Siyabonga ngokuvakashela i-Nature.com. Inguqulo yesiphequluli osisebenzisayo inokusekelwa okulinganiselwe kwe-CSS. Ukuze uthole imiphumela emihle kakhulu, sincoma ukuthi usebenzise inguqulo entsha yesiphequluli sakho (noma ukhubaze i-Compatibility Mode ku-Internet Explorer). Okwamanje, ukuqinisekisa ukwesekwa okuqhubekayo, sibonisa isayithi ngaphandle kwesitayela noma i-JavaScript.
I-Formic acid ingenye yezindlela ezithembisayo kakhulu zokugcina i-hydrogen ewuketshezi isikhathi eside. Lapha sethula uchungechunge lwezinhlanganisela ezintsha ze-ruthenium clamp ezinefomula ejwayelekile [RuHCl(POP)(PPh3)] sisebenzisa ama-ligand e-xanthos-type tridentate POP clamp atholakala kwezentengiselwano noma akhiwe kalula. Sisebenzise la ma-complex ukukhipha i-formic acid ukuze sikhiqize i-CO2 ne-H2 ngaphansi kwezimo ezithambile, ezingenayo i-reflux sisebenzisa i-ionic liquid BMIM OAc (1-butyl-3-methylimidazolium acetate) njenge-solvent. Ngokombono wemvamisa yokuguquka okukhulu, i-catalyst ephumelela kakhulu yi-[RuHCl(xantphos)(PPh3)]Ru-1 complex eyaziwa ezincwadini, enemvamisa yokuguquka ephezulu engu-4525 h-1 ku-90 °C imizuzu eyi-10. Izinga lokuguqulwa ngemuva kokuguqulwa lalingu-74%, futhi ukuguqulwa kwaqedwa zingakapheli amahora ama-3 (>98%). Ngakolunye uhlangothi, i-catalyst enekhono elihle kakhulu, inoveli [RuHCl(iPr-dbfphos)(PPh3)]Ru-2 complex, ikhuthaza ukuguqulwa okuphelele ngaphakathi kwehora eli-1, okuholela esilinganisweni sokujika okuphelele esingu-1009 h-1. Ngaphezu kwalokho, umsebenzi we-catalytic wabonwa futhi emazingeni okushisa afinyelela ku-60 °C. Esigabeni segesi, kwabonwa i-CO2 ne-H2 kuphela; i-CO ayizange itholakale. I-high-resolution mass spectrometry ibonise ukuba khona kwe-N-heterocyclic carbene complexes engxubeni yokusabela.
Isabelo semakethe esikhulayo samandla avuselelekayo kanye nokuguquguquka kwawo kuholele ekudingweni kobuchwepheshe bokugcina amandla obusezingeni lezimboni emkhakheni wamandla, okushisa, wezimboni kanye nowezokuthutha1,2. I-Hydrogen ibhekwa njengenye yezinkampani zamandla ezitholakala kakhulu3, futhi izinkampani ze-hydrogen eziphilayo eziwuketshezi (ama-LOHC) muva nje sezigxile ocwaningweni, zinikeza isithembiso sokugcina i-hydrogen ngendlela ecutshungulwa kalula ngaphandle kwezinkinga ezihambisana nokucindezela noma ubuchwepheshe be-cryogenic4. ,5,6. Ngenxa yezakhiwo zazo zomzimba, iningi lengqalasizinda yezokuthutha ekhona yephethiloli kanye nezinye izinto zikaphethiloli eziwuketshezi zingasetshenziswa ukuthutha i-LOHC7,8. Izakhiwo zomzimba ze-formic acid (FA) zenza kube yinto ethembisayo yokugcina i-hydrogen enokuqukethwe kwesisindo se-hydrogen okungu-4.4%9,10. Kodwa-ke, izinhlelo ze-catalytic ezishicilelwe zokukhishwa kwe-formic acid ngokuvamile zidinga ukusetshenziswa kwezinyibilikisi eziphilayo eziguquguqukayo, amanzi noma i-formic acid emsulwa,11,12,13,14 okungadinga ukusetshenziswa kwamasu okuhlukanisa umusi we-solvent njengokuqina, okungaholela ezinkingeni ezinhlelweni zabathengi. izicelo, umthwalo owengeziwe. Le nkinga inganqotshwa ngokusebenzisa izinyibilikisi ezinengcindezi encane yomhwamuko, njenge-ionic liquids. Ngaphambilini, iqembu lethu elisebenzayo libonise ukuthi i-ionic liquid butylmethylimidazolium acetate (BMIM OAc) iyi-solvent efanelekile kulokhu kusabela kusetshenziswa i-Ru-PNP Ru-MACHO type 15 etholakala kwezentengiselwano. Isibonelo, sibonise i-FA dehydrogenation ohlelweni lokugeleza okuqhubekayo sisebenzisa i-BMIM OAc, safinyelela i-TON engaphezu kwe-18,000,000 ku-95°C. Nakuba ezinye izinhlelo sezifinyelele i-TON ephezulu ngaphambilini, eziningi ziye zathembela ezinyibilikisini eziphilayo eziguquguqukayo (njenge-THF noma i-DMF) noma izithasiselo ezisetshenzisiwe (njengezisekelo). Ngokuphambene nalokho, umsebenzi wethu empeleni usebenzisa uketshezi lwe-ionic olungenakuguquguquka (ILs) futhi azikho izithasiselo.
