3. We also introduced methanol with low boiling point and strong polarity into the solvent system and used milder reaction conditions to gain high quality 2F-MAC-3 single crystal.During the synthesis of 4F-MAC-3, we replaced DMF with DEF, which had better ligand solubility and helped to obtain the single-crystal test-qualified 4F-MAC-3 sample.

    The PXRD pattern ofxF-MAC-3 samples fitted well with the simulated data, confirming the pure phase of all samples(Fig. 1a). The existence of fluorine atoms in the structures was checked by using1H NMR and FT-IR spectroscopy. The FT-IR spectra of 2F-MAC-3 and 4F-MAC-3 had absorption peaks at 1182 and 989 cm-1, respectively, which could be ascribed as the stretching vibration peaks of C–F bonds,showing the presence of fluorine functionalized ligands(Fig. 1b)[39]. Furthermore, the disappearance of C–H non-planar deviational vibration peaks in the range of 950~780 cm-1in 4F-MAC-3 FT-IR spectrum also implied the absence of C–H bonds in 4F-MAC-3, certifying that the carboxylate ligand in 4F-MAC-3 is TFBDC[40]. The1H NMR spectroscopy showed the ligand composition ofxF-MAC-3 structures. The1H NMR spectra of MAC-3 and 2F-MAC-3 had two NMR peaks with different chemical shifts, where the peak atδ7.99 could be ascribed as the benzene ring hydrogen of carboxylate ligand (-PhH) and that atδ2.48 was the methyl hydrogen of the Dmtrz ligand (-CH3), respectively (Fig. 1c).The ratio of the two ligands closed to 1:1 calculated by the peak integrating area, which was consistent with the structural molecular formula results. There was only one peak in the1H NMR spectrum of 4F-MAC-3 atδ2.44, which was the methyl hydrogen (-CH3) of the Dmtrz ligand. The absence of other chemical shift peaks also proved that the carboxylate ligand in 4F-MAC-3 is TFBDC.

    Fig. 1. (a) PXRD pattern; (b) FT-IR spectra; (c) 1H NMR spectra of xF-MAC-3 (x = 0, 2, 4)

    3. 2 X-ray crystal structure

    As a prototype structure, single-crystal X-ray diffraction study revealed that MAC-3 crystallized in monoclinic system,C2/mspace group (Table S1). The asymmetric unit of MAC-3 contained two crystallographically independent Zn(II). Four carboxylate groups in BDC ligands andNatoms in Dmtrz ligands coordinated to Zn(1) and Zn(1)A(A: 1–x,y, 2–z),forming zinc paddle-wheel SBU [Zn2(COO)4N2]. Two Dmtrz ligands coordinated to Zn(2) and Zn(2)B(B: 1–x, 1–y, 1–z)viaaμ1,2-bridging mode to construct triazolate-dinuclear SBUs[Zn2(Dmtrz)2O4] (Fig. 2a). Two SBUs connected with each other to generate a 1D chain structure with a folding angleθof 168.78°, and such chains are linked by BDC ligands along thexandyaxes to form a 3D structure with a 7.0? × 7.0? channel along thecaxis (considering van der Waals radius,Fig. 2b). Considering paddle-wheel and triazolate-dinuclear as 6-connected SBUs, MAC-3 could be defined as a (6,6)-connectedpcu-b topology net (Fig. S1)[41].

    Fig. 2. (a) Secondary building units and organic ligands of xF-MAC-3; (b)~(d) Single-crystal structures of xF-MAC-3

