Supporting information for planar bilayer activities of linear oligoester bolaamphiphiles

1

Synthesis of Linear Bolaamphiphiles

1.1

General Information

Reagents and general chemicals were purchased from Aldrich. Unless specified, all solvents were used as supplied without further purification. Analytical thin-layer chromatography (TLC) was performed on E. Merck aluminium-backed silica gel (Silica Gel F254); compounds were identified by charring with a solution of p-anisaldehyde in aqueous sulfuric acid and ethanol. NMR spectra were recorded with either (i) a Bruker AMX spectrometer operating at 300 MHz for1_{H nuclei,}

75 MHz for13_{C nuclei, and 282MHz for}19_{F nuclei, or (ii) a Bruker AMX spectrometer operating}

at 500MHz for 1_{H nuclei, and 126 MHz for}13_{C nuclei. Low resolution mass spectra (accurate}

to 10−1 _{amu) were recorded with a Q-TOF II (MicroMass/Waters, Milford MA) with 4000m/z}

max quadrapole. Samples were prepared as 1mg/ml solutions in methanol:water, and diluted by a factor of 10. 0.1% trifluoroacetic acid was added to generate more ions. High resolution mass spectra (accurate to 0.5 ppm) were obtained on an LTQ Orbitrap Velos from Thermo Scientific with 200–2000 mass range and 300 nL/min liquid infusion. Samples were prepared as 10ng/µL solutions in methanol.

tBOC Masking of p-anilinobenzoic acid was achieved by procedures described by Norman et al.1.

1.2

Synthesis of 9

O O O O O HO O OH O Cl O Cl HO O OH + R = OH R = Cl

2 eqv. NaOH(aq)

s: water/CHCl3

SOCl2

10 18 ₂₁

9

Scheme 1 Synthesis of 9

Starting material 4-hydroxybenzoic acid was weighed out as a solid (5.78g, 41.9mmol, 3.0 eqv.) in a 250mL beaker and dissolved in 58mL of 1m NaOH (4.1 eqv.) to give a clear, homogenous so-lution. This was then transferred to a 2-neck 250mL round-bottom flask and cooled to 5◦_{C using}

an ice bath. Terephthaloyl chloride (2.89g, 14.2mmol, 1.0 eqv.) was dissolved in Cl2CHCHCl2

(30mL), and poured into a dropping funnel attached to the reaction flask containing bis-anion of 18. This is added dropwise over 1 hour while stirring rapidly. The reaction becomes white and heterogenous, and this was let stirred at room temperature. After 4 hours, the reaction was quenched by acidifying to pH 2 with concentrated HCl, then filtered. The precipitate was washed sequentially with water, Et2O, and EtOH before drying at 60◦C overnight. Starting material

4-hydroxybenzoic acid was shown to be present by1_{H NMR Spectrometry, and was removed by}

grounding the solid in acetone and re-filter, yielding 5.3g white powder (92%). The product is sparingly soluble in common organic solvents and was purified only as the acid chloride. To convert the bis-acid to the bis-acyl chloride 9, the acid 21 (0.70g, 1.7mmol, 1.0 eqv.) was refluxed for 4 hours in 9mL of SOCl2to give a yellow slurry. Excess thionyl chloride was removed

under vacuum, and the product washed with Et2O to give 763mg white flakes in 87% yield. This

material is very moisture sensitive and should be used immediately after its isolation. 1.2.1 Characterization for 9

IR — as KBr pellet: 1782, 1741, 1598, 1497, 1409, 1263, 1214, 1165, 1076, 1014, 886, 816, 725, 712, 642cm−1

1_{H-NMR — (250 MHz; CDCl}

3): δ 8.37 (s, 4H), 8.2 (d, J = 8, 4H), 7.41 (d, J = 8, 4H)

