• <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 ?

    重氮苯與不同親核試劑結(jié)合選擇性:共價(jià)與非共價(jià)作用分析

    2021-07-11 16:25:48王高博
    關(guān)鍵詞:親核共價(jià)化工學(xué)院

    王高博,馬 晶

    (南京大學(xué)化學(xué)化工學(xué)院,介觀化學(xué)教育部重點(diǎn)實(shí)驗(yàn)室,南京210023)

    1 Introduction

    The reaction between diazobenzene and various nucleophiles[Fig.1(A)],one of the important organic synthesis methods,has a history of more than a century.For example,this kind of reaction was applied in the preparation of fluorine-containing aromatic compounds,which occupies a large proportion in medicines and agrochemicals.However,the mechanism of such an important reaction,especially the binding selectivity of nucleophiles,has not been fully elucidated.

    Fig.1 Schematic illustration of the reaction between diazobenzene and various nucleophiles(A),the proposal of cis and trans preference(B)and different binding modes(C)

    From the middle of the last century to the 1980s,American chemist Swainet al.[1]and German chemist Zollinger[2,3]have made important contributions to the study of the mechanism of this reaction.An effective method of introducing F atoms into aromatic rings is the Balz-Schiemann reaction,in which N2is proposed to first leave as a leaving group.In the 1970s,Swainet al.[1]found that the first-order rate constant for the dediazoniation reaction changed less than 2%when the solvent changes from 80%to 105%H2SO4,where the concentration of nucleophiles drops rapidly.The 105%H2SO4means that 5%mole fraction sulfur trioxide is dissolved in pure sulfuric acid[2].That means nucleophiles is not involved in the formation of the transition state,and the rate-determining step is simply a dissociation process.However,the conclusion drawn from tetrafluoroborate diazobenzenes by Swainet al.[1]might not be general for a broad scope of reactions.

    Zollinger[2,3]found that the binding sites of different nucleophiles with diazobenzene were different from each other.This phenomenon was ascribed mainly to kinetic factors.Zollinger proposed that when a transition state was“reactant-like”(e.g.,with OH-,),it tended to form acis-azo-isomer,and when a transition state was“product-like”(e.g.,with PhO-),atrans-isomer was preferred,as shown in Fig.1(B).Such a speculation is explanatory rather than predictive for reactions involving unknown reagents.Note that,as will be mentioned hereafter,the“binding”is just the process of combining diazobenzene and nucleophile,rather than a nucleophilic substitution reaction.

    In this work,we use density functional theory(DFT)to study the electronic structures of complexes of six nucleophilic reagents(Cl-,OH-,CN-,SCN-,BF4-and MeO-)anchoring at three different binding sites in aqueous solution[Fig.1(C)].The conceptual density functional theory(CDFT)[5—7]is used to locate the possible binding sites.The CDFT has also been used in the quantitative description of nucleophilicity,electrophilicity and acid-base strength[8].Based on some qualitative analysis methods,such as average local ionization energy(ALIE),we proposed a descriptor,calledSTC,to predict the activation energy of the reactions.The insight gained in this work will be helpful to find better conditions for the important reaction in organic synthesis.

    2 Computational Details

    All calculations were carried out with the Gaussian 16 software package[9].Geometry optimization and frequency analysis were carried outviaDFT calculations with theoretical level of M06-2X[10]/Def2-TZVP[11].The implicit solvation model SMD[12]was used to model the solvent effect of aqueous solution.In addition,the Hirshfeld population analysis[13],electrostatics surface potential(ESP),ALIE analysis[14]and reduced density gradient(RDG)analysis[15]were performed with Multiwfn software[16]to establish the correlation between the electronic structure properties and the reactivity and selectivity of reactions.The visual molecular dynamics(VMD)[17]code was used for visualization of electron distributions of reactants.

    3 Results and Discussion

    The reaction process has two steps.The reaction is initiated from the approaching of nucleophile to diazobenzene substrate,in which step the covalent bond is not formed yet.As shown from ESP of diazobenzene[Fig.2(A)],the non-covalent interaction between two reactants is mainly dominated by electrostatic interaction.We did not plot the ESP surface of the nucleophiles because the volume of the nucleophiles is relatively small,and the negatively charged atoms are very clear.In the subsequent step,the chemical bond formation is occurred.We will present the detailed analysis of electronic structures of reactive species to understand the role of non-covalent and covalent interactions played in the modulation of reactivity.

