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Formic acid ndi imodzi mwa njira zabwino kwambiri zosungira madzi a hydrogen kwa nthawi yayitali. Pano tikupereka mndandanda wa ma ruthenium clamp complexes atsopano okhala ndi njira yodziwika bwino [RuHCl(POP)(PPh3)] pogwiritsa ntchito ma xanthos-type tridentate POP clamp ligands omwe amapezeka pamsika kapena opangidwa mosavuta. Tinagwiritsa ntchito ma complexes awa kutulutsa hydrogen formic acid kuti apange CO2 ndi H2 pansi pa mikhalidwe yofatsa, yopanda reflux pogwiritsa ntchito madzi a ionic BMIM OAc (1-butyl-3-methylimidazolium acetate) ngati solvent. Kuchokera pakuwona kuchuluka kwa kusintha kwakukulu, chothandizira kwambiri ndi [RuHCl(xantphos)(PPh3)]Ru-1 complex yodziwika m'mabuku, yomwe ili ndi kuchuluka kwa kusintha kwakukulu kwa 4525 h-1 pa 90 °C kwa mphindi 10. Chiŵerengero cha kusintha pambuyo pake chinali 74%, ndipo kusinthaku kunamalizidwa mkati mwa maola atatu (>98%). Kumbali inayi, chothandizira chomwe chili ndi magwiridwe antchito abwino kwambiri, buku latsopano la [RuHCl(iPr-dbfphos)(PPh3)]Ru-2 complex, limalimbikitsa kusintha kwathunthu mkati mwa ola limodzi, zomwe zimapangitsa kuti chiwongola dzanja chonse chikhale 1009 h-1. Kuphatikiza apo, ntchito yothandiza anthu imawonekeranso kutentha mpaka 60 °C. Mu gawo la mpweya, CO2 ndi H2 zokha ndi zomwe zidawonedwa; CO sinazindikirike. Ma spectrometry a mass resolution yapamwamba adawonetsa kukhalapo kwa N-heterocyclic carbene complexes mu reaction mixture.
Kuchuluka kwa msika wa mphamvu zongowonjezedwanso komanso kusiyanasiyana kwake kwapangitsa kuti pakhale kufunika kwa ukadaulo wosungira mphamvu m'mafakitale m'magawo amagetsi, kutentha, mafakitale ndi zoyendera1,2. Hydrogen imaonedwa kuti ndi imodzi mwa zonyamula mphamvu zambiri3, ndipo zonyamula za hydrogen zamadzimadzi (LOHCs) zakhala zikufufuzidwa posachedwapa, zomwe zikupereka lonjezo losunga haidrojeni mu mawonekedwe osavuta kukonzedwa popanda mavuto okhudzana ndi kupanikizika kapena ukadaulo wa cryogenic4. ,5,6. Chifukwa cha mawonekedwe awo enieni, zambiri mwa zomangamanga zomwe zilipo zoyendera mafuta ndi mafuta ena amadzimadzi zitha kugwiritsidwa ntchito kunyamula LOHC7,8. Makhalidwe enieni a formic acid (FA) amapangitsa kuti ikhale yoyenera kusungira haidrojeni yokhala ndi kulemera kwa haidrojeni kwa 4.4%9,10. Komabe, machitidwe ofalitsa othandizira a formic acid dehydrogenation nthawi zambiri amafunikira kugwiritsa ntchito zosungunulira zachilengedwe zosasunthika, madzi kapena asidi woyera,11,12,13,14 zomwe zingafunike kugwiritsa ntchito njira zolekanitsa nthunzi monga condensation, zomwe zingayambitse mavuto mu ntchito za ogula. Vutoli lingathe kuthetsedwa pogwiritsa ntchito zosungunulira zokhala ndi mphamvu yochepa ya nthunzi, monga madzi a ionic. Poyamba, gulu lathu logwira ntchito linawonetsa kuti madzi a ionic butylmethylimidazolium acetate (BMIM OAc) ndi solvent yoyenera mu izi pogwiritsa ntchito Ru-PNP Ru-MACHO type 15 yomwe imapezeka m'masitolo. Mwachitsanzo, tinawonetsa FA dehydrogenation mu continuous flow system pogwiritsa ntchito BMIM OAc, kukwaniritsa TON yoposa 18,000,000 pa 95°C. Ngakhale kuti machitidwe ena adakwanitsa TON yapamwamba kale, ambiri amadalira zosungunulira zachilengedwe zosasunthika (monga THF kapena DMF) kapena zowonjezera zomwe zimagwiritsidwa ntchito (monga maziko). Mosiyana ndi zimenezi, ntchito yathu imagwiritsa ntchito madzi a ionic osasinthasintha (ILs) ndipo palibe zowonjezera.
