Sequential multiphoton absorption enhancement

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C), 1058 (νs C-O-C) cm-1; ESI-MS: C34H50NO11P (m/z): 680 [M + H]+. ... tBuOK (68 mg, 0.61 mmol) in 5 ml of dry DMF was added dropwise over a period of 15 ...
Supporting Information

for

Sequential multiphoton absorption enhancement induced by zinc complexation in functionalized distyrylbenzene analogs

Graziano Fabbrini, Raffaele Riccò, Enzo Menna, Michele Maggini,* Vincenzo Amendola, Mattia Garbin, Massimo Villano, Moreno Meneghetti

Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy.

*To whom correspondence should be addressed Phone: +39-0498275662 /Fax: +39-0498275792 Email address: [email protected]

Contents 1. Synthetic details and characterization for compounds 4, 5, 7, 9-14 (NMR and IR spectra for 2 and 3) 2. Titration for stoichiometry and binding constant determination Figure S1 Figure S2 Figure S3 Figure S4 Figure S5 Figure S6 Figure S7 Figure S8 Figure S9 Figure S10 Figure S11

1

H NMR of 2 C NMR of 2 1 H NMR of 3 13 C NMR of 3 IR spectrum of 2 IR spectrum of 3 ESI-MS of 2 ESI-MS of 3 ESI-MS of 2-Zn2+ complex ESI-MS of 3-Zn2+ complex Fluorescence spectral changes observed upon the addition of Zn2+ to 2 and 3 (stoichiometry and binding constant determination) 13

1

OCH3 3

O X

N O

N

H3CO

N 3 2, X = -CN 3, X = -N(CH3)2

N

OCH3 O

3

3

X

HO

O P OEt OEt

O

CHO O

H3CO

H3CO 3

3 4, X = -CN, 5, X = -N(CH3)2

7

OCH3

OCH3

O

3

NC

OH

OCH3

O

O

3

NC

3

EtOOC

Br

O

COOEt

O

H3CO 3

H3CO 3

O

H3CO

3

9

10

11

OCH3

O

3

HO

O OH

H3CO

OCH3

O

OCH3

3

Br Br

O 3

H3CO

O

H3CO 3

EtO O P EtO

O

O

OEt P O OEt OCH3 3

3 13

12

14

Phosphonate 4. Bromobenzyl derivative 10 (147 mg, 0.24 mmol) and triethylphosphite (213 mg, 1.28 mmol) were brought to 150 °C for 3 h. The crude product was purified by flash column chromatography (SiO2, eluent: ethyl acetate/petroleum ether 1:1, then ethyl acetate/ethanol 9:1). 2

139 mg (87%) of 10 were isolated as a yellow-green oil. 1H-NMR (250 MHz, CDCl3) δ 7.65-7.56 (m, 4H), 7.59-7.52 (d, 1H, Jtrans = 16.5 Hz), 7.31-7.7.06 (d, 1H, Jtrans = 16.5 Hz), 7.11 (s, 1H), 6.98 (s, 1H), 4.20-4.15 (m, 4H), 4.11-4.3.99 (m, 4H), 3.90.3.85 (m, 4H), 3.80-3.62 (m, 12H), 3.57-3.50 (m, 4H), 3.37 (s, 3H), 3.35 (s, 3H), 3.30-3.22 (d, 2H, J = 21.5 Hz), 1.29-1.23 (t, 6H, J = 7.2 Hz); 13

C-NMR (62.9 MHz, CDCl3) δ 151.22-151.10 (d, JCP = 7.4 Hz), 150.97, 143.76, 142.57, 132.54,