    Fig.2 ESP fitting surface(BWR colored,midpoint=0.77)(A)and atomic serial numbers(B)of diazobenzene

    Since diazobenzene is a cation,the ESP is positive and difficult to be illustrated with normal color scheme,which will give a picture in dark blue.Thus,the ESP shown in Fig.2 is BWR colored with the selected Midpoint of 0.77,rather than 0.It can be seen from Fig.2 that the specific electrostatic region is lying around the diazo group.DFT calculations were widely used to evaluate qualitative chemical concepts such as chemical softness,S(which is the reciprocal of hardness,η).For the studied diazobenzene,an N-electron system,softness,S,is denoted as the reciprocal of a difference between ionization potential[obtained from the(N-1)-electron system]and electron affinity[from(N+1)-electron system].The local chemical softness of each atom of diazobenzene was also calculated,as shown in Table 1.The reduced Fukui function was then calculated with Hirshfeld charges of N-,(N-1)-,and(N+1)-electron systems.

    It can be seen from Table 1 that the terminal N atom(called N13 in Fig.2)is the most favorable site for nucleophilic attack,followed by its neighboring N atom(i.e.,N12).The C2 linked to diazo group was not a favorable site for attack,which also implied that the pathway of forming a transition state through nucleophilic attack on C2 is unlikely to take place.

    Table 1 Hirshfeld charges(q),global softness(S),and local softness for electrophilic(s-)and nucleophilic(s+)reactions for diazobenzene

    It is recognized that reagents with high chemical hardness(or in other word,low softness)is not prone to occur the charge transfer reaction,but tends to form ionic bond with reagents with also high chemical hardness.To the other end,reagents with small chemical hardness tend to form covalent bonds with the reagents with also small chemical hardness.As shown in Fig.3,“hard”nucleophiles,such as BF4-(η=0.420)and Cl-(η=0.635)are more likely to be bound in the“Max-potential ring”of diazobenzene through electrostatic interactions;while“soft”nucleophiles as OH-(η=0.232),CN-(η=0.303)and MeO-(η=0.222)are prone to form covalent bonds with N13 atom to form azo structures intrans-orcis-configuration.The configurationsshown in Fig.3(A)and(B)are global minima.Some local minima were also located.For example,the configuration withbinding at edge side is 7942 J/mol higher than that on the top site in Fig.3(A).To further gain more information of the nature of non-covalent interaction,we took DFT-D3 dispersion correction into account.Forsitting in top side,the correction energy is only about 1672 J/mol.

    Fig.3 Binding modes of diazobenzene with five different nucleophiles

    It should be pointed out that tetrafluoroborate cannot attack C2 directly,but hover over the“Max-potential ring”.Then we want to know how the presence of tetrafluoroborate affects the dissociation process of diazobenzene.We carried out the reduced density gradient,reduced density gradient(RDG),analysis for tetrafluoroborate diazobenzene and get the scatter and isosurface diagram,shown in Fig.4.

    As shown in Fig.4,one of the three fluorine atoms,which is in proximity to the benzene ring plane,has a strong electrostatics attraction with C2 atom,and the other two fluorine atoms are attractive to N12 atom.During the dissociation of diazobenzene,the positive charge was gradually concentrated on C2 atom,so the interaction between C2 and fluorine atoms was gradually strengthened,which significantly reduce the dissociation energy.At the same time,after the coplanarity of nitrogen molecule and benzene ring was destroyed,the N12—N13 bond was polarized by fluorine atoms,and was pulled to the direction of tetrafluoroborate(Fig.5).

    Fig.4 RDG scatter and isosurface plot of diazobenzene tetrafluoroborate

    Fig.5 Decomposition process of diazobenzene with the help of tetrafluoroborate

    On the other hand,for covalent binding,when nucleophilic reagents form covalent chemical bonds with N13 atom,there are two possible configurations,cis-ortrans-isomers.Zollinger has proposed that nucleophilic reagents experiencing the mechanism of“reactant-like transition state”tend to generatecis-isomers,while“product-like transition state”prefer to generate trans-isomers.In order to test the applicability of this hypothesis and specifically investigate the factors that determine the mechanism,we first calculated the intrinsic reaction coordinate curves of the formation ofcis-andtrans-isomers with cyanide ions and thiocyanate with sulfur and nitrogen atoms as attacking atoms,respectively.It was found that the attack of sulfur atom is difficult to formcis-isomers,which is different from the other five sets of nucleophilic reagents(Fig.6).