    Based on the MAC-3 prototype structure, we replaced BDC ligand by fluorine-functionalized ligands to synthesize iso-structures and 2F-MAC-3 & 4F-MAC-3 were subsequently isolated (Fig. 2c, d, Fig. S2, 3 and Table S1). Distinct structural changes concerning the carboxylate ligands, 1D chain and SBUs are summarized in Table 1 and Fig. 1b, which mainly included (i) space group elevated fromC2/m(MAC-3)toImmm(2F-MAC-3 & 4F-MAC-3); (ii) the folding angleθof 1D chain changed from obtuse angle (168.78°) into straight angle (180°); (iii) the torsion angle in BDC ligands turned into right angle; (iv) trianzolate-dinuclear SBU changed into a novel zinc tetranuclear SBU when the BDC ligand was replaced by fluorine-functionalized DFBDC ligands. The 1D channel size of 2F-MAC-3 is 4.0? × 6.8? (considering van der Waals radius) which is smaller than MAC-3. The channel of 2F-MAC-3 is smaller than MAC-3 mainly caused by the larger zinc tetranuclear SBU in 2F-MAC-3, which reduced the size of 1D channel in MOFs. Furthermore, the 1D channel size of 4F-MAC-3 is 6.8? × 6.8? (considering van der Waals radius) which is slightly smaller than MAC-3. Considering the SBUs in 4F-MAC-3 are the same with MAC-3, the smaller 1D channel in 4F-MAC-3 is due to the relatively larger size of fluorine atoms.

    There are two important differences in the chemistry of fluorine-functionalized BDC ligands compared to their nonfluorinated analogues, which caused the structural changes inxF-MAC-3 mentioned above. The first difference among three carboxylate ligands is the pKavalue. As discussed, the pKavalue of BDC-derived ligands decreases with the increasing number of fluorine atoms on the ligand, which means the acidities of 2F-MAC-3 & 4F-MAC-3 are stronger than MAC-3. So the fluorinated ligands can be deprotonated more easily and coordinated with zinc ions in a multidentate mode. This explains SBUs in MAC-3 are paddle-wheel and triazolate-dinuclear when SBUs in 2F-MAC-3 & 4F-MAC-3 are paddle-wheel and zinc tetranuclear. Secondly, in 2F-MAC-3 & 4F-MAC-3, the fluorine atoms of BDC ligands enlarge the torsion angle to a right angle, by which the carboxylate groups are twisted out of the benzene ring. This can be attributed to (i) an electrostatic repulsion effect between the fluorine atoms on the benzene ring and the lone-pair oxygen atoms on the carboxylate groups; (ii) the decrease in aromatic character of BDC ligands due to the electron-withdrawing nature of the fluorine atoms[42]. The two differences mentioned above cause the folding angleθof 1D chain inxF-MAC-3 (x= 2, 4) become a straight angle, thus inducing structures to crystallize in a higher symmetry space group (Fig. S4). This suggests that the introduction of fluorine atoms into ligand has a structure directing effect on the synthesizedxF-MAC-3.

    3. 3 Structural stability

    To study the porosity ofxF-MAC-3, we first investigated the thermal and solvent stability ofxF-MAC-3 to determine the activation conditions for gas adsorption test. The TGA analysis reveals that allxF-MAC-3 samples contain two weight loss peaks. The first one from room temperature to 200 °C shows about 25% weight loss, which can be attributed to the departure of guest molecules. The second weight loss peak from 250 to 600 °C results from the decomposition of the framework. For the increasing fluorination degree will weaken the C(-Phenyl)–C(Carboxylate)bond, the decarboxylation reaction will be easy to occur as the degree of fluorination increases, which makes the decomposition temperature significantly shift to lower temperature (420 °C for MAC-3 and 250 °C for 4F-MAC-3, Fig. 3a)[43]. From the variable temperature PXRD patterns ofxF-MAC-3, we can find that the structures will keep the crystallinity until 180 °C, which is consistent with the TGA data (Fig. 3b~d). ImmersingxF-MAC-3 into different solvents (e.g. dichloromethane,methanol, acetone, ethyl acetate) for 2 h, PXRD patterns show no significant changes, indicating thatxF-MAC-3 has good solvent stability and the fluorine-functionalized of the ligands doesn’t affect the solvent stability of the MAC-3 structure(Fig. S5).

    3. 4 Gas adsorption properties

    The N2-77 K adsorption isotherms ofxF-MAC-3 reveal the presence of microporous structures in the structures. The BET surfaces are 532 m2g-1(MAC-3), 459 m2g-1(2F-MAC-3) and 579 m2g-1(4F-MAC-3, Fig. 3a), respectively. For the channel ofxF-MAC-3 is occupied by cationic CH3NH3+molecules,the experimental BET surfaces are remarkably lower than the theoretical accessible surfaces calculated by Material Studio(van der Waals radius of the probe molecule: 1.84 ?;calculated supercell: 2 × 2 × 2 supercell)[44]. The void space ofxF-MAC-3 is calculated by PLATON software and the data are listed in Table S2[45]. The pore size distribution ofxF-MAC-3 is calculated by DFT model and the maximum pore sizes ofxF-MAC-3 are 5.52 ? (MAC-3), 5.88 ?(2F-MAC-3) and 5.73 ? (4F-MAC-3, Fig. 4b), respectively.