127.36-127.33 (d, JCP = 1.8 Hz), 127.33-126.96 (d, JCP = 6.9 Hz), 125.36-125.29 (d, JCP = 4.1 Hz), 122.75-122.59 (d, JCP = 9.7 Hz), 119.25, 116.54-116.45 (d, JCP = 5.5 Hz), 110.90-110.84 (d, JCP = 3.2 Hz), 110.31, 72.03-72.01 (d, JCP = 1.3 Hz), 70.92, 70.90, 70.78, 70.68, 69.99, 69.88, 69.09, 62.16-62.06 (d, JCP = 6.4 Hz), 59.12, 27.90-25.69 (d, JCP = 138.0 Hz), 16.58-16.49 (d, JCP = 6.0 Hz); IR (KBr) ν 2870 (ν C-H), 2222 (ν C≡N), 1409 (ν C=C-H), 1243 (ν O-P=O), 1199 (ν P-OC), 1058 (νs C-O-C) cm-1; ESI-MS: C34H50NO11P (m/z): 680 [M + H]+. Phosphonate 5. To a solution of bis-phosphonate 14 (430 mg, 0.61 mmol) and 4-(N,Ndimethylamino)benzaldehyde (91 mg, 0.61 mmol) in 15 ml of dry DMF at 0 °C, a suspension of tBuOK (68 mg, 0.61 mmol) in 5 ml of dry DMF was added dropwise over a period of 15 min under a nitrogen atmosphere. When the addition was complete, the mixture was stirred at room temperature for 12 h. The mixture was diluted with water (30 ml) and extracted with CH2Cl2 (3 x 30 ml). The combined organic layers were dried over anhydrous Na2SO4 and the solvent was removed under reduced pressure. The crude product purified by flash column chromatography (SiO2, eluent: ethyl acetate/toluene/ethanol 6:4:1). 100 mg (24%) of 5 were isolated as an orange oil. 1H-NMR (250 MHz, CDCl3) δ 7.35-7.32 (d, 2H, J = 8.7 Hz), 7.08-7.03 (d, 1H, Jtrans = 16.6 Hz), 6.84-6.77 (d, 1H, Jtrans = 16.6 Hz), 6.96 (s, 1H), 6.85 (s, 1H), 6.68-6.64 (d, 2H, J = 8.5 Hz), 4.10-3.93 (m, 8H), 3.82-3.80 (m, 4H), 3.70-3.55 (m, 12H), 3.43-3.40 (m, 4H), 3.29 (s, 3H), 3.27 (s, 3H), 3.213.12 (d, 2H, J = 21.7 Hz), 2.91 (s, 6H), 1.20-1.15 (t, 6H, J = 7.0 Hz);

13

C-NMR (62.9 MHz,

CDCl3) δ 150.92, 150.04, 149.98, 129.82, 128.89, 127.49, 116.41-116.32 (d, JCP = 5.3 Hz), 115.90115.82 (d, JCP = 5.3 Hz), 114.16-114.11 (d, JCP = 2.9 Hz), 112.56, 111.94, 109.87-109.82 (d, JCP = 3 Hz), 71.82-71.80 (d, JCP = 1.9 Hz), 70.78, 70.70, 70.57, 70.50, 70.43, 70.42. 69.84, 69.77, 69.63, 69.11, 68.77, 61.91, 61.80, 40.52, 27.52-25.31 (d, JCP = 138 Hz), 16.36-16.27 (d, JCP = 5.6 Hz); IR (KBr) ν (cm-1): 2923 (ν C-H), 1415 (ν C=C-H), 1351 (ν C-N), 1249 (ν O-P=O), 1207 (ν P-O-C), 1053 (νs C-O-C), 959 (δ C=C-H) cm-1; ESI-MS C35H56NO11P (m/z) = 720 [M + Na]+. Aldehyde-alcohol 7. To a solution of bis-alcohol 12 (5.00 g, 10.8 mmol) in 500 ml of CH2Cl2 at 0 °C, a suspension of DDQ (2.45 g, 10.8 mmol) in 300 ml of CH2Cl2 was added dropwise over a period of 2 h. When the addition was complete, the mixture was stirred at room temperature for 12 3

h. The mixture was filtered and the filtrate was concentrated under reduced pressure and the residue purified by flash column chromatography (SiO2, eluent: ethyl acetate/ethanol 9:1). 4.47 g (90%) of 7 were isolated as a yellow oil. Elemental analysis calculated for C22H36O10: C = 57.38, H = 7.88; found: C = 57.37, H = 7.85. 1H-NMR (250 MHz, CDCl3) δ 10.43 (s, 1H), 7.27 (s, 1H), 7.08 (s, 1H), 4.69 (s, 2H), 4.25-4.15 (m, 4H), 3.89-3.80 (m, 4H), 3.71-3.61 (m, 12H), 3.56-3.52 (m, 4H), 3.37 (s, 6H);

