Qhov sib txawv tseem ceeb ntawm cov teebmeem hluav taws xob thiab cov teebmeem steric yog cov teebmeem hluav taws xob yog kev sib txuas lus sib txuas thaum cov teebmeem steric tsis yog kev sib raug zoo.
Cov teebmeem hluav taws xob thiab steric yog ob lub tswv yim tshuaj sib txawv uas piav qhia txog cov txiaj ntsig ntawm kev sib cuam tshuam ntawm cov hluav taws xob hauv cov molecule ntawm nws cov qauv thiab cov khoom. Cov nyhuv hluav taws xob piav qhia txog cov nyhuv ntawm cov electrons uas nyob rau hauv cov tshuaj sib txuas ntawm cov atoms ntawm cov molecule thaum cov nyhuv steric piav txog cov nyhuv ntawm cov electrons uas tsis koom nrog cov tshuaj sib txuas tab sis tshwm sim raws li ib leeg electron khub lossis nonbonding electrons.
Kev cuam tshuam hluav taws xob yog dab tsi?
Cov nyhuv hluav taws xob yog qhov cuam tshuam ntawm kev sib txuas ntawm electrons ntawm ib lub molecule ntawm nws cov qauv thiab cov khoom. Cov teebmeem no cuam tshuam rau cov qauv, kev rov ua haujlwm, thiab cov khoom ntawm cov molecule tab sis cov no tsis yog cov ntawv cog lus ib txwm muaj lossis cov teebmeem steric.
Daim duab 01: Cov nyhuv Stereoelectronic ntawm Esters
Muaj ntau hom kev cuam tshuam hluav taws xob:
- Induction - redistribution ntawm electron ceev los ntawm ib txwm sigma bonds nyob ntawm seb lub electronegativity ntawm lub atoms nyob rau hauv ib tug molecule
- Conjugation – redistribution of electron density that is transmission of interconnecting pi bonds
- Hyperconjugation - stabilizing kev sib cuam tshuam ntawm electrons ntawm sigma daim ntawv cog lus thiab nyob ib sab nonbonding p orbital los yog antibonding pi orbital
- Electrostatic kev sib cuam tshuam - txaus nyiam thiab tsis txaus ntseeg muaj feem cuam tshuam nrog kev tsim hluav taws xob hauv cov molecule Trans cawv - cuam tshuam ntawm kev sib koom ua ke ntawm cov ligands hloov mus rau cov ntawv cog lus (tshwj xeeb ntawm ligands ntawm square planar lossis octahedral complexes ntawm ligands)
Dab tsi yog qhov Steric Effect?
Steric teebmeem yog cov teebmeem ntawm nonbonding electrons ntawm lub molecule ntawm nws cov qauv thiab cov khoom. Cov nyhuv no cuam tshuam rau kev sib haum xeeb thiab kev ua haujlwm ntawm ions thiab molecules. Hom kev cuam tshuam no tshwm sim vim yog lub zog quab yuam ntawm lub molecule, tshwm sim los ntawm overlapping lub electron huab.
Daim duab 2: Cov Khoom Sib Txawv sib txawv siv cov kev sib txawv sib txawv kom txo qis qhov steric hindrance
Qhov tshwm sim loj ntawm qhov kev cuam tshuam no yog qhov cuam tshuam tsis zoo. Steric hindrance yog hais txog kev qeeb ntawm cov tshuaj tiv thaiv vim yog cov steric bulk ntawm cov reactants. Ntxiv mus, nws hloov cov duab ntawm lub molecule. Kev paub txog cov tswv yim tshuaj no tseem ceeb heev hauv thaj chaw ntawm chemistry, biochemistry thiab pharmacology.
Qhov txawv ntawm Electronic thiab Steric Effects yog dab tsi?
Cov teebmeem hluav taws xob thiab steric yog ob lub tswv yim tshuaj sib txawv uas piav qhia txog cov txiaj ntsig ntawm kev sib cuam tshuam ntawm cov hluav taws xob hauv cov molecule ntawm nws cov qauv thiab cov khoom. Qhov sib txawv tseem ceeb ntawm cov teebmeem hluav taws xob thiab qhov tsis zoo yog qhov cuam tshuam hluav taws xob yog kev sib koom ua ke, qhov cuam tshuam tsis zoo yog kev sib cuam tshuam.
Ntxiv mus, lwm qhov sib txawv ntawm cov teebmeem hluav taws xob thiab cov teebmeem steric yog tias cov teebmeem hluav taws xob cuam tshuam rau cov qauv, kev ua haujlwm, thiab cov khoom ntawm cov molecule, thaum cov nyhuv steric cuam tshuam rau kev sib haum xeeb thiab reactivity.
Summary – Electronic vs Steric Effects
Cov teebmeem hluav taws xob thiab steric yog ob lub tswv yim tshuaj sib txawv uas piav qhia txog cov txiaj ntsig ntawm kev sib cuam tshuam ntawm cov hluav taws xob hauv cov molecule ntawm nws cov qauv thiab cov khoom. Cov nyhuv hluav taws xob piav qhia txog cov nyhuv ntawm cov electrons uas nyob rau hauv cov tshuaj sib txuas ntawm cov atoms ntawm cov molecule thaum cov nyhuv steric piav txog cov nyhuv ntawm cov electrons uas tsis koom nrog cov tshuaj sib txuas tab sis tshwm sim raws li ib leeg electron khub lossis nonbonding electrons. Yog li, qhov sib txawv tseem ceeb ntawm cov teebmeem hluav taws xob thiab cov steric yog cov teebmeem hluav taws xob yog kev sib txuas lus sib txuas thaum cov teebmeem steric tsis yog kev sib raug zoo.
