Qhov sib txawv tseem ceeb ntawm kev sib koom ua ke thiab kev sib koom ua ke yog tias cov txheej txheem sib koom ua ke yog tus cwj pwm los ntawm kev khi ntawm kev tawm tsam nucleophile kom muab qhov sib cais thiab kuaj pom nruab nrab tom qab los ntawm kev poob ntawm lwm ligand whereas lub dissociative mechanisms yog tus cwj pwm los ntawm tus nqi. - txiav txim siab cov kauj ruam uas suav nrog kev tso tawm ntawm ligand los ntawm kev sib koom ua ke ntawm cov hlau uas tau hloov pauv.
Ob txoj kev sib koom ua ke, kev sib koom ua ke thiab kev sib koom ua ke yog koom nrog cov organic-chemical synthesis cov tshuaj tiv thaiv qhov kev hloov pauv tshwm sim. Yog li ntawd, peb muaj peev xwm muab cov tshuaj tiv thaiv mechanisms li associative hloov thiab dissociative hloov.
Associative Mechanism yog dab tsi?
Ib qho kev sib koom ua ke lossis kev sib koom ua ke yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas cov ligands sib hloov ntawm cov molecules, thiab yog li, khi ib lub ligand tshiab rau kev sib koom tes. Nws yog ib txoj hauv kev uas cov tebchaw sib pauv ligands. Feem ntau, lo lus no yog siv rau kev sib koom tes thiab organometallic complexes. Tsis tas li ntawd, cov tshuaj tiv thaiv no zoo ib yam li SN2 mechanism hauv cov organic chemistry. Cov txheej txheem rov qab ntawm qhov kev sib koom ua ke no yog kev sib koom ua ke.
Daim duab 01: Associative Mechanism
Ntxiv mus, peb tuaj yeem ua tus cwj pwm sib koom ua ke los ntawm kev khi ntawm cov nucleophile tawm tsam kom muab qhov sib cais, kuaj pom nruab nrab tom qab los ntawm kev poob ntawm lwm ligand. Cov kev sib koom ua ke uas tuaj yeem ua raws li qhov kev hloov pauv no yog kev sib koom ua ke tsis muaj qhov sib xyaws lossis muaj cov ligand uas tuaj yeem hloov nws txoj kev sib txuas rau hlau. Piv txwv rau kev sib koom ua ke muaj xws li kaum rau electron-square planar hlau complexes xws li Vaska's complex.
Dissociative Mechanism yog dab tsi?
Ib qho kev sib cais lossis kev hloov pauv tsis sib xws yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas cov ligands hloov pauv ntawm cov molecules, tso cov ligand los ntawm kev sib koom tes. Nws yog ib txoj hauv kev uas cov tebchaw sib pauv ligands. Cov txheej txheem rov qab ntawm cov txheej txheem no yog kev hloov pauv kev sib koom ua ke. Feem ntau, lo lus no yog siv rau kev sib koom tes thiab organometallic complexes. Cov txheej txheem no zoo ib yam li SN1 txoj hauv kev organic chemistry.
Tsis tas li ntawd, cov complexes uas tuaj yeem hloov pauv tau suav nrog kev sib koom ua ke saturated compounds uas muaj octahedral molecular geometry. Tsis tas li ntawd, nyob rau hauv cov kev tshwm sim no, lub entropy ntawm activation yog tus yam ntxwv zoo, qhia tau hais tias qhov teeb meem ntawm lub reacting system nce nyob rau hauv tus nqi txiav txim kauj ruam.
Qhov txawv ntawm Associative thiab Dissociative Mechanism yog dab tsi?
Qhov sib txawv tseem ceeb ntawm kev sib koom ua ke thiab kev sib koom ua ke yog tias cov txheej txheem sib koom ua ke yog tus cwj pwm los ntawm kev khi ntawm kev tawm tsam nucleophile kom muab qhov sib cais thiab kuaj pom nruab nrab tom qab los ntawm kev poob ntawm lwm ligand whereas lub dissociative mechanisms yog tus cwj pwm los ntawm tus nqi. -Txoj kev txiav txim siab uas suav nrog kev tso tawm ntawm ligand los ntawm kev sib koom ua ke ntawm cov hlau uas tab tom hloov pauv. Nyob rau hauv luv luv, associative mechanisms koom nrog nyob rau hauv khi ib tug tshiab ligand rau lub complex compound whereas dissociative mechanisms koom nyob rau hauv tso ib tug ligand los ntawm complex compound. Tsis tas li ntawd, lub associative mechanism muaj kev sib koom ua ke unsaturated compounds thaum dissociative mechanism muaj coordinatively saturated compounds.
Cov lus hauv qab no qhia txog qhov sib txawv ntawm kev sib koom ua ke thiab kev sib cais ntawm kev nthuav dav ntxiv.
Summary – Associative vs Dissociative Mechanism
Cov ntsiab lus koom nrog thiab kev sib koom ua ke yog siv hauv cov ntawv thov organic synthesis. Qhov sib txawv tseem ceeb ntawm associative thiab dissociative mechanism yog tias cov txheej txheem kev sib koom ua ke yog tus cwj pwm los ntawm kev khi ntawm kev tawm tsam nucleophile kom muab qhov kev txiav txim siab thiab pom tau qhov nruab nrab tom qab los ntawm kev poob ntawm lwm ligand whereas lub dissociative mechanisms yog tus cwj pwm los ntawm tus nqi-kev txiav txim cov kauj ruam uas muaj. kev tso tawm ntawm ligand los ntawm kev sib koom ua ke ntawm cov hlau uas tab tom hloov pauv.