13

C-NMR (62.9 MHz, CDCl3) δ 189.35, 156.53, 150.54, 139.63, 124.22, 113.73, 110.05,

71.93, 70.90, 70.70, 70.62, 70.58, 70.54, 69.71, 69.51, 68.98, 68.52, 61.13, 59.04, 59.01; IR (KBr) 3447 (ν O-H), 2874 (ν C-H), 1676 (ν C=O), 1206 (δ C-H, δ O-H), 1057 (ν C-O-C) cm-1. Stylbene 9. To a solution of 4-cyanobenzyl-diethylphosphonate 8 (275 mg, 1.08 mmol) in 20 ml of dry THF at 0 °C, NaH (105 mg, 2.62 mmol) was added under a nitrogen atmosphere, and the resulting solution was stirred for 15 min. Then, a solution of tris(pyridyl)amino aldehyde-alcohol 7 (500 mg, 1.08 mmol) in 10 ml of dry THF was added and the mixture was stirred at room temperature for 3 h. The solvent was removed under reduced pressure and the crude product purified by flash column chromatography (SiO2, eluent: toluene/ethyl acetate/ethanol 4:5:1). 449 mg (74%) of 9 were isolated as a yellow oil. 1H-NMR (250 MHz, CDCl3) δ 7.59-7.52 (d, 1H, Jtrans = 16.2 Hz), 7.59-7.57 (m, 4H), 7.10-7.04 (d, 1H, Jtrans = 16.2 Hz), 7.07 (s, 1H), 6.97 (s, 1H), 4.65 (s, 2H), 4.17-4.14 (t, 4H, J = 8.7 Hz), 3.86-3.82 (t, 4H, J = 8.6 Hz), 3.72-3.61 (m, 12H), 3.52-3.50 (m, 4H), 3.34 (s, 3H), 3.32 (s, 3H);

13

C-NMR (62.9 MHz, CDCl3) δ 150.98, 150.59, 142.25, 132.37,

132.10, 126.94, 126.57, 126.44, 124.91, 118.82, 113.80, 110.37, 109.80, 71.62, 70.47, 70.41, 70.31, 70.24, 70.21, 69.59, 69.44, 68.84, 68.49, 60.57, 58.60; IR (KBr) 3456 (ν O-H), 2875 (ν C-H), 2222 (ν C≡N), 1418 (ν C=C-H), 1199 (δ O-H), 1060 (νs C-O-C), 967 (δ C=C-H) cm-1; ESI-MS: C30H41NO9 (m/z) = 582 [M + Na]+. Bromobenzyl stylbene 10. To a solution of trans-stylbene 9 (420 mg, 0.75 mmol) in 20 ml of dry THF at 0 °C under a nitrogen atmosphere, a solution of PBr3 (244 mg, 0.90 mmol) in 10 ml of dry THF was added dropwise over a period of 10 min. The resulting solution was stirred for 1 h at 0 °C. The solvent was removed under reduced pressure and the crude product purified by flash column chromatography (SiO2, eluent: ethyl acetate). 390 mg (84%) of 10 were isolated as a yellow-green oil. 1H-NMR (250 MHz, CDCl3) δ 7.65-7.58 (m, 4H), 7.58-7.51 (d, 1H, Jtrans = 16.7 Hz), 7.14-7.08 (d, 1H, Jtrans = 16.7 Hz), 7.11 (s, 1H), 6.94 (s, 1H), 4.57 (s, 2H), 4.25-4.15 (m, 4H), 3.93-3.87 (m, 4H), 3.78-3.62 (m, 12H), 3.57-3.50 (m, 4H), 3.37 (s, 3H), 3.35 (s, 3H); 13C-NMR (62.9 MHz, CDCl3) δ 151.29, 151.07, 142.34, 132.56, 128.08, 127.92, 127.43, 127.09, 127.01, 119.20, 116.17, 111.11, 110.57, 72.05, 72.01, 71.04, 70.93, 70.82, 70.80, 70.70, 70.68, 69.91, 69.29, 69.15, 59.13, 28.87; IR 4

