Qhov sib txawv tseem ceeb ntawm nucleophilic thiab electrophilic ntxiv yog tias, hauv cov tshuaj tiv thaiv nucleophilic ntxiv, cov khoom siv hluav taws xob nplua nuj ua ke nrog cov molecule whereas, nyob rau hauv cov tshuaj tiv thaiv electrophilic ntxiv, xws li hom tsis muaj hluav taws xob lossis cov khoom nruab nrab nrog cov khoob khoob khoob. ua ke nrog cov molecule.
A nucleophile yog hom tshuaj muaj hluav taws xob uas muaj peev xwm pub tau ib khub hluav taws xob rau hom tsis muaj hluav taws xob. Ib qho electrophile, ntawm qhov tod tes, yog tus nqi zoo lossis nruab nrab. Yog hais tias nws yog nruab nrab, ces nws yuav tsum muaj khoob orbitals txais electrons los ntawm lwm hom.
Nucleophilic Ntxiv yog dab tsi?
Qhov sib ntxiv nucleophilic yog txheej txheem ntawm kev ntxiv cov nucleophile rau ib hom kab mob uas tsis muaj hluav taws xob lossis pi daim ntawv cog lus hauv molecule (peb hu ua substrate). Qhov ntxiv nucleophile tsim ib daim ntawv cog lus (sigma daim ntawv cog lus) nrog lub substrate. Cia peb xav txog qee qhov piv txwv kom nkag siab txog cov txheej txheem ntawm nucleophilic ntxiv.
Ntxiv ntawm Nucleophiles rau Carbonyl Carbon
Carbonyl pawg yog polar vim tias lawv muaj cov pa roj carbon atom ob npaug rau cov pa atom. Qhov polarity no tshwm sim vim qhov sib txawv siab ntawm electronegativity qhov tseem ceeb ntawm carbon thiab oxygen. Qhov ntawd txhais tau hais tias cov pa oxygen muaj kev sib raug zoo rau cov khoom siv hluav taws xob ntau dua li cov pa roj carbon. Tom qab ntawd cov pa roj carbon atom ntawm pawg carbonyl tau txais ib feem ntawm qhov zoo. Cov pa roj carbon no yog txoj haujlwm zoo dua rau cov nucleophile los tua cov molecule. Lub nucleophile pub nws cov electrons rau cov pa roj carbon no thiab tsim ib daim ntawv cog lus nrog carbon atom. Yog li, qhov no yog ib qho ntxiv nucleophilic. Tsis tas li ntawd, hom tshuaj tiv thaiv no feem ntau tshwm sim hauv aldehydes thiab ketones.
Daim duab 1: Nucleophilic Ntxiv rau Carbonyl Carbon
Ntxiv Nucleophiles rau Nitriles
Nitile yog ib qho sib xyaw uas muaj cov pa roj carbon triple txuas rau nitrogen atom. Daim ntawv cog lus no yog polar heev vim tias cov electronegativity ntawm nitrogen siab dua carbon. Tom qab ntawd cov pa roj carbon atom ua ib feem zoo them. Raws li qhov tshwm sim, cov pa roj carbon no tuaj yeem dhau mus ntxiv nucleophilic. Lub nucleophile ua ke nrog cov pa roj carbon atom. Cov txiaj ntsig molecule muaj ob daim ntawv cog lus ntawm cov pa roj carbon thiab nitrogen, es tsis yog daim ntawv cog lus triple.
Ntxiv ntawm Nucleophiles rau Ob Daim Ntawv Pov Thawj
Ib daim ntawv cog lus ob zaug muaj pi daim ntawv cog lus thiab daim ntawv cog lus sigma. Ob daim ntawv cog lus muaj nyob hauv alkenes. Thaum ib qho alkene tau txais qhov sib ntxiv ntawm nucleophilic, cov molecule unsaturated yuav saturated nrog cov nucleophile thiab ua ke nrog ib qho ntawm cov vinyl carbon atoms (ob chav sib txuas carbon atoms) ntawm covalent daim ntawv cog lus.
Electrophilic Ntxiv yog dab tsi?
Qhov sib ntxiv ntawm electrophilic yog txheej txheem ntawm kev ntxiv cov electrophile rau pi daim ntawv cog lus ntawm alkene. Thaum kawg ntawm cov tshuaj tiv thaiv, daim ntawv cog lus pi no tawg, tsim ob daim ntawv cog lus tshiab. Lub molecule yuav tsum muaj ob daim ntawv cog lus los yog triple daim ntawv cog lus kom tau txais ib qho electrophile. Nws tshwm sim hauv ob kauj ruam. Cia peb xav txog ib qho piv txwv kom nkag siab txog cov txheej txheem ntawm electrophilic ntxiv.
Daim duab 2: Electrophilic Ntxiv
Ntawm no, peb tau them nyiaj electrophile zoo. Tsis tas li ntawd, daim ntawv cog lus unsaturated los yog ob daim ntawv cog lus yog nplua nuj nrog electrons. Yog li, nws tuaj yeem pub cov khoom siv hluav taws xob rau cov hluav taws xob tsis muaj hluav taws xob. Tom qab ntawd tus nqi zoo raug xa mus rau C-C daim ntawv cog lus thaum lub sij hawm sigma daim ntawv cog lus ntawm carbon atom thiab electrophile. Qhov no ua rau muaj carbocation. Txij li qhov no tsis ruaj khov, cov pa roj carbon atom tau txais electrons los ntawm anion, ua rau lwm daim ntawv cog lus.
Qhov txawv ntawm Nucleophilic thiab Electrophilic Ntxiv yog dab tsi?
Nucleophilic vs Electrophilic Ntxiv |
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| Nucleophilic ntxiv yog cov txheej txheem ntawm kev ntxiv nucleophile rau ib hom kab mob uas tsis muaj hluav taws xob lossis pi daim ntawv cog lus hauv molecule. | Electrophilic ntxiv yog txheej txheem ntawm kev ntxiv ib qho electrophile rau pi daim ntawv cog lus ntawm alkene. |
| Nyob ntxiv | |
| A nucleophile ua ke nrog cov molecule. | Ib qho hluav taws xob ua ke nrog cov molecule. |
| Txawm yog hom tshuaj muaj txiaj ntsig zoo lossis pi daim ntawv cog lus hauv molecule. | Alkene lossis alkyne |
| txheej txheem | |
| A nucleophile tsim ib daim ntawv cog lus nrog cov pa roj carbon atom hauv substrate | Ib qho electrophile tsim ib daim ntawv cog lus nrog cov vinyl carbon atom hauv ob daim ntawv cog lus. |
Summary – Nucleophilic vs Electrophilic Ntxiv
Ob qhov sib ntxiv nucleophilic thiab electrophilic ntxiv yog ob qho tshuaj lom neeg tseem ceeb siv hauv kev sib txuas cov khoom sib txuas los ntawm cov tebchaw unsaturated. Qhov sib txawv tseem ceeb ntawm nucleophilic thiab electrophilic ntxiv yog tias nyob rau hauv nucleophilic ntxiv cov tshuaj tiv thaiv, cov khoom siv hluav taws xob nplua nuj tau ntxiv rau hauv cov molecule, whereas hauv electrophilic ntxiv, ib hom electron-deficient yog ntxiv rau ib lub molecule.