    Fig. 3. (a) TGA curves; (b) Variable temperature PXRD patterns of xF-MAC-3

    Fig. 4. (a) N2-77K adsorption isotherms; (b) Pore size distribution of xF-MAC-3

    H2and CO2adsorption experiments have been used to understand the relationship between gas adsorption capacity and fluorination degree ofxF-MAC-3. CO2-273 K adsorption experiments ofxF-MAC-3 are carried out under 800 mmHg and the uptake ofxF-MAC-3 amount is 23.21 cm3·g-1(1.04 mmol·g-1, MAC-3), 27.50 cm3·g-1(1.23 mmol·g-1,2F-MAC-3) and 36.13 cm3·g-1(1.61 mmol·g-1, 4F-MAC-3)respectively, which show that CO2uptake amount increases when fluorination degree increases on the carboxylate ligands(Fig. 5a~c).

    Fig. 5. (a) Low-pressure CO2 adsorption isotherm at 258 and 273 K (solid line: adsorption isotherm;hollow line: desorption isotherm); (b) Adsorption heat (Qst) for xF-MAC-3

    To further investigate the effect of fluorination degree on CO2adsorption enthalpy (Qst), we preform 258 K CO2adsorption experiments and the isosteric heat of CO2adsorption is calculated from the Virial method (Fig. S6, Fig.5d~f)[46]. The near-zero coverageQstis 29.0, 27.5 and 26.1 kJ·mol-1for MAC-3, 2F-MAC-3 and 4F-MAC-3, respectively. The result illustrates that the interaction between the hostxF-MAC-3 frameworks and guest CO2molecules adsorption decrease as the degree of fluorination increases,which is caused by the lower electronic density on the benzene ring after using fluorine-functionalized ligands[42].

    H2-77 K adsorption experiment results show that the gas uptake amounts ofxF-MAC-3 increase form 24.33 cm3·g-1(MAC-3) to 59.79 cm3·g-1(4F-MAC-3) at 77 K and 1 atm(Fig. S7). Although the H2uptake amounts ofxF-MAC-3 are significantly lower than some classical electrically neutral frameworks due to the presence of anti-balance cation in the channel of structures, 4F-MAC-3 has the highest H2capacity among the ionic fluorinated-MOFs[31,47]. It is further demonstrated that the structural pore properties and adsorption performance can be tuned by functionalization of ligands in MOF materials.

    4 CONCLUSION

    In conclusion, we synthesized three different fluorination degree MOFs (xF-MAC-3) withpcu-b topology. Our studies revealed that the introduction of fluorine atoms into carboxylate ligands would not only enlarge the torsion angle of ligands but also elevate the space group ofxF-MAC-3,which indicated that fluorination is crucial for MOFs structures. Besides, the CO2and H2adsorption abilities ofxF-MAC-3 have a great enhancement after fluorination, in which the H2-77 K uptake of 4F-MAC-3 (59.79 cm3·g-1) is the highest among all anion fluorinated MOFs. Therefore, we do a systematic research on the effect of fluorination inxF-MAC-3, thus offering a potential way to study the ligand pre-functionalization effect on the structures and properties of MOFs analogues.

