Fullerene - dab tsi yog qhov no? Properties thiab daim ntaub ntawv ntawm fullerenes

Molecular allotropic daim ntawv ntawm cov pa roj carbon los yog nws cov kev hloov kho, fullerene, - ib tug kab C _{n (n>} 20) atomic pawg ua ke, uas raug kaw convex polyhedra ua ntawm carbon atoms thiab muaj ib tug pentagonal los yog hexagonal ntsej muag (nyob ntawm no muaj tsawg heev zam). Carbon atoms nyob rau hauv lub unsubstituted fullerenes yuav tau sp ² -Hybrid lub xeev nrog ib tug sib haum tooj ntawm 3. Yog li no tsim ib tug kheej kheej conjugate unsaturated system raws li valence daim ntawv cog lus kev tshawb xav.

piav

Qhov tseem thermodynamically ruaj khov nyob rau hauv ib txwm tej yam kev mob hauv daim ntawv ntawm cov pa roj carbon - graphite, uas zoo li ib pawg tsis yog kev cob cog rua nrog txhua lwm yam graphene los xij: ib tug ca lattice, muaj raws ntawm hexagonal hlwb, qhov chaw uas vertices - carbon atoms. Txhua yam ntawm lawv yog txuam nrog peb neighboring atoms, thiab cov plaub valence electron ntaub ntawv ib tug pi-system. Yog li ntawd, fullerene - nws yog precisely no molecular daim ntawv, piv txwv li hauv daim duab sp ² -Hybrid lub xeev yog cuab kev. Yog hais tias peb qhia nyob rau hauv lub graphene daim ntawv geometrical tsis xws luag inevitably ntaub ntawv ib tug kaw qauv. Piv txwv li, xws tsis xws luag muaj tsib-membered rings (pentagonal ntsej muag), raws nraim tib yam, nrog rau ntau hexagonal carbon Science News for KIDS.

Euler tus theorem hais tias zus tau tej cov ib tug kaw polyhedron nrog vertices trohkoordinirovannymi tau yog hais tias peb ua kom paub kaum ob pentagons, tsis hais txog ntawm lub xov tooj ntawm hexagonal ntsej muag. Li no, qhov tsawg kawg nkaus loj ntawm ib tug fullerene - yog thawm xyoo C ₂₀ dodecahedron. Txawm li cas los curvature zoo xws li cov lug, muaj ib tug me me muaj pes tsawg tus ntawm cov pa roj carbon atoms yog high school, thiab yog li ntawd kom SP ² -Hybrid lub xeev yog tsis heev dej siab, vim cov pa roj carbon prefers planar kom sib haum. Yog vim li cas qhov tsawg tshaj plaws nyob rau hauv nws cov ntshiab daim ntawv tau fullerene - yog C _60, muaj tus qauv ntawm ib truncated kev icosahedron. Nyob rau hauv nws hexagonal ib sab yuav sib cais los ntawm txhua lwm yam tag nrho cov pentagonal. Fullerene Science News for KIDS hu no qhov tseeb cais pentagon txoj cai, thiab nws yog ib yam kev kawm mus rau ib tug tiag tiag siv tau fullerene.

mis

Gidrantirovanny denoted C ₆₀ fullerene (C ₆₀ HyFn). Qhov no check hydrophilic supramolecular complex, uas muaj ib tug qauv ntawm cov fullerene C ₆₀ nyob rau hauv thawj plhaub hydrant thiab nees nkaum plaub dej lwg me me. Qhov no yog qhov fullerene uas nws mis - C ₆₀ (H ₂ O) _24. Nws muaj nees nkaum hexagons thiab kaum ob pentagons, outwardly li ib lub npas. Ntxiv mus, ib tug xov tooj ntawm fullerene C ₇₀ pab raws li intermediate lug, uas yuav ua tau tag nrho cov pentagons yog raug rho tawm, tsis muaj nyob. Txij li thaum C ₇₈ fullerene qauv tso cai rau kom saib ob peb ruaj khov isomers ntawm txhua carbon lub cev pob txha. Raws nws yog tau hais tias muaj fullerenes nrog carbon atoms ntawm tej txawm tooj, "ntau dua fullerenes".

