Supporting information

Halogen free 1,2,3- and 1,2,4-triazolide based ionic liquids: synthesis and properties AleksandrSavateev,*aClemensLiedel,aSteffenTroger-Muller,aAlbertoS.deLeon,bMarkusAntoniettiaandDariyaDontsovaa

aMax-PlanckInstituteofColloidsandInterfaces,DepartmentofColloidChemistry,ResearchCampusGolm,14424Potsdam,Germany.bMax-Planck InstituteofColloidsand Interfaces,Mechano(bio)chemistry,ResearchCampusGolm,14424Potsdam,Germany.Characterization

NMR spectra were recorded on Brucker 400MHz spectrometer using residual signal ofDMSOat2.5ppmasareferencefor1HNMRspectraandat39.52ppm–for13CNMRspectra.1H-13C gradient enhanced Heteronuclear Single Quantum Coherence (HSQC) spectra wereacquired using one bond coupling constant value of 146Hz. 1H-13C gradient enhancedHeteronuclearMultipleBondCorrelation(HMBC)spectrawereacquiredusingmultiplebondcouplingconstantvalueof8Hz.NOESYspectrawereacquiredusingNOEmixingtime200ms.MestReNovav.11.0.4-18998softwarewasusedtoprocessacquiredFIDs.High resolution mass (HR-MS) spectrawere obtained usingWaters Xevo-G2-XS (Q-TOF).SampleswerepreparedbydissolvingtheILinmethanol.Fourier transform infrared (FT-IR)spectrawererecordedonThermoScientificNicoletiD5spectrometer.Thermo gravimetric analysis mass spectroscopy (TGA-MS). TGA-MSmeasurementswereperformed using a thermo microbalance TG 209 F1 Libra (Netzsch, Selb, Germany) withuncertaintyofmassmeasurement0.1µgandtheuncertaintyofpresettemperature0.2K.Thethermomicrobalance TG 209 F1 Librawas coupledwith a ThermostarMass spectrometerGSD301T3(PfeifferVacuum;Asslar/Germany).Theionizationwasbyelectronimpactusinganiridiumfilamentasionsource;ionizationenergywas75eV,andionswereseparatedinaquadrupole mass filter. A platinum crucible was used for themeasurement of 10±1mg ofsamplesinaheliumflowof10mL·min-1andapurgeflowof10mL·min-1.DatawereanalyzedusingProteus(6.0.0)andQuadstar(7.03)softwarepackages.Differential scanning calorimetry (DSC) was performed usingNetzschDSC204 equippedwithTASC414/4andCC200Lcontrollersunderflowofnitrogenattheheatingrate5K·min-1and preset temperature uncertainty 0.2K. The standard uncertainty of glass transitiontemperaturemeasurementdidnotexceed0.3K.Density (ρ)oftheILswasdeterminedinadensityoscillationtube(DMA5000M,AntonPaar,Graz). The declared by themanufacturer accuracy of densitymeasurement is 5·10-6 g·cm-3and temperature 0.01°C. The declared by the manufacturer uncertainty of densitymeasurementis10-6g·cm-3andtemperature0.001°C.Themeasurementswereperformedat

