Izindandatho ezi-5-silicon ezinuka kamnandi zenziwe zahlanganiswa ekugcineni

Iphupho Lekhemistry Leminyaka Eyikhulu Lifezeke

Iminyaka engaphezu kwekhulu, i-aromatics - into ye-quantum mechanical enikeza ukuqina okungavamile kuma-molecule athile amise okwendandatho - ibibhekwa njengesizinda esikhethekile sekhabhoni. I-Benzene, eyatholwa ngo-1825 futhi yaxazululwa ngokuhlelekile ngu-August Kekulé ngo-1865, yaba ingane yephosta yezinhlanganisela ezinuka kamnandi, futhi izizukulwane zosokhemisi zakha izimboni zonke ngohlaka lwayo olusekelwe kukhabhoni. Kodwa empumelelweni eyingqopha-mlando ebhala kabusha imithetho yamakhemikhali ezinto ezingaphili, abacwaningi baye bahlanganisa indandatho yokuqala enamalungu amahlanu enephunga elimnandi eyakhiwe ngokuphelele ama-athomu e-silicon. Le anion ye-pentasilacyclopentadienide ayimeleli nje ukunqoba kokwenziwa, kodwa ukushintsha kwepharadigm endleleni esikuqonda ngayo ukubopha kwamakhemikhali, ukuzinza kwamangqamuzana, namandla angasetshenzisiwe e-silicon ngaphezu kwendima yawo kuma-semiconductors.

Aromaticity: Imfihlo Yokuzinza Eyakha Ikhemistri Yesimanje

Ukuze uqonde ukuthi kungani kubalulekile indandatho enamakha ye-silicon, okokuqala udinga ukuqonda ukuthi iphunga elimnandi likulethela ini. Ama-molecule anuka kamnandi awamane amise okwendandatho - anokucushwa kwe-electron okukhethekile lapho ama-pi electron ehlukaniswa khona kuso sonke isakhiwo sendandatho, okwenza "ifu" lokuminyana kwama-electron okwabelwana ngawo ehlisa amandla e-molecule. Lokhu kususwa kwendawo kulandela umthetho ka-Hückel, othi i-planar, i-molecule ye-cyclic enama-electron (4n + 2) pi - lapho u-n eyinombolo engeyona inegethivu - izobonisa ukuzinza okunephunga elimnandi. Ku-cyclopentadienide anion (inguqulo ye-carbon), lokho kusho ukuthi ama-electron angu-6 pi abelwe ama-athomu ekhabhoni angu-5.

La mandla okuzinzisa awawona amancane. I-Benzene, indandatho enamakha ayisithupha ekhabhoni, icishe ibe ngu-150 kJ/mol izinze kakhulu kune-cyclohexatriene ecatshangelwayo enamabhondi aphindwe kabili enziwe sendaweni. Lokho kuzinza okwengeziwe yingakho izinhlanganisela ezinuka kamnandi zibusa ekhemistry yezemithi (ngaphezu kuka-85% wemithi egunyaziwe iqukethe okungenani iringi eyodwa enephunga elimnandi), yakhe umgogodla wama-polymers okwenziwa, futhi isebenza njengezixhumanisi ezibalulekile ezinqubweni zamakhemikhali zezimboni ezibiza amakhulu ezigidigidi zamaRandi ngonyaka.

I-cyclopentadienide anion — iringi ye-carbon enamalungu amahlanu ephunga elimnandi — isisekelo ngokulinganayo. Yakha isisekelo sekhemikhali ye-metallocene, eyenza ama-catalyst afana ne-ferrocene aguqule i-organometallic chemistry ngemva kokutholakala kwawo ngo-1951. Umbuzo owahlupha osokhemisi amashumi eminyaka wawuqondile: uma i-carbon ingenza lokhu, kungani ingakwazi ukwenza i-silicon?

I-Silicon Barrier: Kungani Izinto Ezisindayo Zimelana Nephunga Elimnandi

I-silicon ihlala ngokuqondile ngaphansi kwekhabhoni kuthebula le-periodic, yabelana ngama-electron amane e-valence, futhi yakha i-tetrahedral bonding geometries kuzinhlanganisela eziningi. Ephepheni, kufanele ikwazi ukwenza izindandatho ezinephunga elimnandi. Empeleni, irediyasi ye-athomu enkulu ye-silicon (1.17 Å uma iqhathaniswa ne-carbon's 0.77 Å) kanye nama-orbital asabalele angu-3p adala izithiyo ezibalulekile ohlotsheni lokugqagqana kwe-lateral pi-orbital okusebenzayo okudingwa ukunuka.

