Ionic liquids Polarity and Solvation in Ionic Liquids...1 Polarity and Solvation in Ionic Liquids Prof. Tom Welton Imperial College Ionic liquids • When you heat a salt it will melt

1

Polarity and Solvation in Ionic

Liquids

Prof. Tom Welton

Imperial College

Ionic liquids

• When you heat a salt it will melt (e.g.,

NaCl, 801°C).

• The melt is composed of mobile ions (ionic

liquid).

Polarity

• Polarity of a liquid is defined as:

– The sum of all possible specific and non-

specific interactions between the solvent and

a potential solute, except for those that lead to

a chemical reaction

• These include:

– Coulombic, dipolar, inductive and dispersive

forces, hydrogen-bonding etc..

Ionic liquids

• Ionic liquid solutions

– Make cation-solute and/or anion solute

interactions

– Break solute-solute and cation-anion

interactions

2

Polarity

• Solvent-solute interactions are how liquids

change the behaviours of solutes.

• Polarity is understood in qualitative terms.

• Good quantitative understandings have

proved elusive.

Polarity

• There is no available measure of polarity.

• All polarity scales are estimates.

• The test of a polarity scale is usefulness.

• There is no concept of right and wrong

Polarity• There is no simple relationship

between different measures of polarity.

"Polarities"

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200 250

dielectric constant

dip

ole

mo

men

t(x 1

0 e

xp

30 /

C m

)

Polarity• There is no simple relationship

between different measures of polarity.

3

Ionic liquid polarity

• Ionic liquids have only moderate εr

liquid εr

PC

DMSO

Acetonitrile

Acetone

[emim][OTf]

[emim][N(Tf)2]

[bmim][OTf]

[bmim][N(Tf)2]

Dichloromethane

THF

64.92

46.45

35.94

20.56

15.1

12.3

13.2

11.6

8.93

7.58

H. Weingärtner, Angew. Chem. Int. Ed., 2008, 47, 654.


• Ionic liquids have a wide range of dielectric constants.

• Anion effect:

– εr is proportional to H-bond basicity

– [HCO2]- > [C2OSO4]

- ≈ [NO3]- >> [OTf]- > [BF4]

- > [NTf2]- ≈ [PF6]

-

• Cation effect:

– εr is proportional to H-bond acidity

– [(HO)C2NH3]+ > [C2NH3]

+ > [CnCmim]+

• Alkyl chain effect:

– εr is proportional to 1/chain length

• Trends similar to those in molecular solvents

• εr assumes that a liquid is

smooth and isotropic.

• ILs are heterogeneous on

the nanoscale.*

• Emission spectra of 2-

amino-7-nitrofluorene shows

the dye molecules occupying

distinct non-exchanging

environments.**


* José N. A. Canongia Lopes; Agílio A. H. Pádua; J.

Phys. Chem. B 2006, 110, 3330-3335.

** Mandal, P.; Sarkar, M.; Samanta, A. J. Phys. Chem. A

2004, 108, 9048.red/green (charged/nonpolar)

• εr from dielectric spectroscopy fails to capture

the defining feature of ionic liquids – the

translation of ions.

• εr from dielectric spectroscopy shows poor

agreement with:

• Lack of kinetically active ion pairs in SN2 reactions

(see later).

• Ionic association of Kosower’s dye at equilibrium (see

later).


4


• εr from dielectric spectroscopy shows good

agreement with:

• These have no solvent reorganisation on

timescale of measurement.

• εr from speed of sound together with densities and

heats of vapourization.*

• Emission spectra of pyrene and PRODAN.

• Timescales are important

*Singh, T.; Kumar, A. J. Phys. Chem. B, 2008, 112, 12968.

**Baker, S. N.; Baker, G. A.; Kane M. A.; Bright, F. V. J. Phys. Chem. B, 2001, 105, 9663

Empirical Polarity Scales

• Empirical polarity scales are based upon

measurements of some solvent dependent

property(ies)

– e.g. spectra, rates or selectivities of reactions.

• The property is selected to:

– Be sensitive to as many solvent-solute interactions as

possible;

– Have a wide range, so that a reasonable resolution of

results can be achieved.

