Constitutional Isomers vs Stereoisomers
Feem ntau, isomer yog ib lo lus siv hauv Chemistry, tshwj xeeb hauv Organic Chemistry, xa mus rau cov tshuaj molecules nrog tib cov qauv molecular tab sis muaj cov qauv tshuaj sib txawv. Vim muaj qhov sib txawv ntawm cov qauv tshuaj, cov molecules no kuj muaj cov tshuaj lom neeg thiab lub cev sib txawv ntawm ib leeg, tab sis tseem muaj cov qauv molecular tib yam.
Cov Cai Isomers yog dab tsi?
Constitutional isomers tseem hu ua structural isomers vim cov molecules uas muaj tib lub qauv molecular xwb txawv ntawm ib leeg nyob rau hauv txoj kev ntawm ib tug neeg atoms txuas. Lub npe qauv isomers nws tus kheej kom meej meej qhia lub tswv yim no. Muaj peb qhov kev faib tawm raws li kev cai lij choj isomers; lawv yog skeletal, positional thiab functional group isomers.
Skeletal isomers yog isomers qhov twg cov saw tseem ceeb hauv cov khoom sib txuas tau muab faib ua ntau txoj hauv kev los ntawm ntau hom kev sib txuas. Piv txwv li, yog tias ib qho chaw muaj rau Carbon atoms, cia peb xav tias nws tsuas yog tsim los ntawm Carbon thiab Hydrogen atoms kom yooj yim; Yog hais tias cov ntsiab lus no tau muab tso rau hauv ib txoj hlua ncaj, lub compound tuaj yeem raug hu ua alkane 'Hexane'. Ib tug raug hexane molecule yuav muaj rau Carbon atoms thiab kaum plaub Hydrogen atoms. Tam sim no cia saib lwm txoj hauv kev sib txuas. Piv txwv tias Carbon atom ntawm qhov kawg ntawm cov saw hlau raug tshem tawm thiab tsau rau ntawm carbon atom thib ob. Tom qab ntawd cov saw tseem ceeb yuav raug luv rau tsib Carbon atoms nrog cov Carbon atom ntxiv ntawm ib ceg taw tes. Qhov chaw tshiab no tuaj yeem raug hu ua alkane '2-methylpentene'. Ib yam li ntawd, lwm cov ntsiab lus tuaj yeem tsim los ntawm kev ntxiv cov methyl pawg rau ntau qhov chaw raws cov saw hlau. Qee lwm txoj hauv kev sib txuas muaj xws li; 2, 3-dimethylbutane, 2, 2-dimethylbutane, 3-methylpentene thiab lwm yam.
Yog tias qhov sib xyaw ua ke uas ib tus cuam tshuam nrog muaj cov pab pawg ua haujlwm hauv nws xws li cawv, amine, ketone / aldehyde thiab lwm yam, los ntawm kev hloov cov pab pawg ua haujlwm mus rau ntau yam Carbon atoms raws cov Carbon cov saw tseem ceeb, ntau lub molecules sib txawv tuaj yeem ua tau. tsim; Txawm li cas los xij, txhua tus muaj tib lub qauv molecular. Hom isomerism no hu ua positional isomerism. Qee lub sij hawm, thaum sim rov npaj cov ntsiab lus txiav txim hauv cov qauv molecular, ib tus tuaj yeem tsim cov molecules uas muaj cov pab pawg ua haujlwm sib txawv, tseem ua raws li tib lub ntsiab lus uas tau muab rau hauv cov mis molecular; Qhov no yog lub npe hu ua ib pawg ua haujlwm isomerism. Cawv thiab ethers tuaj yeem hloov tau yooj yim li no (xws li CH 3-O-CH3 thiab CH3 -CH2-OH) thiab nrog rau qhov zoo ntawm qhov tsis txaus ntseeg tam sim no, nws tuaj yeem hloov pauv nrog ketones thiab aldehydes, thiab. Lwm qhov piv txwv yog ib txoj hlua ncaj ncaj hexene thiab cyclohexane compound. Kev hloov pauv hauv pawg ua haujlwm tau cuam tshuam rau cov khoom siv tshuaj lom neeg ntawm cov khoom sib xyaw thiab nws cov yam ntxwv ntawm lub cev.
Stereoisomers yog dab tsi?
Stereoisomers yog cov sib txuas isomeric nrog tib cov qauv molecular thiab tseem muaj tib qhov kev sib txuas ntawm atoms, tab sis tsuas yog txawv ntawm 3 qhov sib txawv ntawm cov atoms hauv qhov chaw, yog li tseem hu ua spatial isomers. Muaj ntau hom stereoisomers uas yog; enantiomers, diastereomers, cis-trans isomers, conformational isomers thiab lwm yam.
Enantiomers yog cov molecules uas yog daim iav duab ntawm ib leeg; Yog li cov molecules no tsis yog superimposable. Cov khawv koob yog tsim los ntawm cov chaw hu ua chiral centres. Cov no yog Carbon atoms uas muaj plaub pawg sib txawv txuas nrog nws. Chiral cov chaw yog lub luag hauj lwm rau tsim enantiomers, thiab cov molecules muaj yuav luag zoo tib yam zog, tab sis lawv muaj peev xwm raug txheeb xyuas los ntawm txoj kev uas lawv tig lub dav hlau polarized lub teeb. Yog li, cov no tseem hu ua optical isomers. Tseem muaj cov stereoisomers uas tsis yog enantiomers, uas yog lawv tsis yog daim iav dluab ntawm ib leeg, thiab ib co xws li molecules yog; diastereomers, cis-trans isomers thiab conformers. Muaj ib chav tshwj xeeb ntawm diastereomers hu ua meso tebchaw, uas muaj daim iav dav hlau nyob rau hauv lub molecule, tab sis lub molecule coj tag nrho, nws daim iav daim iav tsis tsim lwm molecule, tab sis hloov tau tib molecule. Conformers yog cov molecules uas muaj tib qhov sib txuas tab sis siv cov duab sib txawv; e.g. ntau yam conformations ntawm cyclohexane; rooj zaum, nkoj, ib nrab nkoj thiab lwm yam.
Qhov txawv ntawm Txoj Cai Isomers thiab Stereoisomers yog dab tsi?
• Kev cai lij choj isomers muaj atoms txuas nrog hauv kev txiav txim sib txawv whereas, hauv stereoisomers, kev sib txuas hauv atoms zoo sib xws tab sis 3D kev npaj ntawm atoms hauv qhov chaw txawv
• Chirality pom nyob rau hauv stereoisomers thiab tsis nyob rau hauv txoj cai isomers.
• Kev cai lij choj isomers tuaj yeem muaj cov npe tshuaj sib txawv ntawm ib leeg, qhov stereoisomers feem ntau yuav muaj tib lub npe tshuaj nrog ib tsab ntawv lossis cov cim qhia txog kev taw qhia ntawm lub npe.
• Cov tshuaj lom neeg thiab lub cev muaj zog ntawm txoj cai isomers sib txawv sai dua li ntawm stereoisomers.