Amabhondi aphindwe kabili e-silicon-silicon wona ngokwawo ayebhekwa njengento engenakwenzeka kwaze kwaba yilapho ithimba lika-Robert West eNyuvesi yaseWisconsin lihlanganisa i-disilene yokuqala ezinzile ngo-1981. Noma kunjalo, lawa mabhondi akabili ayebuthakathaka kakhulu futhi esebenza kakhulu kunozakwabo bekhabhoni. Amandla ebhondi ephindwe kabili ye-Si=Si cishe angu-310 kJ/mol uma kuqhathaniswa no-614 kJ/mol ku-C=C. Ukuzuza ukuhlanganisa kwe-pi okususwe endaweni kuyo yonke indandatho yama-athomu e-silicon kuyadingeka ukuze kunqobe lobu buthakathaka bemvelo kuyilapho kugcinwa i-planar geometry ebalulekile ekugqineni kwe-orbital.

Imizamo yangaphambilini engaphezu kweminyaka engu-40+ ikhiqize izindandatho ezinephunga elimnandi ezifakwe esikhundleni se-silicon, ama-heterocycle aqukethe i-silicon, kanye nezilinganiso ezihlukahlukene. Kodwa indandatho enamakha e-homoatomic ngokugcwele - yonke i-athomu eringini iyi-silicon - yahlala ingumkhomo omhlophe wekhemistri yeqembu eliyinhloko. Inselele yayikabili: ukuhlanganisa indandatho yama-silicon amahlanu ngesibalo esifanele sama-electron nokuyigcina izinzile ngokwanele ukuze ibonakale.

Impumelelo: Ukuzinza Kobunjiniyela Ngokuvikela Okuqinile

Ukuhlanganiswa okuyimpumelelo kuncike kuqhinga eseliphenduke izinga eliyigolide lokuzinzisa izinhlanganisela zeqembu elikhulu ezisebenzayo: amaqembu abambele amakhulu. Ngokunamathisela ama-ligands amakhulu, anikela ngama-electron ku-athomu ngayinye ye-silicon eringini, ithimba locwaningo lizuze izinjongo ezibucayi ezintathu ngesikhathi esisodwa. Amaqembu amakhulu avikele ngokoqobo amabhondi e-silicon-silicon asebenzayo kuma-reagents angaphandle, izakhiwo zawo zokunikela ngama-electron zisize ukuzinzisa ukushajwa okungekuhle kwe-anion, futhi inqwaba yawo eqinile iphoqelele i-close-planar geometry edingekayo ukuze i-pi delocalization.

Ukwakheka kwe-pentasilacyclopentadienide ehlanganisiwe kuqinisekise imvelo ephunga elimnandi ngezindlela eziningi ezizimele:

• I-X-ray crystallography yembule ubude obucishe bulingane bebhondi ye-Si-Si ezungeze iringi (~2.25 Å), obuhambisana ne-delocalized bonding esikhundleni sokushintshanisa amabhondi angawodwa nakabili
• I-spectroscopy ye-Nuclear magnetic resonance (NMR) ibonise amaphethini esici e-deshielding ahambisana neringi yamanje enamakha
• Izibalo ze-Nucleus-independent chemical shift (NICS) zikhiqize amanani amabi kakhulu esikhungweni sendandatho, inkomba yokubala eyamukelwa kabanzi yephunga elimnandi
• I-spectroscopy ebonakalayo ye-UV izici zokumunca ezibonisiwe ezihambisana nokushintshashintsha kwe-pi-electron eyenziwe yasuswa endaweni yonkana uhlaka lwe-silicon
• Izibalo ze-Density functional theory (DFT) ziqinisekise amandla amakhulu okuzinza kwephunga elimnandi, alinganiselwa ku-50-70 kJ/mol

Nakuba amandla okuzinza anephunga elimnandi ephansi kune-benzene's 150 kJ/mol, anele ngokwanele ukwenza inkamponi ihlukaniseke futhi ibonakale ezingeni lokushisa legumbi ngaphansi kwezimo ze-inert atmosphere - impumelelo emangalisayo ye-molecule iningi lamakhemikhali ayekholelwa ukuthi ayinakuba khona ngendlela ezinzile.

