Qhov sib txawv tseem ceeb ntawm singlet thiab triplet carbene yog tias singlet carbenes yog spin-paired whereas triplet carbenes muaj ob unpaired electrons.
A carbene yog ib pab pawg ua haujlwm hauv cov organic chemistry. Nws muaj ob lub plhaub valence electrons uas tsis koom nrog kev sib txuas. Cov mis loj rau pawg no yog R-(C:)-R' lossis R=C: uas "R" yog ib qho hydrogen atom lossis alkyl hloov pauv. Peb tuaj yeem faib cov carbenes ua ob pawg ua singlets lossis triplets nyob ntawm cov qauv hluav taws xob.
Single Carbene yog dab tsi?
Singlet carbene yog ib hom carbene pawg uas tsis muaj cov khoom siv hluav taws xob tsis sib xws. Yog li ntawd, peb hu nws ua "spin-paired carbene". Tag nrho cov spin ntawm cov pab pawg no yog xoom. Hom carbene pawg no muaj sp2 hybrid qauv. Cov no yog diamagnetic vim tias tsis muaj cov electrons tsis sib xws. Ntxiv mus, singlet carbene pawg muaj 102 ° daim ntawv cog lus lub kaum sab xis. Cov pab pawg no feem ntau tshwm sim hauv aqueous media vim tias cov no tsis ruaj khov hauv lub xeev gaseous.
Daim duab 01: Qhov yooj yim Carbene yog Methylene
Thaum xav txog qhov kev ua haujlwm ntawm singlet carbene pawg, lawv feem ntau koom nrog cov tshuaj tiv thaiv cheletropic los ntawm kev ua raws li electrophile lossis nucleophiles. Yog li ntawd, cov tshuaj tiv thaiv ntawm lawv yog stereospecific.
Triplet Carbene yog dab tsi?
Triplet carbene yog ib hom carbene pawg uas muaj ob lub electrons tsis sib xws. Lub geometry ntawm pawg no tuaj yeem yog linear lossis bent. Yog hais tias nws yog linear geometry, ces nws muaj sp hybrid qauv. Tab sis yog hais tias nws yog bent geometry, ces nws muaj sp2 hybrid qauv. Txawm li cas los xij, feem ntau ntawm cov sij hawm, triplet carbene muaj cov duab tsis-linear tshwj tsis yog rau cov uas muaj nitrogen, oxygen, lossis sulfur atoms. Ntxiv mus, lub kaum sab xis rau cov pab pawg no yog 125-140 °.
Daim duab 02: Qhov txawv ntawm Singlet thiab Triplet Carbene Geometries
Vim muaj triplet carbene, lawv yog paramagnetic. Yog li ntawd, peb tuaj yeem soj ntsuam lawv ntawm electron spin resonance spectroscopy. Tag nrho cov spin ntawm cov carbenes yog ib qho. Feem ntau, cov pab pawg no ruaj khov ntawm lawv lub xeev gaseous. Thaum xav txog qhov reactivity ntawm triplet carbene, lawv ua raws li diradicals thiab tuaj yeem koom nrog hauv cov kev tawm tsam radical. Txawm li cas los xij, tsis zoo li singlet carbene, cov carbenes triplet no yuav tsum tau mus los ntawm ib qho nruab nrab nrog ob lub electrons tsis sib xws. Cov tshuaj tiv thaiv uas lawv tau txais yog stereoselective.
Qhov txawv ntawm Singlet thiab Triplet Carbene yog dab tsi?
Carbenes yog cov organic ua haujlwm uas muaj cov tshuaj formula R-(C:)-R' lossis R=C: Muaj ob hom carbenes li singlet carbene thiab triplet carbene nyob ntawm cov qauv hluav taws xob. Yog li ntawd, qhov sib txawv tseem ceeb ntawm singlet thiab triplet carbene yog tias singlet carbenes yog spin-paired whereas triplet carbenes muaj ob unpaired electrons. Muaj ntau qhov sib txawv ntawm singlet carbene thiab triplet carbene xws li qhov sib txawv ntawm lawv cov geometry, hybrid qauv, tag nrho cov kiv, cov ces kaum, cov khoom sib nqus, thiab lwm yam.
Cov lus qhia hauv qab no nthuav tawm cov ntaub ntawv ntxiv ntawm qhov sib txawv ntawm singlet thiab triplet carbene hauv daim ntawv teev npe.
Summary – Singlet vs Triplet Carbene
Carbene yog nyob rau hauv ob hom loj li singlet carbene thiab triplet carbene raws li lawv cov qauv hluav taws xob. Qhov sib txawv tseem ceeb ntawm singlet thiab triplet carbene yog tias singlet carbenes yog spin-paired whereas triplet carbenes muaj ob unpaired electrons.