Hazari ndi Bernskoetter adanenanso za kuchepa kwa hydrogen kwa formic acid (FA) pa 80 °C pogwiritsa ntchito Fe-PNP catalyst pamaso pa dioxane ndi LiBF4, zomwe zidapangitsa kuti chiwerengero cha turnover (TON) chikhale chochititsa chidwi cha pafupifupi 1,000,00016. Laurenci adagwiritsa ntchito Ru(II)- complex catalyst TPPPTS mu dongosolo losalekeza la FA dehydrogenation. Njirayi idapangitsa kuti FA dehydrogenation ikhale pafupifupi yonse ndipo panali zochepa kwambiri za CO zomwe zidapezeka pa 80 °C17. Kuti apititse patsogolo gawoli, Pidko adawonetsa kutsika kwa hydrogenation kwa FA pogwiritsa ntchito Ru-PNP clamp catalysts mu DMF/DBU ndi DMF/NHex₃ mixtures, zomwe zidapangitsa kuti TON ikhale ya 310,000 mpaka 706,500 pa 90 °C18. Hull, Himeda ndi Fujita adaphunzira za binuclear Ir complex catalyst momwe KHCO3 ndi H2SO4 zidaperekedwa nsembe, kusinthana CO2 hydrogenation ndi FA dehydrogenation. Machitidwe awo adakwanitsa ma TON opitilira 3,500,000 ndi 308,000 motsatana kuti apereke hydrogenation pa 30°C, CO2/H2 (1:1), 1 bar pressure ndi kuti apereke hydrogenation pakati pa 60 ndi 90°C19. Sponholz, Junge ndi Beller adapanga Mn-PNP complex kuti apereke hydrogenation ya CO2 yosinthika ndi FA dehydrogenation pa 90°C20.
Apa tinagwiritsa ntchito njira ya IL, koma m'malo mogwiritsa ntchito Ru-PNPs, tinafufuza kugwiritsa ntchito ma catalyst a Ru-POP, omwe malinga ndi chidziwitso chathu sanawonetsedwepo kale pankhaniyi.
Chifukwa cha kuphatikiza kwawo kwabwino kwa metal-ligand (MLC), ma amino-PNP clamp complexes ozikidwa pa mfundo za mtundu wa Noyori ndi magulu achiwiri ogwira ntchito a amino 21 (monga Ru-MACHO-BH) nthawi zambiri amakhala otchuka kwambiri m'maselo ang'onoang'ono. Zitsanzo zodziwika bwino ndi monga CO22, hydrogenation ya alkenes ndi carbonyls, transfer hydrogenation23 ndi acceptorless dehydrogenation ya alcohols24. Zanenedwa kuti N-methylation ya PNP clamp ligands imatha kuyimitsa kwathunthu ntchito ya catalyst25, zomwe zitha kufotokozedwa ndi mfundo yakuti amines amagwira ntchito ngati magwero a proton, chomwe ndi chofunikira kwambiri panthawi ya catalytic cycle pogwiritsa ntchito MLC. Komabe, njira yosiyana ya formic acid dehydrogenation idawonedwa posachedwapa ndi Beller, pomwe N-methylated Ru-PNP complexes idawonetsa bwino catalytic dehydrogenation ya formic acid kuposa anzawo omwe alibe methylation26. Popeza gulu loyamba silingathe kutenga nawo mbali mu MLC kudzera mu amino unit, izi zikusonyeza kuti MLC, motero amino unit, ingakhale ndi gawo losafunikira kwenikweni pakusintha kwina kwa hydrogenation kuposa momwe zimaganiziridwira kale.