UHazari noBernskoetter babike ngokususwa kwe-formic acid (FA) ku-80 °C besebenzisa i-Fe-PNP catalyst lapho kukhona i-dioxane ne-LiBF4, bathola inombolo ephawulekayo yokuguquka (TON) engaba ngu-1,000,00016. ULaurenci wasebenzisa i-Ru(II)- complex catalyst TPPPTS ohlelweni oluqhubekayo lokususwa kwe-FA. Le ndlela yaholela ekususweni kwe-FA cishe okuphelele okunezimpawu ezincane kakhulu ze-CO ezitholakale ku-80 °C17. Ukuze athuthukise le nsimu, uPidko wabonisa ukususwa kwe-FA okuguqukayo kusetshenziswa ama-catalyst e-Ru-PNP clamp ku-DMF/DBU kanye ne-DMF/NHex₃ mixtures, efinyelela amanani e-TON angu-310,000 kuya ku-706,500 ku-90 °C18. UHull, uHimeda noFujita bafunde i-catalyst ye-binuclear Ir complex lapho i-KHCO3 ne-H2SO4 zahlatshwa khona, kushintshana i-CO2 hydrogenation kanye ne-FA dehydrogenation. Izinhlelo zabo zafinyelela ama-TON angaphezu kuka-3,500,000 kanye no-308,000 ngokulandelana ukuze kufakwe i-hydrogenation ku-30°C, i-CO2/H2 (1:1), ingcindezi yebha eli-1 kanye nokukhishwa kwe-hydrogenation phakathi kuka-60 no-90°C19. USponholz, uJunge noBeller bathuthukise inhlanganisela ye-Mn-PNP ukuze kufakwe i-hydrogenation ye-CO2 eguquguqukayo kanye nokukhishwa kwe-FA ku-90°C20.
Lapha sisebenzise indlela ye-IL, kodwa esikhundleni sokusebenzisa i-Ru-PNPs, sihlole ukusetshenziswa kwama-catalyst e-Ru-POP, ngokwazi kwethu angakaze aboniswe ngaphambili kulokhu.
Ngenxa yokuhlanganiswa kwazo okuhle kakhulu kwe-metal-ligand (MLC), ama-amino-PNP clamp complexes asekelwe emiqondweni yohlobo lwe-Noyori namaqembu asebenzayo e-amino yesibili asebenzisanayo 21 (njenge-Ru-MACHO-BH) ngokuvamile aya ngokuya ethandwa kakhulu kwezinye izinhlelo zama-molecule amancane. Izibonelo ezidumile zifaka phakathi i-CO22, i-hydrogenation yama-alkenes nama-carbonyl, i-transfer hydrogenation23 kanye ne-acceptorless dehydrogenation yama-alcohols24. Kubikwe ukuthi i-N-methylation yama-PNP clamp ligands ingamisa ngokuphelele umsebenzi we-catalyst25, okungachazwa iqiniso lokuthi ama-amine asebenza njengemithombo ye-proton, okuyisidingo esibalulekile ngesikhathi somjikelezo we-catalytic usebenzisa i-MLC. Kodwa-ke, ukuthambekela okuphambene kokuqedwa kwe-formic acid kubonwe muva nje nguBeller, lapho ama-N-methylated Ru-PNP complexes empeleni abonise ukuqedwa kwe-formic acid okungcono kune-unmethylated counterparts26. Njengoba i-complex yangaphambili ingenakuhlanganyela ku-MLC ngeyunithi yama-amino, lokhu kusikisela ngokuqinile ukuthi i-MLC, ngakho-ke iyunithi yama-amino, ingadlala indima engabalulekile kangako kwezinye izinguquko (ze-hydrogenation) kunalokho okwakucatshangwa ngaphambilini.