Qhov npaj ntawm fullerenes los ntawm arc tshwm sim ntau zaus los yog electron-beam txoj kev thiab los ntawm laser evaporation ntawm graphite nyob rau hauv ib tug Helium cua. Soot, uas condenses rau ntawm qhov chaw ntawm lub reactor, yog kho nyob rau hauv refluxing benzene, toluene, xylene los yog lwm yam organic kuab tshuaj. Cov tshuaj yog evaporated, txoj kev ua ib tug dub condensate, kaum mus rau kaum tsib ib xees uas muaj C ₇₀ thiab C ₆₀ fullerenes raws li tej yam me me ntawm ntau dua fullerenes.

Qhov ratio ntawm txawv furellenami tej zaum yuav txawv, nyob ntawm seb lub synthesis tsis, tab sis feem ntau ₆₀ C prevails, nws yog ob peb lub sij hawm ntau. Ntawm cov feem ntau ntau tshaj C _78, C ₇₆ thiab C _84. Nyob rau hauv lub dav dav daim duab muaj ib tug poob rau hauv kev faib ua feem ntawm fullerene synthesis ntawm tag nrho cov khoom. Qhov no yog vim, feem ntau yuav, nrog ib tug tsawg yuav qhov muaj tseeb ntawm assembling loj lug ntawm me me pawg chiv evaporated.

Dej muaj fullerenes

Cov ntau heev thiab feem kawm yog C _60, nyob qhov twg ib tug qauv ntawm cov tshuaj yeeb dej caw ua tau muaj nees nkaum plaub dej lwg me me. Qhov no fullerene molecule muaj ib tug high symmetry, qhov twg tag nrho cov atoms yog sib npaug. Nws kheej kheej daim ntawv no yog cov kev coj ntawm qhov chaw ntawm lub atomic nuclei mus txog 0,36 nm thiab ib lub vojvoog ntawm hais txog 0.5 nm. Nws cov ntaub ntawv ib tug molecular siv lead ua nyob rau hauv uas molecules yog lub ntsej muag-rau nruab nrab nyhav lattice, peb txheej densest kheej kheej packing. Thaum kub, ₆₀ C sublimes tsis muaj txoj kev ua ib theem ua kua. Qhov zoo tshaj plaws ntawm tag nrho cov nws yog yaj nyob rau hauv lub muaj ntxhiab tshuaj ntawm lub hom ntawm cov pa roj carbon disulfide kuab tshuaj, thiab ncov qaumteb qabteb - heev npaum li cas. Ib tug elongated ellipsoidal zoo ₇₀ C, raws li zoo raws li siab dua fullerenes muaj lub zog zoo heev rau C _60.

Thiab nyob rau hauv lub tshav pob ntawm Science News for KIDS lawv yog cov ntau ntau lub siab dawb siab thiab muab txhua lub sij hawm kom tau lawv kawm txawv ntawm derivatives: Metallofullerenes, heterofullerene. Tsev Neeg ntawm cov khoom richer tag nrho ekzoendralnogo (outer-) kev twb kev txuas, vim hais tias txhua carbon atom - muaj cov tshuaj tiv thaiv qhov chaw. Cov no yog cov khoom ntawm fullerenes. Lawv tuaj koom los ntawm kev tsim tshiab khoom, halogen atoms thiab hydrogen, organic radicals, koom txawm mus yuav tshwm sim. Yog li tau polymer ntaub ntawv uas muaj fullerenes Multigrade compound. ₆₀ K C koom rau plaub caug yim substituents tsis rhuav tseg cov pa roj carbon lub cev pob txha. Yog li, piv txwv li, los ntawm C ₆₀ F _48, thiab ntau yam zoo li tebchaw yog ntaub, nyob rau lub hauv paus yog fullerenes.

daim ntawv thov

Yuav luag fullerenes xav nyob rau hauv sib txawv kiag li cov cheeb tsam. Nyob rau hauv view ntawm lawv hluav taws xob zog yuav suav hais tias lawv thiab lawv derivatives li semiconductors. Fullerenes nkag nqus UV tawg, lawv muaj siab electron-thim muaj peev xwm. Tag nrho cov zog ua rau nws tau mus thov lawv nyob rau hauv lub photovoltaic, photoelectric sensors, hnub ci-powered pab kiag li lawm uas muaj ntau yam molecular electronics. Fullerenes yog siv nyob rau hauv cov tshuaj raws li antiviral thiab antimicrobial agents, raws li cov neeg ua hauj nyob rau hauv photodynamic txoj kev kho thiab m. P.