• Multiparameter scales are more helpful.A. R. Katritsky et al., Chem. Rev. 2004, 104, 175-198

Kamlet-Taft dyes

N

O -

+

Reichardt's dye

NH2

NO2

4-nitroaniline

N

NO2

Et Et

N,N-diethyl-4-nitroaniline

Kamlet-Taft Parameters

• a = the hydrogen bond acidity of the

solvent: {-0.186(10.91-nR)-0.72p*}

• b = the hydrogen bond basicity of the

solvent: {(1.035nNN+2.64-nNA)/2.80}

• p* = dipolarity/polarizability etc.:

{0.314(27.52-nNN)}

5

Ionic liquid ‘polarity’

Solvent p* a b

[bmpy] [OTf] 1.017 0.396 0.461

[bmpy] [N(Tf)2] 0.954 0.427 0.252

[bmim] [OTf] 1.006 0.625 0.464

[bmim] [N(Tf)2] 0.984 0.617 0.243

Acetone 0.704 0.202 0.539

Methanol 0.730 1.050 0.610

Dichloromethane 0.791 0.042 -0.014

DMSO 1.000 0.000 0.760

L. Crowhurst, P. R. Mawdsley, J. M. Perez-Arlandis, P. A. Salter and T. Welton, PCCP., 2003, 5, 2790 - 2794


Solvent p* a b

[bmpy] [OTf] 1.017 0.396 0.461

[bmpy] [N(Tf)2] 0.954 0.427 0.252

[bmim] [OTf] 1.006 0.625 0.464

[bmim] [N(Tf)2] 0.984 0.617 0.243

Acetone 0.704 0.202 0.539

Methanol 0.730 1.050 0.610


DMSO 1.000 0.000 0.760


Effect of the anions on a

The cation can H-bond to the anion

The cation can H-bond to the solute

bmim+ + solute bmim+..solute

K2 =[bmim+...solute]

[bmim+][solute]

K2

bmim+ + An-bmim+...An-

K1 =[bmim+...An-]

[bmim+][An-]

K1


Solvent p* a b

[bmpy] [OTf] 1.017 0.396 0.461

[bmpy] [N(Tf)2] 0.954 0.427 0.252

[bmim] [OTf] 1.006 0.625 0.464

[bmim] [N(Tf)2] 0.984 0.617 0.243

Acetone 0.704 0.202 0.539

Methanol 0.730 1.050 0.610


DMSO 1.000 0.000 0.760


6

Abraham model

• The model is based on a theory of solvation that

describes the process in 3 steps

– A cavity is generated in the solvent

– The solvent reorganises around the cavity

– The solute is introduced to the cavity and any solute-

solvent interactions take place.

• By studying a wide variety of solutes with known

properties a set of solvent parameters can be

generated.

Abraham Parameters

• Log k = c+rR2+sp2H+aa2

H+bb2H+l log L16

k = the property observed

c = constant

r = interactions with p- and n-electrons of the solute

s = dipolarity/polarizability

a = H-bond basicity

b = H-bond acidity

l = dispersion interactions

The Abraham GC experiment

• 17 different ionic liquids, 8 from the same samples

used for the Kamlet-Taft experiment.

• Prepared GC columns

• Ran 36 probe solutes whose Abraham parameters are

known

• Measured retention times at 40, 70 and 100 oC.

• Multiple linear regression analysis was used to derive

the Abraham solvent parameters

The Abraham parameters for

ionic liquids• a (hydrogen bond basicity) generally high and

depends mainly on anion.

• b (hydrogen bond acidity) generally low and depends on both cation and anion.

• s (dipolarity/polarizability) values are high, showing the influence of Coulombic interactions

• s depends on both anion and cation, but no obvious trend has been elucidated so far.

• l (dispersion) nearly constant for all ionic liquids studied

7

Do the Kamlet-Taft and Abraham

parameters agree?

a and b are high in both models and depend mainly on the anion

y = 3.7995x + 1.0823

R2 = 0.8578

0

0.5

1

1.5

2

2.5

3

3.5

0.2 0.25 0.3 0.35 0.4 0.45 0.5

b

a

Do the Kamlet-Taft and Abraham

parameters agree?

b is low whereas a is high – contradiction of the two scales

[N(Tf)2N]- ionic liquids

[bmim]+ ionic liquids

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75

b

a


• Reichardt’s dye agrees with solvatochromism of

merocyanine dyes.