    在线天堂中文资源库| 欧美日韩综合久久久久久| 韩国精品一区二区三区| 激情视频va一区二区三区| 国产老妇伦熟女老妇高清| 欧美日韩精品网址| 久久久久国产精品人妻一区二区| 少妇 在线观看| 久久久久久人人人人人| 国产成人系列免费观看| 国产精品麻豆人妻色哟哟久久| 日韩av不卡免费在线播放| 欧美日韩视频精品一区| 国产精品亚洲av一区麻豆| 亚洲国产精品一区三区| 国产在视频线精品| 日本欧美国产在线视频| 老司机深夜福利视频在线观看 | 在线观看免费日韩欧美大片| 精品国产乱码久久久久久男人| 岛国毛片在线播放| 国产免费又黄又爽又色| 久久亚洲精品不卡| av天堂在线播放| 欧美日韩黄片免| 亚洲国产成人一精品久久久| 亚洲伊人色综图| 少妇粗大呻吟视频| 国产高清视频在线播放一区 | 嫩草影视91久久| 日本黄色日本黄色录像| 一区二区av电影网| 一本久久精品| videos熟女内射| 午夜福利免费观看在线| 视频区图区小说| 欧美日韩视频高清一区二区三区二| 亚洲欧美日韩另类电影网站| 人妻 亚洲 视频| 亚洲av日韩在线播放| 少妇人妻久久综合中文| 又黄又粗又硬又大视频| 国产精品久久久av美女十八| 中文字幕另类日韩欧美亚洲嫩草| 国产精品亚洲av一区麻豆| 女人爽到高潮嗷嗷叫在线视频| 老汉色∧v一级毛片| 尾随美女入室| 久久精品亚洲av国产电影网| 久久久久久久精品精品| 老汉色∧v一级毛片| 在线精品无人区一区二区三| 日本午夜av视频| 亚洲av电影在线观看一区二区三区| 一级黄色大片毛片| 一二三四社区在线视频社区8| 超色免费av| 欧美中文综合在线视频| 亚洲成人免费电影在线观看 | 精品高清国产在线一区| 精品亚洲成国产av| 满18在线观看网站| 一级毛片电影观看| 国产无遮挡羞羞视频在线观看| 国产欧美日韩一区二区三 | 观看av在线不卡| 91老司机精品| 美女视频免费永久观看网站| 成人免费观看视频高清| 日韩一卡2卡3卡4卡2021年| 久久国产精品人妻蜜桃| www.熟女人妻精品国产| 亚洲欧洲日产国产| 久久ye,这里只有精品| 看免费av毛片| 亚洲精品日本国产第一区| 热99国产精品久久久久久7| 精品卡一卡二卡四卡免费| 日日夜夜操网爽| 啦啦啦在线免费观看视频4| 免费一级毛片在线播放高清视频 | av视频免费观看在线观看| 久久精品熟女亚洲av麻豆精品| 国产精品国产av在线观看| 蜜桃在线观看..| 黄频高清免费视频| 国产男女内射视频| 久热爱精品视频在线9| 人妻 亚洲 视频| 国产黄色免费在线视频| 久久青草综合色| 777久久人妻少妇嫩草av网站| 日韩欧美一区视频在线观看| 中文欧美无线码| 欧美大码av| 黄网站色视频无遮挡免费观看| 亚洲精品一二三| 只有这里有精品99| 亚洲成人手机| 日韩 欧美 亚洲 中文字幕| 亚洲国产精品一区二区三区在线| 男女高潮啪啪啪动态图| 国产精品国产三级国产专区5o| 高清视频免费观看一区二区| 别揉我奶头~嗯~啊~动态视频 | 日本黄色日本黄色录像| 日本vs欧美在线观看视频| 一本久久精品| 美女午夜性视频免费| 肉色欧美久久久久久久蜜桃| 伦理电影免费视频| 国产成人欧美| 男女之事视频高清在线观看 | 女人被躁到高潮嗷嗷叫费观| 亚洲av电影在线进入| bbb黄色大片| 亚洲欧美一区二区三区久久| 一区二区日韩欧美中文字幕| 观看av在线不卡| 亚洲国产欧美网| 午夜免费成人在线视频| 欧美精品人与动牲交sv欧美| 高潮久久久久久久久久久不卡| 中文字幕亚洲精品专区| 精品免费久久久久久久清纯 | 性高湖久久久久久久久免费观看| 国产精品人妻久久久影院| 黄色视频在线播放观看不卡| 岛国毛片在线播放| av网站在线播放免费| 一边摸一边做爽爽视频免费| 久久女婷五月综合色啪小说| 免费av中文字幕在线| 国产无遮挡羞羞视频在线观看| 成人免费观看视频高清| 多毛熟女@视频| 国产亚洲一区二区精品| 美女脱内裤让男人舔精品视频| 又粗又硬又长又爽又黄的视频| 一级黄色大片毛片| 十八禁网站网址无遮挡| 中文字幕色久视频| 性色av一级| 国产一区二区激情短视频 | 中文字幕精品免费在线观看视频| 一区福利在线观看| 久9热在线精品视频| 热re99久久国产66热| 天天躁狠狠躁夜夜躁狠狠躁| 亚洲美女黄色视频免费看| 中文字幕高清在线视频| 天天影视国产精品| 男人操女人黄网站| 曰老女人黄片| av有码第一页| 夫妻午夜视频| 99久久人妻综合| 大话2 男鬼变身卡| 啦啦啦中文免费视频观看日本| 精品亚洲成国产av| 视频在线观看一区二区三区| 精品国产国语对白av| 国产真人三级小视频在线观看| 日韩一本色道免费dvd| 脱女人内裤的视频| 欧美黑人精品巨大| 久久这里只有精品19| 老司机影院成人| 人妻一区二区av| 国产精品秋霞免费鲁丝片| 老司机亚洲免费影院| 91麻豆精品激情在线观看国产 | 9191精品国产免费久久| 久久精品aⅴ一区二区三区四区| 久久精品亚洲av国产电影网| www日本在线高清视频| 黄片小视频在线播放| 国产国语露脸激情在线看| 99国产精品一区二区三区| 国产91精品成人一区二区三区 | 观看av在线不卡| 老司机深夜福利视频在线观看 | 成人黄色视频免费在线看| 99久久99久久久精品蜜桃| 国产精品香港三级国产av潘金莲 | 无遮挡黄片免费观看| 日韩大码丰满熟妇| 9191精品国产免费久久| 久久毛片免费看一区二区三区| 精品熟女少妇八av免费久了| 免费在线观看视频国产中文字幕亚洲 | 最近手机中文字幕大全| 亚洲精品一二三| 菩萨蛮人人尽说江南好唐韦庄| 亚洲午夜精品一区,二区,三区| 深夜精品福利| 中文精品一卡2卡3卡4更新| 国产无遮挡羞羞视频在线观看| 一级毛片黄色毛片免费观看视频| av国产精品久久久久影院| 天天躁狠狠躁夜夜躁狠狠躁| 18禁黄网站禁片午夜丰满| 亚洲欧美中文字幕日韩二区| 国产精品久久久人人做人人爽| 操出白浆在线播放| 亚洲熟女毛片儿| 久久女婷五月综合色啪小说| 最新在线观看一区二区三区 | 欧美日韩精品网址| 亚洲图色成人| 欧美日本中文国产一区发布| 汤姆久久久久久久影院中文字幕| 亚洲av欧美aⅴ国产| 欧美日韩一级在线毛片| 丰满人妻熟妇乱又伦精品不卡| www.精华液| 亚洲中文日韩欧美视频| 国产亚洲av高清不卡| 精品亚洲成a人片在线观看| 宅男免费午夜| 久久99一区二区三区| 国产欧美日韩综合在线一区二区| 午夜激情久久久久久久| 国产成人a∨麻豆精品| 一级a爱视频在线免费观看| 亚洲av在线观看美女高潮| 国产欧美亚洲国产| 日韩一卡2卡3卡4卡2021年| 欧美性长视频在线观看| 欧美激情极品国产一区二区三区| 精品第一国产精品| 国产主播在线观看一区二区 | 久久久国产欧美日韩av| 久久精品久久久久久噜噜老黄| 水蜜桃什么品种好| 波野结衣二区三区在线| 久久久久久久久免费视频了| 国产精品久久久人人做人人爽| 欧美另类一区| 欧美成人精品欧美一级黄| 中文字幕人妻丝袜制服| 中文字幕av电影在线播放| 晚上一个人看的免费电影| 大陆偷拍与自拍| 国产精品三级大全| 天堂俺去俺来也www色官网| 