(KBr) 2922 (ν C-H), 2222 (ν C≡N), 1414 (ν C=C-H), 1321 (δ CH2-Br), 1060 (νs C-O-C), 953 (δ C=C-H) cm-1; ESI-MS: C30H40NO8Br (m/z) = 542 [M - Br]+. Bis-ester

11.

To

a

solution

of

2,5-bis(ethoxymethyl)benzene-1,4-diol

diethyl

2,5-

dihydroxyterephthalate (10.17 g, 40 mmol) in 70 ml of dry DMF, anhydrous K2CO3 (18.20 g, 132 mmol) was added under a nitrogen atmosphere, and the resulting mixture was stirred at 60°C for 15 min. Then, 2-(2-(2-methoxy)-ethoxy)ethyl-p-toluensulphonate (28.06 g, 88 mmol) was added under a nitrogen atmosphere and the mixture was stirred at 60°C for 48 h. The solvent was removed under reduced pressure and the residue dissolved in CH2Cl2 (150 ml) and washed with 1 M NaOH solution (3 x 150 ml), 1 M HCl solution (3 x 150 ml) and then with water (3 x 150 ml). The solution was dried over anhydrous MgSO4 and the solvent was removed under reduced pressure. 21.0 g (96%) of 11 were isolated as a colorless oil. A.E. calculated for C26H42O12 (546.6) C = 57.14, H = 7.74; found C = 57.27, H = 7.54. 1H-NMR: (250 MHz, CDCl3) δ 7.40 (s, 2H), 4.40-4.31 (q, 4H, J = 7.2 Hz), 4.20-4.16 (t, 4H, J = 5.2 Hz), 3.88-3.85 (t, 4H, J = 5.2), 3.76-3.72 (m, 4H), 3.68-3.54 (m, 8H), 3.53-3.35 (m, 4H), 3.07 (s, 6H), 1.41-1.35 (t, 6H, J = 7.2 Hz); 13C-NMR (62.9 MHz, CDCl3) δ 165.34, 151.76, 125.04, 117.34, 71.77, 70.76, 70.51, 70.38, 69.73, 69.52, 61.10, 58.81, 14.13; IR (KBr) 2875 (ν C-H), 1728 (ν C=O), 1105 (νs C-O-C) cm-1. Bis-alcohol 12. To a solution of bis-ester 11 (5.02 g, 9.2 mmol) in 30 ml of dry THF at 0 °C, a 1 M solution of LiAlH4 (95 ml, 95 mmol) was added dropwise over a period of 1 h under a nitrogen atmosphere. The solution was heated to reflux for 30 min and then cooled to 0 °C. The excess of LiAlH4 was quenched with ethyl acetate and water. The mixture was concentrated under reduced pressure and then diluted with water (50 ml). The product was extracted with CH2Cl2 (3 x 50 ml) and dried over anhydrous MgSO4. The solvent was removed under reduced pressure. 3.96 g (93%) of 12 were isolated as a colorless oil. 1H-NMR (250 MHz, CDCl3) δ 6.85 (s, 2H), 4.62 (s, 4H), 4.16-4.13 (m, 4H), 3.83-3.80 (m, 4H), 3.68-3.62 (m, 12H), 3.55-3.53 (m, 4H), 3.36 (s, 6H);

