• <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
    99久久国产精品久久久| 中文亚洲av片在线观看爽 | 又黄又粗又硬又大视频| 最新在线观看一区二区三区| 69av精品久久久久久| 人妻 亚洲 视频| 91字幕亚洲| 日韩中文字幕欧美一区二区| 好看av亚洲va欧美ⅴa在| 欧美精品av麻豆av| 一级黄色大片毛片| 国产又爽黄色视频| 亚洲一码二码三码区别大吗| 老司机福利观看| 午夜91福利影院| 三上悠亚av全集在线观看| 久久中文看片网| 国产成人精品无人区| 免费不卡黄色视频| 亚洲一区二区三区不卡视频| 欧美 日韩 精品 国产| 欧美老熟妇乱子伦牲交| 成人手机av| 久久久久精品国产欧美久久久| 女性被躁到高潮视频| 亚洲 国产 在线| www.999成人在线观看| 中亚洲国语对白在线视频| 十分钟在线观看高清视频www| 丝袜美足系列| 亚洲精品在线观看二区| 黄色视频不卡| 女警被强在线播放| 我的亚洲天堂| 亚洲精品成人av观看孕妇| 在线视频色国产色| 一夜夜www| av片东京热男人的天堂| 美国免费a级毛片| 成人国产一区最新在线观看| 日本黄色日本黄色录像| 最新的欧美精品一区二区| 亚洲avbb在线观看| 亚洲欧美精品综合一区二区三区| 人妻 亚洲 视频| 亚洲国产欧美一区二区综合| av天堂久久9| 国产精品1区2区在线观看. | 很黄的视频免费| 91精品国产国语对白视频| 飞空精品影院首页| 成人免费观看视频高清| 欧美日韩福利视频一区二区| 亚洲成人手机| 999久久久国产精品视频| 国产亚洲欧美在线一区二区| 日本wwww免费看| 国产成人免费无遮挡视频| 亚洲精品中文字幕在线视频| 19禁男女啪啪无遮挡网站| 99热国产这里只有精品6| av一本久久久久| 正在播放国产对白刺激| 中国美女看黄片| 丁香六月欧美| 亚洲欧美色中文字幕在线| 男女床上黄色一级片免费看| 亚洲九九香蕉| 1024视频免费在线观看| 欧美成狂野欧美在线观看| 久久草成人影院| 国产欧美日韩综合在线一区二区| 国产精品成人在线| 两性夫妻黄色片| 丝袜人妻中文字幕| 18禁裸乳无遮挡免费网站照片 | 国产欧美日韩精品亚洲av| 在线观看午夜福利视频| 69av精品久久久久久| 一级片免费观看大全| 午夜久久久在线观看| 曰老女人黄片| 99精品欧美一区二区三区四区| 久久人人爽av亚洲精品天堂| 天天躁夜夜躁狠狠躁躁| 久久久国产精品麻豆| 99精品在免费线老司机午夜| 国产99白浆流出| 热99久久久久精品小说推荐| 久9热在线精品视频| 精品国产一区二区三区四区第35| 国产一区二区三区在线臀色熟女 | 国产淫语在线视频| 国产伦人伦偷精品视频| 欧美日韩黄片免| av视频免费观看在线观看| 国产精品电影一区二区三区 | 黄色片一级片一级黄色片| 新久久久久国产一级毛片| 精品久久蜜臀av无| 真人做人爱边吃奶动态| 成年人午夜在线观看视频| 午夜两性在线视频| 亚洲国产毛片av蜜桃av| 欧美精品高潮呻吟av久久| 黄网站色视频无遮挡免费观看| 少妇粗大呻吟视频| 一级片免费观看大全| 狠狠狠狠99中文字幕| 亚洲第一青青草原| a在线观看视频网站| xxx96com| www.