Byrne, R.; et al.. Phys. Chem. Chem. Phys. 2008, 10, 5919

• Reichardt’s dye agrees with Kosower’s z-scale.


• Polarities derived from Reichardt’s dye agree

with:

– Nucleophilic substitution reactions.

Nu + CR3X [NuCR3]+ + X-

Nu- + CR3X NuCR3 + X-

Nu + [CR3X]+ [NuCR3]+ + X

8


• Polarities derived from Reichardt’s dye do not

agree with:

– GC measurements

– solvatochromism of Fe(phen)2(CN)2 (phen = 1, 10-

phenanthroline);

– fluorescence spectra of PRODAN and coumarin 153

– Raman spectra of diphenylcyclopropane

• the derived values were lower, and the relative

effects of changing cations or anions were

different

• All of these are neutral probes!

Empirical Polarity Scales

• Assumptions

– if the response of the probe solute is the same as that

in some known solvent, then the polarities of the two

solvents are the same.

– the effect of transferring from one solvent to another

is the same for all probes.

• The second assumption does not always hold:

– it is important to consider the nature of the solute as

well as the solvent.

Hydrogen bonding in ionic

liquidsTheoretical investigations have shown the

importance of the Coulombic component of the

hydrogen bond.

C H

C H

C H

manifold of

C-H σ* MOs

filled

Cl p-AO

P. A. Hunt,* B. Kirchner, T. Welton, Chem. Eur. J., 2006, 12, 6762-6775.

Empirical Polarity Scales for

ionic liquids• The effect of transferring a solute from a

molecular solvent to an ionic liquid depends

upon the charge on the solute.

– Ionic liquids have a greater effect on charged solutes

than neutral solutes.

• Therefore:

– polarity scales based upon charged solutes correlate

well with the behaviours of other charged solutes

– polarity scales based upon neutral solutes to correlate

well with the behaviours of other neutral solutes

9

Nucleophilic substitutions

• Bimolecular nucleophilic substitutions

have been used historically to investigate

solvent effects on the rates of reactions.

E. D. Hughes and C. K. Ingold, J. Chem. Soc., 1935, 244-255.


• Bimolecular nucleophilic substitutions

have been used historically to investigate

solvent effects on the rates of reactions.

E. D. Hughes and C. K. Ingold, J. Chem. Soc., 1935, 244-255.


We have investigated the reaction of various

nucleophiles with methyl p-nitrobenzenesulfonate.

Nu:(-) + NO2SOMe

O

O

NuMe(+) + NO2S-O

O

O

253 nm

275 nm

N. L. Lancaster and T. Welton J. Org. Chem., 2004, 69, 5986; J. Am. Chem. Soc., 2004,

126, 11549; N. L. Lancaster, P. A. Salter, T. Welton and G. B. Young, J. Org. Chem., 2002,

67, 8855; L. Crowhurst, R. Falcone, N. L. Lancaster, V. Llopis-Mestre and T. Welton, J. Org.

Chem., 2006, 71, 8847-8853 .


It can be followed by u.v. spectroscopy under

pseudo-first order conditions to give kobs.

-0.1

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

1.7

240 250 260 270 280 290 300

wavelength/ nm

Absorb

ance/

Arb

itra

ry U

nits

The isosbestic point shows that it is a simple

A to B reaction

10


It can be followed by u.v. spectroscopy under

pseudo-first order conditions.

k2 is derived from the linear plot of kobs vs [Nu]

[Nu] / mol dm-3

ko

bs

Nucleophilic substitutions in

ionic liquids• We have used Linear Solvation Energy

Relationships (LSER’s) used to analyse

the rates of nucleophilic substitution

reactions:

lnk2 = c + aa + bb + sp*


ionic liquids

R3N + NO2SOMe

O

O

O2N S O-

O

O

MeBu3N++

R3N LSER R2

BuNH2

Bu2NH

Bu3N

lnk2 = -8.77 + 4.57b + 6.32p*

lnk2 = -8.57 + 2.23b + 7.30p*

lnk2 = 0.87 - 2.56a + 12.80p*

0.93

0.92

0.70

(solvents used: [bmim][Tf2N], [bmpy][Tf2N], [bmpy][TfO], DCM, MeCN)

