Synthesis and evaluation of a pseudocyclic tristhiourea-based anion host

Article abstract of DOI:10.1021/jo061774m

A novel methodology for the evaluation of receptor arrangement in structurally flexible anion chemosensors was developed and applied to map the binding site of a new pseudocyclic tristhiourea chemosensor (6). The syntheses of 6 and related macrocyclic chemosensor 10 (a model of the folded monomeric structure of 6) are reported. Both chemosensors were evaluated by titration with a variety of structurally different anions in CH₃Cl and DMSO, showing a common preference for F^-, CH₃CO₂ ^-, and H₂PO₄^-. However, within this group of anions, the binding patterns of the chemosensors differed, indicating dissimilarity in the arrangement of the binding sites of 6 and 10.

Full text of DOI:10.1021/jo061774m

Supporting Information.
Synthesis and Evaluation of
a Pseudocyclic Tristhiourea-Based Anion Host.
Adi Dahan, Tali Ashkenazi, Vladimir Kuznetsov, Svetlana Makievski, Eyal Drug,
Ludmila Fadeev, Maayan Bramson, Sari Schokoroy, Emily Rozenshine-Kemelmakher and
Michael Gozin*
School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv
University, Tel Aviv 69978, Israel.
cogozin@mgchem.tau.ac.il
S1

Content
General Procedures……………………………………………………………………...S3
Synthetic Procedures of 1-5, 7 and 8 ………..………….………………………………S3-S6
NMR Spectra of 1-10……………………………………………………………………S7-S16
IR Spectra of 2, 3, 5, 6, 9 and 10……..………………………………………………….S17-S19
MS Spectra of 1-6, 9 and 10……………………………..…………………...………….S20-S23
UV-Vis Spectra of 5-10…………………………………………………...……………..S24-S26
GCMS Analysis of 2……………………………………………………………………..S27
HPLC-DAD analysis of 7………………………………………………………………..S28
Binding Studies with 6…………………………………………………………..………S29-S36
Binding Studies with 10…………………………………………………………………S37-S43
S2

General Procedures
All operations with air- and moisture-sensitive compounds were performed by Schlenk techniques
under Argon atmosphere. All solvents were of analytical grade or better. THF was distilled over
1
13
sodium/ benzophenone; other solvents were purchased as anhydrous. H and C NMR spectra were
1
recorded on 400 or 500 MHz spectrometers in CDCl and DMSO d . H signals are referenced to the
3
6
1
3
residual proton (7.26 ppm for CDCl and 2.50 ppm for DMSO d ) of a deuterated solvent and for C
3
6
NMR spectra, the signals of CDCl (77.0 ppm) and DMSO-d (40.45 ppm) were used as references.
3
6
Mass spectra were obtained on a magnetic sector spectrometer, equipped with CI, EI and FAB
probes and on quadropole ion trap spectrometer, equipped with ESI probe. HRMS spectra were
obtained on MALDI-TOF and ESI Q-TOF spectrometers. IR spectra were obtained on a FTIR
spectrometer. UV-vis spectra were obtained on an UV-VIS-NIR scanning spectrometer equipped
with double monochromators. 1D Fluorescence and 3D EEM spectra were obtained on a
spectrofluorimeter equipped with excitation and emission double monochromators. The progress of
reactions was monitored by TLC on a silica gel and visualized by UV-light and/or in an iodine
development chamber and by HPLC with diode array detector. Flash chromatography was carried
out on a silica gel (0.040-0.063 mm).
tert-Butyl-2-(2-aminoethoxy)ethylcarbamate (1). A suspension of NaOH (1.24 g, 31.0 mmol) in
methanol (210 mL) was heated to reflux to allow dissolution. This solution was cooled to RT and
solid 3-oxapentane-1,5-diamine dihydrochloride (3.09 g, 17.55 mmol) was added under argon. The
resultant mixture was stirred for 30 min and a solution of di-tert-butylcarbonate (1.83 g, 10.53
mmol) in dry THF (80 mL) was added dropwise at RT. The reaction mixture was stirred overnight at
RT and evaporated to give a white solid residue. The crude product was extracted with CH Cl (3 ×
2
2
3
50 mL; each extraction was performed for at least 6 h). Organic fractions were pulled together and
1
evaporated to yield 1 as a yellow oil (1.76 g, 82%). H NMR (400 MHz, CDCl ): δ 4.94 (br s, 1H),
3
3.50 (t, J = 5.1 Hz, 2H), 3.46 (t, J = 4.9 Hz, 2H), 3.30 (m, 2H), 2.85 (t, J = 4.9 Hz, 2H), 1.42 (s, 9H).
1
3
+
C NMR (125 MHz, DMSO d ): δ 156.5, 78.4, 73.6, 69.9, 42.2, 40.4, 29.1. MS (FAB ): m/z 205.1
6
+
(
MH -HCl).
S3

