electronic supporting information for - rsc.org · electronic supporting information for ......

S1

Electronic supporting information for

“Does the cation really matter? The effect of modifying an ionic liquid

cation on an SN2 process”

Eden E. L. Tanner,a Hon Man Yau,a Rebecca R. Hawker,a Anna K. Croftb and Jason B. Harpera,*

aSchool of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia. bDepartment of Chemical and Environmental Engineering, University of Nottingham, University Park,

Nottingham, NG7 2RD, United Kingdom.

Table of Contents General synthetic procedures 2

Synthesis of the ionic liquids 5-9 31H NMR spectra for new compounds 9

Rate data for the Eyring plot shown in Figure 1, main text 11

Details of molecular dynamics simulations 17

Outputs of molecular dynamics simulations of pyridine 2 in the ionic liquids 4 and 5 18

Details of electrostatic potential surface calculations and outputs 19

References 20

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

S2

General synthetic procedures

Reagents for syntheses of the ionic liquid precursors were purchased from Sigma-Aldrich and

distilled immediately before use, with the exception of 1,4,5-trimethylimidazole, which was pur-

chased from Star Synthesis Co., Ltd and used without further purification. Lithium

bis(trifluoromethylsulfonyl)imide used in metathesis reactions to give the desired ionic liquids

5-9, was purchased from IoLiTec Ionic Liquids Technologies GmbH.

All other reagents used in synthesis were commercially available, purchased from either Sigma

Aldrich or Alfa Aesar and used without further purification.

Organic solvents used in syntheses were either used as received from Ajax Finechem or collected

from a Pure Solv MD Solvent Purification System. All organic solvents used in kinetics experi-

ments were either collected from the aforementioned solvent purification system or purified us-

ing methods available in the literature.1 Milli-Q™ water, where mentioned, was collected from a

Millipore Milli-Q™ Academic System with a resistivity of 18.2 Ω·cm.

Unless stated otherwise in the text, reduced pressure used in all operations was ca. 210 Torr.

High resolution mass spectrometric results were obtained on a Thermo Scientific LTQ Orbitrap

XL mass spectrometer equipped with a nanospray ionisation source (positive ion mode, spray

voltage 1.2 kV, capillary voltage 45 V, capillary temperature 275°C, Lens Voltage 150 V) in the

Bioanalytical Mass Spectrometry Facility within the Mark Wainwright Analytical Centre of the

University of New South Wales by Chowdhury Sarowar. This work was undertaken using infra-

structure provided by NSW Government co-investment in the National Collaborative Research

Infrastructure Scheme (NCRIS) and subsidised access to this facility is gratefully acknowledged.


S3

Synthesis of the ionic liquids 5-9

1-Butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide 52

1,2-Dimethylimidazole (50.0 g, 0.520 mol) and n-chlorobutane (53.0 g, 0.572 mol) were dis-

solved in dry toluene (50 mL) and heated under reflux for 40 hours under a nitrogen atmosphere

at 80°C; during this time, two layers formed. The vessel was allowed to cool to room tempera-

ture before being placed in the freezer at -20°C for 36 hours. The top layer was discarded, whilst

the light yellow bottom layer was washed with toluene (3 x 60 mL) and dried under reduced

pressure at 65°C to give 1-butyl-2,3-dimethylimiazolium chloride as a cream solid (56.4 g, 58%).

1H NMR (300 MHz, CDCl3) δ 0.98 (t, J = 7.3 Hz, 3H, CH2CH3), 1.42 (m, 2H, CH3CH2), 1.80

(m, 2H, NCH2CH2), 2.82 (s, 3H, CqCH3), 4.04 (s, 3H, NCH3), 4.21 (t, J = 7.2 Hz, 2H, NCH2),

7.45 and 7.80 (m, 2H, CHCH).