The change in the rate of the reaction is controlled by both

hydrogen bonding effects and generalised polarity effects.


ionic liquidsX- + NO2SOMe

O

O

MeBr + O2N S O-

O

O

(solvents used: [bmim][Tf2N], [bmpy][Tf2N], [bmpy][TfO], DMSO, DCM, MeOH)

The change in the rate of the reaction is

dominated by specific hydrogen bonding effects.

X- LSER R2

Cl-

Br-

I-

lnk2 = 0.21 - 7.56a

lnk2 = 0.87 - 5.83a

lnk2 = 0.87 - 3.05a + 1.16b

0.99

0.97

0.95

11


ionic liquids

R3N + NO2S [CH3NR3]+ +

H3C

H3C+

NO2S

H3C

R3N LSER R2

BuNH2

Bu2NH

Bu3N

lnk2 = -2.38 - 3.59a - 4.16b + 2.10p*

lnk2 = -2.66 - 2.79a - 5.01b + 2.89p*

lnk2 = -5.62 - 6.46b + 4.26p*

0.96

0.99

0.87

(solvents used: [bmim][Tf2N], [bmpy][Tf2N], [bmim][TfO], [bmpy][TfO], DCM,

MeCN, THF, MeOH)

The change in the rate of the reaction is controlled by both

hydrogen bonding effects and generalised polarity effects.


ionic liquids

Cl- + NO2S CH3Cl +

H3C

H3C+

NO2S

H3C

Only ionic liquids appear in the LSER, because it is only in

ionic liquids that k2 can be derived.

LSER R2

Cl- lnk2 = -2.74 – 6.54a 0.99

([bmim][Tf2N], [bm2im][Tf2N], [bmpy][Tf2N], [bmim][TfO], [bmpy][TfO], [Hbim][TfO])


k2 is derived from the linear plot of kobs vs [Nu]

[bm 2im+][Cl

-] + [S

+][NTf2

-] in [bm2im][NTf2]

0

0.00005

0.0001

0.00015

0.0002

0.00025

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

[Cl-] (M)

ko

bs(s

-1)

K2 = 0.00363 M-1S-1

In molecular solvents the

reaction is not second order

Cl- + NO2S CH3Cl +

H3C

H3C+

NO2S

H3C

0

0.01

0.02

0.03

0.04

0.05

0.06

0 0.1 0.2 0.3 0.4

[Cl-] (M)

kobs

(s-1

)

THF

DCM

Propylene Carbonate

CH3CN

No reaction:

water

methanol

Negative order:

acetone

THF

DCM

Positive but not second order:

Propylene carbonate

Acetonitrile

DMSO

Second order:

Ionic liquids

12


mechanism is via ion pairs

Cl- + NO2S CH3Cl +

H3C

H3C+

NO2S

H3C

S+ S

[R4N][Cl] + [S+][NTf2]

slowsubstitution

[R4N][NTf2] + [S+][Cl]

[S+][Cl]

+

[R4N][Cl]

CH3Cl + S

fastmetathesis

DMSO

Acetonitrile

Propylene carbonate


mechanism is via ion pairs

Cl- + NO2S CH3Cl +

H3C

H3C+

NO2S

H3C

S+ S

acetone

THF

DCM

[R4N][Cl] + [S+][NTf2]

slowsubstitution

[R4N][NTf2] + [S+][Cl]

[S+][Cl]

+ CH3Cl + S

fastmetathesis precipitation

[R4N][Cl]

The ionic liquid effect

• Ionic liquids are highly dissociating

solvents.

A-Bionisation

{[A]+[B]-}

ion pairassociation

[A]+ + [B]-

free solvated ionsmolecule

dissociation

• Ion pairing is dominated by Coulombic

interactions and is usually highly

correlated with dielectric constants.