久久久国产精品麻豆| 精品一区在线观看国产| 日韩精品免费视频一区二区三区| 最新在线观看一区二区三区 | 久久免费观看电影| 欧美 亚洲 国产 日韩一| 91精品三级在线观看| 国产精品人妻久久久影院| 999精品在线视频| cao死你这个sao货| 王馨瑶露胸无遮挡在线观看| 欧美老熟妇乱子伦牲交| 亚洲国产中文字幕在线视频| 午夜福利视频在线观看免费| 亚洲伊人久久精品综合| 好男人电影高清在线观看| 18在线观看网站| 国产精品久久久久成人av| 久久鲁丝午夜福利片| www.精华液| 男女午夜视频在线观看| 国产一区二区在线观看av| 免费看av在线观看网站| 超色免费av| 手机成人av网站| 免费高清在线观看日韩| 黄色毛片三级朝国网站| 欧美老熟妇乱子伦牲交| 久久久久精品国产欧美久久久 | 熟女av电影| 91麻豆av在线| 国产成人系列免费观看| 亚洲av成人精品一二三区| 精品国产超薄肉色丝袜足j| 国产成人精品久久久久久| 91精品伊人久久大香线蕉| 亚洲国产精品999| 又粗又硬又长又爽又黄的视频| av天堂在线播放| 国产熟女午夜一区二区三区| 亚洲精品第二区| 在线看a的网站| 真人做人爱边吃奶动态| av有码第一页| 国产1区2区3区精品| 亚洲精品一二三| 欧美日韩亚洲国产一区二区在线观看 | www.999成人在线观看| 黑人猛操日本美女一级片| 欧美精品高潮呻吟av久久| 精品国产一区二区久久| 三上悠亚av全集在线观看| 在线观看免费日韩欧美大片| 亚洲熟女毛片儿| 亚洲av欧美aⅴ国产| 又黄又粗又硬又大视频| 免费观看人在逋| 精品少妇内射三级| 亚洲中文av在线| 我的亚洲天堂| 亚洲精品美女久久久久99蜜臀 | 精品久久久久久久毛片微露脸 | 99国产精品一区二区三区| 亚洲成色77777| 看免费av毛片| 热99久久久久精品小说推荐| 日本午夜av视频| av国产久精品久网站免费入址| 一个人免费看片子| 在线观看免费日韩欧美大片| 日韩中文字幕欧美一区二区 | 久久久久久久大尺度免费视频| 亚洲av国产av综合av卡| 午夜激情av网站| 男女免费视频国产| 国产片特级美女逼逼视频| 少妇裸体淫交视频免费看高清 | 久久久久国产精品人妻一区二区| 日韩一本色道免费dvd| 五月天丁香电影| 狠狠婷婷综合久久久久久88av| 91精品伊人久久大香线蕉| 亚洲国产日韩一区二区| 久久99热这里只频精品6学生| 国产一卡二卡三卡精品| 精品第一国产精品| 中文字幕人妻丝袜一区二区| 人人澡人人妻人| 欧美老熟妇乱子伦牲交| 久久久久久久久免费视频了| 在线精品无人区一区二区三| 免费在线观看日本一区| 国产淫语在线视频| 国产黄色免费在线视频| 十八禁高潮呻吟视频| 亚洲人成网站在线观看播放| 亚洲人成电影免费在线| 国产免费视频播放在线视频| 国产主播在线观看一区二区 | 曰老女人黄片| 国产一区二区激情短视频 | 精品一区在线观看国产| 天天躁狠狠躁夜夜躁狠狠躁| 免费看十八禁软件| 黄色毛片三级朝国网站| videos熟女内射| 国产欧美亚洲国产| 精品一区二区三区四区五区乱码 | 精品亚洲成a人片在线观看| 大陆偷拍与自拍| 亚洲欧洲国产日韩| 国产精品一区二区精品视频观看| 久久精品人人爽人人爽视色| 国产视频首页在线观看| 亚洲国产毛片av蜜桃av| 一级,二级,三级黄色视频| 亚洲av片天天在线观看| 亚洲国产看品久久| 人人妻人人澡人人看| 手机成人av网站| 亚洲人成77777在线视频| 男女高潮啪啪啪动态图| 亚洲专区中文字幕在线| 黄色视频不卡| 