13

C-

NMR (62.9 MHz, CDCl3) δ 151.32, 130.94, 114.57, 72.12, 70.85, 70.81, 70.76, 69.90, 69.09, 62.02, 59.20; IR (KBr) 3434 (ν O-H), 2874 (ν C-H), 1502 (ν C=C), 1200 (δ C-H, δ O-H), 1061 (ν C-O-C) cm-1; ESI-MS: C22H38O10 (m/z) = 485 [M + Na]+. Dibromobenzyl derivative 13. To a solution of bis-alcohol 12 (2.0 g, 4.3 mmol) in 30 ml of dry THF at 0 °C under a nitrogen atmosphere, a solution of PBr3 (2.91 g, 10.8 mmol) in 5 ml of dry THF was added dropwise over a period of 20 min. The resulting solution was stirred for 1 h at 0 °C and then heated to reflux for 4 h. The solvent was removed under reduced pressure and the crude 5

product purified by flash column chromatography (SiO2, eluent: ethyl acetate/petroleum ether 6:4). 1.80 g (71%) of 13 were isolated as a yellow oil. A.E. calculated for C22H36O8Br2 (588.3) C = 44.91, H = 6.16; found C = 45.07, H = 6.12. 1H-NMR (250 MHz, CDCl3) δ 6.89 (s, 2H), 4.52 (s, 4H), 4.18-4.15 (t, 4H, J = 4.7 Hz), 3.89-3.85 (t, 4H, J = 4.7 Hz), 3.76-3.74 (m, 4H), 3.70-3.65 (m, 8H), 3.56-3.54 (m, 4H), 3.38 (s, 6H);

13

C-NMR (62.9 MHz, CDCl3) δ 150.68, 127.94, 115.36, 71.87,

70.84, 70.64, 70.51, 69.67, 68.95, 58.97, 28.41; IR (KBr) 2872 (ν C-H), 1506 (ν C=C), 1225 (δ C-H), 1105 (δ C-Br), 1058 (ν C-O-C) cm-1. Bis-phosphonate 14. Dibromobenzyl derivative 13 (1.60 g, 2.72 mmol) and triethylphosphite (1.13 g, 6.80 mmol) were brought to 150 °C for 3 h. The crude product was purified by flash column chromatography (SiO2, eluent: ethyl acetate/petroleum ether 1:1, then ethyl acetate/ethanol 9:1). 1.60 g (84%) of 14 were isolated as a colorless oil. A.E. calculated for C30H56O14P2 (702.7) C = 51.28, H = 8.03; found C = 50.96, H = 7.89. 1H-NMR (250 MHz, CDCl3) δ 6.87 (s, 2H), 4.07-3.93 (m, 12H), 3.79-3.75 (m, 4H), 3.69-3.58 (m, 12H), 3.52-3.48 (m, 4H), 3.35 (s, 6H), 3.22-3.12 (d, 4H, J = 25.0 Hz), 1.20-1.15 (t, 12H, J = 6.8 Hz); 13C-NMR (62.9 MHz, CDCl3) δ 150.32, 119.93-119.84 (d, JCP = 5.0 Hz), 115.36, 71.72, 70.56, 70.54, 70.35, 69.63, 68.58, 61.80-61.70 (d, JCP = 6.4 Hz), 58.81, 27.27-25.05 (d, JCP = 139.0 Hz), 16.25-16.19 (d, JCP = 6.3 Hz); IR (KBr) 2874 (ν C-H), 1249 (ν O-P=O), 1213 (ν P-O-C), 1053 (νs C-O-C) cm-1