1.3

Coupling of Membrane Anchor to Triaromatic Core 9

O O O O O O O O Br Br O O O O O Cl O Cl HO Br + 1.1 eqv. pyridine s: THF 11 9 19

Scheme 2 Coupling of Membrane Anchor

A 50mL round-bottom flask equipped with a stir-bar was flame-dried. Upon cooling under a N2 atmosphere, acyl chloride 9 (211mg, 0.476mmol, 1.0 eqv.) was suspended in 8mL of dry

dichloromethane. This heterogenous solution was cooled in an alcohol–ice bath to -4◦_{C before}

bromoalcohol 19 (199mg, 0.952mmol, 2.0 eqv.) and 69µL pyridine (0.95mmol, 2.0 eqv.) were added in that order. The reaction was stirred at 0◦_{C for 1 hour and then allowed to warm to}

room temperature. The reaction was diluted with 25mL CH2Cl2 and washed with brine. The

organic solution was dried over MgSO4, filtered, and concentrated. Column chromatography

(silica gel, with 1:4 EtOAc:Hexanes as eluent) yields 149mg white powder (40%).

O O O O O O O O _O O NHBoc O O BocHN O O O O O O O O Br Br HO O NHBoc + K2CO3 c: NaI s: DMSO 15 11 14

Scheme 3 I–-catalyzed Nucleophilic Displacement in Preparation of 1

To a 50mL round-bottom flask equipped with a stir-bar, dibromide 11 (646mg, 0.819mmol, 1.0 eqv.), protected aniline 14 (447mg, 1.884mmol, 2.3 eqv.), and sodium iodide (25mg, 0.164mmol, 0.2 eqv.) were dissolved in DMSO with vigorous stirring. Tetramethylammonium hydroxide (341mg, 1.884mmol, 2.3 eqv.) was then added, and this cloudy white solution was heated to 60◦_{C. The reaction was shown by TLC (silica gel, 1:1 EtOAc:Hex eluent, UV-254nm detection)}

to be complete in 2 hours (disappearance of compound 11 at Rf = 0.80). Upon completion of reaction, the reaction mixture was diluted with 30mL dichloromethane and washed with 80mL water. The aqueous phase was back-washed with 25mL dichloromethane, and the combined organic layers dried over MgSO4 and filtered to give a clear colorless solution. Solvent was

evaporated and solids recrystallized from 20mL hot CH2Cl2–EtOAc to give 740mg white powder

(82%).

Mass Spectroscopy — m/z calculated for [C₆₂H₇₂N₂O₁₆+Na]+ = 1123.48; found 1123.51.

1_{H-NMR — (300 MHz; CDCl} 3): δ 8.28 (s, 4H), 8.08 (d, J = 8.8, 4H), 7.89 (d, J = 8.8, 4H), 7.35 (d, J = 8.8, 4H), 7.26 (d, J = 8.8, 4H), 6.70 (s, 2H), 4.30-4.18 (m, 8H), 1.75-1.63 (m, 8H), 1.45 (s, 18H), 1.40-1.34 (m, 16H) 13_{C-NMR — (75MHz; CDCl} 3): δ 166.3, 165.9, 163.8, 154.3, 152.2, 142.7, 133.8, 131.4, 130.9, 130.5, 128.5, 124.6, 121.7, 117.3, 81.3, 65.4, 64.9, 29.2, 28.8, 28.3, 26.1

1.4

tBOC Deprotection of 15

The ester-linked tri-aromatic core is acid sensitive, and this peculiar cleavage condition of the

t-Bu carbamate, originally described in Kaiser et al.2_{, was necessary to preserve the core. The}

O O O O O O O O _O O NHBoc O O BocHN O O O O O O O O _O O NH2 O O H2N trifluoroacetic acid, CH2Cl2 15 1

Scheme 4 tBOC Deprotection of 15

reagent was prepared in a 10mL batch beforehand: trimethylsilyl chloride (1.09g, 10mmol) was weighed into a 10mL graduated cylinder and diluted to the 5mL mark with CH2Cl2. Phenol

(2.82g, 30mmol) was added as a solid, and the solution diluted to the 10mL mark. In a flame-dried 5mL round-bottom flask equipped with a stir-bar, protected aniline 15 (95mg, 0.086mmol) was added. To this solid, 2.5mL of the cleavage reagent (described above) was added, upon which a homogenous solution was obtained. The flask was then capped, sealed with teflon tape, and allowed to stir over 14 hours. The reaction slowly turns cloudy over time. The reaction was quenched by addition of an aqueous solution of saturated K2CO3; pH of this solution should be

around 12 at this point. Repeated extractions with chloroform, followed by drying the organic layer over MgSO4, filtering, and drying gives a white solid. Column chromatography (silica gel,

1% MeOH in chloroform) gave product contaminated with phenol. This material was dissolved in 3mL chloroform; precipitation by 25mL of ice-cold hexanes, followed by filtration gives 40mg white powder (51%).