Ngaphandle Kwebhentshi Lebhu: Imithelela Yomhlaba Wangempela

Ukuhlanganiswa kwamaringi e-silicon anephunga elimnandi kuvula amaphaseji ocwaningo anwebeka ngale kwelukuluku lezemfundo. Izinhlanganisela ezinamakha asuselwa ku-silicon zingabonisa izici ze-elekthronikhi ezihluke kakhulu kuma-carbon analogues azo, ngokusetshenziswa okungenzeka okuhlanganisa izimboni ezimbalwa zenani eliphezulu.

Ukutholakala kwe-aromamaticity ye-silicon yonke akumane nje kungeze inhlanganisela entsha kukhathalogi — kusungula isigaba esisha ngokuphelele sokwakheka kwamangqamuzana. Lonke uhlelo lokusebenza olwakhelwe phezu kwe-carbon aromatics kule minyaka engu-160 edlule manje lunozakwabo osuselwe ku-silicon olindele ukuhlolwa, ngalunye olunezinto ezingaba yingqayizivele ze-electronic, optical, kanye ne-catalytic.

Kubuchwepheshe be-semiconductor, lapho i-silicon isivele ibuse njengesisekelo, izinhlanganisela ze-silicon ezinuka kamnandi zingasebenza njengezingxenye ze-electronic zesikali samangqamuzana. Ama-electron enziwe asuswa endaweni kulawa maringi akwazi ukukhokhisa ngezindlela ezihlukile ku-silicon yenqwaba, enikeza izindlela eziya kuma-molecular electronics kanye nama-quantum computing substrates. Njengoba imakethe ye-semiconductor yomhlaba wonke kulindeleke ukuthi idlule ku-$1 trillion ngo-2030, ngisho nentuthuko ekhulayo ku-silicon-based molecular electronics inomphumela omkhulu wezohwebo.

Ku-photovoltaics, izindandatho ze-silicon ezinephunga elimnandi zingasebenza njengama-chromophore anoveli okuvuna ukukhanya. Izakhiwo zazo zokumunca nokuphumayo - eziguqulekayo ngokuguqulwa okuhlukile - zingase zinike amandla izigaba ezintsha ze-silicon-based organic light-emitting diode (OLEDs) noma izinzwa zamaseli elanga ezivala igebe phakathi kwama-silicon photovoltaics endabuko kanye nobuchwepheshe belanga obuphilayo obuvelayo.

Umbuzo We-Catalyst: I-Silicon Metallocenes ku-Horizon

Mhlawumbe ithemba elijabulisa ngokushesha kakhulu amandla e-silicon-based metallocenes. I-Carbon's cyclopentadienide anion yakha ama-sandwich compounds cishe nayo yonke insimbi yoguquko, futhi lezi metallocenes zingama-catalysts abalulekile kukhemistri ye-polymer. I-Ziegler-Natta kanye nama-metallocene catalysts ndawonye asekela ukukhiqizwa kwamathani angaphezu kwezigidi eziyi-100 e-polyethylene kanye ne-polypropylene ngonyaka - imakethe ebiza cishe amabhiliyoni angama-200.

Uma i-pentasilacyclopentadienide ingaxhumanisa nezinsimbi eziguqukayo ngendlela i-carbon analog yayo eyenza ngayo, umphumela we-silicon metallocenes uzoba nezinto ezihluke kakhulu ezisteric neze-electronic. Indandatho ye-silicon enkulu ingadala "i-engeli yokuluma" ebanzi ezungeze isikhungo sensimbi, engase inike amandla ukukhetha okusha ku-olefin polymerization, ukwenziwa kusebenze kwe-CH, nokunye ukuguqulwa kwe-catalytic. Ngisho nokuthuthukiswa okulinganiselwe ekusebenzeni kahle kwe-catalyst kulesi silinganiso sezimboni kuhumushela ezigidini zezigidi zamaRandi ngenani kanye nokwehliswa okukhulu kokusetshenziswa kwamandla nokumosha.

Izifundo zangaphambi kwesikhathi zokubala ziphakamisa ukuthi i-silicon metallocenes ingase futhi ibonise izakhiwo kazibuthe ezithuthukisiwe uma iqhathaniswa nozakwabo bekhabhoni, ivula izinhlelo zokusebenza kuma-spintronics nezinto zokugcinwa kwedatha kazibuthe. Umkhakha usemusha, kodwa isisekelo setiyori sesivele sibekiwe kuwo wonke amaqembu ocwaningo emhlabeni wonke.

