Extended Supplementary Information for · (1 g/10 mL) and 9.26 mL of an aqueous NaBH 4 solution...
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1 Extended Supplementary Information for: Catalytic formation of C(sp 3 )-F bonds via decarboxylative fluorination with mechanochemically-prepared Ag 2 O/TiO 2 heterogeneous catalysts Giulia Tarantino, a Luca Botti, a Nikolaos Dimitratos a and Ceri Hammond* a a Cardiff Catalysis Institute, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT [email protected] Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2017
Transcript of Extended Supplementary Information for · (1 g/10 mL) and 9.26 mL of an aqueous NaBH 4 solution...
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ExtendedSupplementaryInformationfor:
Catalytic formation of C(sp3)-F bonds via decarboxylativefluorination with mechanochemically-prepared Ag2O/TiO2heterogeneouscatalystsGiuliaTarantino,aLucaBotti,aNikolaosDimitratosaandCeriHammond*a
aCardiffCatalysisInstitute,CardiffUniversity,MainBuilding,ParkPlace,Cardiff,CF103AT
Electronic Supplementary Material (ESI) for RSC Advances.This journal is © The Royal Society of Chemistry 2017
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1.Experimentalprocedureforcatalystpreparationandcharacterisation.
Synthesisof1%Ag/TiO2viasolimmobilisation(1Ag/TiO2(SI))
AgsupportedonTiO2waspreparedviasolimmobilisation.31.5mgofAgNO3(20mgofAg)weredissolvedin800mLofdeionisedwater.Undervigorousstirring,1.3mLofanaqueousPVAsolution(1g/10mL)and9.26mLofanaqueousNaBH4solution (37.8mg/10mL)wereaddedtosolution,whichsuddenlyturnedyellow.After30minutes,990mgofTiO2wereaddedtothebrown-orangesolution,thenacidifiedwithfewdropsofsulphuricacidtoachieveapH=1.After2hoursthesolidwasfiltratedandwashedwith2LofH2Oanddriedat110°Cfor16hours.Then,thepurplecatalystobtainedwasgrindedandcalcinedatvarioustemperatures,witharamprateof5°C/minfor3hoursinstaticair,tooxidisethemetallicAg,givingawhitepowder.
PhysicalmixtureAg2O/TiO2(1Ag2O/TiO2(PM))Physicalmixtures of Ag2O/TiO2were prepared by grinding 21.5mgof Ag2O (20mgof Ag) and
1.980gofTiO2inamortarfor20minbyhand.MechanochemicalmixtureAg2O/TiO2(1Ag2O/TiO2(MM))MechanochemicalmixturesofAg2O/TiO2werepreparedmixing21.5mgofAg2O (20mgofAg)
with1.980gofTiO2inaRetschBallMillmodelMM400for20minwithafrequencyof15Hz,usingstainlesssteel25mLJarsand10mmstainlesssteelballs.
CatalystpreparationA PANalytical X’PertPRO X-ray diffractometer was employed for powder XRD analysis. A CuKα
radiationsource(40kVand30mA)wasutilised.Diffractionpatternswererecordedbetween10-80°2θ.XPSspectrawererecordedonaKratosAxisUltraDLDspectrometerusingamonochromaticAlKα source. TPR measurements were performed on a Thermo Scientific TPDRO 1100 instrument.Analysisconditions10%H2/Arat20mlmin-1,Temperatureramprate5°Cmin-1.
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2.Generalprocedureforfluorinationreaction.Substrates
GeneralprocedurefordecarboxylativefluorinationreactionsFluorination reactionswere performed at room temperature using a single neck 10mL round
bottom flask filledwith141.7mg (0.4mmol)ofSelectfluor®,1.0mg (0.0093mmol)of silver fromvariousAg-containing catalyst and 32.0mg (0.23mmol) of K2CO3. For all reactions,N2was fluxedintothe flask for5min,and4mLofanaqueoussolutionof thecarboxylicacid0.05Mwerethenaddedintotheflaskwithasyringe.