Poyerekeza ndi ma clamp a POP, ma ruthenium complexes a ma POP clamps sanaphunzire mokwanira m'derali. Ma POP ligands nthawi zambiri amagwiritsidwa ntchito makamaka pa hydroformylation, komwe amagwira ntchito ngati ma chelating ligands m'malo mwa bidentate bite angle ya pafupifupi 120° ya ma clamping ligands, omwe agwiritsidwa ntchito kukonza kusankha kwa zinthu zolunjika komanso zolumikizidwa27,28,29. Kuyambira pamenepo, ma Ru-POP complexes sanagwiritsidwe ntchito kawirikawiri mu hydrogenation catalysis, koma zitsanzo za ntchito yawo mu transfer hydrogenation zanenedwa kale30. Apa tikuwonetsa kuti Ru-POP complex ndi catalyst yothandiza kwambiri pakuchotsa hydrogenation ya formic acid, kutsimikizira zomwe Beller adapeza kuti amino unit mu Ru-PNP amine catalyst yachikhalidwe siyofunikira kwambiri pa izi.
Kafukufuku wathu umayamba ndi kupanga ma catalyst awiri wamba ndi njira yonse [RuHCl(POP)(PPh3)] (Chithunzi 1a). Kuti tisinthe kapangidwe ka steric ndi electronic, dibenzo[b,d]furan idasankhidwa kuchokera ku 4,6-bis(diisopropylphosphino) yomwe ikupezeka pamsika (Chithunzi 1b) 31. Ma catalyst omwe adaphunziridwa mu ntchitoyi adapangidwa pogwiritsa ntchito njira yodziwika bwino yopangidwa ndi Whittlesey32, pogwiritsa ntchito [RuHCl(PPh3)3]•toluene33 adduct ngati precursor. Sakanizani precursor yachitsulo ndi POP clamp ligand mu THF pansi pa mikhalidwe yopanda madzi komanso yopanda mpweya. Zomwe zimachitikazo zidatsagana ndi kusintha kwakukulu kwa mtundu kuchokera ku utoto wakuda kupita ku wachikasu ndipo zidapereka mankhwala oyera pambuyo pa maola 4 a reflux kapena maola 72 a reflux pa 40°C. Pambuyo pochotsa THF mu vacuo ndikutsuka kawiri ndi hexane kapena diethyl ether, triphenylphosphine idachotsedwa kuti ipereke mankhwalawa ngati ufa wachikasu wochuluka.
Kupanga kwa ma complexes a Ru-1 ndi Ru-2. a) Njira yopangira ma complexes. b) Kapangidwe ka ma complexes opangidwa.
Ru-1 imadziwika kale kuchokera m'mabuku32, ndipo mawonekedwe ena amayang'ana kwambiri pa Ru-2. Sipekitiramu ya 1H NMR ya Ru-2 idatsimikizira kapangidwe ka cis ka atomu ya phosphine mu ligand ya hydride pair. Chithunzi cha peak dt (Chithunzi 2a) chikuwonetsa ma coupling constants a 2JP-H a 28.6 ndi 22.0 Hz, omwe ali mkati mwa kuchuluka komwe kumayembekezeredwa kuchokera ku malipoti am'mbuyomu32. Mu hydrogen decoupled 31P{1H} spectrum (Chithunzi 2b), coupling constant ya 2JP-P ya pafupifupi 27.6 Hz idawonedwa, kutsimikizira kuti ma clamp ligand phosphines ndi PPh3 onse ndi cis-cis. Kuphatikiza apo, ATR-IR ikuwonetsa gulu lotambasula la ruthenium-hydrogen pa 2054 cm-1. Kuti mudziwe zambiri zokhudza kapangidwe kake, Ru-2 complex idapangidwa ndi kufalikira kwa nthunzi kutentha kwa chipinda ndi khalidwe lokwanira maphunziro a X-ray (Chithunzi 3, Gome Lowonjezera 1). Imapangidwa mu dongosolo la triclinic la gulu la malo P-1 ndi gawo limodzi la cocrystalline benzene pa selo iliyonse. Imawonetsa ngodya yayikulu ya P-Ru-P occlusal ya 153.94°, yomwe ndi yayikulu kwambiri kuposa ngodya ya 130° occlusal ya bidentate DBFphos34. Pa 2.401 ndi 2.382 Å, kutalika kwa bond ya Ru-PPOP ndi yayitali kwambiri kuposa kutalika kwa bond ya Ru mpaka PPh3 ya 2.232 Å, zomwe zitha kukhala chifukwa cha ngodya yayikulu ya msana ya DBFphos yomwe imayambitsidwa ndi mphete yake yapakati ya 5. Maonekedwe a pakati pa chitsulo kwenikweni ndi octahedral yokhala ndi ngodya ya O-Ru-PPh3 ya 179.5°. Kugwirizana kwa H-Ru-Cl sikolunjika konse, ndi ngodya ya pafupifupi 175° kuchokera ku ligand ya triphenylphosphine. Mtunda wa atomiki ndi kutalika kwa ma bond zalembedwa mu Table 1.