tert-Butyl-2-(2-isothiocyanatoethoxy)ethyl carbamate (2). A solution of SCCl (333 mg, 2.90
2
mmol) in CHCl (20 mL) was added to a solution of 1 (1.18 g, 5.78 mmol) and 4-(dimethylamino)-
3
pyridine (0.71 g, 5.81 mmol) in CHCl (100 mL) dropwise under argon at RT. After 1 h at RT, the
3
reaction mixture was refluxed overnight, then filtered through celite and evaporated. Oily residue
was re-dissolved in EtOAc (150 mL), washed with brine (3 × 30 mL), dried over MgSO and
4
evaporated. Crude product was purified by flash chromatography (SiO ; hexanes: EtOAc, gradient
2
1
from 1:1 to 1:2, with 0.1% pyridine) to give 2 as a colorless oil (629 mg, 88% yield). H NMR (400
1
3
MHz, CDCl ): δ 1.45 (s, 9H), 3.34 (br s, 2H), 3.56 (t, J = 5.10 Hz, 2H), 3.65 (m, 4H). C NMR (100
3
MHz, DMSO d ): δ 156.0, 79.4, 70.4, 69.1, 45.3, 40.4, 28.4. IR (CHCl ): 1709, 1266, 1095, 757,
6
3
-
1
+
4
2
51cm . MS (FAB ): m/z 190.0 (MH+-C(Me) ). HRMS (MALDI-TOF): calcd. for C H N O NaS
3 10 18 2 3
69.0930, found 269.0935.
1,3-Bis{2-[2-(tert-butoxycarbonylamino)ethoxy]ethyl}thiourea (3). A solution of 1 (465 mg, 2.28
mmol) in dry THF (20 mL) was added to a solution of 2 (530 mg, 2.15 mmol) in dry THF (20 mL)
dropwise under argon at RT. The reaction mixture was stirred overnight, then solvent was
evaporated and the solid residue was purified by flash chromatography (SiO ; EtOAc: hexanes, 3:1,
2
7
with 0.1% pyridine) to give 3 as a white solid (585 mg, 60%). M.p. 101.0-102.0 °C (lit. m.p. 99-101
1
°
C). H NMR (500 MHz, DMSO d ): δ

6
1
3
Hz, 4H), 3.37 (t, J = 6 Hz, 4H), 3.07 (q, J = 6 Hz, 4H), 1.36 (s, 18H). C NMR (125 MHz, DMSO
-
1
+
d6): δ 1 56.5, 78.5, 69.9, 69.6, 44.4, 40.0, 29.1. IR (CHCl ): 3021, 2396, 1216, 755 cm . MS (FAB ):
3
m/z 451.1 (MH+).
1,3-Bis[2-(2-aminoethoxy)ethyl]thiourea dihydrochloride (4). Aqueous HCl (8.0 M, 20 mL) was
added to a solution of 3 (1.15 g, 2.55 mmol) in methanol (40 mL) dropwise at RT. The reaction
mixture was stirred for 8 h, then solvents were evaporated and the crude product was purified by
crystallization from methanol/ethyl acetate to yield 4 as a light yellow powder (800 mg, 97%). M.p.
7
1
1
4
86.0-188.0 °C (lit. m.p. 186-188 °C). H NMR (500 MHz, MeOD d ): δ 3.75 (br s, 4H),