    Fig.6 Intrinsic reaction coordinate plots of the reactions for CN-(A)and SCN-attacking(called ATK in short,B)diazobenzene

    The relative energy ofcis-product is higher than that oftrans-one,so thecis-product is thermodynamically less stable than thetrans-product.However,the formation of transition state along thecis-path is much easier with lower activation energy,in agreement with Zollinger’s hypothesis.There is one exception.In the case of attacking of thiocyanate with N atom,the resultant transition state is much close to the product-like transition state,but the activation energy for reaching thecis-transition state is still lower than that for thetrans-transition state.This is probably because that the volume of sulfur atoms is too large,so the steric hindrance is large.However,it also can be seen that sulfur atom is obviously more favorable as attacking atom than nitrogen atom for a trans-path,which cannot be explained by the factor of steric hindrance.A detailed analysis is given as follows.

    When acis-transition state is formed,due to the steric effect,the coplanarity of diazo structure and benzene ring will be destroyed.For example,when thiocyanate attacks with nitrogen atoms,the dihedral angle between diazo plane and benzene ring plane is 47.4°in transition state,and the conjugation is weakened to a considerable extent(Fig.7).From this perspective,the formation ofcis-transition state is thermodynamically unfavorable.However,there are many examples that nucleophilic reagents are indeed more inclined to form acis-transition state with diazobenzene.This means that some other energetically favorable factors could offset the energy increase caused by conjugation destruction.

    Fig.7 RDG isosurface of the transition state attacked by thiocyanate with nitrogen atom

    We note that the nucleophilic reagent prefers to the formation ofcis-transition state which often has an attacking atom with high chemical hardness.Accor-ding to hard and soft acid and base(HSAB)theory,the energy lowering may originate from non-covalent interactions,that is,the ortho-hydrogen of the benzene ring may form a hydrogen bond with the attacking atom.We analyze the transition state of thiocyanate attacked by nitrogen atoms with RDG method.As shown in Fig.7,there is indeed an obvious attractive interaction(displayed in green color)between nitrogen atoms and the ortho-hydrogen atom,leading to the formation ofcis-product.

    Finally,it is meaningful to correlate the activation energy barrier of nucleophilic attack with a descriptor.Taking the molecular volume or diameter to describe the steric hindrance effect,we calculated the minimum distance,lmin,and maximum distance,lmax,between the nucleophilic reagent binding sites and van der Waals surface.Then based on average local ionization energy,ALIE,we proposed a descriptor of trans-path,ST,as follows:

    Forcis-path,we define theSCdescriptor:

    The above two descriptors,STandSC,are combined into one parameter.The descriptor,STC,is defined asSTC=min{ST,SC}.In other words,ifST>SC,acis-path would be preferred,thenSTC=SC.STCis a good descriptor that can be used to predict the energy barrier of the reactions between nucleophilic reagents and diazobenzene(Fig.8 and Table S1,see the Electronic Supplementary Material of this paper).A good correlation between the activation energy barrier,ΔE,andSTCdescriptor is obtained.

    Note that in fact in Fig.8,STandSC(or cis and trans path)are clustered into two different data groups.The detailed information of nucleophiles and reaction paths are shown in Table S1.

    Fig.8 Relationship between the activation energy barrier,ΔE,and S TC(Pearson’s r=0.99413)

    4 Conclusions

    In this work,we predicted the binding positions of different nucleophiles on diazobenzene with ESP fitting and local chemical hardness calculation.The role of tetrafluoroborate in the dissociation of diazobenzene is revealed.We also found that the‘reactant/product-like transition state’hypothesis cannot always give correct predictions on the spatial selectivity,and thecis-path was mainly dominated by noncovalent interaction.Consequently,we proposed a descriptor,STC,to predict the activation energy barriers.Our results provide useful information for elucidating the reaction mechanism involving aromatic diazonium salts.

    The supporting information of this paper see http://www.cjcu.jlu.edu.cn/CN/10.7503/cjcu20210237.

    This paper is supported by the National Natural Science Foundation of China(Nos.21873045,22033004).