Uma kuqhathaniswa nama-clamp e-POP, ama-ruthenium complexes ama-POP clamps awazange afundwe ngokwanele kule ndawo. Ama-POP ligands asetshenziswa ngokwesiko ikakhulukazi kwi-hydroformylation, lapho esebenza khona njenge-chelating ligands kunokuba yi-characteristic bidentate bite angle engaba ngu-120° yama-clamping ligands, asetshenziswe ukwenza ngcono ukukhetha kwemikhiqizo eqondile nehlanganisiwe27,28,29. Kusukela ngaleso sikhathi, ama-Ru-POP complexes awazange asetshenziswe kakhulu kwi-hydrogenation catalysis, kodwa izibonelo zomsebenzi wawo ekudlulisweni kwe-hydrogenation ziye zabikwa ngaphambilini30. Lapha sibonisa ukuthi i-Ru-POP complex iyi-catalyst ephumelelayo yokususwa kwe-hydrogenation kwe-formic acid, okuqinisekisa ukutholakala kukaBeller kokuthi iyunithi yama-amino ku-classical Ru-PNP amine catalyst ayibalulekanga kangako kulokhu kusabela.
Ucwaningo lwethu luqala ngokuhlanganiswa kwama-catalyst amabili ajwayelekile ngefomula ejwayelekile [RuHCl(POP)(PPh3)] (Isithombe 1a). Ukuze kuguqulwe isakhiwo se-steric nese-elekthronikhi, i-dibenzo[b,d]furan ikhethwe ku-4,6-bis(diisopropylphosphino) etholakala kwezentengiselwano (Isithombe 1b) 31. Ama-catalyst afundwe kulo msebenzi ahlanganiswa kusetshenziswa indlela ejwayelekile eyathuthukiswa yi-Whittlesey32, kusetshenziswa i-[RuHCl(PPh3)3]•toluene33 adduct njenge-precursor. Hlanganisa i-metal precursor kanye ne-POP clamp ligand ku-THF ngaphansi kwezimo eziqinile ze-anhydrous kanye ne-anaerobic. Ukusabela kwakuhambisana noshintsho olukhulu lombala kusuka ku-purple omnyama uye ophuzi futhi kwanikeza umkhiqizo omsulwa ngemuva kwamahora ama-4 e-reflux noma amahora angama-72 e-reflux ku-40°C. Ngemva kokususa i-THF ku-vacuo nokugeza kabili nge-hexane noma i-diethyl ether, i-triphenylphosphine yasuswa ukuze umkhiqizo ube yimpuphu ephuzi enenani eliphezulu.
Ukuhlanganiswa kwe-Ru-1 kanye ne-Ru-2 complexes. a) Indlela yokuhlanganiswa kwe-complexes. b) Isakhiwo se-complex ehlanganisiwe.
I-Ru-1 isivele yaziwa kusukela ezincwadini32, futhi ukucaciswa okwengeziwe kugxile ku-Ru-2. I-spectrum ye-1H NMR ye-Ru-2 iqinisekisile ukucushwa kwe-cis kwe-athomu ye-phosphine ku-ligand ye-hydride pair. I-peak dt plot (Isithombe 2a) ikhombisa ama-coupling constant angu-2JP-H angu-28.6 no-22.0 Hz, angaphakathi kobubanzi obulindelwe bemibiko yangaphambilini32. Ku-spectrum ye-hydrogen decoupled 31P{1H} (Isithombe 2b), i-coupling coupling constant engu-2JP-P engaba ngu-27.6 Hz yabonwa, okuqinisekisa ukuthi ama-clamp ligand phosphines kanye ne-PPh3 yi-cis-cis. Ngaphezu kwalokho, i-ATR-IR ikhombisa ibhendi yokwelula i-ruthenium-hydrogen ephawulekayo ku-2054 cm-1. Ukuze kucaciswe kabanzi ngesakhiwo, i-Ru-2 complex yaqiniswa ngokusabalala komhwamuko ekamelweni lokushisa ngekhwalithi eyanele izifundo ze-X-ray (Isithombe 3, Ithebula Elingeziwe 1). Iqiniswa ohlelweni lwe-triclinic lweqembu lesikhala i-P-1 ngeyunithi eyodwa ye-cocrystalline benzene ngeyunithi ngayinye. Ibonisa i-engeli ebanzi ye-P-Ru-P occlusal engu-153.94°, ebanzi kakhulu kune-engeli ebanzi ye-130° ye-bidentate DBFphos34. Ku-2.401 kanye no-2.382 Å, ubude be-bond ye-Ru-PPOP bude kakhulu kunobude be-bond ye-Ru kuya ku-PPh3 engu-2.232 Å, okungaba umphumela we-engeli ebanzi ye-backbone snack ye-DBFphos ebangelwa yi-5-ring yayo ephakathi. I-geometry yesikhungo sensimbi empeleni iyi-octahedral ene-engeli ye-O-Ru-PPh3 engu-179.5°. Ukuhlanganiswa kwe-H-Ru-Cl akuqondile ngokuphelele, kune-engeli engaba ngu-175° ukusuka ku-ligand ye-triphenylphosphine. Amabanga e-athomu nobude bezibopho kubhalwe kuThebula 1.