NMR spectrum ya Ru-2. a) Gawo la Hydride la 1H NMR spectrum yowonetsa chizindikiro cha Ru-H dt. b) 31 P{ 1 H} NMR spectrum yowonetsa zizindikiro kuchokera ku triphenylphosphine (buluu) ndi POP ligand (wobiriwira).
Kapangidwe ka Ru-2. Ma ellipsoid a kutentha amawonetsedwa ndi mwayi wa 70%. Kuti zimveke bwino, ma atomu a cocrystalline benzene ndi hydrogen pa kaboni achotsedwa.
Kuti aone momwe ma complexes angachotsere hydrogenation ya formic acid, mikhalidwe ya reaction idasankhidwa pomwe ma PNP-clamp complexes ofanana (monga Ru-MACHO-BH) anali otanganidwa kwambiri15. Kuchotsa hydrogenation ya 0.5 ml (13.25 mmol) formic acid pogwiritsa ntchito 0.1 mol% (1000 ppm, 13 µmol) ruthenium complex Ru-1 kapena Ru-2 pogwiritsa ntchito 1.0 ml (5.35 mmol) ionic liquid (IL) BMIM OAc (tebulo-chithunzi) 2; Chithunzi 4);
Kuti tipeze muyezo, choyamba tinachita izi pogwiritsa ntchito precursor adduct [RuHCl(PPh3)3]·toluene. Izi zimachitika pa kutentha kwa 60 mpaka 90 °C. Malinga ndi zomwe zawonedwa mosavuta, zovutazo sizingathe kusungunuka kwathunthu mu IL ngakhale mutasakaniza kwa nthawi yayitali pa kutentha kwa 90 °C, koma kusungunuka kunachitika pambuyo poyambitsa formic acid. Pa 90 °C, kusintha kwa 56% (TOF = 3424 h-1) kunapezeka mkati mwa mphindi 10 zoyambirira, ndipo kusintha kofanana (97%) kunapezeka patatha maola atatu (kulowa 1). Kuchepetsa kutentha kufika pa 80 °C kumachepetsa kusintha ndi theka kufika pa 24% patatha mphindi 10 (TOF = 1467 h-1, kulowa 2), ndikuchepetsanso kufika pa 18% ndi 18% pa 70 °C ndi 60 °C, motsatana 6% (kulowa 3 ndi 4). Muzochitika zonse, palibe nthawi yoyambira yomwe idapezeka, zomwe zikusonyeza kuti chothandizira chingakhale chamoyo chosinthika kapena kuti kusintha kwa mitundu yosinthika ndi kofulumira kwambiri kuti kudziwike pogwiritsa ntchito deta iyi.