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25±0.01°C. The viscosity-related errors are automatically corrected over the full viscosityrange bymeasuring the damping effect of the viscous sample followed by amathematicalcorrectionofthedensityvalue.Theuncertaintyofthemeasurementswerecheckedrepeatingmeasurements three times. In all cases deviation did not exceed 0.001 g·cm-3.The relativestandard uncertainty of water content determination leads to the relative standarduncertaintyof0.1%indensitymeasurement.Linear sweep voltammetry (LSV)wasmeasured usingBioLogicMPG2potentiostat and athree electrode setup with a platinum wire counter electrode, a glassy carbon workingelectrode1 (1.6mm diameter) and a reference electrode for organic media (silver wire in0.01Msilvernitrateand0.1Mtetrabutylammoniumphosphatesolutioninacetonitrile).Scanrate was 1mV·s-1. The potential of the reference electrode was compared to ferrocenemeasured under the same conditions with 0.1M tetrabutylammonium phosphate auxiliaryelectrolyte.Themeasurementswereperformedat25±1°С.Energy dispersive X-Ray (EDX) analysis was performed on JEOL JSM-7500F electronmicroscopeequippedwithtwoOxfordInstrumentsEDXdetectors, locatedatoppositesidesfromthesample.TheanglebetweenthesamplefilmsurfaceandEDXdetectoraxiswas28°.Electronsacceleratingvoltagewassetto6.0keV.Aztec3.3softwarewasusedtoprocessEDXdata and to calculate elemental composition. A homemade specimen holder wasmanufacturedtoperformEDXanalysisoftheILs.Acommercialaluminumspecimenholderofcylindrical shape (diameter 10 mm, height 5 mm) was taken for modification. A circularpunctum(diameter2mm,depth1mm)wasmadeinthecenterofthecommercialspecimenholder.AnamountofIL,sufficienttofillthecavity(ca.2-5µL),wastakenforanalysis.Water mass fraction (w)inILswasdeterminedbyKarlFischertitrationwhichwascarriedout on aMetrohm756KF coulometer,whichhas anominal detection limit 10µgofwater,equippedwithaMetrohm703TiStandusingHydranal–CoulomatAD.Therelativestandarduncertaintyofwatercontentdeterminationdidnotexceed5.6%inallmeasurements.Conductivity(κ)oftheILwasdeterminedbyimpedancespectroscopybetween20kHzand100mHzatanamplitudeof10mV.Themeasurementswereperformedat25±1°C.Weusedatwo electrode Swagelok cell with two stainless steel electrodes and a BioLogic MPG2potentiostat. Conductivity of the electrolyte was obtained from the Nyquist plot using theinterceptwith the real axis in thehigh frequency region after fittingwith aRandles circuitmodel. Measurements were repeated three times to determine the standard deviation ofconductivityvalues.TheaccuracyofconductivitymeasurementwastestedusingstandardKClsolution and was 0.003mS·cm-1. The relative standard uncertainty of conductivitymeasurement did not exceed 15%. The relative standard uncertainty of water contentdetermination leads to the relative standard uncertainty of 0.84% in conductivitymeasurement.Dynamic (shear) viscosity(µ) of the ILwasmeasuredonanAntonPaarMCR301stress-controlledrheometerusinga12mmdiametercone−plategeometrywitha1°coneangleanda20μmtruncation.Thetorquesensorresolutionofthespecifieddeviceis1μN·m.Rotatoryshearratesweeps(500–3000s-1)wereperformedat25±0.2°Candstressresponseof thedifferent IL was monitored. Temperature sweeps (25 - 80°C) were performed at 1000 s-1using a constant heating rate of 2°C·min-1. The relative standard uncertainty of dynamic

viscosity measurement did not exceed 5.3%. The relative standard uncertainty of watercontentdeterminationcausestherelativestandarduncertaintyof0.3%indynamicviscositymeasurement.Thestandarduncertaintyofthemeasuredparameters(w,Tg,µ,ρ,κ)isgivenbelow.Ionic liquid ww[a] Tg,[b] °C µ,[c] cP ρ,[d] g·cm-3 κ,[e] mS·cm-1 IL-1 ww=0.00832±0.0002 Tg=-66.6±0.1 µ =87±1 ρ =1.107±0.001 κ=2.122±0.185IL-2 ww=0.0144±0.0008 Tg=-39.0±0.3 µ =376±4 ρ =1.325±0.001 κ=1.180±0.008IL-3 ww=0.0102±0.0004 Tg=-55.4±0.2 µ =414±5 ρ =1.181±0.001 κ=0.731±0.110[a]watermassfraction;[b]glasstransitiontemperature;[c]dynamicviscosity;[d]density;[e]conductivity.