I-NMR spectrum ye-Ru-2. a) Isifunda se-Hydride se-1H NMR spectrum esibonisa isignali ye-Ru-H dt. b) I-31 P{ 1 H} I-NMR spectrum ekhombisa izimpawu ezivela ku-triphenylphosphine (eluhlaza okwesibhakabhaka) kanye ne-POP ligand (eluhlaza okwesibhakabhaka).
Isakhiwo se-Ru-2. Ama-ellipsoid okushisa aboniswa ngamathuba angu-70%. Ukuze kucace, ama-athomu e-benzene ne-hydrogen e-cocrystalline ku-carbon akhishiwe.
Ukuze kuhlolwe ikhono lama-complexes lokukhipha i-hydrogen ku-formic acid, izimo zokusabela zakhethwa lapho ama-complex e-PNP-clamp ahambisanayo (isb., i-Ru-MACHO-BH) ayesebenza kakhulu khona. Ukuncishiswa kwe-hydrogen ku-0.5 ml (13.25 mmol) formic acid kusetshenziswa i-0.1 mol% (1000 ppm, 13 µmol) ruthenium complex Ru-1 noma i-Ru-2 kusetshenziswa i-1.0 ml (5.35 mmol) ionic liquid (IL) BMIM OAc (ithebula-isithombe) 2; Isithombe 4);
Ukuze kutholakale izinga elijwayelekile, ukusabela kwenziwa okokuqala kusetshenziswa i-precursor adduct [RuHCl(PPh3)3]·toluene. Ukusabela kwenziwa ekushiseni okusuka ku-60 kuya ku-90 °C. Ngokusho kokubukwa okulula okubonakalayo, i-complex ayikwazanga ukuncibilika ngokuphelele ku-IL ngisho nangokuxubha isikhathi eside ekushiseni okungu-90°C, kodwa ukuncibilika kwenzeka ngemuva kokufakwa kwe-formic acid. Ku-90°C, ukuguqulwa okungu-56% (TOF = 3424 h-1) kufinyelelwe phakathi nemizuzu eyi-10 yokuqala, futhi ukuguqulwa okucishe kube yinani (97%) kufinyelelwe ngemva kwamahora amathathu (ukungena 1). Ukunciphisa izinga lokushisa libe ngu-80 °C kunciphisa ukuguqulwa ngaphezu kwengxenye kube ngu-24% ngemva kwemizuzu eyi-10 (TOF = 1467 h-1, ukungena 2), kuqhubeka nokunciphisa kube ngu-18% no-18% ku-70 °C no-60 °C, ngokulandelana ngo-6% (ukungena 3 no-4). Kuzo zonke izimo, akukho sikhathi sokungeniswa esitholiwe, okuphakamisa ukuthi i-catalyst ingaba izinhlobo ezisabelayo noma ukuthi ukuguqulwa kwezinhlobo ezisabelayo kushesha kakhulu ukuthi kungatholakala kusetshenziswa le sethi yedatha.
Ngemva kokuhlolwa kwangaphambili, ama-complex e-Ru-POP clamp i-Ru-1 ne-Ru-2 asetshenziswa ngaphansi kwezimo ezifanayo. Ku-90°C, ukuguqulwa okuphezulu kwabonwa ngokushesha. I-Ru-1 ithole ukuguqulwa okungu-74% phakathi nemizuzu yokuqala eyi-10 yokuhlolwa (TOFmax = 4525 h-1, ukungena 5). I-Ru-2 ibonise umsebenzi omncane kodwa oqhubekayo, ikhuthaza ukuguqulwa okungu-60% phakathi nemizuzu eyi-10 (TOFmax = 3669 h-1) kanye nokuguqulwa okugcwele ngaphakathi kwemizuzu engama-60 (>99%) (ukungena 9). Kuyaphawuleka ukuthi i-Ru-2 iphakeme kakhulu kune-precursor metal kanye ne-Ru-1 ekuguqulweni okugcwele. Ngakho-ke, ngenkathi i-metal precursor kanye ne-Ru-1 zinamanani afanayo e-TOFoverall ekuqedeni ukusabela (330 h-1 kanye ne-333 h-1, ngokulandelana), i-Ru-2 ine-TOFoverall engu-1009 h-1.