    猜你喜歡
    親核共價(jià)化工學(xué)院
    使固態(tài)化學(xué)反應(yīng)100%完成的方法
    有機(jī)化學(xué)微課設(shè)計(jì)思路探討——以雙分子親核取代反應(yīng)為例
    云南化工(2021年9期)2021-12-21 07:44:20
    國家開放大學(xué)石油和化工學(xué)院學(xué)習(xí)中心列表
    基于酞菁的共價(jià)-有機(jī)聚合物的制備及在比色傳感領(lǐng)域的研究
    【鏈接】國家開放大學(xué)石油和化工學(xué)院學(xué)習(xí)中心(第四批)名單
    犧牲鍵對可逆共價(jià)自修復(fù)材料性能的影響
    《化工學(xué)報(bào)》贊助單位
    非共價(jià)作用對氣相中B-DNA雙螺旋結(jié)構(gòu)穩(wěn)定性的貢獻(xiàn):基于GEBF方法的密度泛函理論計(jì)算
    A 3-fold Interpenetrated lvt Cd(II) Network Constructed from 4-[(3-pyridyl)methylamino]benzoate Acid①
    有關(guān)親核取代反應(yīng)和β—消去反應(yīng)的教學(xué)思考
    麻豆精品久久久久久蜜桃| 国产综合精华液| 成人毛片60女人毛片免费| 天堂中文最新版在线下载| 老司机影院毛片| 欧美黄色片欧美黄色片| 亚洲精品美女久久av网站| 国产午夜精品一二区理论片| 精品少妇一区二区三区视频日本电影 | 又黄又粗又硬又大视频| 国产亚洲一区二区精品| 一区二区日韩欧美中文字幕| 美女大奶头黄色视频| 成人国语在线视频| 免费在线观看视频国产中文字幕亚洲 | 中文天堂在线官网| 国产精品免费大片| 欧美日韩av久久| 亚洲欧美色中文字幕在线| 国产男女超爽视频在线观看| 日韩不卡一区二区三区视频在线| 国产成人免费无遮挡视频| 亚洲精品在线美女| 1024香蕉在线观看| 香蕉国产在线看| 久久午夜综合久久蜜桃| 热re99久久精品国产66热6| 欧美变态另类bdsm刘玥| 亚洲激情五月婷婷啪啪| 成人漫画全彩无遮挡| 少妇 在线观看| 久久狼人影院| 国产福利在线免费观看视频| 久久久国产一区二区| 欧美国产精品va在线观看不卡| 老女人水多毛片| 90打野战视频偷拍视频| 日韩制服骚丝袜av| 男男h啪啪无遮挡| 看非洲黑人一级黄片| 亚洲一级一片aⅴ在线观看| 嫩草影院入口| 日本91视频免费播放| 国产白丝娇喘喷水9色精品| 日本色播在线视频| 在线观看免费高清a一片| 久久久久久人人人人人| 欧美精品高潮呻吟av久久| 黑人巨大精品欧美一区二区蜜桃| 国产成人欧美| 国产精品久久久久久精品古装| 777久久人妻少妇嫩草av网站| 一二三四中文在线观看免费高清| 两个人看的免费小视频| 日韩成人av中文字幕在线观看| videossex国产| 最近2019中文字幕mv第一页| 亚洲av综合色区一区| 丝袜喷水一区| 在线看a的网站| 精品午夜福利在线看| 99久久精品国产国产毛片| 91成人精品电影| 久久久久久久久久人人人人人人| 26uuu在线亚洲综合色| 免费观看无遮挡的男女| 亚洲精品一区蜜桃| 精品国产一区二区三区久久久樱花| 少妇人妻 视频| 色播在线永久视频| 女的被弄到高潮叫床怎么办| 一区二区三区激情视频| 视频在线观看一区二区三区| 欧美日韩一区二区视频在线观看视频在线| 母亲3免费完整高清在线观看 | 桃花免费在线播放| 久久ye,这里只有精品| 精品少妇内射三级| 日日啪夜夜爽| 一级毛片黄色毛片免费观看视频| 亚洲国产欧美在线一区| 久久久久网色| 天美传媒精品一区二区| 一边摸一边做爽爽视频免费| 国产毛片在线视频| 欧美日韩成人在线一区二区| 校园人妻丝袜中文字幕| av在线app专区| 国产精品av久久久久免费| 久久久久视频综合| 久久午夜福利片| 美国免费a级毛片| 叶爱在线成人免费视频播放| 欧美日韩综合久久久久久| 男女啪啪激烈高潮av片| 日韩不卡一区二区三区视频在线| www.