1-Butyl-2,3-dimethylimiazolium chloride (56.4 g, 0.299 mol) was dissolved in water (50 mL)

and combined with a solution of lithium bis(trifluoromethylsulfonyl)imide (95.0 g, 0.331 mol) in

water (75 mL). Two layers immediately formed, with the desired ionic liquid forming the bottom

layer. The mixture was stirred at room temperature for an hour, after which the top layer was de-

canted off. The lower layer was washed with water (10 x 50 mL) until the washings tested nega-

tive to a silver nitrate test. The organic layer was dried to constant weight under reduced pressure

at 65°C to yield the ionic liquid 5 as a colourless, viscous liquid (109 g, 84%). 1H NMR (300

MHz, d6-acetone) δ 0.97 (t, J = 7.3 Hz, 3H, CH2CH3), 1.42 (m, 2H, CH3CH2), 1.87 (m, 2H,

NCH2CH2), 2.83 (s, 3H, CqCH3), 3.99 (s, 3H, NCH3), 4.31 (t, J = 7.2 Hz, 2H, NCH2), 7.64 and

7.67 (m, 2H, CHCH).


S4

1-Butyl-3,4,5-trimethylimidazolium bis(trifluoromethylsulfonyl)imide 6

1,4,5-Trimethylimidazole (15.1 g, 0.137 mol) and n-chlorobutane (39.0 g, 0.421 mol) were heat-

ed at 70°C for 13 days. The reaction mixture was allowed to cool to room temperature and the

precipitate collected via filtration and suspended in ethyl acetate (200 ml). After stirring for 2 h

the ethyl acetate was decanted and process repeated twice. The remaining cream solid was dried

under reduced pressure at 90°C to give 1-butyl-3,4,5-trimethylimidazolium chloride (20.1 g,

72%), m.p. 60-61°C. 1H NMR (400 MHz, d6-acetone) δ 0.97 (t, J = 7.4 Hz, 3H, CH2CH3), 1.42

(m, 2H, CH3CH2), 1.79-1.95 (m, 2H, NCH2CH2), 2.34 (s, 3H, NC(CH3)C(CH3)N), 2.36 (s, 3H,

NC(CH3)C(CH3)N), 3.95 (s, 3H, NCH3), 4.29 (t, J = 7.4 Hz, 2H, NCH2CH2CH2CH3), 10.5 (s,

1H, NCHN). 13C NMR (100 MHz, d6-acetone) δ 7.22 (NC(CH3)C(CH3)N), 7.42

(NC(CH3)C(CH3)N), 12.95 (CH2CH3), 19.19 (CH2CH3), 31.53 (NCH2CH2CH2CH3), 32.88

(NCH3), 46.23 (NCH2CH2CH2CH3), 125.98 ((NC(CH3)C(CH3)N), 127.07 (NC(CH3)C(CH3)N),

136.74 (NCHN). Found HR-MS (ESI) m/z: 167.1542 ([imidazolium]+, 100), C10H19N2 requires

m/z: 167.1543; 369.2780 ([imidazolium]2Cl+, 11), C20H38ClN4 requires m/z: 369.2780.

1-Butyl-3,4,5-trimethylimidazolium chloride (20.0 g, 0.099 mol) was dissolved in water (20 ml)

and combined with a solution of lithium bis(trifluoromethylsulfonyl)imide (31.4 g, 0.109 mol) in

water (30 ml). Two layers immediately formed, with the desired ionic liquid forming the bottom

layer. The mixture was stirred for an hour at room temperature. The top layer was discarded

while the lower layer was collected and was washed with water (10 x 30 ml) until the washings

tested negative to the silver nitrate test. The organic layer was decolourised using charcoal in di-

chloromethane, then dried under reduced pressure at 90°C to yield the ionic liquid as a yellow,

viscous liquid (26.4 g, 60%). 1H NMR (400 MHz, d6-acetone) δ 0.97 (t, J = 7.3 Hz, 3H,