I-Ru-1 ne-Ru-2 zabe sezibhekana noshintsho lokushisa lapho izinga lokushisa lancishiswa khona kancane kancane ngokunyuka okungu-10 °C laya okungenani ku-60 °C (Isithombe 3). Uma ku-90°C i-complex ikhombisa umsebenzi osheshayo, ukuguqulwa okucishe kube okuphelele kwenzeka phakathi nehora, khona-ke emazingeni okushisa aphansi umsebenzi wehla kakhulu. Ukuguqulwa kwe-Py-1 kwaba ngu-14% no-23% ngemva kwemizuzu eyi-10 ku-80°C no-70°C, ngokulandelana, futhi ngemva kwemizuzu engama-30 kwanda kwaya ku-79% no-73% (okufakiwe 6 no-7). Zombili izivivinyo zibonise izinga lokuguqulwa elingu-≥90% phakathi kwamahora amabili. Ukuziphatha okufanayo kwabonwa ku-Ru-2 (okufakiwe 10 no-11). Ngokuthakazelisayo, i-Ru-1 yayinamandla kancane ekugcineni kokusabela ku-70 °C nge-TOF iyonke engu-315 h-1 uma kuqhathaniswa ne-292 h-1 ye-Ru-2 no-299 h-1 yesandulela sensimbi.
Ukwehla okwengeziwe kwezinga lokushisa kuya ku-60 °C kwaholela eqinisweni lokuthi akukho ukuguqulwa okwabonwa phakathi nemizuzu yokuqala engama-30 yokuhlolwa. I-Ru-1 yayingasebenzi kakhulu ekushiseni okuphansi kakhulu ekuqaleni kokuhlolwa futhi kamuva yanda umsebenzi, okubonisa isidingo sesikhathi sokusebenza lapho i-Ru-1 precatalyst iguqulwa ibe yizinhlobo ezisebenzayo. Nakuba lokhu kungenzeka kuwo wonke amazinga okushisa, imizuzu eyi-10 ekuqaleni kokuhlolwa yayinganele ukuthola isikhathi sokusebenza emazingeni okushisa aphezulu. Ukuziphatha okufanayo kwatholakala ku-Ru-2. Ku-70 no-60 °C, akukho ukuguqulwa okwabonwa phakathi nemizuzu yokuqala eyi-10 yokuhlolwa. Kubalulekile ukuqaphela ukuthi kuzo zombili izivivinyo, ukwakheka kwe-carbon monoxide akuzange kubonwe ngaphakathi komkhawulo wokutholwa kwethuluzi lethu (<300 ppm), kanti i-H2 ne-CO2 kuphela okubonwe.
Ukuqhathaniswa kwemiphumela yokukhishwa kwe-formic acid etholwe ngaphambilini kuleli qembu elisebenzayo, elimele ubuchwepheshe obusezingeni eliphezulu futhi kusetshenziswa ama-complex e-Ru-PNP clamp, kubonise ukuthi i-Ru-POP clamp esanda kuhlanganiswa inomsebenzi ofana nomlingani wayo we-PNP 15. Ngenkathi i-clamp I-PNP ithole ama-RPM angu-500-1260 h-1 ekuhlolweni kwe-batch, i-POP clamp entsha ithole inani elifanayo le-TOFovertal elingu-326 h-1, kanye namanani e-TOFmax e-Ru-1 kanye ne-1590 h-1 abonwe. ngokulandelana, angama-1988 h-1 kanye ne-1590 h-1. I-Ru-2 ingu-1 ku-80 °C, i-Ru-1 ingu-4525 h-1 kanti i-Ru-1 ingu-3669 h-1 ku-90 °C, ngokulandelana.
Ukuhlolwa kwezinga lokushisa kokukhishwa kwe-formic acid kusetshenziswa ama-catalyst e-Ru-1 kanye ne-Ru-2. Izimo: i-catalyst engu-13 µmol, i-formic acid engu-0.5 ml (13.25 mmol), i-1.0 ml (5.35 mmol) i-BMIM OAc.