Mass Spectroscopy — m/z calculated for [C₅₂H₅₆N₂O₁₂+H]+_{= 901.3908; found 901.3899.} 1_{H-NMR — (300 MHz; CDCl} 3): δ 8.33 (s, 4H), 8.13 (d, J = 8.9, 4H), 7.83 (d, J = 8.8, 4H), 7.32 (d, J = 8.8, 4H), 6.61 (d, J = 8.8, 4H), 4.32 (t, J = 6.7, 4H), 4.24 (t, J = 6.5, 4H), 4.00 (s,br, 4H), 1.77-1.70 (m, 7H), 1.43-1.23 (m, 27H) 13_{C-NMR — (126MHz; CDCl} 3): δ 131.8, 131.5, 130.7, 121.8, 114.0, 65.6, 64.7, 29.4, 29.04,

28.95, 26.27, 26.22. Insufficient sample to observe signals from quaternary carbons. 1.4.1 Coupling of Membrane Anchors to Monoaromatic Core

O O O O O Cl _HO (CH2)n + 1.1 eqv. pyridine s: THF O Cl Br n = 8 n = 12 2 (CH2)n Br n(H2C) Br n = 8 n = 12 10 19 20 12 13

Scheme 5 Coupling of Membrane Anchor to monoaromatic core

General procedure illustrated with compound 13. In a flame-dried 25mL round-bottom flask,

terephthaloyl chloride (250mg, 1.23mmol, 1.0eqv.) was dissolved in 5mL dry CH2Cl2.

1.4.2 Characterization for 12

Mass Spectroscopy — m/z calculated for [C₂₄H₃₆Br₂O₄+H]+ _{= 549.1; found 549.7.} 1_{H-NMR — (300 MHz; CDCl} 3): δ 8.03 (s, 4H), 4.27 (t, J = 6.7, 4H), 3.33 (t, J = 6.9, 4H), 1.83-1.68 (m, J = 14.2, 7.2, 8H), 1.37-1.28 (m, 12H) 13_{C-NMR — (75MHz; CDCl} 3): δ 165.0, 133.3, 128.6, 64.6, 33.2, 28.70, 28.59, 28.40, 27.96, 27.86, 27.3 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 ppm 2 7 .3 1 2 7 .8 6 2 7 .9 6 2 8 .4 0 2 8 .5 9 2 8 .7 0 3 3 .2 4 6 4 .5 5 1 2 8 .5 7 1 3 3 .2 7 1 6 5 .0 2 12.4 8.0 4.0 3.8 3.8 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 ppm 1 .2 1 1 .2 8 1 .2 9 1 .3 0 1 .3 0 1 .3 1 1 .3 1 1 .3 2 1 .3 2 1 .3 4 1 .3 7 1 .3 7 1 .6 8 1 .7 1 1 .7 3 1 .7 5 1 .7 8 1 .8 0 1 .8 3 3 .3 1 3 .3 3 3 .3 6 4 .2 5 4 .2 7 4 .2 9 8 .0 3 A A B B C C D D E E E H H H F F G G hexa nes/ gre ase

}

12 Fig. 1 1_H,13_{C NMR of 12 in CDCl} 3 1.4.3 Characterization for 13

Mass Spectroscopy — m/z calculated for [C₃₂H₅₂Br₂O₄+H]+_{= 661.229; found 661.32 ([M+H]}+_). 1_{H-NMR — (300 MHz; CDCl} 3): δ 8.02 (s, 4H), 4.26 (t, J = 6.7, 4H), 3.33 (t, J = 6.9, 4H), 1.80-1.70 (m, J = 7.0, 8H), 1.37-1.21 (m, 32H) 13_{C-NMR — (126MHz; CDCl} 3): δ 165.9, 134.2, 129.5, 65.6, 34.0, 32.8, 29.49, 29.41, 29.25, 28.75, 28.65, 28.2, 26.0 5