Experimental procedures

Chemicals Diaminomaleonitrile(98%),silvernitrate(≥99%),sodiumnitrite(≥97%),trifluoroaceticacid(99%), and iodomethane (≥99%) were purchased from Sigma-Aldrich; 4H-1,2,4-triazol-4-amine (99%) and 3-aminotriazole-1,2,4 (96%) were purchased from Alfa Aesar;aminoguanidiniumhydrocarbonate(98.5%)waspurchasedfromAcrosOrganics;1-butyl-2,3-dimethyl-1H-imidazol-3-iumchloride(99%)waspurchasedfromIonicLiquidsTechnologies.Allchemicalswereusedasreceivedwithoutadditionalpurification.2H-1,2,3-triazole-4,5-dicarbonitrile was synthesized according to the procedure given inthe literature.2 To a stirred suspension of diaminomaleonitrile (15.63g, 145mmol) in HClsolution(148mL,1mol·L-1),asolutionofHCl(50mL,37wt.%)wasadded.Thesolutionwascooled on the ice bath, and a solution ofNaNO2 (10.2g, 148mmol) inwater (100mL)wasadded dropwise so the temperature inside the reactor remained below+5°C. The reactionmixturewasmaintainedstirringintheicebathforadditional30min, icebathwasremovedand themixturewas stirred at +25°C for 1hour. The precipitate was filtered off, and theaqueoussolutionwasextractedwithdiethylether(4x50mL).Extractswerecombined,driedover anhydrous Na2SO4 and concentrated in vacuum affording a pale-yellow solid. Yield:16.44g,95%.1HNMR(400MHz,DMSO-d6):δ14.4(s,1H,NH).13CNMR(400MHz,DMSO-d6):δ110.79(s,C),123.83(s,C).Silver(I) 4,5-dicyano-1,2,3-triazol-2-ide. 2H-1,2,3-triazole-4,5-dicarbonitrile (2.6g,22mmol) was dissolved in solution of NaOH (0.54mol·L-1, 40mL). A solution of AgNO3(3.71g,22mmol)wasaddeddropwise.Whitesolidwasfilteredoff,washedwithwateranddriedinvacuumaffordingwhitesolid.Yield:4.83g,99%.