Toperform the kinetic studieswhen2,2-dimethylglutaric acid (1a)wasemployedas substrate,duringthereaction,sampleswereregularlywithdrawnusingasyringe,filteredandanalysedintoanHPLC, Agilent 1220 Infinity LC System, using aMetaCarb 87H column 250 x 4.6mm, an aqueoussolution of phosphoric acid 0.1 M as mobile phase and succinic acid as external standard. Theconcentration of 2,2-dimethylglutaric acid and 4-fluoro-4-methylpentanoic acidwere obtained viapreviousHPLCcalibrationwithrespectivestandards.
When substrate3-5awereused, tomeasure theproduct yield, 4mLof a standard solutionofα,α,α-trifluorotoluenein(CH3)2COwasaddedtothereactionmixture,thesamplewascentrifugedtoremovethesolidcatalystand19FNMRspectraofthesolutionwasrun.KineticsforpivalicacidweredeterminedbyHPLCanalysis.
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3.Baseloadingoptimisation
FigureS1Yieldof4F4MPA(1b)at30minwithdifferentK2CO3loadings.Reactionconditions:0.2mmolof1a,0.4mmolofSelectfluor®,100mgof1Ag/TiO2(SI350)(0.0093mmolofAg),4mLH2O,variousamountofK2CO3(equivalentsrespecttosubstrate),N2atmosphere,25°C.
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4.HotfiltrationofA2OandAg2O/TiO2.
Hotfiltrationofthecatalystswasperformedfilteringthereactionmixture(henceremovingthesolidcatalyst)at10minandanalysingthevariationof1aconcentrationofthefilteredsolutionat30min.
FigureS2(Left)Solidline,timeonlineof1byieldwithoutfilteringthecatalyst.Dashedline,catalyticactivityofthereactionsolutionfilteredat10min.Reactionconditions:0.23mmolof1a,0.4mmolofSelectfluor®,1.1mgofAg2O(0.0093mmolofAg),4mLH2O,0.23mmolofK2CO3, N2 atmosphere, 25°C. Figure S3 (Right) Solid line, time on line of1b yieldwithoutfilteringthecatalyst.Dashedline,catalyticactivityofthereactionsolutionfilteredat10min.Reaction conditions: 0.23 mmol of 1a, 0.4 mmol of Selectfluor®, 1.1 mg of Ag2O (0.0093mmolofAg),99mgofTiO2,4mLH2O,0.23mmolofK2CO3,N2atmosphere,25°C.
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5.Reproducibilityof1Ag2O/TiO2(PM)
FigureS3Activityandreproducibilityofdifferentbatchesof1Ag2O/TiO2(PM).Reactionconditions:0.2mmolof1a,0.4mmolofSelectfluor®,100mgof1Ag/TiO2(PM)(0.0093mmolofAg),4mLH2O,0.23mmolofK2CO3,N2atmosphere,25°C.
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6.PowderX-RayDiffraction(pXRD)patterns
Powder X-ray diffraction was performed on a PANalytical X’PertPRO X-ray diffractometer(PANalytical, Almelo, the Netherlands), using a CuKα radiation source (40 kV and 30 mA), withdiffractionpatternsrecordedbetween5°and80°.
FigureS4PowderX-RayDiffraction(pXRD)patternof1Ag2O2/TiO2(15Hz)(redline)and1Ag2O/TiO2(15Hz)
(blackline).
Figure S5 Full Powder X-Ray Diffraction (pXRD) pattern of pure TiO2 (P25) and 1Ag2O/TiO2(MM)preparedatdifferentmillingfrequency(3-30Hz).
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7.Surfaceareaanalysis(N2physisorption)
SurfaceareaanalysiswasperformedusingaQuantachromeQuadrasorbASiQ-Twostation.Surfacearea analysis was performed at 120 °C. Surface areas were calculated using BET theory over therangeP/P0=0-1.
Catalyst BETSurfacearea(m2g-1)1Ag2O/TiO2(7.5Hz) 11.65531Ag2O/TiO2(15Hz) 23.19091Ag2O/TiO2(30Hz) 47.8575
TableS1BETanalysisof1Ag2O/TiO2(MM)preparedatdifferentmillingfrequency.