自偷自拍.com| 母亲3免费完整高清在线观看| 久热爱精品视频在线9| 亚洲片人在线观看| 久久精品亚洲精品国产色婷小说| 在线视频色国产色| 欧美日韩国产mv在线观看视频| 亚洲中文字幕日韩| 黄色视频,在线免费观看| 亚洲五月色婷婷综合| 99久久国产精品久久久| 成人精品一区二区免费| 欧美亚洲 丝袜 人妻 在线| 天天躁夜夜躁狠狠躁躁| 国产av精品麻豆| 亚洲三区欧美一区| 精品一区二区三卡| 亚洲国产欧美网| 美女视频免费永久观看网站| 少妇裸体淫交视频免费看高清 | 亚洲伊人色综图| 19禁男女啪啪无遮挡网站| 91在线观看av| 精品亚洲成a人片在线观看| 中文字幕人妻丝袜制服| 纯流量卡能插随身wifi吗| 久久久国产精品麻豆| 久久精品亚洲熟妇少妇任你| 免费少妇av软件| 亚洲国产中文字幕在线视频| 精品少妇一区二区三区视频日本电影| e午夜精品久久久久久久| 免费在线观看视频国产中文字幕亚洲| 少妇被粗大的猛进出69影院| 99精品在免费线老司机午夜| 老汉色∧v一级毛片| 久久久久久久午夜电影 | 国产在线一区二区三区精| 亚洲熟女精品中文字幕| 看黄色毛片网站| 亚洲黑人精品在线| 最近最新中文字幕大全电影3 | 国产一区在线观看成人免费| 免费高清在线观看日韩| 久久久精品区二区三区| 黄色视频,在线免费观看| 亚洲人成电影免费在线| 国产蜜桃级精品一区二区三区 | 中文亚洲av片在线观看爽 | 国产男靠女视频免费网站| 亚洲成a人片在线一区二区| 免费在线观看完整版高清| 欧美日韩成人在线一区二区| 久久精品国产亚洲av香蕉五月 | 麻豆av在线久日| 成熟少妇高潮喷水视频| 在线观看免费视频日本深夜| 久久国产精品影院| 一本一本久久a久久精品综合妖精| 亚洲三区欧美一区| 大码成人一级视频| 久久香蕉国产精品| 亚洲精品国产区一区二| 侵犯人妻中文字幕一二三四区| 国产麻豆69| 国产精品美女特级片免费视频播放器 | 一进一出抽搐gif免费好疼 | 女同久久另类99精品国产91| 久9热在线精品视频| 波多野结衣一区麻豆| 巨乳人妻的诱惑在线观看| 色在线成人网| 啦啦啦在线免费观看视频4| 我的亚洲天堂| 99riav亚洲国产免费| 自线自在国产av| 欧美中文综合在线视频| 精品国产一区二区三区久久久樱花| 麻豆成人av在线观看| 黄色女人牲交| 国产激情久久老熟女| 黑丝袜美女国产一区| 国产一区二区三区视频了| 欧美精品亚洲一区二区| 69精品国产乱码久久久| 人妻一区二区av| 亚洲av成人一区二区三| 一级作爱视频免费观看| 国产又爽黄色视频| 欧美性长视频在线观看| 免费观看a级毛片全部| 一区福利在线观看| 人妻丰满熟妇av一区二区三区 | 成人黄色视频免费在线看| 啪啪无遮挡十八禁网站| 一级毛片精品| 久久精品亚洲av国产电影网| 宅男免费午夜| 国产在视频线精品| 国产麻豆69| 黄片小视频在线播放| 黑人欧美特级aaaaaa片| 欧美乱码精品一区二区三区| 很黄的视频免费| av片东京热男人的天堂| 亚洲中文av在线| 精品国产国语对白av| 操出白浆在线播放| www.精华液| 在线观看免费日韩欧美大片| av欧美777| 成人永久免费在线观看视频| 亚洲国产精品sss在线观看 | 99久久99久久久精品蜜桃| 黄片大片在线免费观看| 波多野结衣av一区二区av| 亚洲国产毛片av蜜桃av| 午夜福利影视在线免费观看| 日本vs欧美在线观看视频| 后天国语完整版免费观看| 一进一出好大好爽视频| 亚洲熟女毛片儿| 女人被躁到高潮嗷嗷叫费观| 国产伦人伦偷精品视频| 国产精品美女特级片免费视频播放器 | 首页视频小说图片口味搜索| 久久久水蜜桃国产精品网| 欧美不卡视频在线免费观看 | 精品乱码久久久久久99久播| 成人亚洲精品一区在线观看| 91精品国产国语对白视频| 亚洲黑人精品在线| 