I-NMR isetshenziselwa ukuqonda izindlela zokusabela. Njengoba kukhona umehluko obaluleke kakhulu ku-2JH-P phakathi kwama-hydride nama-phosphine ligands, ukugxila kwalolu cwaningo kusesiqongweni se-hydride. Ku-Ru-1, iphethini ejwayelekile ye-dt yeyunithi ye-hydrogenation itholakale ngemizuzu yokuqala engama-60 yokuqedwa kwe-hydrogenation. Nakuba kukhona ushintsho olukhulu oluvela ku-−16.29 kuya ku-−13.35 ppm, ama-coupling constant ayo ne-phosphine angama-27.2 kanye no-18.4 Hz, ngokulandelana (Isithombe 5, I-Peak A). Lokhu kuhambisana nawo wonke ama-phosphine amathathu lapho i-hydrogen ligand isesimweni se-cis futhi kusikisela ukuthi ukumiswa kwe-ligand kuzinzile kancane ku-IL cishe ihora elilodwa ngaphansi kwezimo zokusabela ezilungiselelwe. Ukushintsha okunamandla kwe-downfield kungase kubangelwe ukuqedwa kwama-ligand e-chlorinated kanye nokwakheka kwama-complex e-acetyl-formic acid ahambisanayo, ukwakheka kwe-in situ kwe-d3-MeCN complex ku-NMR tube, noma ukwakheka kwama-N-heterocycle ahambisanayo. kuchaziwe. I-Carbene (NHC) complex. Ngesikhathi sokusabela kwe-dehydrogenation, amandla alesi signali aqhubeka nokwehla, futhi ngemva kwemizuzu engu-180 isignali ayisabonwa. Esikhundleni salokho, kwatholakala amasignali amabili amasha. Eyokuqala ikhombisa iphethini ecacile ye-dd eyenzeka ku--6.4 ppm (peak B). I-doublet ine-coupling constant enkulu engaba ngu-130.4 Hz, okubonisa ukuthi enye yamayunithi e-phosphine ithuthile maqondana ne-hydrogen. Lokhu kungasho ukuthi i-POP clamp ihlelwe kabusha ibe yi-configuration ye-κ2-P,P. Ukuvela kwalesi sinkimbinkimbi sekwephuzile kwe-catalysis kungabonisa ukuthi lolu hlobo luholela ezindleleni zokuvala ukusebenza ngokuhamba kwesikhathi, kwakha i-catalyst sink. Ngakolunye uhlangothi, ukushintsha kwamakhemikhali okuphansi kusikisela ukuthi kungaba uhlobo lwe-dihydrogenous15. I-peak yesibili entsha itholakala ku--17.5 ppm. Nakuba ukugoba kwayo kungaziwa, sikholelwa ukuthi iyi-triplet ene-coupling constant encane engu-17.3 Hz, okubonisa ukuthi i-hydrogen ligand ibopha kuphela ku-phosphine ligand ye-POP clamp, okubonisa nokukhululwa kwe-triphenylphosphine (peak C). Ingashintshwa enye i-ligand, njengeqembu le-acetyl noma i-NHC eyakhiwe endaweni evela ku-ionic liquid. Ukuhlukaniswa kwe-PPh3 kuboniswa futhi yi-singlet enamandla ku--5.9 ppm. ku-spectrum ye-31P{1H} ye-Ru-1 ngemuva kwemizuzu engu-180 ku-90 °C (bheka ulwazi olwengeziwe).
Isifunda se-Hydride se-spectrum ye-1H NMR ye-Ru-1 ngesikhathi sokukhishwa kwe-formic acid. Izimo zokusabela: i-formic acid engu-0.5 ml, i-1.0 ml ye-BMIM OAc, i-catalyst engu-13.0 µmol, 90 °C. I-NMR ithathwe ku-MeCN-d 3, 500 μl ye-solvent ekhishwe, cishe i-10 μl yengxube yokusabela.
Ukuze kuqinisekiswe ngokwengeziwe ukuba khona kwezinhlobo ezisebenzayo ohlelweni lwe-catalytic, ukuhlaziywa kwe-high resolution mass spectrometry (HRMS) kwe-Ru-1 kwenziwa ngemuva kokujova i-formic acid imizuzu eyi-10 ku-90 °C. Lokhu kusikisela ukuba khona kwezinhlobo ezingenayo i-chlorine ligand precatalyst engxubeni yokusabela. kanye nama-complexes amabili e-NHC, izakhiwo zawo eziboniswa ku-Figure 6. I-spectrum ye-HRMS ehambisanayo ingabonakala ku-Supplementary Figure 7.
Ngokusekelwe kule datha, siphakamisa indlela yokusabela ngaphakathi kwe-sphere efana naleyo ephakanyiswe nguBeller, lapho ama-N-methylated PNP clamps ekhuthaza ukusabela okufanayo. Ukuhlolwa okwengeziwe okukhipha uketshezi lwe-ionic akubonisanga msebenzi, ngakho-ke ukubandakanyeka kwayo ngqo kubonakala kudingekile. Sicabanga ukuthi ukusebenza kwe-Ru-1 ne-Ru-2 kwenzeka ngokuhlukaniswa kwe-chloride kulandelwa ukwengeza okungenzeka kwe-NHC kanye nokuhlukaniswa kwe-triphenylphosphine (Iskimu 1a). Lokhu kusebenza kuzo zonke izinhlobo kuye kwabonwa ngaphambilini kusetshenziswa i-HRMS. I-IL-acetate iyisisekelo se-Bronsted esinamandla kune-formic acid futhi ingasusa kakhulu i-latter35. Sicabanga ukuthi ngesikhathi somjikelezo we-catalytic (Scheme 1b), izinhlobo ezisebenzayo ze-A ezithwala i-NHC noma i-PPh3 zihlanganiswa nge-formate ukuze zakhe izinhlobo ze-B. Ukulungiswa kabusha kwale complex ibe yi-C ekugcineni kuphumela ekukhululweni kwe-CO2 kanye ne-trans-dihydrogen complex D. I-protonation elandelayo ye-asidi ibe yi-dihydro complex ene-acetic acid eyakhiwe ngaphambilini ukuze yakhe i-dihydro complex E ifana nesinyathelo esibalulekile esiphakanyiswe nguBeller esebenzisa ama-homologues e-N-methylated PNP clamp. Ngaphezu kwalokho, i-analogue ye-complex EL = PPh3 yasungulwa ngaphambilini nge-stoichiometric reaction kusetshenziswa i-Ru-1 emoyeni we-hydrogen ngemuva kokukhishwa kwe-chloride nosawoti we-sodium. Ukususwa kwe-hydrogen kanye nokuhlanganiswa kwe-formate kunikeza i-A futhi kuqedela umjikelezo.