Ionic liquid polarity• Ionic liquids are far more dissociating than expected

from :

liquid εr

PC

DMSO

Acetonitrile

Acetone

[emim][OTf]

[emim][N(Tf)2]

[bmim][OTf]

[bmim][N(Tf)2]

Dichloromethane

THF

64.92

46.45

35.94

20.56

15.1

12.3

13.2

11.6

8.93

7.58

H. Weingärtner, Angew. Chem. Int. Ed., 2008, 47, 654.

13


reaction is not second order

Cl- + NO2S CH3Cl +

H3C

H3C+

NO2S

H3C

0

0.01

0.02

0.03

0.04

0.05

0.06

0 0.1 0.2 0.3 0.4

[Cl-] (M)

ko

bs (s

-1)

THF

DCM

Propylene Carbonate

CH3CN

No reaction:

water

methanol

Negative order:

acetone

THF

DCM

Positive but not second order:

Propylene carbonate

Acetonitrile

DMSO

Second order:

Ionic liquids

Ionic liquids

• When you heat a salt it will melt (e.g.,

NaCl, 801°C).

• The melt is composed of mobile ions (ionic

liquid).

Ion pairs

• In a molecular solvent:

Decreasing Ion Separation

Solvent separated

ion pair

Solvent shared

(loose) ion pair

Contact (tight) ion

pair

• In an ionic liquid all ions are surrounded by

other ions.

The ionic liquid effect

• Ionic liquids are super dissociating

solvents._

+_ +

_

+_

+

_ + _

_+

_ +

+_

+ _

+_

+

_+

_+

_ +_

+_ +

_+

_+

_ + _

+_

+_ +

_+ _ +

_

+_

+_

+

_ + _ +

_

_

+ _ +_

+_

+_ +

+_

+ _ +_

+_ + _

_ +_

+ _+

_+

+_ +

_+

_ +

_

+_

+_ +

_

+ _ + _ +_

+_

_

+_ +

_+

_ + _+

+_ _ +

_+ _

_+ +

_ +

+_

+_

+_

+ _

_+ _ + _ + _ + _

+

+_

+_

+_

+ _

_

+_

+ _+ _

+

_+

+_

_+

+_

_ +

+_

_+

+ _

_+

+_

_ +

+ _

_+

+ _

_ +

14

Charge screening of ion pairs in

ionic liquids (MD simulation)

9 Å ≈ 100% screening 3 Å ≈ 55% screening

R. M. Lynden-Bell, Phys. Chem. Chem. Phys., 2010, 12, 1733.


• Ionic liquids are super dissociating

solvents.

– Ion pairing in molecular solvents is dominated

by Coulombic interactions.

– In an ionic liquid there is little difference

between these of the solute-solute and of the

solute-solvent interactions (highly screened).

– Ion contacts that do form are rapidly disrupted

by the constant motion of the ions of the

solution (both solute and solvent).

Kosower’s Dye

0

0.5

1

1.5

2

2.5

3

300 320 340 360 380 400 420 440 460 480 500

Ab

so

rba

nc

e

Wavelength / nm

MeCN

Kosower’s Dye

0

0.5

1

1.5

2

2.5

3

300 320 340 360 380 400 420 440 460 480 500

Ab

so

rba

nc

e

Wavelength / nm

1-butanol

15

Kosower’s Dye

0

0.5

1

1.5

2

2.5

3

300 400 500

Ab

so

rba

nc

e

Wavelength / nm

[C4C1im]NTf2

Kosower’s Z-scale

• First comprehensive polarity scale

solvents using a solvatochromic dye.

• Z-values of selective solvents

Liquid Z Liquid Z

Water 94.6 MeCN 71.3

Methanol 83.6 DMSO 71.1

Ethanol 79.6 Acetone 65.5

[bmim][OTf] 76.0 DCM 64.7

[bmim][NTf2] 74.3 Ethyl acetate 59.4

[bmpy][NTf2] 73.3 Benzene 54.0

Kosower’s Dye

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

50 55 60 65 70 75 80 85 90 95 100

ETN

Z

• Z correlates well with ETN for both ionic

liquids and molecular solvents.

Kosower’s dye

• For the spectrum to be seen some [py]+

and I- ions must be in contact.