精品一区二区三区av网在线观看| 啦啦啦在线免费观看视频4| 99国产精品一区二区三区| 1024香蕉在线观看| 免费在线观看视频国产中文字幕亚洲| 亚洲情色 制服丝袜| 日本黄色日本黄色录像| 亚洲国产欧美网| 99re6热这里在线精品视频| 国产精品1区2区在线观看. | 日韩欧美在线二视频 | 成在线人永久免费视频| а√天堂www在线а√下载 | 精品人妻1区二区| 看片在线看免费视频| 青草久久国产| 色尼玛亚洲综合影院| 黄色视频,在线免费观看| 日韩制服丝袜自拍偷拍| 免费观看精品视频网站| 手机成人av网站| 免费在线观看亚洲国产| 中文字幕另类日韩欧美亚洲嫩草| 在线播放国产精品三级| 新久久久久国产一级毛片| 久久久国产精品麻豆| 成人18禁在线播放| 老汉色av国产亚洲站长工具| 亚洲国产精品合色在线| 精品熟女少妇八av免费久了| 久久天躁狠狠躁夜夜2o2o| 黄色成人免费大全| 亚洲一区高清亚洲精品| 一级片'在线观看视频| 亚洲七黄色美女视频| 亚洲精品在线观看二区| 搡老熟女国产l中国老女人| 视频在线观看一区二区三区| 最新在线观看一区二区三区| а√天堂www在线а√下载 | 久热爱精品视频在线9| 欧美国产精品一级二级三级| 男女下面插进去视频免费观看| 一级作爱视频免费观看| 一个人免费在线观看的高清视频| 午夜免费成人在线视频| www日本在线高清视频| 国产精品一区二区精品视频观看| 中文字幕色久视频| 国产男女超爽视频在线观看| 亚洲国产欧美日韩在线播放| netflix在线观看网站| 亚洲午夜精品一区,二区,三区| 黄色视频,在线免费观看| 精品国产乱码久久久久久男人| 飞空精品影院首页| 精品国产国语对白av| 日本撒尿小便嘘嘘汇集6| 国产主播在线观看一区二区| 国产麻豆69| 五月开心婷婷网| 丰满迷人的少妇在线观看| 亚洲自偷自拍图片 自拍| 操美女的视频在线观看| 国产一区二区激情短视频| 伊人久久大香线蕉亚洲五| 精品国产美女av久久久久小说| 国产精品1区2区在线观看. | 色婷婷av一区二区三区视频| 亚洲精品中文字幕在线视频| 国产99久久九九免费精品| 成年人黄色毛片网站| 十八禁网站免费在线| 少妇粗大呻吟视频| 免费在线观看日本一区| 成人黄色视频免费在线看| 色老头精品视频在线观看| 久久国产精品人妻蜜桃| 中文字幕人妻熟女乱码| 亚洲一区中文字幕在线| 色尼玛亚洲综合影院| 9191精品国产免费久久| 美女午夜性视频免费| 黄色视频,在线免费观看| 国产成人欧美在线观看 | 又紧又爽又黄一区二区| av超薄肉色丝袜交足视频| 免费日韩欧美在线观看| 欧美日韩亚洲综合一区二区三区_| 国产av又大| 黑人巨大精品欧美一区二区mp4| 天天躁日日躁夜夜躁夜夜| 99国产综合亚洲精品| tube8黄色片| 波多野结衣一区麻豆| 99国产综合亚洲精品| 国产xxxxx性猛交| 少妇 在线观看| 亚洲欧美日韩高清在线视频| 亚洲视频免费观看视频| 99国产精品免费福利视频| 日本vs欧美在线观看视频| 亚洲全国av大片| 成年人午夜在线观看视频| 亚洲av电影在线进入| 国产真人三级小视频在线观看| 午夜老司机福利片| 亚洲熟妇中文字幕五十中出 | 乱人伦中国视频| 亚洲一区中文字幕在线| 免费女性裸体啪啪无遮挡网站| 动漫黄色视频在线观看| 日韩大码丰满熟妇| 亚洲欧美日韩另类电影网站| 亚洲一区二区三区欧美精品| 久久国产精品大桥未久av| 亚洲欧美日韩高清在线视频| 久久精品成人免费网站| 国产欧美日韩精品亚洲av| 91字幕亚洲| 