32.0 7.7 3.9 3.7 3.6 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 ppm 1 .2 1 1 .3 0 1 .3 0 1 .3 2 1 .3 2 1 .3 4 1 .3 6 1 .3 6 1 .3 7 1 .6 8 1 .7 1 1 .7 3 1 .7 5 1 .7 8 1 .8 0 3 .3 1 3 .3 3 3 .3 5 4 .2 4 4 .2 6 4 .2 9 8 .0 2 30 40 50 60 70 80 90 100 110 120 130 140 150 160 ppm 2 6 .0 0 2 8 .1 7 2 8 .6 5 2 8 .7 5 2 9 .2 5 2 9 .4 1 2 9 .4 9 3 2 .8 3 3 4 .0 3 6 5 .5 7 1 2 9 .4 7 1 3 4 .1 9 1 6 5 .8 8 A A A B B B C C C D D D H H H E E E F F G G

}

13 Fig. 2 1H,13C NMR of 13 in CDCl3

1.5

I

–

-catalyzed Nucleophilic Displacement to give tBOC-Protected

16 and 17

HO O NHBoc K2CO3 c: NaI s: DMSO O O O O (CH2)n Br n(H2C) Br n = 8 n = 12 O O O O (CH2)n n(H2C) n = 8 n = 12 O O NHBoc O O BocHN 12 13 14 16 17

Scheme 6 I–-catalyzed Nucleophilic Displacement in Preparation of Bolaamphiphiles 2 and 3

General procedure illustrated with compound 16. In a 10mL round-bottom flask, dibromide 12

(503mg, 0.937mmol, 1.0 eqv.), BOC-protected p-anilinocarboxylic acid 14 (478mg, 2.02mmol, 2.2 eqv.), and sodium iodide (28mg, 0.19mmol, 0.2 eqv.) was dissolved in DMSO. Tetramethy-lammonium hydroxide (367mg, 2.02mmol, 2.2 eqv.) was added, and the reaction was stirred at 70◦_{C for 1 hour, after which TLC (silica gel, 1:1 EtOAc:Hexanes, UV-254nm visualization)}

indi-cates that the reaction was completed. The reaction was quenched into 120mL distilled water, extracted thrice with 50mL chloroform. (Addition of brine was necessary in some cases for clear separation of the organic and aqueous layers.) The combined organic layers was washed with 30mL water, dried over MgSO4, filtered, and evaporated to afford a yellow oil. This yellow oil was

chromatographed (silica gel, with chloroform as eluent) to give 593mg white solid (66%). 6

30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 ppm 2 6 .0 6 2 8 .2 8 2 8 .6 8 2 8 .8 0 2 9 .1 6 6 4 .8 9 6 5 .6 2 8 1 .2 0 1 1 7 .3 4 1 2 4 .6 2 1 2 9 .4 9 1 3 0 .8 2 1 3 4 .1 2 1 4 2 .7 3 1 5 2 .1 7 1 6 5 .9 5 1 6 6 .3 9 15.9 15.5 7.6 3.4 3.8 1.5 3.3 3.3 4.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 ppm 1 .1 8 1 .2 3 1 .2 7 1 .3 3 1 .3 6 1 .4 5 1 .4 8 1 .5 1 1 .6 6 1 .6 8 1 .7 1 1 .7 2 1 .7 3 4 .1 9 4 .2 1 4 .2 3 4 .2 4 4 .2 6 4 .2 9 6 .7 1 7 .3 5 7 .3 8 7 .8 8 7 .9 1 8 .0 2 A A D D F F F G G G J J J K K L L M K L M M N N N Q Q Q B B C C E E H O O P P I I I 16 Fig. 3 1_H,13_{C NMR of 16 in CDCl} 3 1.5.2 Characterization for 17 1_{H-NMR — (300 MHz; CDCl} 3): δ 8.02 (s, 4H), 7.89 (d, J = 8.8, 4H), 7.36 (d, J = 8.8, 4H), 6.71 (s, 2H), 4.26 (t, J = 6.7, 4H), 4.21 (t, J = 6.7, 4H), 1.73-1.66 (m, 8H), 1.45 (s, 18H), 1.36-1.18 (m, 32H)

1.6

tBOC Deprotection to give Bolaamphiphiles 2 and 3

Deprotection of the suite of mono-aromatic compounds proceeded using the same TMSCl/phenol reagent was reported above for the deprotection of compound 1.

