Qhov sib txawv tseem ceeb ntawm kev rov qab sib koom ua ke thiab kev sib txuas yog lawv qhov kev sib cog lus. Backbonding yog kev txav ntawm electrons los ntawm ib qho atomic orbital ntawm ib lub atom mus rau ib qho kev tiv thaiv pi orbital ntawm lub ligand thaum hyperconjugation yog kev sib cuam tshuam ntawm sigma bonds nrog ib lub network pi, thiab conjugation yog sib tshooj ntawm pi orbitals raws li daim ntawv cog lus sigma.
Peb tuaj yeem sib tham txog cov ntsiab lus rov qab, hyperconjugation thiab conjugation nrog rau kev siv tshuaj sib txawv hauv cov khoom sib txuas. Tag nrho peb nqe lus piav qhia txog kev sib tshooj ntawm electron orbitals uas tsis yog cov kev sib cog lus loj hauv cov molecule.
Yuav ua li cas yog Backbonding
Backbonding yog hais txog kev txav ntawm electrons los ntawm ib qho atomic orbital ntawm ib lub atom mus rau ib qho antibonding pi orbital ntawm ib lub ligand. Ntawm no, lub antibonding orbital thiab lub atomic orbital yuav tsum muaj qhov tsim nyog symmetry thiaj li yuav sib tshooj zoo kawg nkaus. Hom tshuaj sib txuas no muaj nyob rau hauv organometallic chemistry ntawm cov hlau hloov pauv uas muaj ntau yam sib txawv xws li carbon monoxide, ethylene, thiab lwm yam.
Daim duab 01: Rov qab
Hyperconjugation yog dab tsi?
Lub sij hawm hyperconjugation yog hais txog kev sib cuam tshuam ntawm σ-bonds nrog pi network. Hauv qhov kev cuam tshuam no, cov khoom siv hluav taws xob hauv ib daim ntawv cog lus sigma cuam tshuam nrog ib feem (lossis tag nrho) puv p orbital, lossis nrog pi orbital. Hom kev sib cuam tshuam no tshwm sim los ua kom muaj kev ruaj ntseg ntawm cov molecule.
Daim duab 02: Hyperconjugation
Feem ntau, hyperconjugation tshwm sim vim qhov sib tshooj ntawm cov khoom siv hluav taws xob hauv C-H sigma daim ntawv cog lus nrog p orbital lossis pi orbital ntawm cov pa roj carbon atom. Ntawm no, hydrogen atom nyob ze ze li ib tug proton. Tus nqi tsis zoo uas tsim tawm ntawm cov pa roj carbon atom yog delocalized vim qhov sib tshooj ntawm p orbital lossis pi orbital.
Kev sib txuas yog dab tsi?
Lub sij hawm conjugation piav txog qhov sib tshooj ntawm p-orbitals hla ib daim ntawv cog lus σ (sigma daim ntawv cog lus). Nyob rau hauv chemistry, ib daim ntawv cog lus sigma yog ib hom ntawm covalent daim ntawv cog lus. Feem ntau, unsaturated compounds uas muaj ob daim ntawv cog lus yog tsim los ntawm ib tug sigma daim ntawv cog lus thiab ib daim ntawv cog lus pi. Cov pa roj carbon atoms ntawm cov tebchaw no undergo sp2 hybridization ua ntej tsim daim ntawv cog lus. Tom qab ntawd, muaj qhov tsis sib haum xeeb p orbital rau txhua cov pa roj carbon atom.
Daim duab 03: Alternating Pi System
Yog tias muaj ib qho sib xyaw uas muaj kev sib hloov ib daim ntawv cog lus (sigma daim ntawv cog lus) thiab ob daim ntawv cog lus (sigma daim ntawv cog lus thiab daim ntawv cog lus pi), qhov tsis sib haum xeeb p orbitals tuaj yeem sib tshooj nrog ib leeg, tsim cov huab cua hluav taws xob. Tom qab ntawd, cov electrons nyob rau hauv cov p orbitals tau delocalized nyob rau hauv no electron huab. Hom kev delocalized no yog lub npe hu ua conjugated system, thiab peb tuaj yeem hu qhov sib tshooj ntawm p orbitals li conjugation.
Qhov txawv ntawm Backbonding Hyperconjugation thiab Conjugation yog dab tsi?
Peb tuaj yeem sib tham txog cov ntsiab lus rov qab, hyperconjugation thiab conjugation nrog rau kev siv tshuaj sib txawv hauv cov khoom sib txuas. Backbonding yog kev txav ntawm cov hluav taws xob los ntawm ib qho atomic orbital ntawm ib lub atom mus rau ib qho kev tiv thaiv pi orbital ntawm lub ligand thiab hyperconjugation yog kev sib cuam tshuam ntawm sigma khi nrog ib lub network pi whereas conjugation yog sib tshooj ntawm pi orbitals nrog sigma daim ntawv cog lus. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm backbonding hyperconjugation thiab conjugation.
Hauv qab infographic tabulates ntau qhov sib txawv ntawm backbonding hyperconjugation thiab conjugation.
Summary – Backbonding Hyperconjugation vs Conjugation
Qhov sib txawv tseem ceeb ntawm nraub qaum hyperconjugation thiab conjugation yog qhov rov qab yog qhov txav ntawm cov hluav taws xob los ntawm lub atomic orbital ntawm ib lub atom mus rau ib qho kev tiv thaiv pi orbital ntawm lub ligand thiab hyperconjugation yog hais txog kev sib cuam tshuam ntawm sigma khi nrog lub network pi whereas conjugation yog hais txog kev sib tshooj ntawm pi orbitals raws ib daim ntawv cog lus sigma.