1-Butyl-2,3-dimethyl-1H-imidazol-3-ium 4,5-dicyano-1,2,3-triazol-2-ide (IL1). To astirredsuspensionofsilver(I)4,5-dicyano-1,2,3-triazol-2-ide (1.83g,8.1mmol) inmethanol(10mL),asolutionof1-butyl-2,3-dimethyl-1H-imidazol-3-iumchloride(1.53g,8.1mmol)inmethanol (20mL) was added. The reaction mixture was stirred at room temperatureovernight.Theprecipitatewasfilteredoffandwashedwithmethanol.Methanolsolutionwasflash chromatographed through silica gel. Aftermethanol evaporation, theoily residuewasdriedinvacuum(0.1mbar,80°C).Yield:2.06g,94%.1HNMR(400MHz,DMSO-d6):δ0.893(t,3JH,H=7.5Hz,3H,CH3),1.273(sex,3JH,H=7.5Hz,2H,CH2),1.677(quin,3JH,H=7.5Hz,2H,CH2),2.575(s,3H,CH3),3.744(s,3H,CH3),4.097(t,3JH,H=7.5Hz,2H,CH2),7.605(d,3JH,H=2.0Hz,1H,CH),7.635(d,3JH,H=2.0Hz,1H,CH).13CNMR(400MHz,DMSO-d6):δ9.15(s,CH3),13.4(s,CH2),18.9 (s,CH2),31.2 (s,CH2), 34.7 (s,CH3),47.3 (s,CH2),113.9 (s),120.9 (s),121.0 (s),122.3 (s), 144.2 (s). HR-MS: 153.1467 (cation) (Calculated 153.1386), 118.0166 (anion)(Calculated118.0159).Elementalanalysis.CalculatedC57.55,N36.14,H6.32FoundC57.24,N36.20,H6.29,O0.27.1-Methyl-4-amino-4H-1,2,4-triazol-1-ium iodide was synthesized according to theliterature procedure.3 To a solution of 4H-1,2,4-triazol-4-amine (2.93g, 35mmol) in iso-propanol(150mL),iodomethane(14.86g,105mmol)wasaddedinoneportion.Thesolutionwas stirred at room temperature for6days.An additional amount of iodomethane (2.84g,20mmol)wasaddedtothereactionmixtureandstirringwascontinuedforanother6days.The precipitatewas filtered off,washedwith cold iso-propanol (3x5mL) and diethyl ether(2x10mL) and dried in vacuum affordingwhite solid. Yield: 6.6g, 84%. Elemental analysiscalculated C 15.94, N 24.79, H 3.12 Found C 16.05, N 23.62, H 3.168. 1H NMR (400MHz,DMSO-d6):δ4.03(s,3H,CH3),6.93(br.s.,2H,NH2),9.15(s,1H,CH),10.11(s,1H,CH).13CNMR(400MHz,DMSO-d6):δ39.07(s,CH3),142.86(s,CH),144.96(s,CH). 1-Methyl-4-amino-4H-1,2,4-triazol-1-ium 4,5-dicyano-1,2,3-triazol-2-ide (IL2). To astirred suspension of silver(I) 4,5-dicyano-1,2,3-triazol-2-ide (2.36g, 10mmol) in MeOH(15mL), a solutionof 4-amino-1-methyl-4H-1,2,4-triazol-1-ium iodide (2.36g,10mmol) inMeOH (25mL) was added in one portion. The reaction mixture was stirred at roomtemperatureovernight.Theprecipitatewasfilteredoffandwashedwithmethanol.Methanolsolution was flash chromatographed through silica gel. After methanol evaporation, theyellow oily residue was dried in vacuum (0.1 mbar, 80°C). Yield: 2.13g, 94%. 1H NMR(400MHz,DMSO-d6):δ4.029(s,3H,CH3),6.963(s,2H,NH2),9.148(s,1H,CH),10.079(s,1H,CH). 13CNMR(400MHz,DMSO-d6):δ38.9(s,CH3),113.9(s,C),121.0(s,C),143.0(s,CH),145.1(s,CH).HR-MS:99.0668(cation)(Calculated99.0665),118.0156(Calculated118.0159)(anion). Elemental analysis. CalculatedC 38.71,N 58.04,H 3.25 FoundC 38.57,N 57.50,H3.57,O0.35.3-Nitro-1H-1,2,4-triazole. 3-aminotriazole-1,2,4 (8.4g, 100mmol) was dissolved in HClsolution (18.2mL, 37wt.%).4 The resultant solution was carefully added dropwise to asolution of NaNO2 (19.32g, 280mmol) in water (45mL), stirred at room temperature.Evolutionofbrowngaswasobserved.Reactionmixturewasstirredatroomtemperaturefor1hour,thenheatedat+50°Cfor30minandcooledtoroomtemperature.AsolutionofHClwas added to pH = 1, followed by addition of urea (3.5g) solution in water (4mL). Themixturewascooledinanicebath.Theprecipitatewasfiltered,washedthoroughlywithwateranddriedinvacuumaffordingawhitesolid.Yield:8.04g,71%.1HNMR(400MHz,DMSO-d6):δ8.84(s,1H,CH).13CNMR(400MHz,DMSO-d6):δ146.18(s,CH),163.09(s,C).