99香蕉大伊视频| 国产在视频线精品| 亚洲精品国产av蜜桃| 五月开心婷婷网| 久久性视频一级片| 久久99热这里只频精品6学生| 久久人人爽人人片av| 一区二区日韩欧美中文字幕| 电影成人av| 午夜激情久久久久久久| 欧美性长视频在线观看| 热99久久久久精品小说推荐| 91国产中文字幕| 亚洲精品久久午夜乱码| 十八禁高潮呻吟视频| 日本午夜av视频| 中文字幕制服av| 狂野欧美激情性xxxx| 黑人巨大精品欧美一区二区蜜桃| 国产麻豆69| 精品亚洲成a人片在线观看| 一本色道久久久久久精品综合| 欧美精品高潮呻吟av久久| 亚洲国产欧美在线一区| 国产午夜精品一二区理论片| 成人18禁高潮啪啪吃奶动态图| 91麻豆精品激情在线观看国产 | 丰满饥渴人妻一区二区三| 久久九九热精品免费| 免费看av在线观看网站| 人人妻人人澡人人看| 亚洲国产精品国产精品| 色综合欧美亚洲国产小说| 午夜免费观看性视频| 久久ye,这里只有精品| 亚洲av美国av| 91精品伊人久久大香线蕉| 亚洲成色77777| 一本久久精品| 一级片免费观看大全| 侵犯人妻中文字幕一二三四区| 免费人妻精品一区二区三区视频| 午夜视频精品福利| 老司机午夜十八禁免费视频| 美女午夜性视频免费| 欧美少妇被猛烈插入视频| 国产又色又爽无遮挡免| 啦啦啦中文免费视频观看日本| 视频区欧美日本亚洲| 美国免费a级毛片| 在线看a的网站| 狂野欧美激情性bbbbbb| 亚洲天堂av无毛| 男人舔女人的私密视频| 可以免费在线观看a视频的电影网站| 久久狼人影院| 9色porny在线观看| 午夜福利免费观看在线| 色婷婷久久久亚洲欧美| 超色免费av| 少妇粗大呻吟视频| 最新在线观看一区二区三区 | 两人在一起打扑克的视频| 天天躁狠狠躁夜夜躁狠狠躁| av一本久久久久| 91精品三级在线观看| 中文字幕高清在线视频| 高清黄色对白视频在线免费看| 久久国产精品影院| 男人操女人黄网站| 男女午夜视频在线观看| svipshipincom国产片| 一本一本久久a久久精品综合妖精| 一区二区三区四区激情视频| 少妇裸体淫交视频免费看高清 | 亚洲精品一区蜜桃| 一边亲一边摸免费视频| 男女床上黄色一级片免费看| 亚洲欧美一区二区三区久久| 亚洲av欧美aⅴ国产| 最近最新中文字幕大全免费视频 | 久9热在线精品视频| 亚洲国产精品国产精品| www.精华液| 高清视频免费观看一区二区| 99九九在线精品视频| 99国产精品一区二区蜜桃av | e午夜精品久久久久久久| 久久狼人影院| 日本av手机在线免费观看| 日韩熟女老妇一区二区性免费视频| 无限看片的www在线观看| 老鸭窝网址在线观看| 免费看av在线观看网站| av片东京热男人的天堂| 国产午夜精品一二区理论片| 啦啦啦视频在线资源免费观看| 一级毛片黄色毛片免费观看视频| 秋霞在线观看毛片| 国产国语露脸激情在线看| 精品人妻1区二区| 国产97色在线日韩免费| 国产亚洲av片在线观看秒播厂| 精品久久久久久电影网| 人人妻,人人澡人人爽秒播 | 亚洲精品日本国产第一区| 在线看a的网站| 在线 av 中文字幕| 天天操日日干夜夜撸| 午夜激情av网站| 亚洲av国产av综合av卡| 一级黄色大片毛片| 最新的欧美精品一区二区| 在线观看www视频免费| 国产精品久久久久久人妻精品电影 | 五月开心婷婷网| 日日摸夜夜添夜夜爱| www.av在线官网国产| 看免费av毛片| 免费在线观看完整版高清| 亚洲欧洲精品一区二区精品久久久| 男人添女人高潮全过程视频| 爱豆传媒免费全集在线观看| 