CH2CH3), 1.42 (m, 2H, CH3CH2), 1.79-1.92 (m, 2H, NCH2CH2), 2.34 (s, 3H,


S5

NC(CH3)C(CH3)N), 2.36 (s, 3H, NC(CH3)C(CH3)N), 3.89 (s, 3H, NCH3), 4.22 (t, J = 7.4 Hz,

2H, NCH2CH2CH2CH3), 8.81 (s, 1H, NCHN). 13C NMR (100 MHz, d6-acetone) δ 7.20

(NC(CH3)C(CH3)N), 7.39 (NC(CH3)C(CH3)N), 12.80 (CH2CH3), 19.15 (CH2CH3), 31.34

(NCH2CH2CH2CH3), 33.08 (NCH3), 46.57 (NCH2CH2CH2CH3), 120.06 (q, JHF = 321 Hz,

NSO2((CF3)2), 126.85 ((NC(CH3)C(CH3)N), 127.83 (NC(CH3)C(CH3)N), 134.20 (NCHN).

Found HR-MS (ESI) m/z: 167.1541 ([imidazolium]+, 100), C10H19N2 requires m/z: 167.1543;

614.2262 ([imidazolium]2[N(CF3SO2)2]+, 4), C22H38F6N5O4S2 requires m/z: 614.2264.*

1-Butyl-2,3,4,5-tetramethylimidazolium bis(trifluoromethylsulfonyl)imide 72

1,2,4,5-Tetramethylimidazole (10.0 g, 0.0806 mol) and n-chlorobutane (13.6 g, 0.147 mol) were

combined and heated under reflux for 24 hours under a nitrogen atmosphere at 80°C; during this

time two layers formed. The vessel was allowed to cool to room temperature before being placed

in the freezer at -20°C for 36 hours. The top layer was discarded, whilst the bottom layer was

dried under reduced pressure at 140°C. This yielded a dark brown viscous oil (14.2 g) containing

ca. 5% of the imidazole starting material by 1H NMR spectroscopy, which was used without fur-

ther purification. 1H NMR (400 MHz, CDCl3) δ 0.90 (t, J = 7.4 Hz, 3H, CH2CH3), 1.39 (m, 2H,

CH2CH2CH3), 1.73 (m, 2H, NCH2CH2CH2CH3), 2.21 (s, 3H, NC(CH3)C(CH3)N), 2.23 (s, 3H,

NC(CH3)C(CH3)N), 2.86 (s, 3H, NC(CH3)N), 3.55 (s, 3H, NCH3), 3.83 (m, 2H,

NCH2CH2CH2CH3).

1-Butyl-2,3,4,5-tetramethylimidazolium chloride (14.2 g, from above) was dissolved in water

(50 mL) and acetone (40 mL) and combined with a solution of lithium

* No signal was detected at m/z 369.2780, c.f. 1-butyl-3,4,5-trimethylimidazolium chloride.


S6

bis(trifluoromethylsulfonyl)imide (20.9 g, 0.0727 mol) in water (60 mL). The mixture was

stirred at room temperature for 12 hours, at which point the top layer was decanted off. The low-

er layer was washed with water (3 x 100 mL) until the washings tested negative to a silver nitrate

test. The organic layer was decolourised using charcoal in dichloromethane, which was removed

in vacuo, and dried to constant weight under reduced pressure at 90°C to yield the ionic liquid 7

as light yellow crystals (20.09 g, 66% over two steps) which contained none of imidazole start-

ing material, m.p. 31-32°C. 1H NMR (300 MHz, CDCl3) δ 0.94 (t, J = 7.3 Hz, 3H, CH2CH3),

1.36 (h, J = 7.3 Hz, 2H, CH2CH2CH3), 1.64 (m, 2H, NCH2CH2CH2CH3), 2.17 (m, 6H,

NC(CH3)C(CH3)N), 2.53 (s, 3H, NC(CH3)N), 3.57 (s, 3H, NCH3), 3.91 (m, 2H,

NCH2CH2CH2CH3). 13C NMR (75.5 MHz, CDCl3) δ 8.35 (NC(CH3)C(CH3)N), 8.36

(NC(CH3)C(CH3)N), 9.95 (NC(CH3)N), 13.33 (CH2CH3), 19.66 (CH2CH3), 31.41

(NCH2CH2CH2CH3), 31.77 (NCH3), 45.31 (NCH2CH2CH2CH3), 119.60 (q, JHF = 320 Hz,

NSO2(CF3)2), 124.94 (NC(CH3)C(CH3)N), 126.12 (NC(CH3)C(CH3)N), 141.7 (NC(CH3)N).