Kuphakanyiswa indlela yokusabela kwe-intrasphere kwe-formic acid dehydrogenation kusetshenziswa i-fixing complex Ru-POP Ru-1.
Kuye kwahlanganiswa i-complex entsha [i-RuHCl(iPr-dbfphos)(PPh3)]. Le complex yabonakala ngokuhlaziywa kwe-NMR, ATRIR, EA kanye ne-X-ray diffraction yamakristalu angawodwa. Siphinde sibike ukusetshenziswa kokuqala okuphumelelayo kwe-Ru-POP pincer complexes ekukhishweni kwe-formic acid ku-CO2 kanye ne-H2. Nakuba i-metal precursor ithole umsebenzi ofanayo (kufika ku-3424 h-1), i-complex ifinyelele imvamisa ephezulu yokujika efika ku-4525 h-1 ku-90 °C. Ngaphezu kwalokho, ku-90 °C, i-complex entsha [i-RuHCl(iPr-dbfphos)(PPh3)] ithole isikhathi sokundiza (1009 h-1) ukuze iqedele i-formic acid dehydrogenation, ephakeme kakhulu kuneyokuqala kwensimbi (330 h-1). kanye ne-complex ebikwe ngaphambilini [i-RuHCl(xantphos)(PPh3)] (333 h-1). Ngaphansi kwezimo ezifanayo, ukusebenza kahle kwe-catalytic kufana nokwe-Ru-PNP clamp complex. Idatha ye-HRMS ikhombisa ukuba khona kwe-carbene complex engxubeni yokusabela, yize kuyinani elincane. Okwamanje sifunda ngemiphumela ye-catalytic ye-carbene complexes.
Yonke idatha etholwe noma ehlaziywe phakathi nalolu cwaningo ifakiwe kulesi sihloko esishicilelwe [namafayela olwazi asekelayo].
U-Azarpour A., ​​​​Suhaimi S., Zahedi G. kanye noBahadori A. Ukubuyekezwa kokushiyeka kwemithombo yamandla avuselelekayo njengomthombo othembisayo wamandla esikhathi esizayo. Unjiniyela we-Arab. J. Science. 38, 317–328 (2013).
UMoriarty P. noHonery D. Iyini amandla omhlaba wonke amandla avuselelekayo? buyekeza. ukwesekwa. Amandla Rev 16, 244–252 (2012).
URao, PC kanye noYoon, M. Izinhlelo ezingenzeka zokuthwala i-hydrogen organic (Lohc): isibuyekezo sentuthuko yakamuva. Amandla 13, 6040 (2020).
Niermann, M., Beckendorf, A., Kaltschmitt, M. kanye noBohnhoff, K. Abathwali be-hydrogen organic (LOHC) – ukuhlolwa okusekelwe ezimpahleni zamakhemikhali nezomnotho. ubuzwe. J. Amandla e-hydrogen. 44, 6631–6654 (2019).
Teichmann, D., Arlt, W., Wasserscheid, P. kanye noFreimann, R. Imithombo yamandla yesikhathi esizayo esekelwe kubathwali be-hydrogen ephilayo ewuketshezi (LOHC). imvelo yamandla. isayensi. 4, 2767–2773 (2011).
Niermann, M., Timmerberg, S., Drunert, S. kanye noKaltschmitt, M. Abathwali be-hydrogen ephilayo ewuketshezi kanye nezinye izindlela zokuthutha i-hydrogen evuselelekayo emhlabeni jikelele. buyekeza. ukwesekwa. Energy Ed. 135, 110171 (2021).
URong Y. nabanye. Ukuhlaziywa kobuchwepheshe kanye nokwezomnotho kwamazwe ngamazwe kokugcinwa kwe-hydrogen kanye nokuthuthwa kusuka esitshalweni sokukhiqiza i-hydrogen kuya esiteshini sokugcina i-hydrogenation. J. Amandla e-hydrogen. 1–12 https://doi.org/10.1016/j.ijhydene.2023.01.187 (2023).