Niaj hnub nimno yees tau tso cai kuj sai sai rau kom tag nrho cov xov tooj ntawm chav nyob kom tau ntau fullerenes kuj zoo thiab ntau npaum ua hauj lwm txoj kev rau lawv cov kev kho mob. Uas yog vim li cas tus nqi ntawm, piv txwv li, C ₆₀ tau tsis yeem tshuam tshaj yav dhau los xyoo caum thiab ib tug ib nrab (nrog kaum txhiab mus rau kaum mus rau kaum tsib las rau ib gram). Tam sim no peb yuav ntsib nrog ib tug teeb meem uas rau tiag tiag muaj daim ntaub ntawv thiab fullerenes poob mus rau tus neeg. Lawv siv yog loj hlob thiab loj hlob txhua txhua hnub.

Rau cov lus qhia txog qhib

Fullerenes muaj npe tom qab tus naas ej vajtse thiab engineer Richarda Bakminstera Fullera, uas nyob rau hauv lub hauv paus ntawm lawv cov qauv invented lub geodesic qauv. Thaum xub thawj, qhov no hauv chav kawm ntawv ntawm tebchaw yog tas rau cov qauv, uas muaj lub nkaus xwb rau-thiab pentagonal ntsej muag. Yog hais tias muaj pes tsawg leeg ntawm lub fullerene molecule nyob rau hauv tas li ntawd rau cov atoms yog tam sim no ntau yam tshuaj hais, thiab lawv nyob hauv cov pa roj carbon lub cev pob txha, cov neeg hu ua endohedral fullerenes. Yog hais tias lub atoms ntawm lwm yam ntsiab yog nyob sab nraum lub fullerenes yog tau exohedrally. Lawv cov npe, qhov no molecular daim ntawv yog tsis heev ntev dhau los - nyob rau hauv 1985, thaum ib pab pawg neeg ntawm kev soj ntsuam ua tus npaj txhij txog discovery ntawm fullerene. Me me, Kroto, Caws thiab lwm yam chemists kawm graphite officers uas tau muab los ntawm laser ablation (irradiation) khoom. peaks twb pom uas muaj ib tug ib txhis amplitude coj mus rau lub pawg ntawm cov caum thiab xya caum carbon atoms.

Yog li ntawd peb xam cov molecule C ₆₀ thiab C _70, raws li zoo raws li lub hypothesis hais tias cov thawj molecule yog ua nyob rau hauv tus duab ntawm ib tug truncated icosahedron. Nws yog feem ntau C ₆₀ lub npe hu ua bakminsterfullerenom thiab tus so ntawm lub molecule - cia li fullerenes.

Zaum-chemists zoo versed nyob rau hauv architecture thiab nco Fuller, leej twg los ua lub dome rau lub vaj tse yog li - pentagons, hexagons cloven, uas yog lub hauv paus ntawm cov qauv ntawm cov molecular skeletons kiag li tag nrho cov fullerenes. Txawm li cas los, qhov no yog - ib tug fascinating zaj dabneeg, thiab tsis yog tsis muaj ib qho kev nthuav keeb kwm. Nyob rau hauv lub hav zoov ntawm xws molecules dog dig ua ntej lawm nws sau nyob rau hauv Nyiv (1971), thiab lub theoretical lub hauv paus twb tau thiab luam tawm nyob rau hauv lub USSR (1973). Cuaj kaum, nws Kroto, caws thiab Me txais lub Nobel nqi zog nyob rau hauv Science News for KIDS.

Xwm thiab technology

Kev npaj ntawm ntshiab fullerene yog tau los ntawm kev dag synthesis. Cov tebchaw ntxiv sib kawm nyob rau hauv ntau lub teb chaws, qhov chaw kawm tej yam kev mob nyob rau hauv uas lawv tsim tshwm sim, thiab yog pom tias fullerene qauv thiab lawv lub zog. Ib qho kev nce loj hlob teb ntawm daim ntawv thov. Nws pom hais tias ib tug tseem ceeb npaum li cas ntawm fullerenes muaj nyob rau hauv lub soot, uas yog tsim nyob rau graphite electrodes nyob rau hauv ib tug arc tawm. Nyuam qhuav pib no fact tsuas yeej tsis tau pom dua.