3.71 (t, J =
4
1
3
.5 Hz, 4H), 3.65 (t, J = 5.2 Hz, 4 H), 3.15 (t, J = 4.5 Hz, 4H). C NMR (125 MHz, DMSO d ): δ
6
+
+
1 83.9, 69.7, 67.2, 44.3, 39.6. MS (FAB ): m/z 251.0 (MH -2HCl).
S4

1
-(Isothiocyanatomethyl)pyrene (5). A solution of CS (475 μL, 7.90 mmol) in MeOH (20 mL)
2
was added to a mixture of pyren-1-ylmethanamine hydrochloride (1.0 g, 3.74 mmol), NaOH (155
mg, 3.88 mmol) and triethylamine (0.5 mL) in MeOH (40 mL) dropwise at 0°C. Then the reaction
mixture was allowed to warm up to RT, stirred for 3 h at RT, cooled again to 0°C and ethyl
chloroformate (755 μL, 7.90 mmol) was added dropwise. The reaction mixture was allowed to warm
to RT, stirred overnight and evaporated. CH Cl (150 mL) and water (150 mL) were added to the
2
2
resulting residue and the aqueous layer was separated and extracted with CH Cl (2 × 80 mL). The
2
2
combined organic fractions were washed with brine (50 mL), dried over sodium sulfate and
evaporated. The residue was heated to about 110°C under vacuum (30-40 mbar) for 3 h and then
purified by flash chromatography (SiO ; EtOAc: hexanes, 3:97) to give 5 as a yellow powder (1.0 g,
2
1
13
9
8 % yield). M.p. 139-143ºC. H NMR (500 MHz, DMSO d ): δ 
6
6
-
1
1
25.9, 125.8, 125.1, 124.2, 123.8, 122.7, 46.8. IR (CHCl ): 3020, 2081, 1213, 851 cm . λ
3 max
+
+
+

(DMSO) 344 nm. MS (EI ): m/z 273.1 (M ), 215 (M-Me-NCS). HRMS (EI ) calcd. for C H NSNa
1
8
11
296.0600, found 296.0504.
1
,8-Diaminoanthracene-9,10-dione (7). A solution of Na S·9H O (48.0 g, 200 mmol) in water (1
2 2
L) was added to a solution of 1,8-dinitroanthracene-9,10-dione (15.0 g, 50.3 mmol) in EtOH (300
mL) at RT. The reaction mixture was refluxed for 12 h, cooled to RT and then poured into an
ice/water mixture (1 L) with stirring. The resulting precipitate was collected by filtration, washed
with water (2 × 150 mL) and dried in vacuo. Recrystallization from EtOH yielded 7 as red-purple
needles (11.7 g, 98%). TLC (SiO ; ethyl acetate/hexanes, 4:1; r.t. = 3.1 min). M.p. 265.0-266.0°C
2
9
1
(
lit. m.p. 270.0-271.0°C). H NMR (200 MHz, DMSO d ): δ 7 .84 (br s, 4H), 
6
1
3
3
188.6, 184.3, 152.4, 134.5, 134.4, 124.4, 115.7, 114.0. λmax (DMSO): 261, 279, 478, 520 nm. MS
+
(
EI ): m/z 238.1.
S5

Anthracene-1,8-diamine (8). NaBH (19.0 g, 502.2 mmol) was added to a solution of 7 (11.0 g,
4
46.2 mmol) and NaOH (0.4 g, 10.0 mmol) in isopropanol (400 mL) portionwise under argon. The
reaction mixture was refluxed for 8 h under argon and then poured into an ice/water mixture (1000
mL) with stirring. The resulting precipitate was collected by filtration, washed with water (2 × 100
mL) and dried in vacuo. The crude residue was purified by flash chromatography (SiO ; CH OH:
2
3
9
CHCl , 1:9) to yield 8 as a yellow-brown solid (8.0 g, 83%). M.p. 175.0-176.0 °C (lit. m.p. 154-156
3
1
°
C). H NMR (500 MHz, DMSO d ): δ 8.80 (s, 1H), 8.16 (s, 1H), 7.16 (d, J = 4.4 Hz, 4H), 6.53 (t, J
6
1
3
=
4.4 Hz), 5.83 (br s, 4H). C NMR (125 MHz, DMSO d ): δ