8. Reusability performances of 1% Ag2O/TiO2(MM) with 2,2-dimethylglutaricacid(1a).
Each reusability test, without intermediate base regeneration of the catalyst, wasperformedfilteringthecatalystandtheendofthereaction,washingthecatalystwith20mLofH2Oanddryingitinanovenat100°Cfor30min.
For K2CO3 treatment, the used catalyst was previously stirred into 4mL of an aqueoussolutionofK2CO30.0575Mfor1handdriedinanovenat100°Cfor30min.
FigureS6 (Left)Reusabilityperformancesof theusedcatalystwashedwithH2O. FigureS5(Right)Reusabilityperformancestheusedcatalyst treatedwithanaqueousK2CO3solution.Reaction conditions: 0.2mmol of DMGA, 0.4mmol of Selectfluor®, 100mg of 1%Ag/TiO2(0.0093mmolofAg),4mLH2O,0.23mmolofK2CO3,N2atmosphere,30°C.
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9.19FNMRSpectraofProducts.
19FspectrawererunonaJEOLEclipse(+)300MHzequippedwitha5mmautotunableBBOprobeandona400MHzBrukerUltraShieldTMusingα,α,α-trifluorotolueneasreference(δ=-63.72ppm),1H of pure 4-fluoro-4-methylpentanoic acid was run on a 400 MHz Bruker UltraShieldTMspectrometerusingTMSasreference(δ=0ppm).
(1b)
4-fluoro-4-methylpentanoic acid (1b), 4F4MPA. Prepared from 2,2-dimethylglutaric acid (1a)according to the general procedure. 19F NMR (CDCl3, 283 MHz): δ –141.29 (m, 1F). 19F NMR(H2O/(CH3)2CO, 283 MHz): -135.19 (m, 1F). 19F NMR (D2O, 283 MHz) δ -137.21 (m, 1F). In goodagreementwiththevaluefoundinliterature.1
FigureS7.1HNMRspectraof4-fluoro-4-methylpentanoicacidinCDCl3.
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FigureS8.19FNMRspectraof4-fluoro-4-methylpentanoicacidinCDCl3.
FigureS9.19FNMRspectraof4-fluoro-4-methylpentanoicacidinH2O/(CH3)2CO.
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FigureS10.19FNMRspectraof4-fluoro-4-methylpentanoicacidinD2O.
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(3b)
3-Fluoropropanoicacid (3b).Prepared fromsuccinicacid (3a)according to thegeneralprocedure.19F NMR (no solvent, 376 MHz): δ –217.29 (m, 1F). In good agreement with the value found inliterature.2
FigureS11.19FNMRspectraofcrudereactionusingsuccinicacidassubstrate.
Selectfluor α,α,α-trifluorotoluene
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(4b)
2-Fluoro-2-methylpentane (4b). Prepared from 2,2-dimethylvaleric acid (4a) according to thegeneralprocedure.19FNMR(CDCl3,376MHz):δ–136.94(m,1F).Ingoodagreementwiththevaluepresentinliterature.3
FigureS12.19FNMRspectraof2-fluoro-2-methylpentaneinCDCl3.
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(5b)
(2-fluoro-2-methylpropyl)benzene (5b). Prepared from 2,2-dimethyl-3-phenylpropionic acid (5a)according to the general procedure. 19F NMR (no solvent, 376 MHz) δ –137.89 (m, 1F). In goodagreementwiththevaluefoundinliterature.2
FigureS13.19FNMRspectraofcrudereactionwith2,2-dimethyl-3-phenylpropionicacidassubstrate.
10.Referencesforknowncompounds
Allthesubstratesusedwerecommerciallypurchasedinhighpurityandusedwithoutfurtherpurifications.
1. N.R.PatelandR.A.Flowers.J.Org.Chem.2015,80,5834.2. J.-B.Xia,C.Zhu,andC.ChenChem.Commun.,2014,50,11701.3. a)WSS:WolfgangRobien /University ofVienna (SpectralDatawereobtained fromWiley
SubscriptionServices,Inc.(US));b)F.J.Weigert,J.Org.Chem.1980,45(17),3476.
Selectfluor α,α,α-trifluorotoluene