熟女人妻精品国产| 婷婷色综合www| 久久久a久久爽久久v久久| 永久网站在线| 久久久久人妻精品一区果冻| 超碰成人久久| 成人国语在线视频| 国产高清不卡午夜福利| 欧美日韩综合久久久久久| 男女下面插进去视频免费观看| av在线观看视频网站免费| 在线天堂最新版资源| 你懂的网址亚洲精品在线观看| 成人毛片a级毛片在线播放| 日韩中字成人| 久久久国产一区二区| 亚洲国产最新在线播放| 黑人巨大精品欧美一区二区蜜桃| 午夜福利在线观看免费完整高清在| 欧美精品国产亚洲| 国产亚洲一区二区精品| 人体艺术视频欧美日本| 亚洲精品国产色婷婷电影| 在线观看www视频免费| 亚洲精品美女久久av网站| 亚洲国产av影院在线观看| 春色校园在线视频观看| 人妻一区二区av| 男人操女人黄网站| 色播在线永久视频| 国产免费又黄又爽又色| 国产精品一国产av| 又黄又粗又硬又大视频| 亚洲人成网站在线观看播放| 国产极品粉嫩免费观看在线| 五月天丁香电影| 久热这里只有精品99| 丝袜人妻中文字幕| videossex国产| 纯流量卡能插随身wifi吗| 欧美变态另类bdsm刘玥| 欧美日韩一级在线毛片| 中文乱码字字幕精品一区二区三区| 国产av一区二区精品久久| 91国产中文字幕| 国产1区2区3区精品| 自线自在国产av| 日本-黄色视频高清免费观看| 欧美中文综合在线视频| 中文字幕亚洲精品专区| 满18在线观看网站| 青青草视频在线视频观看| 男人舔女人的私密视频| 男女下面插进去视频免费观看| 国产高清国产精品国产三级| 丝袜在线中文字幕| 久久99一区二区三区| 国产亚洲最大av| 国产精品蜜桃在线观看| 男女下面插进去视频免费观看| 青春草亚洲视频在线观看| 黄色 视频免费看| 色网站视频免费| 国产精品 欧美亚洲| 亚洲精品中文字幕在线视频| 国产成人精品久久二区二区91 | 啦啦啦在线观看免费高清www| 日韩一区二区三区影片| 国产熟女欧美一区二区| 久久人人爽av亚洲精品天堂| 电影成人av| 亚洲av成人精品一二三区| 2021少妇久久久久久久久久久| 18+在线观看网站| 欧美日韩一级在线毛片| 最近的中文字幕免费完整| 成人午夜精彩视频在线观看| 国产福利在线免费观看视频| 哪个播放器可以免费观看大片| 日韩中文字幕视频在线看片| 精品少妇久久久久久888优播| 亚洲四区av| 国产精品国产三级国产专区5o| 国产精品久久久av美女十八| 成年人免费黄色播放视频| 日本vs欧美在线观看视频| 欧美日韩av久久| 久久久久国产网址| 97在线视频观看| 欧美日韩亚洲高清精品| 天天躁夜夜躁狠狠久久av| 日本av手机在线免费观看| 老女人水多毛片| 欧美日韩成人在线一区二区| 五月天丁香电影| 久久久久精品人妻al黑| 97在线视频观看| 久久久久久人妻| 母亲3免费完整高清在线观看 | 亚洲人成网站在线观看播放| 中国三级夫妇交换| 亚洲一区中文字幕在线| 精品亚洲乱码少妇综合久久| 欧美少妇被猛烈插入视频| 一级毛片我不卡| 亚洲国产精品国产精品| 叶爱在线成人免费视频播放| 亚洲成国产人片在线观看| 一本久久精品| 久久久国产欧美日韩av| 久久精品国产亚洲av高清一级| 18在线观看网站| 美女国产视频在线观看| 午夜免费鲁丝| 麻豆精品久久久久久蜜桃| 天堂俺去俺来也www色官网| 国产精品久久久av美女十八| 肉色欧美久久久久久久蜜桃| 