Pambuyo poyesa precursor, Ru-POP clamp complexes Ru-1 ndi Ru-2 zinagwiritsidwa ntchito pansi pa mikhalidwe yomweyi. Pa 90°C, kusintha kwakukulu kunawonedwa nthawi yomweyo. Ru-1 idapeza kusintha kwa 74% mkati mwa mphindi 10 zoyambirira za kuyesaku (TOFmax = 4525 h-1, kulowa 5). Ru-2 idawonetsa ntchito yochepa koma yokhazikika, ikukweza kusintha kwa 60% mkati mwa mphindi 10 (TOFmax = 3669 h-1) ndi kusintha kwathunthu mkati mwa mphindi 60 (>99%) (gawo 9). Ndikofunikira kudziwa kuti Ru-2 ndi yapamwamba kwambiri kuposa precursor metal ndi Ru-1 pakutembenuka kwathunthu. Chifukwa chake, ngakhale precursor yachitsulo ndi Ru-1 zili ndi ma TOFoverall ofanana pakumaliza kuchitapo kanthu (330 h-1 ndi 333 h-1, motsatana), Ru-2 ili ndi TOFoverall ya 1009 h-1.
Kenako Ru-1 ndi Ru-2 zinasinthidwa kutentha komwe kutentha kunachepetsedwa pang'onopang'ono ndi 10 °C mpaka 60 °C (Chithunzi 3). Ngati pa 90°C chipangizocho chinawonetsa ntchito yomweyo, kusintha kwathunthu kunachitika mkati mwa ola limodzi, ndiye kuti kutentha kotsika ntchitoyo inatsika kwambiri. Kusintha kwa Py-1 kunali 14% ndi 23% pambuyo pa mphindi 10 pa 80°C ndi 70°C, motsatana, ndipo patatha mphindi 30 kunawonjezeka kufika pa 79% ndi 73% (zolemba 6 ndi 7). Mayesero onsewa adawonetsa kuchuluka kwa kusintha kwa ≥90% mkati mwa maola awiri. Khalidwe lofananalo linawonedwa pa Ru-2 (zolemba 10 ndi 11). Chosangalatsa n'chakuti, Ru-1 inali yolamulira pang'ono kumapeto kwa reaction pa 70 °C ndi TOF yonse ya 315 h-1 poyerekeza ndi 292 h-1 ya Ru-2 ndi 299 h-1 ya precursor yachitsulo.
Kutsika kwina kwa kutentha kufika pa 60 °C kunapangitsa kuti pasakhale kusintha komwe kunawonedwa mkati mwa mphindi 30 zoyambirira za kuyesaku. Ru-1 sinali yogwira ntchito kwambiri kutentha kotsika kwambiri kumayambiriro kwa kuyesaku ndipo pambuyo pake ntchito inawonjezeka, zomwe zikusonyeza kufunikira kwa nthawi yoyambitsa pomwe Ru-1 precatalyst imasinthidwa kukhala mitundu yogwira ntchito. Ngakhale izi ndizotheka kutentha konse, mphindi 10 kumayambiriro kwa kuyesaku sizinali zokwanira kuzindikira nthawi yoyambitsa kutentha kwambiri. Khalidwe lofananalo linapezeka pa Ru-2. Pa 70 ndi 60 °C, palibe kusintha komwe kunawonedwa mkati mwa mphindi 10 zoyambirira za kuyesaku. Ndikofunikira kudziwa kuti mu kuyesa konseku, kupangika kwa carbon monoxide sikunawonedwe mkati mwa malire ozindikira a chida chathu (<300 ppm), ndipo H2 ndi CO2 ndizo zinthu zokha zomwe zinawonedwa.
Kuyerekeza zotsatira za formic acid dehydrogenation zomwe zidapezeka kale mu gulu logwira ntchitoli, zomwe zikuyimira zamakono komanso pogwiritsa ntchito Ru-PNP clamp complexes, zawonetsa kuti Ru-POP clamp yatsopanoyo ili ndi ntchito yofanana ndi ya PNP 15. Ngakhale clamp PNP idapeza ma RPM a 500-1260 h-1 mu kuyesa kwa batch, POP clamp yatsopano idapeza TOFovertal value yofanana ya 326 h-1, ndipo TOFmax values ​​​​za Ru-1 ndi 1590 h-1 zidawonedwa. motsatana, ndi 1988 h-1 ndi 1590 h-1. Ru-2 ndi 1 pa 80 °C, Ru-1 ndi 4525 h-1 ndipo Ru-1 ndi 3669 h-1 pa 90 °C, motsatana.