6

ppm

ppm 7.80

9.0 7.70 7.60 7.50

8.0 7.40 7.30

7.0 7.20 7.10 7.00

6.0

7 ppm 3.80

5.0

3.70 3.60

4.0

3.50

3.0 3.40

3.362

3.374

3.382

3.397

3.512 3.492 3.475 3.456

3.528

3.566 3.556 3.545

3.647 3.635 3.625

3.749

3.837 3.817 3.799 3.788

7.038

7.058 7.045

7.065

7.086 7.073

7.094

7.129

7.161

7.167

7.174

7.259 7.231

7.359

7.388

7.541 7.503

7.557

7.564

7.586 7.571

3.456 3.397 3.382 3.374 3.362 3.210 3.197

3.475

3.492

3.512

3.528

3.749 3.647 3.635 3.625 3.566 3.556 3.545

3.799 3.788

3.817

3.837

4.138

4.157

4.175

7.094 7.086 7.073 7.065 7.058 7.045 7.038

7.129

7.231 7.174 7.167 7.161

7.359 7.259

7.388

7.503

7.541

7.624 7.617 7.603 7.593 7.586 7.571 7.564 7.557 7.593

7.793

7.617 7.603

8.439 8.435 8.432 8.428 8.419 8.413 8.409 7.858

7.624

7.793

7.858

FIGURE S1

3.30

ppm 150 150.0 145.0

140 140.0

130 135.0

120 130.0

110 125.0

100

8

120.0 115.0

90 80

71.0 70.0

70 69.0

110.0

60

68.058

68.204

68.830

69.829 69.673 69.517

70.866

110.626 109.292

110.814

119.019 118.134

120.225

123.135 122.206 121.312

125.208

126.006 125.925 125.809

126.432

126.614

128.717

131.448

135.836 135.758

136.103

136.290

136.966

141.395

147.274

147.986 147.545

150.448 150.384

154.461

58.841 57.977

68.204 68.058 61.726

68.830

69.829 69.673 69.517

70.866

109.292

110.814 110.626

119.019 118.134

120.225

121.312

122.206

125.208 123.135

126.006 125.925 125.809

128.717 126.614 126.432

135.836 135.758 131.448

136.290 136.103

136.966

141.395

147.274

147.545

147.986

150.448 150.384

154.461

FIGURE S2

68.0

ppm 7.90

ppm 8.50 7.80 7.70

8.00 7.60 7.50 7.40

7.50 7.30 7.20

7.00 7.10 7.00 6.90

6.50 6.80

6.00

ppm

9 5.50 4.20

5.00

4.10 4.00

4.50 3.90

4.00

3.80

4.026 3.953 3.941 3.816

3.70

3.50

3.60

6.70

3.00

3.489

3.545

3.608

4.054 3.903

2.995

3.338

3.354

3.489

3.545

3.903 3.816 3.608

3.920

4.187 3.920

4.208

4.227

4.250

4.268

6.706

6.742

7.034

7.100

7.162

7.189

7.363 7.312 7.268 7.256 7.247

7.395

7.417

7.453

7.617 7.603

7.633

7.659 7.652

7.688 7.680

7.719 7.712

7.863

7.928

8.541

3.953 3.941

4.054 4.026

4.187

4.208

4.227

4.250

4.268

6.706

6.742

7.189 7.162 7.100 7.034

7.247

7.256

7.312 7.268

7.363

7.417 7.395

7.603 7.453

7.617

7.633

7.719 7.712 7.688 7.680 7.659 7.652

7.928 7.863

8.560

FIGURE S3

3.50

ppm 150.0

150 145.0

140 130

125.841

136.859 120

135.0 130.0

110 125.0

100 120.0

90

10 80

115.0 72.00

70 71.50 71.00

60

70.50 70.00

50

69.50 69.081

69.233

69.855

70.501

70.638

70.797

70.883

71.847

118.598

119.753

120.988 120.894

121.998

122.263

122.479

123.205

123.472

125.277

125.841

126.161

127.535

127.723

129.174

40.449

69.233 69.081 60.044 59.899 58.979

69.855

71.847 70.883 70.797 70.638 70.501

110.571

111.798

112.400

118.598

119.753

121.998 120.988 120.894

122.479 122.263

123.205

125.277 123.472

126.161

137.076

129.697

140.0 136.706

127.723 127.535

129.174

129.697

137.076 136.859 136.706

137.766

150.085 149.085 148.992 148.837

155.758 151.551 150.560

137.766

148.837

149.085 148.992

150.560 150.085

151.551

FIGURE S4

69.00

40

FIGURE S5

FIGURE S6

11

FIGURE S7

12

FIGURE S8

13

FIGURE S9 Intens. x10 6

+M S, 0.1-5.1m in #(8-284) 453.7

1.25

454.7 1.00 454.2 455.7

0.75 455.2

0.50 456.2 0.25 456.7 457.2 0.00 450

m/z 453.7 454.2 454.7 455.2 455.7 456.2 456.7

451

452

453

454

455

456

457

458

459

460

m /z

relative intensity (%) 1409711 (100) 835890 (59.3) 1053838 (74.8) 681474 (48.3) 760059 (53.9) 359662 (25.5) 122393 (8.7)