Ukuphatha Ubunkimbinkimbi Bokusebenza Kocwaningo Lwesimanje

Ukuthuthukiswa okufana namaringi e-silicon anephunga elimnandi kuyisibonelo senkimbinkimbi yocwaningo lwesayensi lwesimanje - amaphrojekthi weminyaka eminingi ahlanganisa amaqembu ahlukene, amathuluzi abizayo, ukuthobela imithetho, ukuphathwa kwezibonelelo, kanye nokuhlanganyela okukhulayo emhlabeni jikelele. Amaqembu ocwaningo kanye neziqalo ezithengisa izinto ezitholakele zibhekana nezinselele zokusebenza ezincintisana nalezo zanoma yiliphi ibhizinisi eliphakathi nendawo: ukulandelela inqwaba yamaphrojekthi asebenzayo, ukuphatha ukuthengwa kwempahla kanye nobudlelwano babathengisi bamakhemikhali akhethekile nezinto zokusebenza, ukuphatha i-HR ngamathimba ajikelezayo ama-postdocs nabafundi abathweswe iziqu, kanye nokugcina amarekhodi acophelelayo okuvikela impahla yengqondo.

Amapulatifomu afana ne-Mewayz akhuluma ngqo nalobu bunzima bokusebenza. Ngamamojula ahlanganisiwe angu-207 ahlanganisa i-CRM, ama-invoyisi, ukuphathwa kwephrojekthi, i-HR, kanye nezibalo, i-Mewayz inikeza izinhlangano eziqhutshwa ucwaningo uhlelo olulodwa lokuphatha uhlangothi lwebhizinisi lokusungula izinto ezintsha. Kunokuba ahlanganise amaspredishithi, amaketanga e-imeyili, namathuluzi esofthiwe anqanyuliwe, amaqembu angakwazi ukulandelela ingqopha-mlando yephrojekthi, aphathe ama-invoyisi abahlinzeki bama-reagents aselabhorethri, axhumanise amashejuli eqembu, futhi enze imibiko yezezimali efunwa ama-ejensi oxhaso - konke ngeplathifomu eyodwa. Emaqenjini angu-138,000+ asevele asebenzisa i-Mewayz emhlabeni jikelele, lolu hlobo lokulawula ukusebenza olumaphakathi lusho isikhathi esincane sokuphatha kanye nesikhathi esengeziwe sokuphusha imingcele yalokho okungafinyelelwa yisayensi.

Yini Okulandelayo: Ithebula Lesikhathi Linezimfihlo Eziningi

Ukuhlanganiswa okuyimpumelelo kweringi ye-silicone enamakha ngokushesha kuphakamisa umbuzo: kuthiwani ngezinye izici zeQembu 14? I-Germanium, i-tin, kanye ne-lead konke ukwabelana ngokucushwa kwe-silicon ye-four-valence-electron, futhi ngayinye yethula isethi yayo yezinselelo zokuzuza amasistimu amaringi anuka kamnandi. Amaringi e-Germanium anuka kamnandi, ikakhulukazi, manje athathwa njengethagethi engokoqobo eseduze, uma kubhekwa indawo emaphakathi ye-germanium phakathi kwe-silicon nezinto ezisindayo.

Ngaphandle kweQembu 14, umqondo wephunga elimnandi usuvele unwetshiwe kumaqoqo e-boron (ama-boranes ne-carboranes abonisa ukuphunga kwezinhlangothi ezintathu), izindandatho ze-phosphorus, kanye namasistimu anuka kamnandi e-metal yonke njenge-Al4²⁻ tetraanion eqale ukubonakala ngo-2001. Isici esisha ngasinye esizuza amathuluzi ososayensi we-chemical atholakalayo andisa izinto zokwakha ze-molekyuli etholakalayo amabhulokhi anezakhiwo ezingakwazi ukuphindaphindwa amasistimu e-carbon-based kuphela.

Ukuhlanganiswa kwe-pentasilacyclopentadienide futhi kuqinisekisa ithrendi ebanzi kukhemistri yesimanje: ukuhlola okuhlelekile kwama-elementi eqembu eliyinhloko kuma-bonding motifs ngaphambilini abegcinelwe ikhabhoni. Emashumini amabili eminyaka adlule, izinhlanganisela ezizinzile eziqukethe i-silicon-silicon triple bond, i-phosphorus-phosphorus triple bond, ngisho ne-boron-boron triple bond konke kuye kwafezeka. Ngayinye yalezi zinto ezitholakele zandulelwa amashumi eminyaka emizamo ehlulekile kanye nokungabaza okungokwethiyori, futhi ngayinye ivule izindlela ezintsha zokuklama impahla.