两性夫妻黄色片| 美女高潮到喷水免费观看| 久久影院123| 欧美老熟妇乱子伦牲交| 69av精品久久久久久| av国产精品久久久久影院| 人人妻人人爽人人添夜夜欢视频| 黄色片一级片一级黄色片| 香蕉久久夜色| 久久国产亚洲av麻豆专区| 水蜜桃什么品种好| 久久久水蜜桃国产精品网| 久久 成人 亚洲| 成在线人永久免费视频| 99久久99久久久精品蜜桃| 亚洲熟妇熟女久久| 亚洲色图综合在线观看| 欧美人与性动交α欧美精品济南到| 大陆偷拍与自拍| 久久 成人 亚洲| 中文字幕色久视频| 欧美精品一区二区免费开放| 18禁美女被吸乳视频| 丝袜美足系列| 欧美大码av| 亚洲一区高清亚洲精品| 精品亚洲成国产av| 999精品在线视频| 亚洲午夜精品一区,二区,三区| 久久国产精品人妻蜜桃| 亚洲片人在线观看| 久久国产精品人妻蜜桃| 可以免费在线观看a视频的电影网站| av线在线观看网站| 欧美激情久久久久久爽电影 | 女人被躁到高潮嗷嗷叫费观| 夜夜爽天天搞| 国产精品1区2区在线观看. | 亚洲精品久久午夜乱码| 女人被躁到高潮嗷嗷叫费观| 大片电影免费在线观看免费| 在线永久观看黄色视频| 黄片播放在线免费| 久久精品国产a三级三级三级| 久久精品91无色码中文字幕| 少妇猛男粗大的猛烈进出视频| 99精品欧美一区二区三区四区| 免费av中文字幕在线| 亚洲成人国产一区在线观看| 91大片在线观看| 中文字幕人妻丝袜制服| 午夜福利影视在线免费观看| 国产精品偷伦视频观看了| 精品国产亚洲在线| 99国产精品一区二区蜜桃av | 国产精品.久久久| 男男h啪啪无遮挡| 精品人妻熟女毛片av久久网站| 亚洲av成人一区二区三| 99久久精品国产亚洲精品| 午夜亚洲福利在线播放| 免费在线观看完整版高清| 在线播放国产精品三级| 亚洲少妇的诱惑av| 国产精品美女特级片免费视频播放器 | 亚洲三区欧美一区| 久久国产精品人妻蜜桃| 悠悠久久av| 99热国产这里只有精品6| 国产一区二区三区视频了| 欧美丝袜亚洲另类 | 日韩 欧美 亚洲 中文字幕| 99精品久久久久人妻精品| 老司机在亚洲福利影院| 精品少妇久久久久久888优播| 欧美精品av麻豆av| 久久中文看片网| 精品一品国产午夜福利视频| 午夜成年电影在线免费观看| 一级片'在线观看视频| 99re在线观看精品视频| 久久国产精品人妻蜜桃| 色94色欧美一区二区| 一本大道久久a久久精品| 大码成人一级视频| 久久热在线av| 亚洲色图 男人天堂 中文字幕| 19禁男女啪啪无遮挡网站| 日韩人妻精品一区2区三区| 亚洲欧洲精品一区二区精品久久久| 欧美最黄视频在线播放免费 | 中文字幕人妻丝袜制服| videosex国产| 欧美黑人欧美精品刺激| 大型av网站在线播放| 操出白浆在线播放| 黄色a级毛片大全视频| 飞空精品影院首页| 日本精品一区二区三区蜜桃| 电影成人av| 免费久久久久久久精品成人欧美视频| 国产欧美日韩综合在线一区二区| 91大片在线观看| 美女国产高潮福利片在线看| 亚洲伊人色综图| 99国产精品免费福利视频| 久久天躁狠狠躁夜夜2o2o| 狂野欧美激情性xxxx| 九色亚洲精品在线播放| 另类亚洲欧美激情| 高清毛片免费观看视频网站 | 精品国产亚洲在线| 黄片小视频在线播放| 在线看a的网站| 欧美精品av麻豆av| 国产无遮挡羞羞视频在线观看| 老汉色av国产亚洲站长工具| 久9热在线精品视频| 人人澡人人妻人| 国产99白浆流出| 日韩欧美三级三区| 两性夫妻黄色片| 免费一级毛片在线播放高清视频 | 