Silver(I) 3-nitro-1,2,4-triazol-1-ide. 3-nitro-1H-1,2,4-triazole (1.0g, 8.8mmol) wasdissolvedinasolutionofNaOH(342mg,8.6mmol)inwater(30mL)followedbyadditionofAgNO3(1.49g,8.8mmol)solution inwater(20mL).Apaleyellowsolidprecipitated. Itwasfiltered,washedthoroughlywithwateranddriedinvacuumat+50°C.Yield:1.89g,100%.1-Bbutyl-2,3-dimethyl-1H-imidazol-3-ium 3-nitro-1,2,4-triazol-1-ide (IL3). To asuspension of silver(I) 3-nitro-1,2,4-triazol-1-ide (1.91g, 8.6mmol) in MeOH (25mL), asolution of 1-butyl-2,3-dimethyl-1H-imidazol-3-ium chloride (1.61g, 8.5mmol) in MeOH(10mL)wasaddedinoneportion.Themixturewasstirredatroomtemperatureovernight.The precipitate was filtered off and washed with methanol. Methanol solution was flashchromatographedthroughsilicagel.Aftermethanolevaporation,theoilyresiduewasdriedinvacuum (0.1 mbar, 80°C) affording a yellow liquid. Yield: 2.08g, 92%. 1H NMR (400MHz,DMSO-d6):δ0.891(t,3JH,H=7.5Hz,3H,CH3),1.268(sex,3JH,H=7.5Hz,2H,CH2),1.674(quint,3JH,H=7.5Hz,2H,CH2),2.579(s,3H,CH3),3.747(s,3H,CH3),4.101(t,3JH,H=7.5Hz,2H,CH2),7.630(d,3JH,H=2.0Hz,1H,CH),7.657(d,3JH,H=2.0Hz,1H,CH),7.727(s,1H,CH).13CNMR(400MHz,DMSO-d6):δ9.13(s,CH3),13.4(s,CH3),18.9(s,CH2),31.2(s,CH2),34.7(s,CH3),47.3(s,CH2),120.9(s,CH),122.3(s,CH),144.2(s,C),151.6(s,CH).HR-MS:153.1471(cation)(Calculated 153.1386), 113.0090 (Calculated 113.0105) (anion). Elemental analysis.CalculatedC49.61,N31.56,H6.81,O12.02FoundC49.55,N31.52,H6.85,O12.08.TableS1.ElementalcompositionofILs. C,a wt.% H,awt.% N,a wt.% O,b wt.% Cl,bwt.% Ag,bwt.% ww c xwd PurityeIL-1 Calc. 57.55 6.32 36.14 - - - Found 57.24±0.065 6.29±0.026 36.20±0.025 0.27±0.03 0.00 0.00 0.00832 0.112 0.982IL-2 Calc. 38.71 3.25 58.04 - - - Found 38.57±0.06 3.57±0.002 57.50±0.025 0.35±0.07 0.00 0.00 0.0144 0.150 0.968IL-3 Calc. 49.61 6.81 31.56 12.02 - - Found 49.55±0.095 6.85±0.072 31.52±0.024 12.08±0.16 0.00 0.00 0.0102 0.133 0.982a C, H, N were determined by combustion elemental analysis as an average of twomeasurements;bO,Cl,AgelementsweredeterminedbyEDX;cwatermassfractiondeterminedbyKarl-Fischertitrationmethod;dwatermolefraction;edeterminedcombining1HNMR,EDXandwatercontentdata.

FigureS1SX.FT-IRspectraofIL-X(X=1,2,3,4).a) b)

c) d)

FigureS2.EDXspectraofIL-1(a),IL-2(b)andIL-3(c).

FigureS3.IL-11HNMRspectrum.

FigureS4.IL-113CNMRspectrum.

FigureS5.IL-1COSYspectrum.

FigureS6.IL-1NOESYspectrum.

FigureS7.IL-113CAPTspectrum.

FigureS8.IL-1HSQCspectra.

FigureS9.IL-1HMBCspectra.

FigureS10.IL-21HNMRspectrum.

FigureS11.IL-213CNMRspectrum.