1.6.1 Characterization for 2

Mass Spectroscopy — m/z calculated for [C₃₈H₄₈N₂O₈+H]+_{= 661.349; found 661.3485.}

A B B C C D D E E F F G G

{

H H I I J J dmso Fig. 4 1H NMR of 17 in CDCl3 O O O O (CH2)n n(H2C) n = 8 n = 12 O O NHBoc O O BocHN O O O O (CH2)n n(H2C) n = 8 n = 12 O O NH2 O O H2N HCl in MeOH s: MeOH t: room temperature, 1h 16 17 2 3

Scheme 7 tBOC Deprotection to give Bolaamphiphiles 2 and 3

1_{H-NMR — (300 MHz; CDCl} 3): δ 8.02 (s, 4H), 7.80-7.75 (m, 4H), 6.58-6.54 (m, 4H), 4.26 (t, J = 6.6, 4H), 4.18 (t, J = 6.6, 4H), 3.97 (s,br, 4H), 1.71-1.67 (m, 8H), 1.39-1.33 (m, 16H) 13_{C-NMR — (126MHz; CDCl} 3): δ 167.0, 165.5, 150.0, 134.7, 131.5, 129.4, 119.7, 113.7, 66.2, 64.4, 29.3, 28.1, 26.4 1.6.2 Characterization for 3

Mass Spectroscopy — m/z calculated for [C₄₆H₆₄N₂O₈+H]+_{= 773.474; found 773.4720.} 1_{H-NMR — (300 MHz; CDCl} 3): δ 8.03 (s, 4H), 7.78 (d, J = 8.8, 4H), 6.57 (d, J = 8.8, 4H), 4.26 (t, J = 6.7, 4H), 4.18 (t, J = 6.7, 4H), 3.98 (s,br, 4H), 1.75-1.61 (m, 8H), 1.37-1.22 (m, 32H) 13_{C-NMR — (75MHz; CDCl} 3): δ 166.8, 165.9, 150.8, 134.2, 131.6, 129.6, 120.1, 113.8, 65.7, 64.5, 29.6, 29.3, 28.9, 28.6, 26.13, 25.96 8

16.8 7.8 2.9 3.7 4.1 3.6 3.6 4.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 ppm A C G K H J N A C D G H I I I J K N B E F M L 2 Fig. 5 1_H,13_{C NMR of 2 in CDCl} 3 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 ppm 2 5 .9 6 2 6 .1 3 2 8 .6 0 2 8 .8 9 2 9 .3 3 2 9 .6 1 6 4 .4 7 6 5 .6 5 1 1 3 .8 3 1 2 0 .1 4 1 2 9 .5 5 1 3 1 .6 2 1 3 4 .1 6 1 5 0 .7 6 1 6 6 .0 1 1 6 6 .7 9 32.2 7.9 3.0 3.9 4.1 3.6 3.6 4.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 ppm 1 .2 2 1 .2 9 1 .3 5 1 .3 7 1 .6 1 1 .6 3 1 .6 6 1 .6 8 1 .7 0 1 .7 0 1 .7 3 1 .7 5 3 .9 8 4 .1 5 4 .1 8 4 .2 0 4 .2 4 4 .2 6 4 .2 9 6 .5 5 6 .5 8 7 .7 7 7 .8 0 8 .0 3 A C D G HJ _I J K N A C D G H I K N B E F M L 3 Fig. 6 1H,13C NMR of 3 in CDCl3 9

2

Voltage Clamp Records of Linear Bolaamphiphiles

In this section, annotated activity grids, as well as full conductance records (and expansions where appropriate), are provided for every compound studied. These are arranged first by compounds, then individual experiments. Within each experiment, the first page(s) summarizes the experimental conditions as well as activity grids charted; subsequent pages shows the full conductance record as the top panel, with expansions indicated by corresponding letters. For the aromatic bolaamphiphiles, traces were acquired prior to establishing a protocol that automates the acquisition of potential—time records, and the data analysis were performed by hand.