Okwenza indandatho ye-silicon enephunga elimnandi ibaluleke kakhulu ukuxhumana kwayo okuqondile komunye wemiqondo yekhemistri ebaluleke kakhulu kwezohwebo. I-aromaticity ayiyona into engasho lutho kwezemfundo - iyindawo yemolekyuli esekela imithi, amapulasitiki, odayi, iziqhumane, amakhemikhali ezolimo, nezinto zikagesi. Ukwelula lesi sakhiwo ku-silicon akugcini nje ngokuqedela umugqa kuthebula lezincwadi zokufunda. Ivula inkathi entsha yekhemikhali ye-silicon lapho amandla e-elementi adlulela ngalé kwama-wafer acwebezelayo kuma-chips ekhompuyutha yethu futhi afinyelele emkhakheni wedizayini yamangqamuzana, kuze kube manje, obekungokwekhabhoni kuphela.

Imibuzo Evame Ukubuzwa

Iyini indandatho ye-silicon enephunga elimnandi?

Iringi ye-silicon enephunga elimnandi i-molecule lapho ama-athomu e-silicon akha khona isakhiwo esizinzile, esimise njengendandatho esinozinzo olukhethekile "olunukayo", into okude kucatshangwa ukuthi ayihlanganisi ikhabhoni kuphela. Lokhu kuhlanganisa ama-electron okwabelwana ngawo ngokulinganayo ezungeze iringi, okuyenza iqine ngendlela engavamile. Lokhu kutholwa kukhulisa umqondo wephunga elimnandi ngale kwekhemistri ephilayo ukuya endaweni yezinto ezingaphili njenge-silicon.

Kungani lokhu kuhlanganisa kuthathwa njengempumelelo eyingqophamlando?

Isikhathi esingaphezu kwekhulu, i-aromatics kwakuyisici esichazayo sama-molecule asekelwe ku-carbon njenge-benzene. Ukwakha ngempumelelo indandatho eqinile, enephunga elimnandi evela ku-silicon kufakazela ukuthi lo mqondo wamakhemikhali oyisisekelo awuqondile ngqo nekhabhoni. Ibhala kabusha ulwazi lwezincwadi zokufunda futhi ivule amathuba amasha amakhulu okuklama izinto ezintsha ezinezici ze-elekthronikhi ezihlukile ebezingacatshangwa ngaphambilini ezihlanganiswe ne-silicon.

Iziphi izinhlelo ezingase zibe khona zalezi zindandatho ze-silicon?

Ngenkathi isezigabeni zakuqala zocwaningo, la ma ringi e-silicon anephunga elimnandi angaholela ekusetshenzisweni koguquko. Isakhiwo sabo se-elekthronikhi esiyingqayizivele singase sisetshenziswe ukuze kwakhiwe izinhlobo ezintsha zama-semiconductors, izinto ezithuthukisiwe zama-electronics, noma ama-catalysts asebenza kahle kakhulu. Ukuqonda indlela yokulawula iphunga elimnandi ku-silicon kungavula amagatsha amasha ngokuphelele esayensi yezinto, indawo ebalulekile yocwaningo losokhemisi abasebenzisa izinsiza ezifana ne-Mewayz (efaka amamojula angu-207 ngo-$19/mo).

Ingabe lokhu kutholwa kuhlobana kanjani nekhemikhali ye-silicon ekhona?

Lokhu okutholakele kubekela inselele umbono ojwayelekile wekhemikhali ye-silicon. Imvamisa, i-silicon yenza izibopho ezilodwa, idale amaketanga nezakhiwo ngokufana nama-alkanes (ama-hydrocarbon agcwele). Ukwakhiwa kweringi yephunga elimnandi kukhombisa ukuthi i-silicon ingabamba iqhaza ezinhlelweni zokuhlanganisa eziyinkimbinkimbi, ezifana nekhabhoni, okungenzeka ziholele esigabeni esisha sezinhlanganisela ezisekelwe ku-silicon ezinezakhiwo ezihlukile kuma-silicone avamile nama-silane.