CALCULATED ISO:C49H57N5O8Zn 100

453.6755

100

90

80 454.6750 70

% Intensity

60

454.1771 455.6744

50 455.1757 40

30 456.1754 20

10

456.6763 457.1772

0 453

454

455

456 Mass (m/z)

m/z 453.7 454.2 454.7 455.2 455.7 456.2 456.7

relative intensity (%) 100.0 57.2 75.1 45.2 54.3 25.6 8.8

14

457

0 458

FIGURE S10 Intens. x10 6

+M S, 1.7-2.9m in #(94-161)

1.2

462.3

1.0 463.3 0.8 462.8 0.6 463.8 0.4 464.3 0.2 464.8 461.3

458.8 459.3 0.0 458

m/z 462.3 462.8 463.3 463.8 464.3 464.8

459

460

461

465.3 462

463

464

465

467.2

465.7 466

467

468

m /z

relative intensity (%) 1155944 (100) 667345 (57.8) 919709 (79.6) 441130 (38.2) 245403 (21.2) 98008 (8.5)

CALCULATED ISO:C50H63N5O8Zn 100

462.6990

100

90

80

463.6985

70 463.2005

% Intensity

60

464.6979 50

464.1992

40

30

465.1989

20 465.6998

10

466.2007 0 462

463

464

465 Mass (m/z)

m/z Relative Intensity (%) 462.7 100 463.2 58.4 463.7 75.8 464.2 46.1 464.7 54.9 465.2 26.6 465.7 9.2

15

466

0 467

Spectrophotometric titrations Zn(ClO4)2•6H2O was an analytical grade product from Aldrich. Zn2+ stock solutions were titrated against EDTA following standard procedures (ammonium buffer at pH = 10 and Eriochrome Black T as indicator). Solutions for spectrophotometric measurements and titrations were prepared using HPLC-grade CH3CN. The binding constant determination for 2-Zn2+ and 3-Zn2+was performed by plotting the fluorescence changes as a function of [Zn2+] (see figure S12). Fitting of the titration curves was carried out with the software package Scientist 2.01 [1]. A model involving the formation of a 1:1 complex of Zn2+ with 2 and 3 was used. Total concentration of 2 and 3 was set as invariable parameter.

[1] Scientist 2.01, Micromath Scientific Software, Salt Lake City, 1995.

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FIGURE S11 480 nm

600

493 nm

500

Emission (u.a.)

2+

400

506 nm 300

200

[Zn ] 0M 0.0123 μM 0.0246 μM 0.0369 μM 0.0492 μM 0.0615 μM 0.0738 μM 0.0861 μM 0.0984 μM 0.1107 μM 0.123 μM

100

0 500

600

700

Wavelength (nm)

Fluorescence spectral changes observed upon the addition of Zn(ClO4)2•6H2O to 0.099 μM of 2 in CH3CN. λexc = 413 nm.

Change in the emission intensity as a function of [Zn2+] for 2. The apparent dissociation constant (pKd > 7) for Zn2+ was calculated from the above data with the software package Scientist 2.01.

17

1200

573 nm

2+

[Zn ] 0M 0.0208 μM 0.0416 μM 0.0624 μM 0.0832 μM 0.104 μM 0.1248 μM 0.1456 μM 0.1664 μM 0.1872 μM 0.208 μM

Emission (u.a.)

1000

800

600

400

498 nm

200

λexc = 433 nm 0 500

600

700

800

Wavelength (nm)

Fluorescence spectral changes observed upon the addition of Zn(ClO4)2•6H2O to 0.104 μM of 3 in CH3CN. λexc = 433 nm.

Change in the emission intensity as a function of [Zn2+] for 3. The apparent dissociation constant (pKd > 7) for Zn2+ was calculated from the above data with the software package Scientist 2.01.

18