1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide 83

1-Methylpyrrolidine (50.0 g, 0.587 mol) and n-chlorobutane (60.0 g, 0.763 mol) were dissolved

in dry acetonitrile (50 mL) and heated under reflux for 18 hours under a nitrogen atmosphere at

70°C. The solvent was removed under reduced pressure and the remaining solid was washed in

petroleum ether (3 x 150 mL) and the residue dried under reduced pressure at 65°C for 6 hours to

give 1-butyl-1-methylpyrrolidinium chloride as a pale yellow solid (100 g, 95%). 1H NMR (400

MHz, CDCl3) δ 1.01 (t, J = 7.5 Hz, 3H, CH2CH3); 1.41 (m, 2H, CH2CH2CH3), 1.80 (m, 2H,


S7

NCH2CH2CH2CH3), 2.23 (m, 4H, CH3NCH2(CH2)2CH2), 3.06 (s, 3H, NCH3), 3.35 (m, 2H,

NCH2(CH2)2CH3), 3.52 (m, 4H, CH3NCH2(CH2)2CH2).

1-Butyl-1-methylpyrrolidinium chloride (100 g, 0.565 mol) was dissolved in water (300 mL) and

combined with a solution of lithium bis(trifluoromethylsulfonyl)imide (162 g, 0.565 mol) in wa-

ter (300 mL). Two layers immediately formed, with the desired ionic liquid forming in the bot-

tom layer. The mixture was stirred at room temperature for 17 hours, after which the top layer

was decanted off. The lower layer was washed with water (7 x 50 mL) until the washings tested

negative to a silver nitrate test. The bright yellow organic layer was decolourised twice using

charcoal in dichloromethane, the solvent was removed in vacuo and the residue was dried to con-

stant weight under reduced pressure at 65°C to give the title compound 8 as a pale yellow vis-

cous liquid (207 g, 88%). 1H NMR (400 MHz, CDCl3) δ 1.02 (t, J = 7.4 Hz, 3H, CH2CH3), 1.45

(h, J = 7.4 Hz, 2H, CH2CH2CH3), 1.77 (m, 2H, NCH2CH2CH2CH3), 2.30 (m, 4H,

CH3NCH2(CH2)2CH2), 3.08 (s, 3H, NCH3), 3.34 (m, 2H, NCH2(CH2)2CH3), 3.58 (m, 4H,

CH3NCH2(CH2)2CH2).

Tetraoctylammonium bis(trifluoromethylsulfonyl)imide 94

To a solution of tetraoctylammonium bromide (24.9 g, 0.0455 mol) in acetone (100 mL) and wa-

ter (50 mL) was added a solution of lithium bis(trifluoromethylsulfonyl)imide (15.0 g, 0.0519

mol) in water (50 mL) and stirred at room temperature for 12 hours. The top water layer was de-

canted off and the bottom layer containing the ionic liquid was washed with water (3 x 100 mL)

until the washings tested negative to silver nitrate. The organic layer was dried to constant

weight under reduced pressure at 65°C to give the title compound 9 which was isolated as col-

ourless crystals on standing (22.1 g, 96%), m.p. 30-31°C.


S8

1H NMR (300 MHz, CDCl3) δ 0.88 (t, J = 6.5 Hz, 12H, N(CH2CH2(CH2)5CH3)4), 1.13-1.44 (m,

40H, N(CH2CH2(CH2)5CH3)4), 3.10 (m, 8H, NCH2CH2(CH2)5CH3)4), 4.52-4.91 (m, 8H,

NCH2CH2(CH2)5CH3)4). 19F NMR (300 MHz, CDCl3) δ -78.75 (s, NSO2(CF3)2).


1H NMR

1-Butyl-

R spectra fo

-3,4,5-trime

or new comp

ethylimidazo

N.B. Resid

pounds

olium chlori

dual solvent si

S9

ide

ignal at 2.10 and water siggnal at 3.10.