Thaum lub fullerenes tau ua nyob rau hauv laboratory tej yam kev mob, carbon molecules thiab pib yuav ntes tau nyob rau hauv cov xwm. Nyob rau hauv Karelia, peb pom lawv nyob rau hauv shungites kuaj, Is Nrias teb thiab hauv lub tebchaws United States - nyob rau hauv furulgitah. Tsis tas li ntawd muaj ntau yam thiab nquag carbon molecules nyob rau hauv meteorites thiab sediments nyob rau hauv qab, uas yog tsis tsawg tshaj li rau caum-tsib lab lub xyoo. Nyob rau lub ntiaj teb ntshiab fullerenes peev xwm yuav tsim los ntawm xob laim thiab lub combustion ntawm tej yam ntuj tso pa. Cua kuaj noj lub Mediterranean, tau kawm nyob rau hauv 2011, thiab nws tau pom tias tag nrho cov kuaj noj - los ntawm Istanbul rau Barcelona - muaj ib tug fullerene. Lub cev thaj chaw ntawm lub substance ua rau lub txawj tsim. Tsis tas li ntawd lossis loj nyiaj ntawm nws muaj nyob rau hauv qhov chaw - thiab nyob rau hauv lub gaseous lub xeev, thiab nyob rau hauv ib tug khoom daim ntawv.

synthesis

Tus thawj thwmsim ntawm kev rho tawm ntawm fullerenes tshwm sim los ntawm condensed vapors ntawm graphite, uas twb tau los ntawm irradiation ntawm laser irradiation cov khoom graphite kuaj. Muaj kev tswj kom tau xwb ib co kua nplaum ntawm fullerenes. Tsuas yog nyob rau hauv 1990 los ntawm chemists Huffman, Me Nyuam Yaj thiab Kretschmer tsim ib tug tshiab txoj kev zus tau tej cov fullerenes nyob rau hauv gram ntau. Nws muaj nyob rau hauv kub graphite electrodes los ntawm ib tug hluav taws xob arc nyob rau hauv ib qho chaw ntawm Helium thiab nyob rau hauv tsis tshua muaj siab. Yog lub yaig ntawm lub anode thiab lub chamber phab ntsa los tshwm rau muaj hmoov quav muaj fullerenes.

Ntxiv mus, muaj hmoov quav yog yaj nyob rau hauv toluene los yog benzene, thiab lub resulting tov sawv grams ntshiab molecules C ₇₀ thiab C _60. Piv - 1: 3. Tsis tas li ntawd, ib tug tov muaj hnyav thiab ob feem pua siab dua thiaj fullerenes. Tam sim no nws yog ib qho yooj yim: xaiv qhov pom tsis rau evaporating - nyob tus yeees ntawm cov cua, siab, electrode txoj kab uas hla, tam sim no thiab thiaj li nyob, mus cuag lub siab tshaj plaws tawm los ntawm fullerenes. Lawv mus mus txog kaum ob feem pua ntawm lub sij anode khoom. Uas yog vim li cas thiaj kim fullerenes yog.

ntau lawm

Tag nrho cov me nyuam no yuav sim zaum thaum xub thawj nyob rau hauv vain: cov khoom thiab cheaper txoj kev ua fullerenes yog. Tsis yog tus twg lub nplaim hluav taws ntawm hydrocarbons los yog tshuaj synthesis twb hai. hluav taws xob arc txoj kev tau lub feem ntau tsim, tso cai rau koj yuav tau txais txog ib gram ntawm fullerenes ib teev. Lub tuam txhab Mitsubishi tau tsim ib tug qauv ntawm cov raug lub combustion ntawm hydrocarbons, tab sis lawv yuav tsis ntshiab fullerenes - lawv muaj oxygen molecules. Thiab kom deb li deb nws tseem paub tsis meej lub mechanism ntawm tsim ntawm no yeeb tshuaj, vim hais tias cov arc dab yog cov tsis tshua tsis ruaj tsis khov los ntawm ib tug thermodynamic taw tes ntawm view, thiab nws yog heev xav cheeb saib xyuas ntawm qhov kev tshawb xav. Tsuas yog irrefutable pov thawj uas sau ib tug neeg fullerene carbon atoms, i.e. C ₂ thooj. Txawm li cas los, qhov tseeb daim duab ntawm lub tsim ntawm no substance tsis tau tsim.