高清视频免费观看一区二区| 国产色视频综合| 成人18禁在线播放| 欧美日韩精品网址| 他把我摸到了高潮在线观看| 18禁裸乳无遮挡免费网站照片 | 午夜免费成人在线视频| 久久人妻熟女aⅴ| 国产精品免费大片| 一区二区三区激情视频| 国产午夜精品久久久久久| 国产成人免费观看mmmm| 欧美日韩精品网址| 99在线人妻在线中文字幕 | 一级黄色大片毛片| 人人妻人人爽人人添夜夜欢视频| 十八禁人妻一区二区| 午夜免费鲁丝| av线在线观看网站| 人人妻人人澡人人爽人人夜夜| bbb黄色大片| 亚洲一区二区三区不卡视频| tube8黄色片| 久久99一区二区三区| 校园春色视频在线观看| 欧美成人午夜精品| 亚洲熟妇中文字幕五十中出 | 亚洲av成人av| 女人高潮潮喷娇喘18禁视频| 色94色欧美一区二区| 女人被狂操c到高潮| 激情在线观看视频在线高清 | 欧美精品一区二区免费开放| 精品少妇久久久久久888优播| 久久人人97超碰香蕉20202| 视频区欧美日本亚洲| 十分钟在线观看高清视频www| 美女国产高潮福利片在线看| 国产精品国产av在线观看| 成年人黄色毛片网站| 真人做人爱边吃奶动态| 搡老岳熟女国产| 亚洲精华国产精华精| 亚洲欧美日韩高清在线视频| av线在线观看网站| 久久99一区二区三区| 最近最新中文字幕大全电影3 | 亚洲七黄色美女视频| 少妇的丰满在线观看| 色播在线永久视频| 999久久久国产精品视频| 日本欧美视频一区| 国产一区有黄有色的免费视频| 久久婷婷成人综合色麻豆| 老司机靠b影院| 男女午夜视频在线观看| 日韩欧美国产一区二区入口| 91成人精品电影| 国产精品永久免费网站| 国产乱人伦免费视频| 国产精品九九99| 一级片'在线观看视频| 久久久久久人人人人人| 国产成人精品久久二区二区91| 精品第一国产精品| 国产精品影院久久| 十八禁人妻一区二区| 美国免费a级毛片| 国产精品免费一区二区三区在线 | 婷婷丁香在线五月| 亚洲国产欧美日韩在线播放| 男女免费视频国产| 脱女人内裤的视频| 久久久国产欧美日韩av| 国产精品成人在线| 美女国产高潮福利片在线看| 在线免费观看的www视频| 国产97色在线日韩免费| 亚洲中文字幕日韩| 狠狠狠狠99中文字幕| 9热在线视频观看99| 亚洲精品成人av观看孕妇| 高清毛片免费观看视频网站 | 欧洲精品卡2卡3卡4卡5卡区| 国产野战对白在线观看| 在线观看免费午夜福利视频| 999精品在线视频| 亚洲aⅴ乱码一区二区在线播放 | 成在线人永久免费视频| av国产精品久久久久影院| 亚洲av成人av| 久久 成人 亚洲| 亚洲av电影在线进入| 色播在线永久视频| av有码第一页| 免费观看精品视频网站| 天堂动漫精品| 精品第一国产精品| 精品国产美女av久久久久小说| 亚洲综合色网址| 国产亚洲精品第一综合不卡| 免费在线观看亚洲国产| 悠悠久久av| 制服诱惑二区| 妹子高潮喷水视频| 国产精品偷伦视频观看了| 手机成人av网站| 久久亚洲真实| 国产亚洲av高清不卡| 十八禁人妻一区二区| 建设人人有责人人尽责人人享有的| 1024视频免费在线观看| 黄色成人免费大全| av网站免费在线观看视频| 女性被躁到高潮视频| 欧美在线一区亚洲| 午夜激情av网站| 久久天躁狠狠躁夜夜2o2o| 国产精品亚洲一级av第二区| 18在线观看网站| 动漫黄色视频在线观看| 中文欧美无线码| 丝袜在线中文字幕| 视频区图区小说| av中文乱码字幕在线| 欧美黄色淫秽网站| tube8黄色片| 色综合欧美亚洲国产小说|