1-Butyl--3,4,5-trimeethylimidazoolium bis(trif

N.B. Resid

S10

ifluoromethy

dual solvent sig

ylsulfonyl)im

gnal at 2.10.

mide 6


S11

Rate data for the Eyring plot shown in Figure 1, main text

Table S1. Rate constants for the reaction of benzyl bromide 1 and pyridine 2 in the molecular solvent acetonitrile. [Pyridine] = 0.496 mol L-1

Rate constants

Temperature / K kobs / 10-4 s-1 k2 / 10-4 L mol-1 s-1

278.7 0.888 1.79

278.0 0.965 1.95

278.4 0.937 1.89

287.8 1.86 3.76

288.4 2.02 4.07

287.0 1.69 3.41

297.7 3.67 7.40

297.8 3.88 7.82

298.1 3.82 7.70

308.0 7.61 15.3

307.7 7.39 14.9

308.0 7.52 15.2


S12

Table S2. Rate constants for the reaction of benzyl bromide 1 and pyridine 2 in the ionic liquid

5. [Pyridine] = 0.496 mol L-1

Rate constants


267.0 0.546 1.10

267.8 0.678 1.37

268.0 0.622 1.25

278.6 1.73 3.50

278.8 1.90 3.82

286.6 4.40 8.87

286.8 3.49 7.03

286.8 4.07 8.21

297.5 7.99 16.1

298.0 8.43 17.0

298.0 9.07 18.3


S13



Rate constants


274.7 0.630 1.20

274.7 0.557 1.06

274.7 0.603 1.15

284.1 1.47 2.81

284.3 1.39 2.66

284.1 1.37 2.62

295.2 3.71 7.09

295.2 3.78 7.23

295.2 3.06 5.85

295.2 3.47 6.63

305.8 8.30 15.9

305.7 8.32 15.9

305.7 7.41 14.2


S14



Rate constants


308.0 6.48 12.9

307.9 7.04 14.1

307.8 7.70 15.4

313.2 8.37 16.7

313.2 8.98 17.9

313.2 9.04 18.0

317.7 14.4 28.3

317.7 12.2 23.9

317.7 13.6 26.6

324.0 20.5 41.0

324.0 22.7 45.4


S15

Table S5. Rate constants for the reaction of benzyl bromide 1 and pyridine 2 in the ionic liquid 8. [Pyridine] = 0.501 mol L-1

Rate constants


268.1 0.848 1.71

268.0 0.955 1.92

268.1 0.901 1.81

278.0 2.33 4.68

278.0 2.20 4.43

278.1 2.54 5.10

288.1 5.06 10.2

288.0 4.55 9.16

288.1 4.92 9.89

298.0 9.26 18.6

298.0 9.56 19.2

298.0 10.4 21.0


S16

Table S6. Rate constants for the reaction of benzyl bromide 1 and pyridine 2 in the ionic liquid 9. [Pyridine] = 0.497 mol L-1

Rate constants


303.1 2.42 4.87

303.0 2.19 4.40

303.0 2.37 4.76

313.0 5.01 10.1

313.1 4.23 8.51

313.0 5.45 11.0

323.0 9.08 18.3

323.0 10.3 20.7

323.1 9.89 19.9

333.0 16.2 32.7

333.0 15.7 31.7

333.1 17.9 36.1


S17

Details of molecular dynamics simulations

All structures were calculated using Gaussian 035 at the B3LYP level of theory using the

6-31G(d) basis set. Molecular dynamics simulation were performed with the DL_POLY 2.20

software package.6 Aten 1.87 was used to generate initial configurations for molecular dynamics

simulations and for the visualisation of probability densities. The Canongia-Lopes force field for

ionic liquids8 was applied to the components belonging to the ionic liquids and the OPLS-AA

force field9-13 was used for pyridine. Molecular dynamics simulations were carried out under

cubic periodic boundary conditions with short-range and long-range cutoffs set to 12.0 Å and an

Ewald precision of 10-6. Configurations were initially allowed to reach the densities appropriate

for each of the ionic liquids through a series of low-temperature, constant-pressure simulations

with increasing timestep size, starting at 2 x 10-5 fs. Equilibration runs were carried out at 400 K

for 400 ps prior to production runs where data was collected over 4 ns with 2 fs timesteps and

configurations were recorded every 250 steps.


