Qhov sib txawv tseem ceeb ntawm classical thiab nonclassical carbocation yog tias classical carbocations muaj cov pa roj carbon atom muaj rau electrons nyob rau hauv peb cov tshuaj bonds, whereas nonclassical carbocations muaj peb-center ob-electron qauv.
YA carbocation yog hom tshuaj uas yog moiety ntawm cov organic molecule. Nws muaj tus nqi zoo ntawm cov pa roj carbon atom. Ib qho piv txwv yooj yim ntawm cov carbocation yog CH
3+ Qee cov carbocations muaj ntau tshaj ib qho zoo, ntawm tib lub atom los yog sib txawv atom. Ntxiv mus, carbocations yog reactive intermediates nyob rau hauv cov organic tshua vim muaj ib tug zoo nqi; muaj rau lub electrons nyob rau hauv ib tug carbon atom, uas ua rau nws tsis ruaj tsis khov (muaj yim electrons kom lub stability); yog li ntawd nws nyiam mus nrhiav electrons.
Classical Carbocation yog dab tsi?
A classical carbocation yog ib qho ion uas muaj cov pa roj carbon zoo uas muaj rau lub tshuab hluav taws xob uas koom nrog peb daim ntawv cog lus tshuaj. Peb tuaj yeem muab lub npe no carbon atom ua peb-coordinate zoo carbon.
Daim duab 01: Tsim cov Carbocation Classical
Txhawm rau kom muaj kev ruaj ntseg siab tshaj plaws, cov pa roj carbon atom yuav tsum muaj yim valence electrons. Tab sis nyob rau hauv carbocation, tsuas muaj rau electrons nyob rau hauv cov pa roj carbon atom muaj ib tug zoo nqi. Yog li ntawd, nws nyiam muab ob lub electrons ntxiv los ntawm ib hom electronegative. Qhov no ua rau carbon atom ruaj khov thiab neutralizes tus nqi zoo. Qhov no yog vim li cas rau siab reactivity ntawm classical carbocations. Txawm li cas los xij, lub zog ntawm classical carbocation yog tsawg piv rau lub zog ntawm cov carbocation uas tsis yog classical. Tab sis qhov sib txawv ntawm lawv lub zog no tsawg heev.
Nonclassical Carbocation yog dab tsi?
A nonclassical carbocation yog ib qho ion uas muaj cov pa roj carbon zoo nyob rau hauv peb-center ob-electron center. Qhov no txhais tau tias, muaj peb lub atom sib koom ob lub electrons hauv cov carbocations. Hom kev sib koom electron no yog hu ua delocalization ntawm cov electrons.
Daim duab 02: Lub zog sib txawv ntawm Classical thiab Nonclassical Carbocations
Cov piv txwv feem ntau ntawm cov carbocation tsis yog classic yog 2-norbornyl cation. Nws muaj nyob rau hauv ib tug tsawg symmetrical peb-center ob-electron qauv. Muaj qhov sib txawv me ntsis ntawm lub zog ntawm cov classical thiab nonclassical carbocations. Yog li ntawd, nws yog qhov nyuaj heev kom paub qhov txawv ntawm lawv qhov kev sim.
Qhov txawv ntawm Classical thiab Nonclassical Carbocation yog dab tsi?
Peb tuaj yeem faib cov carbocations ua ob pawg ua cov carbocations classical thiab nonclassical, nyob ntawm seb cov qauv tshuaj. Qhov sib txawv tseem ceeb ntawm classical thiab nonclassical carbocation yog tias classical carbocations muaj cov pa roj carbon atom muaj rau electrons nyob rau hauv peb chemical bonds, whereas nonclassical carbocations muaj peb-center ob-electron qauv. Lub zog ntawm nonclassical carbocation yog siab dua lub zog ntawm classical carbocation, tab sis qhov sib txawv ntawm cov energies no tsawg heev; yog li ntawd, nws yog ib qho nyuaj heev kom paub qhov txawv ntawm classical thiab nonclassical lug.
Ntxiv mus, lub zog ua kom muaj zog rau kev hloov pauv ntawm cov carbocation classical rau hauv cov carbocation uas tsis yog classical lossis vice versa yog qhov tsawg heev. Ntxiv rau cov no, cov carbocations classical muaj qhov zoo ntawm cov pa roj carbon atom thiab cov nod electron khub nyob ib ncig ntawm cov pa roj carbon atom, tab sis nyob rau hauv nonclassical carbocations, cov electrons yog delocalized nyob ib ncig ntawm cov pa roj carbon atom. Ib qho piv txwv ntawm cov carbocation classical yog methenium ion, thaum piv txwv rau cov carbocation nonclassical yog 2-norboryl ion.
Summary – Classical vs Nonclassical Carbocation
Peb tuaj yeem faib cov carbocations ua ob pawg ua cov carbocations classical thiab noncalssical, nyob ntawm seb cov qauv tshuaj. Qhov sib txawv tseem ceeb ntawm classical thiab nonclassical carbocation yog tias classical carbocations muaj cov pa roj carbon atom muaj rau electrons nyob rau hauv peb cov tshuaj bonds, whereas nonclassical carbocations muaj peb-center ob-electron qauv. Ib qho piv txwv ntawm cov carbocation classical yog methenium ion thaum piv txwv ntawm cov carbocation nonclassical yog 2-norboryl ion.