6
+
1
16.2, 115.9, 104.8


(DMSO): 259, 273, 378 nm.
max
S6

O
O
H N
N
O
2
H
1
11.7
ppm (f1)
10.0
8.3
6.7
5.0
3.3
1.7
0.0
-1.7
1
Figure S1. H NMR of 1 in CDCl at 400 MHz.
3
O
O
H N
N
O
2
H
1
150
100
50
ppm (t1)
1
3
Figure S2. C NMR of 1 in DMSO d at 125 MHz.
6
S7

SCN
NHBoc
O
2
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
ppm (t1)
1
Figure S3. H NMR of 2 in CDCl at 500 MHz.
3
SCN
O
NHBoc
2
2
00
150
100
50
0
ppm (t1)
1
3
Figure S4. C NMR of 2 in DMSO d at 500 MHz.
6
S8

S
O
O
O
O
O
N
N
N
N
O
H
H
H
H
3
7
.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
ppm (t1)
1
Figure S5. H NMR of 3 in DMSO d at 500 MHz.
6
S
O
O
O
O
O
N
N
N
N
H
O
H
H
H
3
175
ppm (t1)
163
150
138
125
113
100
88
75
63
50
38
25
13
1
3
Figure S6. C NMR of 3 in DMSO d at 125 MHz.
6
S9

S
O
O
H N
N
N
NH2
2
H
H
+ .
2
HCl
4
8
.50
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
ppm (t1)
1
Figure S7. H NMR of 4 in MeOD d at 400 MHz.
4
S
O
O
H N
N
N
NH2
2
H
H
+ .
2
HCl
4
1
ppm (t1)
88
175
163
150
138
125
113
100
88
75
63
50
38
25
13
1
3
Figure S8. C NMR of 4 in DMSO d at 125 MHz.
6
S10

NCS
5
7.5
5.0
2.5
ppm (t1)
1
Figure S9. H NMR of 5 in DMSO d6 at 500 MHz .
NCS
5
1
3 0 .0
1 2 7 .5
1 2 5 .0
1 2 2 .5
1
75
150
125
100
75
50
25
ppm (t1)
1
3
Figure S10. C NMR of 5 in DMSO d6 at 500 MHz .
S11

S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
6
8
.3
6.7
5.0
3.3
1.7
0.0
ppm (t1)
1
Figure S11. H NMR of 6 in DMSO d6 at 500 MHz.
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
6
1
32.5
130.0
127.5
125.0
122.5
m (t1)
1
25
100
75
50
25
ppm (t1)
1
3
Figure S12. C NMR of 6 in DMSO d6 at 125 MHz.
S12

NH O
NH2
2
O
7
8.00
7.75
7.50
7.25
7.00
ppm (t1)
8.50 8.00 7.50
ppm (t1)
7.00 6.50 6.00
5.50 5.00 4.50
4.00 3.50 3.00
2.50 2.00 1.50
1.00 0.50
1
Figure S13. H NMR of 7 in DMSO d at 500 MHz.
6
NH O
NH2
2
O
7
1
80
ppm (t1)
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
1
3
Figure S14. C NMR of 7 in DMSO d at 125 MHz.
6
S13

NH2
NH2
8
8.50 8.00
ppm (t1)
7.50 7.00 6.50
6.00 5.50 5.00
4.50 4.00 3.50
3.00 2.50 2.00
1.50 1.00 0.50
1
Figure S15. H NMR of 2 in DMSO d at 500 MHz.
6
NH2
NH2
8
1
40
130
120
110
100
90
80
70
60
50
40
30
20
10
ppm (t1)
1
3
Figure S16. C NMR of 2 in DMSO d at 125 MHz.
6
S14

NCS
NCS
9
8.50
ppm (t1)
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
1
Figure S17. H NMR of 9 in DMSO d at 500 MHz.
6
NCS
NCS
9
1
25
100
75
50
25
ppm (t1)
1
3
Figure S18. C NMR of 9 in CDCl +CS at 125 MHz.
3
2
S15

S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
10
1
0.0
8.8
7.5
6.3
5.0
3.8
2.5
1.3
0.0
ppm (t1)
1
Figure S19. H NMR of 10 in DMSO d at 500 MHz at 40 °C.
6
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
10
150
100
50
ppm (t1)
1
3
Figure S20. C NMR of 10 in DMSO d at 125 MHz at 40 °C.
6
S16