brush transfer

baseline drift 10-18pS;

no activity otherwise

109-0000

A

B

C

B

109-0002

A

B

B

A

14

A

B

D

D

C

C

B

15

electrolyte 17/25uM lipid contact injection brush transfer

0005

0006

0009

0010

0012

0014

0015

0016

0011

br oken bila yer br oken bila yer br oken bila yer br oken bila yer

0001 - mechanical noise from

changing gas cylinder

IV

A

B

B

24 pS

43 pS

2.1 sec

17

98-0001

A

B

B

A

18

A

B

B

A

5.2 sec

43 pS

19

A

B

C

98-0004

A

B

C

20

A

B

B

98-0006

A

B

C

A

19 pS

C

22

A

B

C

98-0008

A

A

A

B

98-0010

A

B

B

A

26

A

B

B

98-0012

A

B

C

B

A

multiple populations of (small) openings

A

B

C

B

D

D

29

98-0014

A

B

C

D

B

A

C

D

30

A

B

C

B

98-0016

A

A

0004

0006

0mV

0mV

106-0000

A

A

43 pS

21 pS

510ms

_70ms

31 pS

2 sec

0.37 sec

34

A

B

C

B

106-0004

A

B

C

B

136 pS

16 pS

C

37

106-0006

0.51s

8 pS

24 pS

A

A

BB

B

38

A

B

C

C

B

A

45 pS

6.6 sec

40

electrolyte

lipid

contact injection

brush transfer

electrolyte 18/12uM

lipid

contact injection 9/6uM

brush transfer br oken bila yer br oken bila yer 27/18uM

no activity

42

A

B

B

50 pS

17 sec (cont.)

43

112-0001

17 sec (continued from 0000)

A

A

A

B

B

A

112-0003

112-0004

A

A

3.9 sec

734 pS

940 pS

930 pS

40 sec

15 sec

B

B

46

0003

0002

0004

0005

0006

0007

0008

0009

I think it is fair to conclude that:

- both 8-12-8-G(12) and G(12)-8-12-8 can form similar discrete channels, - G(12)-8-12-8 has a variety of other membrane-active modes,

- and with weak evidence we'll say that G(12)-8-12-8 forms these discrete channels more readily.

99-0002

67 pS

>17 sec

A

B

B

A

48

A

B

C

C

B

A

5.6 sec

41 pS

88 pS

111 pS

D

D

49

99-0004

~19 pS

>100 sec

A

A

50

A

38 pS

99-0006

A

B

D

C

C

B

A

41 pS

35 pS

D

52

A

99-0008

A

A

B

B

C

C

54

A

A

B

C

C

B

D

E

55

D

E

br oken 5 sec 100pS A C D B B C 200 msec 100pS 20 sec 50pS 5 sec 50 pS 57

40-0002

2

10 sec 420pS 1 sec 420 pS A A

1M CsCl inj., +120mV

58

A

0.5 sec 500pS

41-0011

2

A A B B 2 sec 420pS 0.2 sec 420pS

1M CsCl 2uM in cmpd, -120mV

60

A B 0.5 sec 350pS 0.5 sec 140pS 61

50-0003

2

A A 5 sec 110pS 100 msec 55pS

1M CsCl pH 7 4uM in cmpd, +180mV

62

5 sec 12pS

A

5 s 500 pS 20 s 50 pS 20 s 8.3 pS 10 s 500 pS 2 s 50 pS A B C D E 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS

3

1M KCl pH 5, 120mV 1M KCl pH 7, +100mV 1M KCl pH 7, +100mV 1M KCl pH 5, +100mV 1M KCl pH 5, -100mV 2 s 310 pS 2 s 420 pS 2 s 400 pS 10 s 25 pS 5 s 770 pS 100 ms 100 pS A B C D E F 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS 10 ms 100 ms 1 s ec10 sec 100 s ec 1000 s ec 3 pS 10 pS 30 pS 100 pS 300 pS 1000 pS 3000 pS

1M KCl buffered to pH 5, cmpd brushed on, 200mV

1M CsCl unbuffered, +130mV

1M KCl unbuffered; cmpd by injection; 4.6mM x 10ul; +100mV

1M CsCl unbuffered; 1mol% premixed, +120mV 1M CsCl unbuffered; 1mol% premixed, -50mV

1M CsCl unbuffered; 1mol% premixed, +160mV

1