Kuwunika kutentha kwa formic acid dehydrogenation pogwiritsa ntchito Ru-1 ndi Ru-2 catalysts. Mikhalidwe: 13 µmol catalyst, 0.5 ml (13.25 mmol) formic acid, 1.0 ml (5.35 mmol) BMIM OAc.
NMR imagwiritsidwa ntchito kumvetsetsa njira zochitira zinthu. Popeza pali kusiyana kwakukulu pakati pa 2JH-P pakati pa hydride ndi phosphine ligands, cholinga cha kafukufukuyu chili pa hydride peak. Pa Ru-1, njira ya dt ya hydrogenation unit idapezeka mkati mwa mphindi 60 zoyambirira za dehydrogenation. Ngakhale pali kusintha kwakukulu kuchokera ku −16.29 mpaka −13.35 ppm, ma coupling constants ake ndi phosphine ndi 27.2 ndi 18.4 Hz, motsatana (Chithunzi 5, Peak A). Izi zikugwirizana ndi ma phosphine onse atatu momwe hydrogen ligand ili mu cis configuration ndipo zikusonyeza kuti ligand configuration ndi yokhazikika pang'ono mu IL kwa pafupifupi ola limodzi pansi pa mikhalidwe yabwino ya reaction. Kusintha kwamphamvu kwa downfield kungakhale chifukwa cha kuchotsedwa kwa ma ligand a chlorinated ndi kupangidwa kwa ma acetyl-formic acid complexes ofanana, kupangidwa kwa d3-MeCN complex mu chubu cha NMR, kapena kupangidwa kwa N-heterocycles yofanana. tafotokoza. Carbene (NHC) complex. Panthawi ya dehydrogenation reaction, mphamvu ya chizindikiro ichi inapitirira kuchepa, ndipo patatha mphindi 180 chizindikirocho sichinawonekenso. M'malo mwake, zizindikiro ziwiri zatsopano zinapezeka. Choyamba chikuwonetsa mawonekedwe omveka bwino a dd omwe akuchitika pa -6.4 ppm (peak B). Doublet ili ndi coupling constant yayikulu ya pafupifupi 130.4 Hz, zomwe zikusonyeza kuti imodzi mwa mayunitsi a phosphine yasuntha poyerekeza ndi hydrogen. Izi zitha kutanthauza kuti POP clamp yasinthidwa kukhala κ2-P,P configuration. Kuwoneka kwa complex iyi kumapeto kwa catalysis kungasonyeze kuti mtundu uwu umabweretsa njira zoletsa pakapita nthawi, ndikupanga catalyst sink. Kumbali ina, kusintha kochepa kwa mankhwala kukusonyeza kuti ikhoza kukhala mtundu wa dihydrogenous15. Nsonga yachiwiri yatsopano ili pa -17.5 ppm. Ngakhale kuti fold yake siidziwika, tikukhulupirira kuti ndi katatu yokhala ndi coupling constant yaying'ono ya 17.3 Hz, zomwe zikusonyeza kuti hydrogen ligand imangogwirizana ndi phosphine ligand ya POP clamp, zomwe zimasonyezanso kutulutsidwa kwa triphenylphosphine (peak C). Ikhoza kusinthidwa ndi ligand ina, monga gulu la acetyl kapena NHC yopangidwa mu situ kuchokera ku ionic liquid. Kugawanika kwa PPh3 kumasonyezedwanso ndi singlet yamphamvu pa -5.9 ppm. mu 31P{1H} spectrum ya Ru-1 pambuyo pa mphindi 180 pa 90 °C (onani zina).
Gawo la Hydride la 1H NMR spectrum ya Ru-1 panthawi ya dehydrogenation ya formic acid. Mikhalidwe ya reaction: 0.5 ml formic acid, 1.0 ml BMIM OAc, 13.0 µmol catalyst, 90 °C. NMR idatengedwa kuchokera ku MeCN-d 3, 500 μl ya deuterated solvent, pafupifupi 10 μl ya reaction osakaniza.