BocHN
NCS
O
2
3000
2500
2000
Wavenumber cm-1
1500
1
Figure S21. IR spectrum of 2 in KBr.
S
O
O
O
O
O
N
N
N
N
O
H
H
H
H
3
3000
2000
Wavenumbers (cm-1)
1000
Figure S22. IR spectrum of 3 in chloroform.
S17

NCS
5
Figure S23. IR spectrum of 5 in KBr.
S
N
N
H
H
O
O
NH
NH
HN
S
HN
S
6
.
3
500
3000
2500
2000
Wavenumber cm-1
1500
1000
Figure S24. IR spectrum of 6 in KBr.
S18

NCS
NCS
9
3000
2000
1000
Wavenumbers (cm-1)
Figure S25. IR spectrum of 9 in KBr.
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
10
3000
2000
Wavenumbers (cm-1)
1000
Figure S26. IR spectrum of 10 in KBr.
S19

O
O
H N
N
O
2
H
1
Figure S27. FAB-MS spectrum of 1.
O
O
SCN
N
H
O
2
8
Figure S28. MALDI-MS spectrum of 2.
S20

S
O
O
O
O
O
N
N
N
N
O
H
H
H
H
3
Figure S29. FAB-MS spectrum of 3.
S
O
O
H N
N
N
NH2
2
H
H
+ .
2
HCl
4
Figure S30. FAB-MS spectrum of 4.
S21

NCS
5
Figure S31. EI MS spectrum of 5.
819.3
S
100
1
N
N
H
H
O
O
90
80
70
60
50
40
30
20
10
8
35.2
NH
HN
S
NH
HN
S
8
20.3
6
836.2
821.3
837.2
8
01.2
8
38.2
802.3
822.3
825. 82 27.8
861.2
860.2
833.2
8
17.3
803.8
839.3
851.2
8
20.6
845.1
808.8
855.1
857.6
864.1 868.2
0
00.0
8
814.4
828.8
843.2
872
Mass (m/z)
Figure S32. MALDI TOF MS spectrum of 6.
S22

NCS
NCS
9
Figure S33. CI MS spectrum of 9.
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
10
Figure S34. MALDI TOF MS spectrum of 10.
S23

1
1
.4
.2
1
NCS
0
0
0
0
.8
.6
.4
.2
0
5
2
50
350
450
Wavelength (nm
550
650
)
Figure S35. UV-Vis spectrum of 5 in DMSO.
2
S
N
N
H
H
O
O
1
0
.5
1
NH
HN
HN
S
NH
S
6
.5
0
2
50
350
450
Wavelength (nm)
550
650
Figure S36. UV-Vis spectrum of 6 in DMSO.
S24

1
1
1
1
.8
.6
.4
.2
1
NH O
NH2
2
O
7
0
0
0
0
.8
.6
.4
.2
0
2
55
355
455
555
655
755
Wavelength (nm)
Figure S37. UV-Vis spectrum of 7 in DMSO.
1
1
.4
.2
1
NH2
NH2
0
0
0
0
.8
.6
.4
.2
0
8
2
55
355
455
555
655
755
Wavelength (nm )
Figure S38. UV-Vis spectrum of 8 in DMSO.
S25

3
2
1
0
.5
3
NCS
NCS
.5
2
9
.5
1
.5
0
2
50
350
450
550
650
Wavelength (nm)
Figure S39. UV-Vis spectrum of 9 in DMSO.
S
1
1
.4
.2
1
N
H
N
H
O
O
NH
NH
HN
S
HN
S
0
0
0
0
.8
.6
.4
.2
0
10
2
50
350
450
550
650
Wavelength (nm
)
Figure S40. UV-Vis spectrum of 10 in DMSO.
S26

1
1
20000
00000
O
SCN
NHBoc
8
6
4
2
0000
0000
0000
0000
0
2
3
8
13
18
min
23
28
33
Abundance
Scan 2901 (20.227 min): TAI25_Q.D\ data.ms
57
1
6000
4000
2000
0000
000
000
000
000
1
1
1
8
86
6
70
4
129
100
2
117
190
173
147
0
50 60 70 80 90 100 110 120 130 140 150 160 170 180 190
m/ z-->
Figure S41. GC-MS analysis of 2.
S27