Cov nqi ntawm fullerene yog txiav txim tsis tsuas tsis muaj loo thaum hlawv. Rho tawm, purification, sib cais ntawm fullerenes ntawm txawv masses ntawm hmoov quav - tag nrho cov kev yog heev. Tshwj xeeb tshaj yog nws kev txhawj xeeb cais cov sib tov rau hauv cais molecular fractions, uas yog nyob rau ntawm kua kem chromatography thiab kub siab. Thaum kawg theem ntawm kuab residues raug muab tshem tawm los ntawm lub twb khoom fullerene. No qauv yog khaws cia nyob rau hauv dynamic lub tshuab nqus tsev ntawm ib tug kub ntawm txog li ob puas thiab tsib caug degrees. Tab sis qhov kom zoo dua yog tias thaum lub sij hawm txoj kev loj hlob ntawm fullerene C ₆₀ thiab tau txais nws nyob rau hauv macroscopic ntau twb organic Science News for KIDS tau zus ywj siab ceg - lub Science News for KIDS ntawm fullerenes, uas tau ua incredibly nrov.

kev pab

Fullerene derivatives yog siv nyob rau hauv ntau yam teb ntawm technology. Foils thiab fullerene muaju - semiconductor muaj photoconductivity nyob rau hauv kho qhov muag irradiation. Muaju C _60, Yog hais tias doped atoms ntawm alkaline co, hloov mus rau ib lub xeev ntawm superconductivity. fullerene kev daws teeb meem muaj nonlinear kho qhov muag zog, thiab yog li ntawd yuav siv tau raws li lub hauv paus ntawm kho qhov muag shutters uas tsim nyog rau kev pab tiv thaiv los ntawm qhov khaus tawg. Tsis tas li ntawd fullerene siv raws li ib lub hauv paus rau pob zeb diamond synthesis. Fullerenes yog lug siv nyob rau hauv ib thiab tshuaj. Nws ntiav peb thaj chaw ntawm cov molecules: kev txiav txim membranotropnyh lipophilicity, elektronodefitsit muab peev xwm sis raug zoo nrog dawb radicals, tab sis kuj muaj peev xwm mus hloov cov pa molecule pa lawv tus kheej zoo siab heev li lub xeev thiab tig lub oxygen singlet.

Tej reactive tshuaj tua biomolecules: nucleic acids, cov nqaijrog, lipids. Reactive pa hom yog siv nyob rau hauv photodynamic txoj kev kho rau kev kho mob cancer. Tus neeg mob cov ntshav yog tswvcuab photosensitizers, generating reactive pa hom - ua tau fullerenes los yog derivatives thereof. Cov ntshav txaus nyob rau hauv lub qog yog weaker tshaj nyob rau hauv kev noj qab nyob ntaub so ntswg, thiab vim hais tias photosensitizers noog nyob rau hauv nws, thiab tom qab lub irradiation kev taw qhia ntawm cov molecule yog zoo siab heev los ntawm generating reactive pa hom. kev mob hlwb muaj kev puas ntsoog, thiab cov qog puas lawm. Nyob rau hauv Ntxiv rau cov uas - fullerenes muaj antioxidant zog thiab cuab reactive pa hom.

Fullerene txo HIV integrase kev ua si, ib tug protein uas yog lub luag hauj lwm rau lub koom ua ke ntawm tus kab mob no mus rau hauv lub DNA los ntawm interacting nrog nws los hloov tus conformation thiab depriving nws ntawm wrecking lub ntsiab muaj nuj nqi. Ib txhia ntawm fullerene derivatives INTERACTIONS ncaj qha nrog DNA thiab inhibit qhov kev txiav txim restiktaz.

Ntxiv txog cov tshuaj

Nyob rau hauv 2007, cov dej-soluble fullerenes pib yuav tsum tau siv rau kev noj mov rau lawv raws li antiallergic agents. Kev tshawb fawb tau ua rau tib neeg cov ntshav thiab hlwb uas tau raug fullerene derivatives - C60 (net) x thiab C60 (OH) x. Nyob rau hauv thwmsim rau muaj sia nyob - nas - soj ntsuam tau zoo.

Twb, ib yam khoom uas siv raws li ib tug yeeb tshuaj tus me nyuam vector, vim hais tias cov dej uas muaj fullerenes (txheejtxheem hydrophobicity C ₆₀₎ penetrates rau hauv lub cell daim nyias nyias yog heev yooj yim. Piv txwv li, erythropoietin - raum lawm nkag mus hauv ncaj qha mus rau hauv cov hlab ntsha, yog degraded nyob rau hauv ib tug tseem ceeb npaum li cas, thiab yog hais tias nws yog siv ua ke nrog fullerenes, lub concentration nce mus rau ntau tshaj ob npaug, vim hais tias nws tau txais mus rau hauv lub cell.