S18

Outputs of molecular dynamics simulations of pyridine 2 in the ionic liquids 4 and 5

Figure S1. Organisation of the components of the cations (blue) and anions (red) of the ionic liquid 5 about pyridine 2. Configurations were pre-equilibrated and final trajectories were ob-tained at 400 K over 4 ns with 2 fs timesteps. The probability densities shown above have a cut-off of 0.0055.

Figure S2. Radial distribution functions of the centre of mass of the cation of either ionic liquid 4 (green) or ionic liquid 5 (blue) about the nucleophilic nitrogen of pyridine 2.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0.00 2.00 4.00 6.00 8.00 10.00 12.00

Probab

ility

den

sitry

Distance / Å

1,3‐dialkylimidazolium

1,2,3‐trialkylimidazolium


Details

Calculat

level of

ised usin

Figure ons of tof the sspectrum

of electrosta

tion of elec

f theory usin

ng WebMO

S3. Scaled the ionic liqspectrum arm are relativ

atic potentia

ctrostatic po

ng the 6-31

Pro 10.0.14

electrostaticquid 4 (left) re relativelyvely electron

al surface ca

otential surf

+G(d,p) ba4

c potentialsand the ion

y electron-dn-rich.

S19

alculations a

faces were c

sis set and

surfaces (mnic liquid 5deficient and

and outputs

carried out

electrostatic

min = 0.06 (right). Ar

d areas sha

using Gaus

c potential

eV, max = 0reas shaded aded toward

ssian 031 at

surfaces we

0.25 eV) fotowards the

ds the red e

t the MP2

ere visual-

or the cati-e blue end end of the


S20

References

1. W. L. F. Armarego and C. Chai, Purification of Laboratory Chemicals, 5th Edition, Butterworth-Heinemann, Boston, 2003.

2. L. Cammarata, S. G. Kazarian, P. A. Salter and T. Welton, Phys. Chem. Chem. Phys, 2001, 3, 5192-5200.

3. A. K. Burrell, R. E. D. Sesto, S. N. Baker, T. M. McCleskey and G. A. Baker, Green Chem., 2007, 9, 449-454.

4. H. Matsumoto, H. Kageyama and Y. Miyazaki, Chem. Lett., 2001, 182-183. 5. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman,

J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez and J. A. Pople, Gaussian, Inc., Pittsburgh PA, 2003.

6. W. Smith, M. Leslie and T. R. Forester, The DL_POLY_2 Reference Manual, Warrington, CCLRC, Daresbury Laboratory, 2003.

7. T. G. A. Youngs, J. Comput. Chem., 2009, 31, 639. 8. J. N. Canongia Lopes, J. Deschamps and A. A. H. Pádua, J. Phys. Chem. B, 2004, 108,

2038-2047. 9. W. L. Jorgensen, D. S. Maxwell and J. Tirado-Rives, J. Am. Chem. Soc., 1996, 118,

11225-11236. 10. W. L. Jorgensen and N. A. McDonald, Theochem., 1998, 424, 145-155. 11. R. C. Rizzo and W. L. Jorgensen, J. Am. Chem. Soc., 1999, 121, 4827-4836. 12. C. G. Hanke, S. L. Price and R. M. Lynden-Bell, Mol. Phys., 2001, 99, 801-809. 13. E. K. Watkins and W. L. Jorgensen, J. Phys. Chem. A, 2001, 105, 4118-4125. 14. J. R. Schmidt and W. F. Polik, WebMO Pro, version 10.0; WebMO LLC: Holland, MI,

USA, 2009; http://www.webmo.net (accessed May, 2013).


electronic supporting information for - rsc.org · electronic supporting information for ......

Documents