16

Kosower’s Dye Absorbance

0

2

4

6

8

10

12

14

16

18

20

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

Ab

so

rba

nc

e/P

ath

len

gth

(c

m-1

)

Concentration / M

MeCN


0

5

10

15

20

25

30

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05

Ab

so

rba

nc

e/P

ath

len

gth

(c

m-1

)

Concentration / M

1-butanol


0

5

10

15

20

25

30

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Ab

so

rba

nc

e/P

ath

len

gth

(c

m-1

)

Concentration / M

[C4C1im]NTf2

Kosower’s Dye

0

2

4

6

8

10

12

14

16

18

20

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Ab

so

rba

nc

e/P

ath

len

gth

(c

m-1

)

Concentration / M

[C4C1im]OTf

17

Beer-Lambert Law

• A = εcl

– ε = molar absorptivity (constant)

– c = concentration

– l = path length

• Non-linear A vs c indicates that there is an

equilibrium.

Kosower’s Dye Equilibrium

Model• Consider the simple equilibrium of ion

association:

the following equilibrium model was

derived:

CIP = (CT - 0.5/K) – 0.5*SQRT{4*CT/K + 1/(K2)}


Model

0

200

400

600

800

1000

1200

1400

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05

Ex

tin

cti

on

co

eff

icie

nt

Concentration, M

K=1000

K=100

K=50

K=10

K=1

ε = A/cTl

CIP = (CT - 0.5/K) – 0.5*SQRT{4*CT/K + 1/(K2)}

Kosower’s Dye

0

200

400

600

800

1000

1200

1400

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05

Ex

tin

cti

on

co

eff

icie

nt

Concentration / M

DCE

1-butanol

MeCN

18

Kosower’s Dye in ionic liquids

y = 592.94x + 5.5254

y = 681.33x + 5.8247

0

20

40

60

80

100

120

140

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Ex

tin

cti

on

co

eff

icie

nt

Concentration / M

[bmim]BF4

[bmim]OTf

Kosower’s Dye in ionic liquids

0

20

40

60

80

100

120

140

160

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Ex

tin

cti

on

c

oe

ffc

ien

t

Concentration / M

[bmpy]NTf2

[bmim]NTf2

Kosower’s Dye

0

5

10

15

20

25

30

35

40

45

50

55

60

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045

Ex

tin

cti

on

co

eff

icie

nt

concentration, M

K=1

K = 1

ΔG = -RTlnK = 0

What is the reaction?

• This is a metathesis reaction.

19

Simplest possible model for metathesis

•Two lowest energy structures for each complex on B3LYP/6-31++G(d,p)

level of theory with small core ECP for iodide

•Singlepoint calculations using zero-point energy (+Z) and basis set

superposition error (+B) correction on B3LYP level

•Singlepoint MP2 energies on B3LYP geometry


Model


Model

DFT DFT+Z DFT+Z+B MP2 MP2+Z

AVR 22.13 19.60 20.02 3.95 1.42

MIN 23.09 18.37 18.40 -2.83 -4.90

MAX 21.16 20.83 21.64 10.73 7.75

Two energies per complex → Energy of metathesis not unambiguous

AVR: calculated from the average energy per complex

MIN: calculated from the lowest energy per complex

MAX: calculated from the highest energy per complex

On highest level of theory: Metathesis energy neutral within simple model

system

Ion solvation

• All ions are randomly associated

• Dynamic system prevents long-lived ion

contacts

• There are no special ion pairs in solutions

of Kosower’s dye in ionic liquids.

Acknowledgements

Dr Patricia Hunt (theory)

Dr Lorna Crowhurst (polarity)

Dr Jason P. Hallett (kinetics)

Dr Patricia Hunt (theory)

Dr Juan Perez-Arlandis (polarity and kinetics)

Dr Guiseppe Ranieri (kinetics)

Mr Matthew Lui (polarity)

Mr Heiko Niedermeyer (theory)

Leverhulme Trust, Kodak Foundation, EPSRC, ERC

(funding)

Documents

Ionic liquids Polarity and Solvation in Ionic Liquids...1 Polarity and Solvation in Ionic Liquids Prof. Tom Welton Imperial College Ionic liquids • When you heat a salt it will melt