FigureS12.IL-213CAPTspectrum.

FigureS13.IL-2COSYspectrum.

FigureS14.IL-2NOESYspectrum.

FigureS15.IL-2HSQCspectrum.

FigureS16.IL-2HMBCspectrum.

FigureS17.IL-31HNMRspectrum.

FigureS18.IL-313CNMRspectrum.

FigureS19.IL-313CAPTNMRspectrum.

FigureS20.IL-3COSYspectrum.

FigureS21.IL-3NOESYspectrum.

FigureS22.IL-3HSQCspectrum.

FigureS23.IL-3HMBCspectrum.

Figure S24. ILsNMRpeaks assignment. Chemical shifts of carbon atoms are shown in bolditalic; chemical shifts of the neighbor protons with observed multiplicity and couplingconstantsaredepictedbelow.

FigureS25.HR-MSspectraofIL-1:positive(top)andnegative(bottom)ionmode.

FigureS26.HR-MSspectraofIL-2:positive(top)andnegative(bottom)ionmode.

FigureS27.HR-MSspectraofIL-3:positive(top)andnegative(bottom)ionmode.

a) b)

c)

FigureS28.DSCcurvesrecordedintherangeoftemperaturesof-100…+140°CofIL-1(a),IL-2(b)andIL-3(c).

FigureS29.IL-1TGA-MSioncurrentprofiles.

N

N

nBu

NN

NN

N

N

N

N NN N

m/z 52 m/z 28

+ C N+

m/z 26

+ HC

m/z 13

+

m/z 54 m/z 53 m/z 52 m/z 51 m/z 50

m/z 43 m/z 42 m/z 41 m/z 40 m/z 39

m/z 29 m/z 28 m/z 27 m/z 26

H H

m/z 26

+

NN

NNH

N

N

N

nBum/z 153

N

N

NH

N

m/z 68

N

N

m/z 66

m/z 30

m/z 38m/z 44

FigureS30.TheproposedmechanismofIL-1thermaldecomposition.MassesofhypotheticalproductsthatwereobservedbyMSareindicatedbelowthestructures.

FigureS31.IL-2TGA-MSioncurrentprofiles.

N N

NNH2

NN

NN

N N N

m/z 52

+

m/z 38

m/z 39

m/z 40m/z 41m/z 42m/z 44

m/z 43

N NH2HN N

N N

NH

m/z 17

m/z 18

NH3

NH4NH2

m/z 16

N

m/z 14

NH

m/z 15

C N

m/z 26

C NH

m/z 27

N N

m/z 28

CH3N

m/z 29

N NH

H

m/z 30

HN N

C2HN

C2N

N N

NNH2

NN

NN

N

++

+

2-methyl-2H-1,2,3-triazole-4,5-dicarbonitrile

FigureS32.TheproposedmechanismofIL-2thermaldecomposition.MassesofhypotheticalproductsthatwereobservedbyMSareindicatedbelowthestructures.

FigureS33.IL-3TGA-MSioncurrentprofiles.N

NNO2N N

N

N

nBuN

N+

m/z 52

m/z 43 m/z 42 m/z 41 m/z 40 m/z 39

m/z 29 m/z 28 m/z 27 m/z 26

H H

m/z 26

+N

N

nBum/z 153

N

N

NH

N

m/z 34

N

NH

NO2N

m/z 30

N

NNN

O

HO

+ OH

m/z 17

O + N N +

m/z 28 m/z 39

HC C N

m/z 38

m/z 30

m/z 12 m/z 14 m/z 15m/z 16

m/z 36

m/z 18m/z 44 m/z 22 m/z 45

m/z 64

O

C3

NC CO2 CO2NH

N

N

CHO2 H2O

FigureS34.TheproposedmechanismofIL-3thermaldecomposition.MassesofhypotheticalproductsthatwereobservedbyMSareindicatedbelowthestructures.

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