免费观看性生交大片5| 丝袜喷水一区| 欧美精品人与动牲交sv欧美| 日韩伦理黄色片| 午夜福利,免费看| 欧美xxⅹ黑人| 七月丁香在线播放| 国语对白做爰xxxⅹ性视频网站| 高清在线视频一区二区三区| 看十八女毛片水多多多| 亚洲国产av新网站| 丰满少妇做爰视频| 另类亚洲欧美激情| 一本—道久久a久久精品蜜桃钙片| 麻豆精品久久久久久蜜桃| 国产有黄有色有爽视频| 男女边吃奶边做爰视频| 欧美日韩视频高清一区二区三区二| 91国产中文字幕| 中文字幕色久视频| 亚洲,一卡二卡三卡| 韩国高清视频一区二区三区| 国产成人精品一,二区| 在线精品无人区一区二区三| 一级片免费观看大全| 欧美日韩亚洲国产一区二区在线观看 | 欧美中文综合在线视频| 女人高潮潮喷娇喘18禁视频| 美女主播在线视频| 亚洲欧美精品综合一区二区三区 | 天堂8中文在线网| av在线老鸭窝| 日本色播在线视频| 麻豆精品久久久久久蜜桃| 天堂中文最新版在线下载| 日本爱情动作片www.在线观看| 一区福利在线观看| 久久久久国产一级毛片高清牌| 亚洲av综合色区一区| 精品福利永久在线观看| av电影中文网址| 亚洲精品美女久久av网站| 多毛熟女@视频| 国产亚洲精品第一综合不卡| 国产极品粉嫩免费观看在线| 黄网站色视频无遮挡免费观看| 国产免费福利视频在线观看| 亚洲精品国产av成人精品| 精品人妻熟女毛片av久久网站| 夫妻午夜视频| 天天躁狠狠躁夜夜躁狠狠躁| 久久这里只有精品19| 秋霞在线观看毛片| 国产精品 国内视频| 王馨瑶露胸无遮挡在线观看| 亚洲在久久综合| 免费av中文字幕在线| 日日啪夜夜爽| 一区二区av电影网| 三级国产精品片| 久久人妻熟女aⅴ| 久久韩国三级中文字幕| 国产在线免费精品| 亚洲 欧美一区二区三区| 少妇的逼水好多| 国产精品人妻久久久影院| 狠狠精品人妻久久久久久综合| 18在线观看网站| 亚洲精品日本国产第一区| av有码第一页| 欧美少妇被猛烈插入视频| 国产日韩欧美亚洲二区| 日本wwww免费看| 欧美精品亚洲一区二区| 久久人妻熟女aⅴ| 99久久综合免费| 尾随美女入室| 久久午夜综合久久蜜桃| 赤兔流量卡办理| 久久久久久伊人网av| 国产精品蜜桃在线观看| 精品人妻偷拍中文字幕| 日日爽夜夜爽网站| 老司机影院成人| 精品第一国产精品| 欧美日韩精品网址| 91精品三级在线观看| 免费人妻精品一区二区三区视频| 欧美日韩视频高清一区二区三区二| 亚洲精品中文字幕在线视频| 成年人免费黄色播放视频| 国产精品二区激情视频| 成年女人在线观看亚洲视频| 欧美日韩一区二区视频在线观看视频在线| 菩萨蛮人人尽说江南好唐韦庄| 丝袜美足系列| 天堂俺去俺来也www色官网| 国产午夜精品一二区理论片| 69精品国产乱码久久久| 黑丝袜美女国产一区| 欧美日韩视频精品一区| 亚洲欧美一区二区三区久久| 成年女人在线观看亚洲视频| 亚洲熟女精品中文字幕| 国产在视频线精品| 精品国产露脸久久av麻豆| 中文字幕av电影在线播放| 伦精品一区二区三区| 国产人伦9x9x在线观看 | 免费不卡的大黄色大毛片视频在线观看| 成年av动漫网址| av免费观看日本| 黄网站色视频无遮挡免费观看| 欧美精品一区二区大全| 国产片特级美女逼逼视频| 丝袜美腿诱惑在线| 人妻人人澡人人爽人人| av.