黑人巨大精品欧美一区二区蜜桃| 操出白浆在线播放| 久久久久久人人人人人| 一区在线观看完整版| 一区二区三区激情视频| 丝袜人妻中文字幕| 久久久久国产精品人妻一区二区| 天天躁夜夜躁狠狠久久av| 夜夜骑夜夜射夜夜干| 最近中文字幕2019免费版| av国产久精品久网站免费入址| 五月开心婷婷网| 久久国产亚洲av麻豆专区| 十八禁网站网址无遮挡| 久久久久久久久免费视频了| 久久av网站| 久久久久久久久免费视频了| 午夜福利一区二区在线看| 久久久久精品国产欧美久久久 | 欧美在线一区亚洲| 欧美日韩亚洲高清精品| 高清av免费在线| 精品一品国产午夜福利视频| 久久 成人 亚洲| 欧美精品一区二区大全| 国产欧美日韩一区二区三区在线| 熟女少妇亚洲综合色aaa.| 中文字幕人妻丝袜一区二区| 不卡av一区二区三区| 制服诱惑二区| 国产xxxxx性猛交| 久久99热这里只频精品6学生| 亚洲欧美一区二区三区黑人| 亚洲精品中文字幕在线视频| xxx大片免费视频| 国产欧美日韩精品亚洲av| 热99国产精品久久久久久7| 如日韩欧美国产精品一区二区三区| 极品少妇高潮喷水抽搐| av天堂久久9| 叶爱在线成人免费视频播放| 国产精品一二三区在线看| 桃花免费在线播放| 亚洲成人国产一区在线观看 | 又大又爽又粗| av天堂在线播放| 青春草亚洲视频在线观看| 丝袜美腿诱惑在线| 韩国高清视频一区二区三区| 爱豆传媒免费全集在线观看| 精品人妻熟女毛片av久久网站| 亚洲成人手机| 亚洲欧美精品自产自拍| 狂野欧美激情性bbbbbb| 韩国高清视频一区二区三区| 亚洲av日韩在线播放| 国产精品免费视频内射| 久9热在线精品视频| 国产野战对白在线观看| 99久久人妻综合| 亚洲欧美精品自产自拍| 一级黄片播放器| 别揉我奶头~嗯~啊~动态视频 | 成人影院久久| 波多野结衣av一区二区av| 亚洲av男天堂| 91麻豆精品激情在线观看国产 | 操美女的视频在线观看| 日本91视频免费播放| 日韩av免费高清视频| 80岁老熟妇乱子伦牲交| 91老司机精品| 亚洲av日韩精品久久久久久密 | 久久精品熟女亚洲av麻豆精品| 久久久久精品国产欧美久久久 | 国产免费又黄又爽又色| 欧美少妇被猛烈插入视频| 欧美人与善性xxx| 高清不卡的av网站| 中文字幕人妻丝袜制服| 9热在线视频观看99| 欧美亚洲 丝袜 人妻 在线| 欧美成人精品欧美一级黄| 日韩一卡2卡3卡4卡2021年| 新久久久久国产一级毛片| 久久影院123| 亚洲欧美一区二区三区黑人| 18禁观看日本| 欧美大码av| 亚洲欧美一区二区三区黑人| 18禁观看日本| 欧美大码av| 亚洲av日韩在线播放| 伊人久久大香线蕉亚洲五| 在线观看国产h片| 国产免费福利视频在线观看| 999精品在线视频| 多毛熟女@视频| 国产熟女欧美一区二区| 欧美 日韩 精品 国产| www.熟女人妻精品国产| 中文字幕人妻丝袜制服| 午夜精品国产一区二区电影| 国产精品一区二区在线不卡| 在线看a的网站| av线在线观看网站| 精品一区二区三区av网在线观看 | av视频免费观看在线观看| 一本综合久久免费| 欧美人与性动交α欧美精品济南到| h视频一区二区三区| 国产av国产精品国产| 狠狠婷婷综合久久久久久88av| 亚洲精品成人av观看孕妇| 精品一区二区三区四区五区乱码 | 男女高潮啪啪啪动态图| 肉色欧美久久久久久久蜜桃| 亚洲专区中文字幕在线| 两个人看的免费小视频| 天天操日日干夜夜撸| 国产亚洲精品第一综合不卡| 啦啦啦在线免费观看视频4|