Pofuna kutsimikiziranso kupezeka kwa mitundu yogwira ntchito mu catalytic system, kusanthula kwa high resolution mass spectrometry (HRMS) kwa Ru-1 kunachitika pambuyo pobayira formic acid kwa mphindi 10 pa 90 °C. Izi zikusonyeza kupezeka kwa mitundu yopanda chlorine ligand precatalyst mu reaction mixture. komanso ma NHC complexes awiri, omwe kapangidwe kake kakuwonetsedwa mu Chithunzi 6. HRMS spectrum yofananayo ikuwoneka mu Chithunzi Chowonjezera 7.
Kutengera ndi deta iyi, tikupereka njira yochitira zinthu mkati mwa intrasphere yofanana ndi yomwe Beller adapereka, momwe ma clamp a N-methylated PNP amathandizira kuchita zomwezo. Kuyesa kwina kupatula zakumwa za ionic sikunawonetse ntchito iliyonse, kotero kulowerera kwake mwachindunji kumawoneka kofunikira. Tikuganiza kuti kuyambitsa kwa Ru-1 ndi Ru-2 kumachitika kudzera mu kugawanika kwa chloride kutsatiridwa ndi kuwonjezera kwa NHC ndi kugawanika kwa triphenylphosphine (Scheme 1a). Kuyambitsa kumeneku m'mitundu yonse kwawonedwa kale pogwiritsa ntchito HRMS. IL-acetate ndi maziko olimba a Bronsted kuposa formic acid ndipo amatha kuchotsa protonite kwambiri latter35. Tikuganiza kuti panthawi ya catalytic cycle (Scheme 1b), mitundu yogwira ntchito ya A yokhala ndi NHC kapena PPh3 imagwirizanitsidwa kudzera mu formate kuti ipange mitundu B. Kukonzanso kwa complex iyi kukhala C pamapeto pake kumapangitsa kuti CO2 ndi trans-dihydrogen complex D. Kuphatikizika kwa asidi kukhala dihydro complex ndi acetic acid yomwe idapangidwa kale kuti ipange dihydro complex E ndikofanana ndi gawo lofunika lomwe Beller adapereka pogwiritsa ntchito N-methylated PNP clamp homologues. Kuphatikiza apo, analogue ya complex EL = PPh3 idapangidwa kale ndi stoichiometric reaction pogwiritsa ntchito Ru-1 mumlengalenga wa hydrogen atachotsa chloride ndi sodium salt. Kuchotsa hydrogen ndi kulumikizana kwa formate kumapereka A ndikumaliza kuzungulira.
Njira yogwiritsira ntchito njira yopangira intrasphere ya formic acid dehydrogenation pogwiritsa ntchito fixing complex Ru-POP Ru-1 ikuperekedwa.
Kapangidwe katsopano [RuHCl(iPr-dbfphos)(PPh3)] kapangidwa. Kapangidwe kameneka kanadziwika ndi kusanthula kwa NMR, ATRIR, EA ndi X-ray diffraction ya makristalo amodzi. Tikuwonetsanso kugwiritsa ntchito koyamba bwino kwa Ru-POP pincer complexes mu dehydrogenation ya formic acid ku CO2 ndi H2. Ngakhale kuti chitsulo choyambira chinachita ntchito yofanana (mpaka 3424 h-1), kapangidwe kameneka kanafika pa frequency yokwanira yozungulira mpaka 4525 h-1 pa 90 °C. Komanso, pa 90 °C, kapangidwe katsopano [RuHCl(iPr-dbfphos)(PPh3)] kanapeza nthawi yonse youluka (1009 h-1) kuti kakwaniritse formic acid dehydrogenation, yomwe ndi yayikulu kwambiri kuposa ya kalembedwe kachitsulo (330 h-1). ndi kalembedwe kamene kananenedwa kale [RuHCl(xantphos)(PPh3)] (333 h-1). Pazifukwa zofanana, mphamvu ya catalytic imafanana ndi ya Ru-PNP clamp complex. Deta ya HRMS imasonyeza kukhalapo kwa carbene complex mu reaction mix, ngakhale pang'ono. Pakadali pano tikuphunzira za catalytic effects ya carbene complexes.
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