在线天堂| 天天躁日日躁夜夜躁夜夜| 人人妻人人澡人人爽人人夜夜| 久久精品久久精品一区二区三区| 九草在线视频观看| 日日爽夜夜爽网站| 深夜精品福利| 青春草亚洲视频在线观看| 另类亚洲欧美激情| 日韩不卡一区二区三区视频在线| 欧美精品亚洲一区二区| tube8黄色片| 天天躁狠狠躁夜夜躁狠狠躁| 寂寞人妻少妇视频99o| 在线观看国产h片| 久久久久久久大尺度免费视频| 亚洲国产精品一区二区三区在线| 国产一区二区 视频在线| 九九爱精品视频在线观看| 纵有疾风起免费观看全集完整版| 我的亚洲天堂| 久久精品国产a三级三级三级| 18在线观看网站| a 毛片基地| 欧美精品人与动牲交sv欧美| 少妇 在线观看| 亚洲精品视频女| 午夜激情av网站| 寂寞人妻少妇视频99o| 一本大道久久a久久精品| 亚洲,欧美,日韩| 亚洲色图 男人天堂 中文字幕| 午夜av观看不卡| 日日摸夜夜添夜夜爱| 精品国产一区二区三区四区第35| 亚洲熟女精品中文字幕| 亚洲一区中文字幕在线| 岛国毛片在线播放| 中文精品一卡2卡3卡4更新| 丝袜在线中文字幕| 中文天堂在线官网| 毛片一级片免费看久久久久| 精品视频人人做人人爽| 又大又黄又爽视频免费| 韩国高清视频一区二区三区| 永久免费av网站大全| 9191精品国产免费久久| 免费在线观看完整版高清| 亚洲成国产人片在线观看| 另类精品久久| 中文字幕另类日韩欧美亚洲嫩草| 亚洲综合精品二区| 满18在线观看网站| 少妇人妻精品综合一区二区| 欧美精品一区二区免费开放| 亚洲精品国产av蜜桃| 99香蕉大伊视频| 国产精品蜜桃在线观看| 日韩一卡2卡3卡4卡2021年| 精品人妻一区二区三区麻豆| 大码成人一级视频| 秋霞伦理黄片| 久久午夜综合久久蜜桃| 少妇被粗大的猛进出69影院| 在线观看美女被高潮喷水网站| 不卡视频在线观看欧美| 亚洲国产欧美网| 丝袜美腿诱惑在线| 亚洲国产精品成人久久小说| freevideosex欧美| 建设人人有责人人尽责人人享有的| 青草久久国产| 18禁动态无遮挡网站| 亚洲欧洲国产日韩| videos熟女内射| 亚洲国产av影院在线观看| 日日啪夜夜爽| 大片电影免费在线观看免费| 宅男免费午夜| 日韩成人av中文字幕在线观看| 欧美激情极品国产一区二区三区| 丰满少妇做爰视频| 人成视频在线观看免费观看| 韩国高清视频一区二区三区| 人人妻人人澡人人看| 久久精品国产a三级三级三级| 成人国产av品久久久| 国产精品香港三级国产av潘金莲 | 亚洲欧美一区二区三区久久| 久久毛片免费看一区二区三区| 亚洲第一区二区三区不卡| 在线观看三级黄色| 亚洲av综合色区一区| 人成视频在线观看免费观看| 亚洲国产欧美网| 深夜精品福利| 国产精品 欧美亚洲| 日本91视频免费播放| 日韩中字成人| 国产精品嫩草影院av在线观看| 亚洲精品aⅴ在线观看| 九色亚洲精品在线播放| 亚洲熟女精品中文字幕| 97在线人人人人妻| 国产精品免费大片| 国产成人一区二区在线| 热re99久久国产66热| 中文字幕人妻丝袜制服| 少妇 在线观看| 亚洲熟女精品中文字幕| 新久久久久国产一级毛片| 国产成人精品婷婷| 人妻一区二区av| 一二三四中文在线观看免费高清| 久久人妻熟女aⅴ| 国产黄色视频一区二区在线观看| 成人手机av| 久久久久久免费高清国产稀缺| 免费在线观看黄色视频的| 精品亚洲成国产av| 丰满乱子伦码专区| 日韩,欧美,国产一区二区三区| 精品少妇内射三级| 午夜福利网站1000一区二区三区| 婷婷色av中文字幕| 少妇被粗大猛烈的视频| 欧美精品高潮呻吟av久久| 欧美国产精品一级二级三级| 亚洲久久久国产精品| 丝袜美足系列| 成人毛片a级毛片在线播放| 国产精品国产三级国产专区5o| av福利片在线| av在线老鸭窝| 久久久久人妻精品一区果冻| 国产白丝娇喘喷水9色精品| 2021少妇久久久久久久久久久| 久久免费观看电影| 亚洲国产成人一精品久久久| 精品久久蜜臀av无| 国产毛片在线视频| 咕卡用的链子| 午夜日本视频在线| 免费黄网站久久成人精品| av又黄又爽大尺度在线免费看| 成人午夜精彩视频在线观看| 中文字幕av电影在线播放| 免费女性裸体啪啪无遮挡网站| 97精品久久久久久久久久精品| 