UGuo, J. et al. I-Formic acid njengendlela yokugcina i-hydrogen engaba khona: ukuthuthukiswa kwama-catalyst ensimbi alinganayo okusabela kokukhishwa kwe-hydrogen. I-Seuss Chemistry Chemistry. 14, 2655–2681 (2021).
Muller, K., Brooks, K., kanye no-Autry, T. Isitoreji se-hydrogen ku-formic acid: ukuqhathanisa izinketho zenqubo. Uphethiloli wamandla. 31, 12603–12611 (2017).
UWang, Z., uLu, SM, uLi, J., uWang, J. kanye noLi, Q. I-Iridium complex ene-N,N'-diimine ligand inomsebenzi omkhulu we-formic acid dehydrogenation emanzini. Amakhemikhali. – EURO. J. 21, 12592–12595 (2015).
UHong D. nabanye. Umphumela wokubambisana kwama-complexes e-heterobinuclear IrIII-MII ekukhululweni kwe-catalytic kwe-H2 ngesikhathi sokukhishwa kwe-formic acid emanzini. Izinto ezingaphili. I-Chemical. 59, 11976–11985 (2020).
UFink K., uLaurenci GA kanye nesikhuthazo esiyigugu sokukhishwa kwe-hydrogen kwe-formic acid emanzini yi-rhodium. EURO. J.Inorg. Chemical. 2381–2387 (2019).
USeraj, JJA, et al. Isikhuthazi esisebenzayo sokukhishwa kwe-asidi ye-formic emsulwa. I-Nat. communicate. 7, 11308 (2016).
UPiccirelli L. nabanye. I-catalysis yemisebenzi eminingi ye-CO2 hydrogenation-dehydrogenation kusetshenziswa uhlelo lwe-Ru-PNP/ionic liquid. J. Am. Bitch. 145, 5655–5663 (2023).
UBelinsky EA nabanye. Ukukhishwa kwe-formic acid nge-Lewis acid kusetshenziswa i-iron catalyst ekusekelweni kwe-Pinzer. J. Am. Bitch. 136, 10234–10237 (2014).
UHenriks V., Juranov I., Autissier N. kanye noLaurenci G. Ukususwa kwe-formic acid kuma-catalyst e-Ru-TPPTS afanayo: ukwakheka kwe-CO okungafuneki kanye nokususwa kwayo ngempumelelo nge-catalyst ye-PROX. 7, 348 (2017).
I-Filonenko GA njll. I-hydrogenation esebenza kahle futhi eguquguqukayo ye-carbon dioxide ibe yi-formate kusetshenziswa i-ruthenium catalyst PNP-Pinzer. I-Chemistry Cat chemistry. 6, 1526–1530 (2014).
Hull, J. et al. Isitoreji se-hydrogen esiguqulwayo sisebenzisa i-carbon dioxide kanye nama-catalyst e-iridium ashintshiwe e-proton ezindaweni zamanzi emazingeni okushisa aphakathi kanye nokucindezela. Nat. Chemical. 4, 383–388 (2012).
UWei, D. nabanye. I-Mn-Pincer complex isetshenziselwa ukuguqula i-carbon dioxide ibe yi-formic acid ibe yi-hydrogenation uma kukhona i-lysine. I-Nat. vivacity. 7, 438–447 (2022).
UPiccirilli L., uPinheiro DL noNielsen M. Pincer Intuthuko yakamuva kuma-catalyst ensimbi aguqukayo ukuze kuthuthukiswe ngendlela esimeme. catalyst. 10, 773 (2020).
Wei, D., Junge, H. kanye noBeller, M. Izinhlelo ze-amino acid zokubamba i-carbon dioxide kanye nokusetshenziswa kwe-catalytic ekukhiqizweni kwe-formate. Isayensi yamakhemikhali. 12, 6020–6024 (2021).
I-Subramanian M. nabanye. Ukudluliselwa kwe-ruthenium okujwayelekile nokukhethiwe kwe-hydrogenation, i-deuteration kanye ne-methylation yamakhemikhali asebenzayo ane-methanol. J. Cutler. 425, 386–405 (2023).
UNi Z., uPadilla R., uPramanik R., uJorgensen MSB noNielsen M. Ukuhlanganiswa kwe-ethanol ne-ethyl acetate okungenasisekelo futhi okungenamamukeli kusetshenziswa ama-PNP complexes. I-Dalton's span. 52, 8193–8197 (2023).
UFu, S., uShao, Z., uWang, Y., kanye noLiu, Q. I-Manganese-yabangela ukuthuthukiswa kwe-ethanol ibe yi-1-butanol. J. Am. Bitch. 139, 11941–11948 (2017).