RT: 0.00 - 9.98
3
.10
NL:
1
.95E4
1
1
1
1
1
1
1
1
1
1
9000
8000
7000
6000
5000
4000
3000
2000
1000
0000
nm=519.5-
5
PDA
SM017d
20.5
NH O
NH2
2
O
7
9
8
7
6
5
4
3
2
1
000
000
000
000
000
000
000
000
000
0
3
.57
2
2
.12
5
.17
7.50 7.67
9.95
0
1
3
4
5
6
7
8
9
Time (min)
SM017d #186 RT: 3.08 AV: 1 NL: 2.75E4 microAU
74.0
2
2
2
2
2
1
1
1
1
1
6000
4000
2000
0000
8000
6000
4000
2000
0000
4
93.0
2
52.0
303.0
8
6
4
2
000
000
000
000
0
2
29.0
2
18.0
3
80.0
7
42.0 757.0 794.0
750 800
6
34.0 652.0 666.0
650
2
00
250
300
350
400
450
500
wavelength (nm)
550
600
700
Figure S42. RP-18 HPLC-DAD analysis of 7.
S28

3
3
2
2
1
1
5
0
.50E+06
.00E+06
.50E+06
.00E+06
.50E+06
.00E+06
.00E+05
.00E+00
4.5
4
0
1
2
3
4
5
6
7
8
9
1
2
F-
CHCl3)
F-
0
.1
.2
0
3
2
1
0
.5
3
(
(CHCl3)
0.3
.4
0
.5
2
0.5
0.6
0.7
0.8
.5
1
0.9
1
0
0
.5
0
30
40
2
50
300
350
400
450
500
4
00 430 460 490 520 550 580 610 640
nm
nm
7
6
5
4
3
2
1
0
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+00
9
8
7
6
5
4
3
2
1
0
Observed
Calculated
K = 3428
a
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
5
10
15
20
25
30
35
40
45
equiv
[H
0
]/([H
]+[G ])
0
0
7
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+00
1
:1 Binding Stoichiometry
2
6
5
4
3
2
1
0
R = 0.9559
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
0
.0
0.1
0.2
0.3
0.4
0.5
HG]/[H0]
0.6
0.7
0.8
0.9
1.0
[
Figure S43. (left column): Fluorescent titration results of 6 with tetrabutylammonium fluoride in
chloroform; (right column): Corresponding Job’s plot results, obtained by UV-vis spectroscopy
titration.
S29

0
1
2
3
equiv
eq
6
5
4
3
2
1
0
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+05
.00E+00
4.5
4
1
F-
DMSO)
eq
F-
DMSO)
0.9
0.8
0.7
eq
(
3
2
1
.5
3
(
4 eq
0.6
0.5
0.4
0.3
5
6
7
8
9
1
2
3
eq
eq
.5
2
eq
.5
1
eq
0.2
.1
eq
0
0 eq
0 eq
0 eq
0.5
0
3
50
365
380 395
nm
410
425
440
250
300
350
400
450
500
40 eq
nm
4.00E+05
3.50E+05
3.00E+05
2.50E+05
2.00E+05
1.50E+05
1.00E+05
5.00E+04
0.00E+00
8
7
6
5
4
3
2
1
0
Observed
Calculated
K = 5111
a
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
5
10
15
20
25
30
35
40
45
[
H ]/([H ]+[G ])
0 0 0
equiv
4.20E+05
3.60E+05
3.00E+05
2.40E+05
1.80E+05
1.20E+05
6.00E+04
0.00E+00
1
:1 Binding Stoichiometry
2
R = 0.9346
S
N
N
H
H
O
O
NH
HN
S
NH
HN
S
0
.0
0.1
0.2
0.3
0.4
0.5
HG]/[H
0.6
0.7
0.8
0.9
1.0
[
0
]
Figure S44. (left column): Fluorescent titration results of 6 with tetrabutylammonium fluoride in
DMSO; (right column): Corresponding Job’s plot results, obtained by UV-vis spectroscopy
titration.
S30