婷婷色综合大香蕉| 天天影视国产精品| 黄片播放在线免费| 黑丝袜美女国产一区| a 毛片基地| 一区在线观看完整版| 91成人精品电影| 男女国产视频网站| 90打野战视频偷拍视频| 欧美精品亚洲一区二区| 26uuu在线亚洲综合色| 国产又爽黄色视频| 青青草视频在线视频观看| 免费高清在线观看日韩| 欧美日韩av久久| 日本午夜av视频| 少妇精品久久久久久久| 两个人看的免费小视频| 老司机影院毛片| 欧美精品亚洲一区二区| 国产极品粉嫩免费观看在线| 成年动漫av网址| 久久精品久久精品一区二区三区| 制服丝袜香蕉在线| 精品国产超薄肉色丝袜足j| 美女国产视频在线观看| 18+在线观看网站| 大片免费播放器 马上看| 伊人亚洲综合成人网| 女的被弄到高潮叫床怎么办| 一级片'在线观看视频| 精品少妇黑人巨大在线播放| 99久国产av精品国产电影| 国产精品成人在线| 久久久国产欧美日韩av| 亚洲情色 制服丝袜| 丝袜美腿诱惑在线| 国产亚洲一区二区精品| 日韩大片免费观看网站| 人人妻人人爽人人添夜夜欢视频| 婷婷色综合www| 日产精品乱码卡一卡2卡三| 久久久久久人妻| 国产精品三级大全| 成人亚洲精品一区在线观看| 国产片特级美女逼逼视频| 看免费成人av毛片| av一本久久久久| 97在线人人人人妻| 精品国产超薄肉色丝袜足j| 亚洲av欧美aⅴ国产| 五月天丁香电影| 大话2 男鬼变身卡| 我要看黄色一级片免费的| 90打野战视频偷拍视频| av国产久精品久网站免费入址| 久久女婷五月综合色啪小说| 一级毛片我不卡| 欧美xxⅹ黑人| a 毛片基地| freevideosex欧美| 国产亚洲一区二区精品| 国产成人91sexporn| 18禁国产床啪视频网站| 国语对白做爰xxxⅹ性视频网站| 只有这里有精品99| 老女人水多毛片| 人人妻人人添人人爽欧美一区卜| 欧美xxⅹ黑人| 国产欧美日韩一区二区三区在线| 麻豆乱淫一区二区| 亚洲国产av新网站| 熟女av电影| 国产在视频线精品| 亚洲熟女精品中文字幕| 国产精品香港三级国产av潘金莲 | 欧美xxⅹ黑人| av国产精品久久久久影院| 免费看av在线观看网站| 亚洲人成电影观看| 最近2019中文字幕mv第一页| 2022亚洲国产成人精品| 熟妇人妻不卡中文字幕| 成年女人毛片免费观看观看9 | 欧美黄色片欧美黄色片| 制服人妻中文乱码| 日韩熟女老妇一区二区性免费视频| 国产精品嫩草影院av在线观看| 亚洲激情五月婷婷啪啪| 免费看av在线观看网站| 精品久久久久久电影网| 精品国产超薄肉色丝袜足j| 少妇人妻 视频| 国产成人精品一,二区| av天堂久久9| 大香蕉久久网| 亚洲,一卡二卡三卡| 国产免费福利视频在线观看| 国产日韩欧美视频二区| 国产一区二区在线观看av| 精品一品国产午夜福利视频| 久久人人爽av亚洲精品天堂| 看十八女毛片水多多多| 亚洲国产色片| 亚洲美女黄色视频免费看| 精品人妻一区二区三区麻豆| 精品一区在线观看国产| 欧美激情极品国产一区二区三区| 亚洲四区av| av在线观看视频网站免费| av线在线观看网站| 97在线视频观看| 亚洲中文av在线| 免费在线观看视频国产中文字幕亚洲 | 欧美日韩一区二区视频在线观看视频在线| 国产精品免费视频内射| 99香蕉大伊视频| 国产色婷婷99| 看免费av毛片| 国产男女超爽视频在线观看| 最近2019中文字幕mv第一页| 欧美日韩一级在线毛片| 日韩电影二区| 久久 成人 亚洲| 精品人妻偷拍中文字幕| 如何舔出高潮| 哪个播放器可以免费观看大片| 蜜桃国产av成人99| 搡女人真爽免费视频火全软件| 18禁观看日本| 欧美bdsm另类| 国产乱来视频区| 欧美精品一区二区免费开放| 国产精品一二三区在线看| 精品国产乱码久久久久久小说|